The influences of cold treatment, gibberellic acid and red light treatment on rate of germination of seeds of Ginkgo biloba L. were followed for a 12-wk period. Dispersal units were collected, and the outer fleshy layer was removed soon after harvest. Of water-imbibed, non-cold-treated seeds, 50% of those which germinated did so within 11 wk after planting. A single application of red light accelerated the 50% germination time by 3 wk. Imbibition in GA3 solution did not appear to accelerate germination. With 4-wk cold treatment the 50% germination time was accelerated 6 wk in water-imbibed seeds. Both red light and GA3 treated seeds also were accelerated 6 wk by cold treatment. An 8-wk cold treatment accelerated the 50% germination time 7 wk for all three treatment groups. The influence of red light observed on non-cold-treated seeds was not seen with seeds receiving a cold treatment prior to irradiation. A 12-wk cold treatment period delayed germination in all treated groups. Dry storage of seeds for 4mo at 25 C also delayed germination regardless of red light, GA3 or cold treatment

Johnson, Michael I.

Wickliff, James L.

English

UARK (University of Arkansas )

Journal of the Arkansas Academy of Science Volume 28 Article 13 1974 Seed Germination in Ginkgo biloba L. I. Influences of Cold Treatment, Gibberellic Acid and Red Light Michael I. Johnson University of Arkansas, Fayetteville James L. Wickliff University of Arkansas, Fayetteville Follow this and additional works at: https://scholarworks.uark.edu/jaas  Part of the Plant Biology Commons Recommended Citation Johnson, Michael I. and Wickliff, James L. (1974) "Seed Germination in Ginkgo biloba L. I. Influences of Cold Treatment, Gibberellic Acid and Red Light," Journal of the Arkansas Academy of Science: Vol. 28 , Article 13. Available at: https://scholarworks.uark.edu/jaas/vol28/iss1/13 This article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able to read, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author. This Article is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu. 1134 Arkansas Academy of Science Proceedings, Vol. XXVIII,1974Seed Germination inGinkgo biloba L.I.Influences of Cold Treatment, Gibberellic Acid and Red LightMICHAELI.JOHNSON and JAMES L.WICKLIFFDepartment of Botany and Bacteriology, University of ArkansasFayetteville, Arkansas 72701ABSTRACTThe influences of cold treatment, gibberellic acid and red light treatment on rate ofgermination of seeds of Ginkgo bilohu L. were followed for a 12-wk period. Dispersal unitswere collected, and the outer fleshy layer was removed soon after harvest. Ofwater-imbibed, non-cold-treated seeds, 50% of those which germinated did so within 11 wkafter planting. A single application of red light accelerated the 50% germination time by 3wk. Imbibition in GA3 solution did not appear to accelerate germination. With 4-wk coldtreatment the 50% germination time was accelerated 6 wk inwater-imbibed seeds. Both redlight and GA3 treated seeds also were accelerated 6 wk by cold treatment. An 8-wk coldtreatment accelerated the 50% germination time 7 wkfor all three treatment groups. Theinfluence of red lightobserved onnon-cold-treated seeds was not seen with seeds receiving acold treatment prior to irradiation. A 12-wk cold treatment period delayed germination inall treated groups. Dry storage of seeds for4mo at 25 Calso delayed germination regardlessof red light, GA3 or cold treatment.INTRODUCTIONSeeds of Ginkgo biloba L. germinate under a variety ofcontrolled conditions (Davis and Harry, 1972; West et al.,1970). The writers have observed, however, that seeds seldomgerminate in nature, although they may receive adequateamounts ofcold treatment, moisture and light. This failure ofGinkgo seed germination under natural conditions suggests aneed for additional studies of germination under controlledconditions. Described herein are initial investigations concern-ing the interaction ofcold treatment with light and gibberellicacid treatments during Ginkgo seed germination.MATERIALSANDMETHODSFertilization and embryo differentiation of the dispersalunit* of Ginkgo may be delayed until after abscission, and inoutward appearance seeds with embryo and seeds withunfertilized ovules are similar (Eames, 1955; Lee, 1955).Therefore, to predict the percentage ofcollected dispersal unitsthat were actually seeds, a preliminary collection of 150dispersal units was examined for presence ofan embryo. Thisrandomly collected sample indicated that 70.4% of thedispersal units had recognizable embryos. An additionalcollection of 377 naturally overwintered dispersal units wasmade the following spring from the same site. Examinationshowed that 71.6% contained an embryo. Apparently about70% of the abscissed dispersal units collected for theinvestigation were in fact seeds. This finding was supported bythe presence of about 30% non-embryo-containing dispersalunits inthe ungerminated fraction ofeach experimental sampleafter 12 wk under germinating conditions. Therefore, theresults of allgermination tests in this investigation are reportedas percentage germination based on the number of seeds whichactually germinated. Germination was determined by emer-gence of the shoot from the planting substrate.?The writers favor the term "dispersal unit" (Evenari, 1965),because what constitutes the morphological seed of Ginkgo isill-defined and because the physiological and anatomicalmaturity of the "seed" cannot be judged from outwardappearance of the dispersal unit.Dispersal units were collected in late September 1973 fromthe ground under four trees in Memphis, Tennessee. Theouter, fleshy portion of the seed coat was removed and eachdispersal unit was washed briefly in water, then air dried atroom temperature for 10 days. A group of120 dispersal unitswas divided randomly into three experimental lots of 40 units,each of which was subdivided into duplicate 20-unit samples.Each lot received one of the following treatments: (a) 30-hrimbibition in distilled water followed by a 15-min exposure tored light (500 erg/cmVsec, halfband width 65 nra); (b) 30-hrimbibition in distilled water; (c) 30-hr imbibition in 120 ppmaqueous gibberellic acid (GA,). All treatments were performedin darkness at 21-24 C. The treated dispersal units wereplanted immediately in vermiculite and were placed in darkgrowth chambers for controlled temperature (18-25 C). Threeother groups of120 dispersal units each were stored in the darkat 2C without added moisture for the cold treatment. At theendof 4, 8 and 12 wkof cold, a group was removed and dividedinto three lots of 40 dispersal units each. These lots, asduplicate 20-unit samples, were treated and planted asdescribed for the non-cold-treated dispersal units.Two additional groups of120 dispersal units were stored inthe dark for 16 wk at room temperature (25 ± 2C) after thebrief washing and air-drying period. After this prolongedstorage, one group was divided into three lots, treated withoutprior cold treatment and planted as described heretofore; theother group was cold-treated for 4 wk, then subdivided andsimilarly treated and planted.Observations of germination were continued at 1- or 2-dayintervals for 12 wk, then any ungerminated dispersal units werechecked for presence of embryos. All manipulations afterbeginning imbibition were conducted in darkness orunder dimgreen light, including the planting and subsequent wateringoperations and observations of germination.RESULTS ANDDISCUSSIONEffects of the treatments on the progressive germination ofGinkgo seeds during 12 wk after imbibition are presented inFigure 1. The results (Fig. 1A) indicate that seeds plantedimmediately after embryo formation will germinate. Eames(1955) reviewed the opposing views on dormancy in Ginkgo34Journal of the Arkansas Academy of Science, Vol. 28 [1974], Art. 13Published by Arkansas Academy of Science, 1974Arkansas Academy of Science Proceedings, Vol.XXVIII,1974 35Seed Germination in Ginkgo biloba L. I. Influences of Cold Treatment, Gibberellic Acid and Red LightFigure 1. Progress ofgermination of Ginkgo seeds expressed as percentage of total seeds germinated in each treatment. Allseeds were imbibed 30 hr inwater or GA3solution at 25 C in the dark; red light exposures for 15 min were at the end ofimbibition in water. Each point is the weekly accumulated mean percent germination of duplicate seed samples. Waterimbibed*; GA3 imbibed D;red light exposed O- A. Seed not cold-treated. B. Seeds receiving 4 wk at 2 C in the dark prior toimbibition. C. Cold treatment 8 wk. D. Cold treatment 12 wk.seeds. He suggested that after fertilization and a short period (4wk) for embryo development, germination willbegin immed-iately if environmental conditions are suitable. Delay ingermination until spring under natural conditions is caused,therefore, by the unsuitability of the environment. Thus, thefailure of West et al. (1970) to achieve high germination in their"non-stratified" control group may be attributed to a largepercentage of immature embryos, rather than a lack of coldtreatment per se. ("Stratification" used by West et al. was acontinuous cold temperature period without added moisture,and was similar to the cold treatment used in thisinvestigation).Aperiod ofcold treatment has been shown to accelerate seedgermination in Ginkgo (West et al., 1970). The data of FigureIBindicate that a 4-wk cold treatment accelerated the initialgermination time by 2 wk. Eight weeks of cold treatmentresulted in similar acceleration of initial and 50% germinationtimes (Fig. 1C). Twelve weeks of continuous cold treatment(Fig. ID) seemed to have a promotive effect on some seeds(early initial germination) but effected a slower germinationrate (later 50% germination).Imbibitionofseeds withintact seed coats in GA3 solution didnot promote germination significantly over that observed inwater-imbibed seeds (Fig. 1A). This was apparent for 4- or8-wk cold-treated seeds also (Fig. IB, 1C). However, 12 wk ofcold treatment (Fig. ID)may have caused changes in seed coatpermeability, because the GA 3 treatment seems to haveaccelerated seed germination in comparison with that ofwater-imbibed seeds. These results are in contrast to those ofWest et al. (1970) who reported that exogenous GA3 applied to"non-stratified" Ginkgo seeds whose seed coats had beenremoved accelerated germination as much as a 4-wk"stratification" treatment.Red light promoted the germination of non-cold-treatedseeds (Fig. 1A). Germination was initiated 2 wk earlier and50% germination was attained 3 wk earlier than innon-irradiated seeds. After 4-8 wk of cold treatment, thepromotive effect was no longer observed (Figs. IB, 1C),although the apparent delaying effect of extensive coldtreatment may have been reversed by red light (Fig. ID).For dispersal units stored 16 wk at above naturaloverwintering temperatures, non-cold-treated, water-imbibedand GA, treated seeds had initial germination and 50%germination times comparable to those ofnon-cold-treated, red35Journal of the Arkansas Academy of Science, Vol. 28 [1974], Art. 13https://scholarworks.uark.edu/jaas/vol28/iss1/13\>Arkansas Academy of Science Proceedings, Vol.XXVII,197436Table I. Initial and 50% Germination Week for Water-Imbibed, Red Light and GA3 Treated Ginkgo Seeds Exposedfor Different Lengths of Time to ColdUnstored seeds were treated and planted or cold-treated at2C shortly after collection. Stored seeds were kept at 25 C for15 wk prior to treatment and planting or cold treatment.Germination (wk) after ImbibitionNo. Weeks ofCold Water- Water- GA3-Before Planting Imbibed Imbibed Imbibed+ Red LightInitial 50% Initial 50% Initial 50%Not stored 0 6 11 4 8 7 114 4 5 4 5 4 58 4 5 4 4 3 412 3 9 3 6 3 5Stored 0 7 11 7 10 7 114 5 9 4 9 5 9light or GAj seeds which were planted shortly after collection(Table I).The extended storage at high temperature eliminatedthe promotive effect of red light observed in non-stored seeds(Fig. 1A, Table I). Stored seeds which received a 4-wk coldtreatment prior to red light or GA3 appeared to have initialgermination times comparable with those of non-stored,similiarly treated seeds (Fig. IB, Table I).However, the timenecessary to achieve 50% germination was longer for storedseeds (Table I).Phytochrome has been detected in the endosperm andembryos ofGinkgo seeds (Grilland Spruit, 1972). Its presencein the seed coat is suggested by the results shown inFigure 1A,based on the germination of seeds with intact seed coats.Indeed, the results of these investigations indicate that seeds ofGinkgo are red light sensitive in their germination require-ments. Further, the red light sensitive mechanism seems tointeract with amechanism influenced by prolonged low or hightemperatures. The change ofseed sensitivity to irradiation aftersuch temperature exposure isknown in other species (Evenari,1965), but has not been reported in Ginkgo seeds. Althoughdirect interaction of red light with applied GA3 was not stud-ied, an interaction is suggested by indications that red lighttreatment of seeds with intact coats (Fig. 1A) promotedgermination to an extent similar to a GA3 treatment of seedswith coats removed as reported by West et al. (1970).Possibility of such interaction warrants further investigation.ACKNOWLEDGEMENTSThe writers express sincerest appreciation toIvor G. Johnson of Memphis, Tennessee, forobtaining the seeds used in this study, and toHarvey B.Morter, Jr., University of Arkansas, forhis assistance with the project.LITERATURECITEDDAVIS, S.H., JR. and J.B. HARRY. 1972. A Xylariapathogenic to Ginkgo biloba L. seeds. Phytopathology32:91-93.EAMES, A.J. 1955. The seed and Ginkgo. J. Arnold Arb.36:165-170.EVENARI,M. 1965. Light and seed dormancy, p. 804-847 InW. Ruhland (ed.). Encyclopedia ofplant physiology, vol.XV,part 2. Springer-Verlag, New York.GRILL, R., and C.J.P. SPRUIT. 1972. Properties ofphytochrome in gymnosperms. Planta 108:203-213.LEE, C.L. 1955. Fertilization in Ginkgo biloba. Bot. Gaz.117:79-100.WEST, W.C., F.J. FRATTARELLIand K.J. RUSSIN. 1970.Effect ofstratification and gibberellin on seed germinationin Ginkgo biloba. Bull. Torrey Bot. Club 97:380-384.36Journal of the Arkansas Academy of Science, Vol. 28 [1974], Art. 13Published by Arkansas Academy of Science, 1974

Seed Germination in Ginkgo biloba L. I. Influences of Cold Treatment, Gibberellic Acid and Red Light

ScholarWorks@UARK

Journal of the Arkansas Academy of ScienceVolume 28 Article 131974Seed Germination in Ginkgo biloba L. I. Influencesof Cold Treatment, Gibberellic Acid and Red LightMichael I. JohnsonUniversity of Arkansas, FayettevilleJames L. WickliffUniversity of Arkansas, FayettevilleFollow this and additional works at: http://scholarworks.uark.edu/jaasPart of the Plant Biology CommonsThis article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able toread, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking priorpermission from the publisher or the author.This Article is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academyof Science by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu, ccmiddle@uark.edu.Recommended CitationJohnson, Michael I. and Wickliff, James L. (1974) "Seed Germination in Ginkgo biloba L. I. Influences of Cold Treatment, GibberellicAcid and Red Light," Journal of the Arkansas Academy of Science: Vol. 28 , Article 13.Available at: http://scholarworks.uark.edu/jaas/vol28/iss1/131134 Arkansas Academy of Science Proceedings, Vol. XXVIII,1974Seed Germination inGinkgo biloba L.I.Influences of Cold Treatment, Gibberellic Acid and Red LightMICHAELI.JOHNSON and JAMES L.WICKLIFFDepartment of Botany and Bacteriology, University of ArkansasFayetteville, Arkansas 72701ABSTRACTThe influences of cold treatment, gibberellic acid and red light treatment on rate ofgermination of seeds of Ginkgo bilohu L. were followed for a 12-wk period. Dispersal unitswere collected, and the outer fleshy layer was removed soon after harvest. Ofwater-imbibed, non-cold-treated seeds, 50% of those which germinated did so within 11 wkafter planting. A single application of red light accelerated the 50% germination time by 3wk. Imbibition in GA3 solution did not appear to accelerate germination. With 4-wk coldtreatment the 50% germination time was accelerated 6 wk inwater-imbibed seeds. Both redlight and GA3 treated seeds also were accelerated 6 wk by cold treatment. An 8-wk coldtreatment accelerated the 50% germination time 7 wkfor all three treatment groups. Theinfluence of red lightobserved onnon-cold-treated seeds was not seen with seeds receiving acold treatment prior to irradiation. A 12-wk cold treatment period delayed germination inall treated groups. Dry storage of seeds for4mo at 25 Calso delayed germination regardlessof red light, GA3 or cold treatment.INTRODUCTIONSeeds of Ginkgo biloba L. germinate under a variety ofcontrolled conditions (Davis and Harry, 1972; West et al.,1970). The writers have observed, however, that seeds seldomgerminate in nature, although they may receive adequateamounts ofcold treatment, moisture and light. This failure ofGinkgo seed germination under natural conditions suggests aneed for additional studies of germination under controlledconditions. Described herein are initial investigations concern-ing the interaction ofcold treatment with light and gibberellicacid treatments during Ginkgo seed germination.MATERIALSANDMETHODSFertilization and embryo differentiation of the dispersalunit* of Ginkgo may be delayed until after abscission, and inoutward appearance seeds with embryo and seeds withunfertilized ovules are similar (Eames, 1955; Lee, 1955).Therefore, to predict the percentage ofcollected dispersal unitsthat were actually seeds, a preliminary collection of 150dispersal units was examined for presence ofan embryo. Thisrandomly collected sample indicated that 70.4% of thedispersal units had recognizable embryos. An additionalcollection of 377 naturally overwintered dispersal units wasmade the following spring from the same site. Examinationshowed that 71.6% contained an embryo. Apparently about70% of the abscissed dispersal units collected for theinvestigation were in fact seeds. This finding was supported bythe presence of about 30% non-embryo-containing dispersalunits inthe ungerminated fraction ofeach experimental sampleafter 12 wk under germinating conditions. Therefore, theresults of allgermination tests in this investigation are reportedas percentage germination based on the number of seeds whichactually germinated. Germination was determined by emer-gence of the shoot from the planting substrate.?The writers favor the term "dispersal unit" (Evenari, 1965),because what constitutes the morphological seed of Ginkgo isill-defined and because the physiological and anatomicalmaturity of the "seed" cannot be judged from outwardappearance of the dispersal unit.Dispersal units were collected in late September 1973 fromthe ground under four trees in Memphis, Tennessee. Theouter, fleshy portion of the seed coat was removed and eachdispersal unit was washed briefly in water, then air dried atroom temperature for 10 days. A group of120 dispersal unitswas divided randomly into three experimental lots of 40 units,each of which was subdivided into duplicate 20-unit samples.Each lot received one of the following treatments: (a) 30-hrimbibition in distilled water followed by a 15-min exposure tored light (500 erg/cmVsec, halfband width 65 nra); (b) 30-hrimbibition in distilled water; (c) 30-hr imbibition in 120 ppmaqueous gibberellic acid (GA,). All treatments were performedin darkness at 21-24 C. The treated dispersal units wereplanted immediately in vermiculite and were placed in darkgrowth chambers for controlled temperature (18-25 C). Threeother groups of120 dispersal units each were stored in the darkat 2C without added moisture for the cold treatment. At theendof 4, 8 and 12 wkof cold, a group was removed and dividedinto three lots of 40 dispersal units each. These lots, asduplicate 20-unit samples, were treated and planted asdescribed for the non-cold-treated dispersal units.Two additional groups of120 dispersal units were stored inthe dark for 16 wk at room temperature (25 ± 2C) after thebrief washing and air-drying period. After this prolongedstorage, one group was divided into three lots, treated withoutprior cold treatment and planted as described heretofore; theother group was cold-treated for 4 wk, then subdivided andsimilarly treated and planted.Observations of germination were continued at 1- or 2-dayintervals for 12 wk, then any ungerminated dispersal units werechecked for presence of embryos. All manipulations afterbeginning imbibition were conducted in darkness orunder dimgreen light, including the planting and subsequent wateringoperations and observations of germination.RESULTS ANDDISCUSSIONEffects of the treatments on the progressive germination ofGinkgo seeds during 12 wk after imbibition are presented inFigure 1. The results (Fig. 1A) indicate that seeds plantedimmediately after embryo formation will germinate. Eames(1955) reviewed the opposing views on dormancy in Ginkgo34Journal of the Arkansas Academy of Science, Vol. 28 [1974], Art. 13Published by Arkansas Academy of Science, 1974Arkansas Academy of Science Proceedings, Vol.XXVIII,1974 35Seed Germination in Ginkgo biloba L. I. Influences of Cold Treatment, Gibberellic Acid and Red LightFigure 1. Progress ofgermination of Ginkgo seeds expressed as percentage of total seeds germinated in each treatment. Allseeds were imbibed 30 hr inwater or GA3solution at 25 C in the dark; red light exposures for 15 min were at the end ofimbibition in water. Each point is the weekly accumulated mean percent germination of duplicate seed samples. Waterimbibed*; GA3 imbibed D;red light exposed O- A. Seed not cold-treated. B. Seeds receiving 4 wk at 2 C in the dark prior toimbibition. C. Cold treatment 8 wk. D. Cold treatment 12 wk.seeds. He suggested that after fertilization and a short period (4wk) for embryo development, germination willbegin immed-iately if environmental conditions are suitable. Delay ingermination until spring under natural conditions is caused,therefore, by the unsuitability of the environment. Thus, thefailure of West et al. (1970) to achieve high germination in their"non-stratified" control group may be attributed to a largepercentage of immature embryos, rather than a lack of coldtreatment per se. ("Stratification" used by West et al. was acontinuous cold temperature period without added moisture,and was similar to the cold treatment used in thisinvestigation).Aperiod ofcold treatment has been shown to accelerate seedgermination in Ginkgo (West et al., 1970). The data of FigureIBindicate that a 4-wk cold treatment accelerated the initialgermination time by 2 wk. Eight weeks of cold treatmentresulted in similar acceleration of initial and 50% germinationtimes (Fig. 1C). Twelve weeks of continuous cold treatment(Fig. ID) seemed to have a promotive effect on some seeds(early initial germination) but effected a slower germinationrate (later 50% germination).Imbibitionofseeds withintact seed coats in GA3 solution didnot promote germination significantly over that observed inwater-imbibed seeds (Fig. 1A). This was apparent for 4- or8-wk cold-treated seeds also (Fig. IB, 1C). However, 12 wk ofcold treatment (Fig. ID)may have caused changes in seed coatpermeability, because the GA 3 treatment seems to haveaccelerated seed germination in comparison with that ofwater-imbibed seeds. These results are in contrast to those ofWest et al. (1970) who reported that exogenous GA3 applied to"non-stratified" Ginkgo seeds whose seed coats had beenremoved accelerated germination as much as a 4-wk"stratification" treatment.Red light promoted the germination of non-cold-treatedseeds (Fig. 1A). Germination was initiated 2 wk earlier and50% germination was attained 3 wk earlier than innon-irradiated seeds. After 4-8 wk of cold treatment, thepromotive effect was no longer observed (Figs. IB, 1C),although the apparent delaying effect of extensive coldtreatment may have been reversed by red light (Fig. ID).For dispersal units stored 16 wk at above naturaloverwintering temperatures, non-cold-treated, water-imbibedand GA, treated seeds had initial germination and 50%germination times comparable to those ofnon-cold-treated, red35Journal of the Arkansas Academy of Science, Vol. 28 [1974], Art. 13http://scholarworks.uark.edu/jaas/vol28/iss1/13\>Arkansas Academy of Science Proceedings, Vol.XXVII,197436Table I. Initial and 50% Germination Week for Water-Imbibed, Red Light and GA3 Treated Ginkgo Seeds Exposedfor Different Lengths of Time to ColdUnstored seeds were treated and planted or cold-treated at2C shortly after collection. Stored seeds were kept at 25 C for15 wk prior to treatment and planting or cold treatment.Germination (wk) after ImbibitionNo. Weeks ofCold Water- Water- GA3-Before Planting Imbibed Imbibed Imbibed+ Red LightInitial 50% Initial 50% Initial 50%Not stored 0 6 11 4 8 7 114 4 5 4 5 4 58 4 5 4 4 3 412 3 9 3 6 3 5Stored 0 7 11 7 10 7 114 5 9 4 9 5 9light or GAj seeds which were planted shortly after collection(Table I).The extended storage at high temperature eliminatedthe promotive effect of red light observed in non-stored seeds(Fig. 1A, Table I). Stored seeds which received a 4-wk coldtreatment prior to red light or GA3 appeared to have initialgermination times comparable with those of non-stored,similiarly treated seeds (Fig. IB, Table I).However, the timenecessary to achieve 50% germination was longer for storedseeds (Table I).Phytochrome has been detected in the endosperm andembryos ofGinkgo seeds (Grilland Spruit, 1972). Its presencein the seed coat is suggested by the results shown inFigure 1A,based on the germination of seeds with intact seed coats.Indeed, the results of these investigations indicate that seeds ofGinkgo are red light sensitive in their germination require-ments. Further, the red light sensitive mechanism seems tointeract with amechanism influenced by prolonged low or hightemperatures. The change ofseed sensitivity to irradiation aftersuch temperature exposure isknown in other species (Evenari,1965), but has not been reported in Ginkgo seeds. Althoughdirect interaction of red light with applied GA3 was not stud-ied, an interaction is suggested by indications that red lighttreatment of seeds with intact coats (Fig. 1A) promotedgermination to an extent similar to a GA3 treatment of seedswith coats removed as reported by West et al. (1970).Possibility of such interaction warrants further investigation.ACKNOWLEDGEMENTSThe writers express sincerest appreciation toIvor G. Johnson of Memphis, Tennessee, forobtaining the seeds used in this study, and toHarvey B.Morter, Jr., University of Arkansas, forhis assistance with the project.LITERATURECITEDDAVIS, S.H., JR. and J.B. HARRY. 1972. A Xylariapathogenic to Ginkgo biloba L. seeds. Phytopathology32:91-93.EAMES, A.J. 1955. The seed and Ginkgo. J. Arnold Arb.36:165-170.EVENARI,M. 1965. Light and seed dormancy, p. 804-847 InW. Ruhland (ed.). Encyclopedia ofplant physiology, vol.XV,part 2. Springer-Verlag, New York.GRILL, R., and C.J.P. SPRUIT. 1972. Properties ofphytochrome in gymnosperms. Planta 108:203-213.LEE, C.L. 1955. Fertilization in Ginkgo biloba. Bot. Gaz.117:79-100.WEST, W.C., F.J. FRATTARELLIand K.J. RUSSIN. 1970.Effect ofstratification and gibberellin on seed germinationin Ginkgo biloba. Bull. Torrey Bot. Club 97:380-384.36Journal of the Arkansas Academy of Science, Vol. 28 [1974], Art. 13Published by Arkansas Academy of Science, 1974

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Seed Germination in Ginkgo biloba L. I. Influences of Cold Treatment, Gibberellic Acid and Red Light

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