Pegtel, Dirk Michiel

The perennial sowthistle (Sonchus arvensis L.) - a geophytic composite - is found throughout the temperature regions of the world. From the middle of the 19th century dispersal has occured from the origin area of distribution in Europe and western Africa. [...] This study aims to find out by what mean(s) the varieties are adapted to their particular habitats and to trace the mechanisms responsible for their distribution patterns.... Zie: Summar

Dissertations of the University of Groningen

   University of GroningenOn the ecology of varieties of Sonchus arvensis L.Pegtel, Dirk MichielIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1976Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Pegtel, D. M. (1976). On the ecology of varieties of Sonchus arvensis L. s.n.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 11-10-2022SUMMARYThe perennial sowthistle (Sonchus arvensis L.) - a geophytic composite - is foundthroughout he temperature regions of the world. From the middle of the 1gthcentury dispersal has occurred from the original area of distribution in Europe andWestern Asia.In The Netherlands two varieties can be distinguished. Both show distinct distribu-tion patterns. The coastal type, var.marit imus G. F. W. Mey., has relatively narrow.long and irregularly indented, prickly leaves with a waxy surface. This varietyoccurs predominantly on the outer coastal dunes.Leaves of the arable type, var. arvensis, are mesophytic in appearance. They areshorter and broader than those of the coastal type. The arable type may be foundin a number of different habitats, always on ferti le soils and principally on arableland.  The two var iet ies have the same chromosome number,2n=54.Proof that the leaf morphological differences between the two varieties are geneti-cally determined is provided by the fact that these remain unchanged when they aregrown from achenes under identical conditions.This study aims to find out by what mean(s) the varieties are adapted to their parti-cular habitats and to trace the mechanisms responsible for their distribution pat-terns.Previous l iterature indicates that coastal sand dunes are chemically less ferti le thanarable land. Chemical analysis of outer dune soil of the West Frisian lsland ofSchiermonnikoog confirms that nitrogen and plant available phosphate levels arelow. The question thus arises as to whether and by what mean the inadequate N-and P- supplies of the dunes is responsible for the presence of the coastal, and theabsence of the arable type.Achenes of both varieties own in the outer dune area of Schiermonnikoog germi-137nate successfully. However, eventually all seedlings of the arable type die and only afraction of the coastal type seedlings urvive. These survivals how a slow rate ofgrowth. Persisting coastal type plants grow from relatively large and heavy achenes.Development to flowering takes about 3 to 4 years. Desiccation appears to be theultimate cause of seedlinq death.Seedlings of the arable type raised under favourable conditions fail to establishthemselves when planted on the dune site of Schiermonnikoog. On the other handmany of the individuals of the coastal type develop into flowering and achenebearing plants. Dressings of superphosphate show no effects on the growth of eitherthe coastal or the arable type. Application of nitrogenous ferti l izer make no diffe-rence to the growth of the arable type. When administered to the coastal type,groMh improves considerably and development was noticeablv accelerated. Com-bined dressings of N- and P-ferti l izers result in greatly stimulated growth and deve-lopment of both types to such an extent that their l i fe-cycle can be completedduring the year of planting.When grown on balanced nutrient solutions well supplied with minerals the drymatter production per unit t ime proves to be larger for the arable type than for thecoastal type, This higher rate growth of the arable type is largely explained by thestorage of total water soluble carbohydrates in thickened roots. The total dryvveight of structural material, i.e. the dry matter of both roots and shoots minus thev\rater soluble carbohydrates. isalso higher in the arable than in the coastal type.The coastal type produces relatively few thickened roots. The ratio shoot: totalroot dry weight is lower in the arable type than in the coastal type. The oppositeholds for the ratio shoot: thin root dry weight. The abil ity to generate an extensivefibrous root system appears to be one reason why the coastal type can survive on N-and P-deficient dune sano.Chemical analysis demonstrates the thickened roots of the arable type to be out-standing in their relatively high content of organic nitrogen and possibly organicphosphate as well. Varietal differences in mineral contents of other plant parts havenot been ascertained.The higher Norg. and possibly Porg. contents mentioned, all ied to a larger drymatter production of the arable type, is indicative of the comparatively high nu-trient demands of this varietv.On non-ferti l ized coastal dune sands these demands cannot be met by the spatiallyrestricted root system of this type. The limited nutrient supplies of the dune sandcan be exploited more eff iciently by the root system of the coastal type, but evenfor this variety the N-supplies are inadequate for optimal growth and development.138Seedlings of neither variety have been found on arable land. Despite this, sowing ofboth varieties at the inland experimental garden of Haren show good germination.This indicates that  establ ishment  f rom achenes is  possib le.  l f le f t  undisturbed seed-l ings grow wel l  and develop in to v igorous p lants that  f lower and bear achenes in thesecond year after sowing due to the relatively late date of sowing.lf left undisturbed seedlings grow well and develop into vigorous plants that f lowerand bear achenes in the second year after sowing.Both varieties can be propagated vegetatively from pieces of thickened root. Propa-gation from similar sized root fragments of the two types carried out in springresults in a much more vigorous shoot growth in the arable type. This is probablydue to the larger amounts of total water soluble carbohydrates found in the thicke-ned roots of the arable type. Per unit weight of stored total water soluble carbohy-drates. the shoot dry weight of plants regenerated from root buds is the same forboth types. The rate of sprouting is lower in the autumn than in the spring. Theseasonal differences are more pronounced for the arable type than for the coastaltype. The number of buds per unit length of thickened roots shows neither varietaldifferences nor differences depending on season.Fol lowing mechanical  defo l ia t ion in  spr ing and summer of  prev iously  establ ishedplants regrowth of the arable type is more vigorous than of the coastal one. Thisalso is thought to be due to the differences in total amounts of stored water solublecarbohydrates in the two varieties. After mid-summer egrowth after defoliation isno longer possible at the prevail ing temperatures.The above results i l lustrate the relatively low capacity of the coastal type to over-come mechanical  d is turbances such as would occur  on agr icu l tura l  land.  Fur ther-more, previously established coastal type plants disappear completely after beinggrown among agricultural crops for three years. Neither the density and surfacecoverage of the crop plant. nor the species grown (e.9. oats or potatoes) are thesignificant factors. The arable type is not eradicated by the agricultural operations,but its growth is diminished by the competing crop.Differences in the distribution patterns of the two varieties must have originated inhabitat-adapted selection. In the coastal sand dunes selection for:(i) the extensive root system that is capable of exploit ing the soil nitrogen andplant available phosphate supply most effectively;( i i )  the re lat ive ly  low ni t rogen demand;{i i i) the rate of growth and development keeping pace with the nitrogen supply;139(ivl the comparatively small restriction in the rate of shoot growth from root budsin ear ly  spr ing.On arable land and on ferti le sites selection for:(i) the rate of dry matter production that is efficient enough to compete withthat of (cultivated) plants;(i i) the more frequent formation of thickened roots with a relatively high contentof non-structural carbohydrates;(i i i) the substantial l imitation during low spring temperatures of the rate atwhichshoots grow from root buds; thus preventing premature sprouting as a safe-guard against adverse growing conditions;(iv) the ease with which, in spring and summer, regeneration from fragmentsof thickened roots takes place and defoliated plants develop new shoots.Cross-poll ination between the types might result in hybrid populations that cannotbe distinguished on the basis of leaf morphology from populations of the arabletype. These hybrids are also l ikely to resemble the arable type physiologically.There is no evidence to prove whether or not uncontrolled hybridization occurs.140

English

On the ecology of varieties of <i>Sonchus arvensis</i> L.

ARTS repository - University of Groningen

   University of GroningenOn the ecology of varieties of Sonchus arvensis L.Pegtel, Dirk MichielIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1976Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Pegtel, D. M. (1976). On the ecology of varieties of Sonchus arvensis L. s.n.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 20-06-2022SUMMARYThe perennial sowthistle (Sonchus arvensis L.) - a geophytic composite - is foundthroughout he temperature regions of the world. From the middle of the 1gthcentury dispersal has occurred from the original area of distribution in Europe andWestern Asia.In The Netherlands two varieties can be distinguished. Both show distinct distribu-tion patterns. The coastal type, var.marit imus G. F. W. Mey., has relatively narrow.long and irregularly indented, prickly leaves with a waxy surface. This varietyoccurs predominantly on the outer coastal dunes.Leaves of the arable type, var. arvensis, are mesophytic in appearance. They areshorter and broader than those of the coastal type. The arable type may be foundin a number of different habitats, always on ferti le soils and principally on arableland.  The two var iet ies have the same chromosome number,2n=54.Proof that the leaf morphological differences between the two varieties are geneti-cally determined is provided by the fact that these remain unchanged when they aregrown from achenes under identical conditions.This study aims to find out by what mean(s) the varieties are adapted to their parti-cular habitats and to trace the mechanisms responsible for their distribution pat-terns.Previous l iterature indicates that coastal sand dunes are chemically less ferti le thanarable land. Chemical analysis of outer dune soil of the West Frisian lsland ofSchiermonnikoog confirms that nitrogen and plant available phosphate levels arelow. The question thus arises as to whether and by what mean the inadequate N-and P- supplies of the dunes is responsible for the presence of the coastal, and theabsence of the arable type.Achenes of both varieties own in the outer dune area of Schiermonnikoog germi-137nate successfully. However, eventually all seedlings of the arable type die and only afraction of the coastal type seedlings urvive. These survivals how a slow rate ofgrowth. Persisting coastal type plants grow from relatively large and heavy achenes.Development to flowering takes about 3 to 4 years. Desiccation appears to be theultimate cause of seedlinq death.Seedlings of the arable type raised under favourable conditions fail to establishthemselves when planted on the dune site of Schiermonnikoog. On the other handmany of the individuals of the coastal type develop into flowering and achenebearing plants. Dressings of superphosphate show no effects on the growth of eitherthe coastal or the arable type. Application of nitrogenous ferti l izer make no diffe-rence to the growth of the arable type. When administered to the coastal type,groMh improves considerably and development was noticeablv accelerated. Com-bined dressings of N- and P-ferti l izers result in greatly stimulated growth and deve-lopment of both types to such an extent that their l i fe-cycle can be completedduring the year of planting.When grown on balanced nutrient solutions well supplied with minerals the drymatter production per unit t ime proves to be larger for the arable type than for thecoastal type, This higher rate growth of the arable type is largely explained by thestorage of total water soluble carbohydrates in thickened roots. The total dryvveight of structural material, i.e. the dry matter of both roots and shoots minus thev\rater soluble carbohydrates. isalso higher in the arable than in the coastal type.The coastal type produces relatively few thickened roots. The ratio shoot: totalroot dry weight is lower in the arable type than in the coastal type. The oppositeholds for the ratio shoot: thin root dry weight. The abil ity to generate an extensivefibrous root system appears to be one reason why the coastal type can survive on N-and P-deficient dune sano.Chemical analysis demonstrates the thickened roots of the arable type to be out-standing in their relatively high content of organic nitrogen and possibly organicphosphate as well. Varietal differences in mineral contents of other plant parts havenot been ascertained.The higher Norg. and possibly Porg. contents mentioned, all ied to a larger drymatter production of the arable type, is indicative of the comparatively high nu-trient demands of this varietv.On non-ferti l ized coastal dune sands these demands cannot be met by the spatiallyrestricted root system of this type. The limited nutrient supplies of the dune sandcan be exploited more eff iciently by the root system of the coastal type, but evenfor this variety the N-supplies are inadequate for optimal growth and development.138Seedlings of neither variety have been found on arable land. Despite this, sowing ofboth varieties at the inland experimental garden of Haren show good germination.This indicates that  establ ishment  f rom achenes is  possib le.  l f le f t  undisturbed seed-l ings grow wel l  and develop in to v igorous p lants that  f lower and bear achenes in thesecond year after sowing due to the relatively late date of sowing.lf left undisturbed seedlings grow well and develop into vigorous plants that f lowerand bear achenes in the second year after sowing.Both varieties can be propagated vegetatively from pieces of thickened root. Propa-gation from similar sized root fragments of the two types carried out in springresults in a much more vigorous shoot growth in the arable type. This is probablydue to the larger amounts of total water soluble carbohydrates found in the thicke-ned roots of the arable type. Per unit weight of stored total water soluble carbohy-drates. the shoot dry weight of plants regenerated from root buds is the same forboth types. The rate of sprouting is lower in the autumn than in the spring. Theseasonal differences are more pronounced for the arable type than for the coastaltype. The number of buds per unit length of thickened roots shows neither varietaldifferences nor differences depending on season.Fol lowing mechanical  defo l ia t ion in  spr ing and summer of  prev iously  establ ishedplants regrowth of the arable type is more vigorous than of the coastal one. Thisalso is thought to be due to the differences in total amounts of stored water solublecarbohydrates in the two varieties. After mid-summer egrowth after defoliation isno longer possible at the prevail ing temperatures.The above results i l lustrate the relatively low capacity of the coastal type to over-come mechanical  d is turbances such as would occur  on agr icu l tura l  land.  Fur ther-more, previously established coastal type plants disappear completely after beinggrown among agricultural crops for three years. Neither the density and surfacecoverage of the crop plant. nor the species grown (e.9. oats or potatoes) are thesignificant factors. The arable type is not eradicated by the agricultural operations,but its growth is diminished by the competing crop.Differences in the distribution patterns of the two varieties must have originated inhabitat-adapted selection. In the coastal sand dunes selection for:(i) the extensive root system that is capable of exploit ing the soil nitrogen andplant available phosphate supply most effectively;( i i )  the re lat ive ly  low ni t rogen demand;{i i i) the rate of growth and development keeping pace with the nitrogen supply;139(ivl the comparatively small restriction in the rate of shoot growth from root budsin ear ly  spr ing.On arable land and on ferti le sites selection for:(i) the rate of dry matter production that is efficient enough to compete withthat of (cultivated) plants;(i i) the more frequent formation of thickened roots with a relatively high contentof non-structural carbohydrates;(i i i) the substantial l imitation during low spring temperatures of the rate atwhichshoots grow from root buds; thus preventing premature sprouting as a safe-guard against adverse growing conditions;(iv) the ease with which, in spring and summer, regeneration from fragmentsof thickened roots takes place and defoliated plants develop new shoots.Cross-poll ination between the types might result in hybrid populations that cannotbe distinguished on the basis of leaf morphology from populations of the arabletype. These hybrids are also l ikely to resemble the arable type physiologically.There is no evidence to prove whether or not uncontrolled hybridization occurs.140

   University of GroningenOn the ecology of varieties of Sonchus arvensis L.Pegtel, Dirk MichielIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1976Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Pegtel, D. M. (1976). On the ecology of varieties of Sonchus arvensis L. s.n.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 09-09-2023SUMMARYThe perennial sowthistle (Sonchus arvensis L.) - a geophytic composite - is foundthroughout he temperature regions of the world. From the middle of the 1gthcentury dispersal has occurred from the original area of distribution in Europe andWestern Asia.In The Netherlands two varieties can be distinguished. Both show distinct distribu-tion patterns. The coastal type, var.marit imus G. F. W. Mey., has relatively narrow.long and irregularly indented, prickly leaves with a waxy surface. This varietyoccurs predominantly on the outer coastal dunes.Leaves of the arable type, var. arvensis, are mesophytic in appearance. They areshorter and broader than those of the coastal type. The arable type may be foundin a number of different habitats, always on ferti le soils and principally on arableland.  The two var iet ies have the same chromosome number,2n=54.Proof that the leaf morphological differences between the two varieties are geneti-cally determined is provided by the fact that these remain unchanged when they aregrown from achenes under identical conditions.This study aims to find out by what mean(s) the varieties are adapted to their parti-cular habitats and to trace the mechanisms responsible for their distribution pat-terns.Previous l iterature indicates that coastal sand dunes are chemically less ferti le thanarable land. Chemical analysis of outer dune soil of the West Frisian lsland ofSchiermonnikoog confirms that nitrogen and plant available phosphate levels arelow. The question thus arises as to whether and by what mean the inadequate N-and P- supplies of the dunes is responsible for the presence of the coastal, and theabsence of the arable type.Achenes of both varieties own in the outer dune area of Schiermonnikoog germi-137nate successfully. However, eventually all seedlings of the arable type die and only afraction of the coastal type seedlings urvive. These survivals how a slow rate ofgrowth. Persisting coastal type plants grow from relatively large and heavy achenes.Development to flowering takes about 3 to 4 years. Desiccation appears to be theultimate cause of seedlinq death.Seedlings of the arable type raised under favourable conditions fail to establishthemselves when planted on the dune site of Schiermonnikoog. On the other handmany of the individuals of the coastal type develop into flowering and achenebearing plants. Dressings of superphosphate show no effects on the growth of eitherthe coastal or the arable type. Application of nitrogenous ferti l izer make no diffe-rence to the growth of the arable type. When administered to the coastal type,groMh improves considerably and development was noticeablv accelerated. Com-bined dressings of N- and P-ferti l izers result in greatly stimulated growth and deve-lopment of both types to such an extent that their l i fe-cycle can be completedduring the year of planting.When grown on balanced nutrient solutions well supplied with minerals the drymatter production per unit t ime proves to be larger for the arable type than for thecoastal type, This higher rate growth of the arable type is largely explained by thestorage of total water soluble carbohydrates in thickened roots. The total dryvveight of structural material, i.e. the dry matter of both roots and shoots minus thev\rater soluble carbohydrates. isalso higher in the arable than in the coastal type.The coastal type produces relatively few thickened roots. The ratio shoot: totalroot dry weight is lower in the arable type than in the coastal type. The oppositeholds for the ratio shoot: thin root dry weight. The abil ity to generate an extensivefibrous root system appears to be one reason why the coastal type can survive on N-and P-deficient dune sano.Chemical analysis demonstrates the thickened roots of the arable type to be out-standing in their relatively high content of organic nitrogen and possibly organicphosphate as well. Varietal differences in mineral contents of other plant parts havenot been ascertained.The higher Norg. and possibly Porg. contents mentioned, all ied to a larger drymatter production of the arable type, is indicative of the comparatively high nu-trient demands of this varietv.On non-ferti l ized coastal dune sands these demands cannot be met by the spatiallyrestricted root system of this type. The limited nutrient supplies of the dune sandcan be exploited more eff iciently by the root system of the coastal type, but evenfor this variety the N-supplies are inadequate for optimal growth and development.138Seedlings of neither variety have been found on arable land. Despite this, sowing ofboth varieties at the inland experimental garden of Haren show good germination.This indicates that  establ ishment  f rom achenes is  possib le.  l f le f t  undisturbed seed-l ings grow wel l  and develop in to v igorous p lants that  f lower and bear achenes in thesecond year after sowing due to the relatively late date of sowing.lf left undisturbed seedlings grow well and develop into vigorous plants that f lowerand bear achenes in the second year after sowing.Both varieties can be propagated vegetatively from pieces of thickened root. Propa-gation from similar sized root fragments of the two types carried out in springresults in a much more vigorous shoot growth in the arable type. This is probablydue to the larger amounts of total water soluble carbohydrates found in the thicke-ned roots of the arable type. Per unit weight of stored total water soluble carbohy-drates. the shoot dry weight of plants regenerated from root buds is the same forboth types. The rate of sprouting is lower in the autumn than in the spring. Theseasonal differences are more pronounced for the arable type than for the coastaltype. The number of buds per unit length of thickened roots shows neither varietaldifferences nor differences depending on season.Fol lowing mechanical  defo l ia t ion in  spr ing and summer of  prev iously  establ ishedplants regrowth of the arable type is more vigorous than of the coastal one. Thisalso is thought to be due to the differences in total amounts of stored water solublecarbohydrates in the two varieties. After mid-summer egrowth after defoliation isno longer possible at the prevail ing temperatures.The above results i l lustrate the relatively low capacity of the coastal type to over-come mechanical  d is turbances such as would occur  on agr icu l tura l  land.  Fur ther-more, previously established coastal type plants disappear completely after beinggrown among agricultural crops for three years. Neither the density and surfacecoverage of the crop plant. nor the species grown (e.9. oats or potatoes) are thesignificant factors. The arable type is not eradicated by the agricultural operations,but its growth is diminished by the competing crop.Differences in the distribution patterns of the two varieties must have originated inhabitat-adapted selection. In the coastal sand dunes selection for:(i) the extensive root system that is capable of exploit ing the soil nitrogen andplant available phosphate supply most effectively;( i i )  the re lat ive ly  low ni t rogen demand;{i i i) the rate of growth and development keeping pace with the nitrogen supply;139(ivl the comparatively small restriction in the rate of shoot growth from root budsin ear ly  spr ing.On arable land and on ferti le sites selection for:(i) the rate of dry matter production that is efficient enough to compete withthat of (cultivated) plants;(i i) the more frequent formation of thickened roots with a relatively high contentof non-structural carbohydrates;(i i i) the substantial l imitation during low spring temperatures of the rate atwhichshoots grow from root buds; thus preventing premature sprouting as a safe-guard against adverse growing conditions;(iv) the ease with which, in spring and summer, regeneration from fragmentsof thickened roots takes place and defoliated plants develop new shoots.Cross-poll ination between the types might result in hybrid populations that cannotbe distinguished on the basis of leaf morphology from populations of the arabletype. These hybrids are also l ikely to resemble the arable type physiologically.There is no evidence to prove whether or not uncontrolled hybridization occurs.140

University of Groningen

   University of GroningenOn the ecology of varieties of Sonchus arvensis L.Pegtel, Dirk MichielIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1976Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Pegtel, D. M. (1976). On the ecology of varieties of Sonchus arvensis L. s.n.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 12-11-2019SUMMARYThe perennial sowthistle (Sonchus arvensis L.) - a geophytic composite - is foundthroughout he temperature regions of the world. From the middle of the 1gthcentury dispersal has occurred from the original area of distribution in Europe andWestern Asia.In The Netherlands two varieties can be distinguished. Both show distinct distribu-tion patterns. The coastal type, var.marit imus G. F. W. Mey., has relatively narrow.long and irregularly indented, prickly leaves with a waxy surface. This varietyoccurs predominantly on the outer coastal dunes.Leaves of the arable type, var. arvensis, are mesophytic in appearance. They areshorter and broader than those of the coastal type. The arable type may be foundin a number of different habitats, always on ferti le soils and principally on arableland.  The two var iet ies have the same chromosome number,2n=54.Proof that the leaf morphological differences between the two varieties are geneti-cally determined is provided by the fact that these remain unchanged when they aregrown from achenes under identical conditions.This study aims to find out by what mean(s) the varieties are adapted to their parti-cular habitats and to trace the mechanisms responsible for their distribution pat-terns.Previous l iterature indicates that coastal sand dunes are chemically less ferti le thanarable land. Chemical analysis of outer dune soil of the West Frisian lsland ofSchiermonnikoog confirms that nitrogen and plant available phosphate levels arelow. The question thus arises as to whether and by what mean the inadequate N-and P- supplies of the dunes is responsible for the presence of the coastal, and theabsence of the arable type.Achenes of both varieties own in the outer dune area of Schiermonnikoog germi-137nate successfully. However, eventually all seedlings of the arable type die and only afraction of the coastal type seedlings urvive. These survivals how a slow rate ofgrowth. Persisting coastal type plants grow from relatively large and heavy achenes.Development to flowering takes about 3 to 4 years. Desiccation appears to be theultimate cause of seedlinq death.Seedlings of the arable type raised under favourable conditions fail to establishthemselves when planted on the dune site of Schiermonnikoog. On the other handmany of the individuals of the coastal type develop into flowering and achenebearing plants. Dressings of superphosphate show no effects on the growth of eitherthe coastal or the arable type. Application of nitrogenous ferti l izer make no diffe-rence to the growth of the arable type. When administered to the coastal type,groMh improves considerably and development was noticeablv accelerated. Com-bined dressings of N- and P-ferti l izers result in greatly stimulated growth and deve-lopment of both types to such an extent that their l i fe-cycle can be completedduring the year of planting.When grown on balanced nutrient solutions well supplied with minerals the drymatter production per unit t ime proves to be larger for the arable type than for thecoastal type, This higher rate growth of the arable type is largely explained by thestorage of total water soluble carbohydrates in thickened roots. The total dryvveight of structural material, i.e. the dry matter of both roots and shoots minus thev\rater soluble carbohydrates. isalso higher in the arable than in the coastal type.The coastal type produces relatively few thickened roots. The ratio shoot: totalroot dry weight is lower in the arable type than in the coastal type. The oppositeholds for the ratio shoot: thin root dry weight. The abil ity to generate an extensivefibrous root system appears to be one reason why the coastal type can survive on N-and P-deficient dune sano.Chemical analysis demonstrates the thickened roots of the arable type to be out-standing in their relatively high content of organic nitrogen and possibly organicphosphate as well. Varietal differences in mineral contents of other plant parts havenot been ascertained.The higher Norg. and possibly Porg. contents mentioned, all ied to a larger drymatter production of the arable type, is indicative of the comparatively high nu-trient demands of this varietv.On non-ferti l ized coastal dune sands these demands cannot be met by the spatiallyrestricted root system of this type. The limited nutrient supplies of the dune sandcan be exploited more eff iciently by the root system of the coastal type, but evenfor this variety the N-supplies are inadequate for optimal growth and development.138Seedlings of neither variety have been found on arable land. Despite this, sowing ofboth varieties at the inland experimental garden of Haren show good germination.This indicates that  establ ishment  f rom achenes is  possib le.  l f le f t  undisturbed seed-l ings grow wel l  and develop in to v igorous p lants that  f lower and bear achenes in thesecond year after sowing due to the relatively late date of sowing.lf left undisturbed seedlings grow well and develop into vigorous plants that f lowerand bear achenes in the second year after sowing.Both varieties can be propagated vegetatively from pieces of thickened root. Propa-gation from similar sized root fragments of the two types carried out in springresults in a much more vigorous shoot growth in the arable type. This is probablydue to the larger amounts of total water soluble carbohydrates found in the thicke-ned roots of the arable type. Per unit weight of stored total water soluble carbohy-drates. the shoot dry weight of plants regenerated from root buds is the same forboth types. The rate of sprouting is lower in the autumn than in the spring. Theseasonal differences are more pronounced for the arable type than for the coastaltype. The number of buds per unit length of thickened roots shows neither varietaldifferences nor differences depending on season.Fol lowing mechanical  defo l ia t ion in  spr ing and summer of  prev iously  establ ishedplants regrowth of the arable type is more vigorous than of the coastal one. Thisalso is thought to be due to the differences in total amounts of stored water solublecarbohydrates in the two varieties. After mid-summer egrowth after defoliation isno longer possible at the prevail ing temperatures.The above results i l lustrate the relatively low capacity of the coastal type to over-come mechanical  d is turbances such as would occur  on agr icu l tura l  land.  Fur ther-more, previously established coastal type plants disappear completely after beinggrown among agricultural crops for three years. Neither the density and surfacecoverage of the crop plant. nor the species grown (e.9. oats or potatoes) are thesignificant factors. The arable type is not eradicated by the agricultural operations,but its growth is diminished by the competing crop.Differences in the distribution patterns of the two varieties must have originated inhabitat-adapted selection. In the coastal sand dunes selection for:(i) the extensive root system that is capable of exploit ing the soil nitrogen andplant available phosphate supply most effectively;( i i )  the re lat ive ly  low ni t rogen demand;{i i i) the rate of growth and development keeping pace with the nitrogen supply;139(ivl the comparatively small restriction in the rate of shoot growth from root budsin ear ly  spr ing.On arable land and on ferti le sites selection for:(i) the rate of dry matter production that is efficient enough to compete withthat of (cultivated) plants;(i i) the more frequent formation of thickened roots with a relatively high contentof non-structural carbohydrates;(i i i) the substantial l imitation during low spring temperatures of the rate atwhichshoots grow from root buds; thus preventing premature sprouting as a safe-guard against adverse growing conditions;(iv) the ease with which, in spring and summer, regeneration from fragmentsof thickened roots takes place and defoliated plants develop new shoots.Cross-poll ination between the types might result in hybrid populations that cannotbe distinguished on the basis of leaf morphology from populations of the arabletype. These hybrids are also l ikely to resemble the arable type physiologically.There is no evidence to prove whether or not uncontrolled hybridization occurs.140

   University of GroningenOn the ecology of varieties of Sonchus arvensis L.Pegtel, Dirk MichielIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1976Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Pegtel, D. M. (1976). On the ecology of varieties of Sonchus arvensis L. s.n.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 16-07-2023SUMMARYThe perennial sowthistle (Sonchus arvensis L.) - a geophytic composite - is foundthroughout he temperature regions of the world. From the middle of the 1gthcentury dispersal has occurred from the original area of distribution in Europe andWestern Asia.In The Netherlands two varieties can be distinguished. Both show distinct distribu-tion patterns. The coastal type, var.marit imus G. F. W. Mey., has relatively narrow.long and irregularly indented, prickly leaves with a waxy surface. This varietyoccurs predominantly on the outer coastal dunes.Leaves of the arable type, var. arvensis, are mesophytic in appearance. They areshorter and broader than those of the coastal type. The arable type may be foundin a number of different habitats, always on ferti le soils and principally on arableland.  The two var iet ies have the same chromosome number,2n=54.Proof that the leaf morphological differences between the two varieties are geneti-cally determined is provided by the fact that these remain unchanged when they aregrown from achenes under identical conditions.This study aims to find out by what mean(s) the varieties are adapted to their parti-cular habitats and to trace the mechanisms responsible for their distribution pat-terns.Previous l iterature indicates that coastal sand dunes are chemically less ferti le thanarable land. Chemical analysis of outer dune soil of the West Frisian lsland ofSchiermonnikoog confirms that nitrogen and plant available phosphate levels arelow. The question thus arises as to whether and by what mean the inadequate N-and P- supplies of the dunes is responsible for the presence of the coastal, and theabsence of the arable type.Achenes of both varieties own in the outer dune area of Schiermonnikoog germi-137nate successfully. However, eventually all seedlings of the arable type die and only afraction of the coastal type seedlings urvive. These survivals how a slow rate ofgrowth. Persisting coastal type plants grow from relatively large and heavy achenes.Development to flowering takes about 3 to 4 years. Desiccation appears to be theultimate cause of seedlinq death.Seedlings of the arable type raised under favourable conditions fail to establishthemselves when planted on the dune site of Schiermonnikoog. On the other handmany of the individuals of the coastal type develop into flowering and achenebearing plants. Dressings of superphosphate show no effects on the growth of eitherthe coastal or the arable type. Application of nitrogenous ferti l izer make no diffe-rence to the growth of the arable type. When administered to the coastal type,groMh improves considerably and development was noticeablv accelerated. Com-bined dressings of N- and P-ferti l izers result in greatly stimulated growth and deve-lopment of both types to such an extent that their l i fe-cycle can be completedduring the year of planting.When grown on balanced nutrient solutions well supplied with minerals the drymatter production per unit t ime proves to be larger for the arable type than for thecoastal type, This higher rate growth of the arable type is largely explained by thestorage of total water soluble carbohydrates in thickened roots. The total dryvveight of structural material, i.e. the dry matter of both roots and shoots minus thev\rater soluble carbohydrates. isalso higher in the arable than in the coastal type.The coastal type produces relatively few thickened roots. The ratio shoot: totalroot dry weight is lower in the arable type than in the coastal type. The oppositeholds for the ratio shoot: thin root dry weight. The abil ity to generate an extensivefibrous root system appears to be one reason why the coastal type can survive on N-and P-deficient dune sano.Chemical analysis demonstrates the thickened roots of the arable type to be out-standing in their relatively high content of organic nitrogen and possibly organicphosphate as well. Varietal differences in mineral contents of other plant parts havenot been ascertained.The higher Norg. and possibly Porg. contents mentioned, all ied to a larger drymatter production of the arable type, is indicative of the comparatively high nu-trient demands of this varietv.On non-ferti l ized coastal dune sands these demands cannot be met by the spatiallyrestricted root system of this type. The limited nutrient supplies of the dune sandcan be exploited more eff iciently by the root system of the coastal type, but evenfor this variety the N-supplies are inadequate for optimal growth and development.138Seedlings of neither variety have been found on arable land. Despite this, sowing ofboth varieties at the inland experimental garden of Haren show good germination.This indicates that  establ ishment  f rom achenes is  possib le.  l f le f t  undisturbed seed-l ings grow wel l  and develop in to v igorous p lants that  f lower and bear achenes in thesecond year after sowing due to the relatively late date of sowing.lf left undisturbed seedlings grow well and develop into vigorous plants that f lowerand bear achenes in the second year after sowing.Both varieties can be propagated vegetatively from pieces of thickened root. Propa-gation from similar sized root fragments of the two types carried out in springresults in a much more vigorous shoot growth in the arable type. This is probablydue to the larger amounts of total water soluble carbohydrates found in the thicke-ned roots of the arable type. Per unit weight of stored total water soluble carbohy-drates. the shoot dry weight of plants regenerated from root buds is the same forboth types. The rate of sprouting is lower in the autumn than in the spring. Theseasonal differences are more pronounced for the arable type than for the coastaltype. The number of buds per unit length of thickened roots shows neither varietaldifferences nor differences depending on season.Fol lowing mechanical  defo l ia t ion in  spr ing and summer of  prev iously  establ ishedplants regrowth of the arable type is more vigorous than of the coastal one. Thisalso is thought to be due to the differences in total amounts of stored water solublecarbohydrates in the two varieties. After mid-summer egrowth after defoliation isno longer possible at the prevail ing temperatures.The above results i l lustrate the relatively low capacity of the coastal type to over-come mechanical  d is turbances such as would occur  on agr icu l tura l  land.  Fur ther-more, previously established coastal type plants disappear completely after beinggrown among agricultural crops for three years. Neither the density and surfacecoverage of the crop plant. nor the species grown (e.9. oats or potatoes) are thesignificant factors. The arable type is not eradicated by the agricultural operations,but its growth is diminished by the competing crop.Differences in the distribution patterns of the two varieties must have originated inhabitat-adapted selection. In the coastal sand dunes selection for:(i) the extensive root system that is capable of exploit ing the soil nitrogen andplant available phosphate supply most effectively;( i i )  the re lat ive ly  low ni t rogen demand;{i i i) the rate of growth and development keeping pace with the nitrogen supply;139(ivl the comparatively small restriction in the rate of shoot growth from root budsin ear ly  spr ing.On arable land and on ferti le sites selection for:(i) the rate of dry matter production that is efficient enough to compete withthat of (cultivated) plants;(i i) the more frequent formation of thickened roots with a relatively high contentof non-structural carbohydrates;(i i i) the substantial l imitation during low spring temperatures of the rate atwhichshoots grow from root buds; thus preventing premature sprouting as a safe-guard against adverse growing conditions;(iv) the ease with which, in spring and summer, regeneration from fragmentsof thickened roots takes place and defoliated plants develop new shoots.Cross-poll ination between the types might result in hybrid populations that cannotbe distinguished on the basis of leaf morphology from populations of the arabletype. These hybrids are also l ikely to resemble the arable type physiologically.There is no evidence to prove whether or not uncontrolled hybridization occurs.140

Proceedings - University of Groningen

University of Groningen Research Database

  
 University of Groningen
On the ecology of varieties of Sonchus arvensis L.
Pegtel, Dirk Michiel
IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from
it. Please check the document version below.
Document Version
Publisher's PDF, also known as Version of record
Publication date:
1976
Link to publication in University of Groningen/UMCG research database
Citation for published version (APA):
Pegtel, D. M. (1976). On the ecology of varieties of Sonchus arvensis L. s.n.
Copyright
Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the
author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).
Take-down policy
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately
and investigate your claim.
Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the
number of authors shown on this cover page is limited to 10 maximum.
Download date: 10-02-2018
SUMMARY
The perennial sowthistle (Sonchus arvensis L.) - a geophytic composite - is found
throughout he temperature regions of the world. From the middle of the 1gth
century dispersal has occurred from the original area of distribution in Europe and
Western Asia.
In The Netherlands two varieties can be distinguished. Both show distinct distribu-
tion patterns. The coastal type, var.marit imus G. F. W. Mey., has relatively narrow.
long and irregularly indented, prickly leaves with a waxy surface. This variety
occurs predominantly on the outer coastal dunes.
Leaves of the arable type, var. arvensis, are mesophytic in appearance. They are
shorter and broader than those of the coastal type. The arable type may be found
in a number of different habitats, always on ferti le soils and principally on arable
land.  The two var iet ies have the same chromosome number,2n=54.
Proof that the leaf morphological differences between the two varieties are geneti-
cally determined is provided by the fact that these remain unchanged when they are
grown from achenes under identical conditions.
This study aims to find out by what mean(s) the varieties are adapted to their parti-
cular habitats and to trace the mechanisms responsible for their distribution pat-
terns.
Previous l iterature indicates that coastal sand dunes are chemically less ferti le than
arable land. Chemical analysis of outer dune soil of the West Frisian lsland of
Schiermonnikoog confirms that nitrogen and plant available phosphate levels are
low. The question thus arises as to whether and by what mean the inadequate N-
and P- supplies of the dunes is responsible for the presence of the coastal, and the
absence of the arable type.
Achenes of both varieties own in the outer dune area of Schiermonnikoog germi-
137
nate successfully. However, eventually all seedlings of the arable type die and only a
fraction of the coastal type seedlings urvive. These survivals how a slow rate of
growth. Persisting coastal type plants grow from relatively large and heavy achenes.
Development to flowering takes about 3 to 4 years. Desiccation appears to be the
ultimate cause of seedlinq death.
Seedlings of the arable type raised under favourable conditions fail to establish
themselves when planted on the dune site of Schiermonnikoog. On the other hand
many of the individuals of the coastal type develop into flowering and achene
bearing plants. Dressings of superphosphate show no effects on the growth of either
the coastal or the arable type. Application of nitrogenous ferti l izer make no diffe-
rence to the growth of the arable type. When administered to the coastal type,
groMh improves considerably and development was noticeablv accelerated. Com-
bined dressings of N- and P-ferti l izers result in greatly stimulated growth and deve-
lopment of both types to such an extent that their l i fe-cycle can be completed
during the year of planting.
When grown on balanced nutrient solutions well supplied with minerals the dry
matter production per unit t ime proves to be larger for the arable type than for the
coastal type, This higher rate growth of the arable type is largely explained by the
storage of total water soluble carbohydrates in thickened roots. The total dry
vveight of structural material, i.e. the dry matter of both roots and shoots minus the
v\rater soluble carbohydrates. isalso higher in the arable than in the coastal type.
The coastal type produces relatively few thickened roots. The ratio shoot: total
root dry weight is lower in the arable type than in the coastal type. The opposite
holds for the ratio shoot: thin root dry weight. The abil ity to generate an extensive
fibrous root system appears to be one reason why the coastal type can survive on N-
and P-deficient dune sano.
Chemical analysis demonstrates the thickened roots of the arable type to be out-
standing in their relatively high content of organic nitrogen and possibly organic
phosphate as well. Varietal differences in mineral contents of other plant parts have
not been ascertained.
The higher Norg. and possibly Porg. contents mentioned, all ied to a larger dry
matter production of the arable type, is indicative of the comparatively high nu-
trient demands of this varietv.
On non-ferti l ized coastal dune sands these demands cannot be met by the spatially
restricted root system of this type. The limited nutrient supplies of the dune sand
can be exploited more eff iciently by the root system of the coastal type, but even
for this variety the N-supplies are inadequate for optimal growth and development.
138
Seedlings of neither variety have been found on arable land. Despite this, sowing of
both varieties at the inland experimental garden of Haren show good germination.
This indicates that  establ ishment  f rom achenes is  possib le.  l f le f t  undisturbed seed-
l ings grow wel l  and develop in to v igorous p lants that  f lower and bear achenes in the
second year after sowing due to the relatively late date of sowing.
lf left undisturbed seedlings grow well and develop into vigorous plants that f lower
and bear achenes in the second year after sowing.
Both varieties can be propagated vegetatively from pieces of thickened root. Propa-
gation from similar sized root fragments of the two types carried out in spring
results in a much more vigorous shoot growth in the arable type. This is probably
due to the larger amounts of total water soluble carbohydrates found in the thicke-
ned roots of the arable type. Per unit weight of stored total water soluble carbohy-
drates. the shoot dry weight of plants regenerated from root buds is the same for
both types. The rate of sprouting is lower in the autumn than in the spring. The
seasonal differences are more pronounced for the arable type than for the coastal
type. The number of buds per unit length of thickened roots shows neither varietal
differences nor differences depending on season.
Fol lowing mechanical  defo l ia t ion in  spr ing and summer of  prev iously  establ ished
plants regrowth of the arable type is more vigorous than of the coastal one. This
also is thought to be due to the differences in total amounts of stored water soluble
carbohydrates in the two varieties. After mid-summer egrowth after defoliation is
no longer possible at the prevail ing temperatures.
The above results i l lustrate the relatively low capacity of the coastal type to over-
come mechanical  d is turbances such as would occur  on agr icu l tura l  land.  Fur ther-
more, previously established coastal type plants disappear completely after being
grown among agricultural crops for three years. Neither the density and surface
coverage of the crop plant. nor the species grown (e.9. oats or potatoes) are the
significant factors. The arable type is not eradicated by the agricultural operations,
but its growth is diminished by the competing crop.
Differences in the distribution patterns of the two varieties must have originated in
habitat-adapted selection. In the coastal sand dunes selection for:
(i) the extensive root system that is capable of exploit ing the soil nitrogen and
plant available phosphate supply most effectively;
( i i )  the re lat ive ly  low ni t rogen demand;
{i i i) the rate of growth and development keeping pace with the nitrogen supply;
139
(ivl the comparatively small restriction in the rate of shoot growth from root buds
in ear ly  spr ing.
On arable land and on ferti le sites selection for:
(i) the rate of dry matter production that is efficient enough to compete with
that of (cultivated) plants;
(i i) the more frequent formation of thickened roots with a relatively high content
of non-structural carbohydrates;
(i i i) the substantial l imitation during low spring temperatures of the rate atwhich
shoots grow from root buds; thus preventing premature sprouting as a safe-
guard against adverse growing conditions;
(iv) the ease with which, in spring and summer, regeneration from fragments
of thickened roots takes place and defoliated plants develop new shoots.
Cross-poll ination between the types might result in hybrid populations that cannot
be distinguished on the basis of leaf morphology from populations of the arable
type. These hybrids are also l ikely to resemble the arable type physiologically.
There is no evidence to prove whether or not uncontrolled hybridization occurs.
140


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On the ecology of varieties of <i>Sonchus arvensis</i> L.

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