Du, Guozhen

Li, Wenlong

Li, Zizhen

Xu, Jing

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XXI International Grassland Congress / VIII International Rangeland Congress The Effect of Temperature on Seed Dormancy in an Alpine Meadow on the Eastern Tsinghai‐Tibet Plateau Wenlong Li Lanzhou University, China Jing Xu Lanzhou Commercial College, China Guozhen Du Lanzhou University, China Zizhen Li Lanzhou University, China Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/14-1/5 The XXI International Grassland Congress / VIII International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　 瞯 ]553　 瞯Grasslands/Rangelands Production Systems——— Seed Science and TechnologyThe effect of temperature on seed dormancy in an alpine meadow on the eastern Tsinghai‐Tibet plateauWenlong L ia , Jing Xub , Guoz hen Duc , Ziz hen L ica School o f Pastoral A griculture Science and Technology , L anz hou University , L anz hou 730000 ,China ; b Institute o fEnv ironmental and Ecological Economics , L anz hou Commercial College , L anz hou , 730020 ,China ;c Key L aboratory o f A ridand Grassland A groecology , L anz hou University , L anz hou 730000 ,China .Key words : seed dormancy ,alpine meadow ,temperature treatment ,seed germination ,Tsinghai‐Tibet plateauIntroduction In this experiment , the temperature effects on dormancy levels of １５９ plants (２０families) occurring in an alpine meadow onthe eastern Tsinghai‐Tibet plateau , were investigated . The objective was to determine the effects of varying temperature on the seeddormancy and the differences of dormancy responses to temperature among families .Material and method The ５ temperatures were chosen ( Figure １ ) . Experiment includes three replications of ５０ seeds of eachspecies per temperature treatment . Seeds were incubated under darkness treatment for ６０ days . Seeds not germinated weretested for viability using tetrazolium staining techniques . Results are reported as proportion of total viable seeds . Totalproportion dormancy for families across temperature treatment was compared by GLM with the SPSS １３ .０ . All statements ofsignificance are at p ＜ ０ .０５ where stated .Results Alternating temperature , family and their interaction had significant effects on seed proportion dormancy ( Table１ ) .Generally , high proportion dormancy occurred at １０ /２０ ℃ , low proportion dormancy occurred at ５ /１５ ℃ and １０ /２５ ℃ ( Figure１ ) ; Seeds of Dipsacaceae showed a higher proportion dormancy , while the proportion dormancy of Juncaceae , Rosaceae ,Caryophy llaceae and A steraceae were lower ( Figure ２ ) ; There was no significant relationship between dormancy andtemperature in Fabaceae( p ＝ ０ .０８ , F ＝ ２ .１２) . However , A steraceae( p ＜ ０ .００１ , F ＝ ８ .０５ ) and Ranunculaceae( p ＝ ０ .０１ , F ＝３ .４８ ) differed significantly in mature seed dormancy based on the ５ alternating temperature regimes . High proportiondormancy occurred at ５ /２５ ℃ in A steraceae , Fabaceae and Ranunculaceae . Still temperature ５ /２５ ℃ favored relatively lowproportion of dormancy in Cy peraceae and Gentianaceae ( Figure ３ ) .Figure 1 The e f f ect o falternating temperatureon mean ( ± SE ) totalp roportion dormancy o f１５９ p lants .Table 1 Results o f GLM f or the e f f ects o f temperature on thep roportion dormancy .Source df F pConect model ９５ 　４ 6.８４ ＜ ０ 7.００１Family １９ 　９ 6.６４ ＜ ０ 7.００１Temperature ４ 妸９ 6.４５ ＜ ０ 7.００１Family × Temperature ７２ 　２ 6.９８ ＜ ０ 7.００１Figure 2 Mean p roportion dormancy o f seed f rom ２０f amilies(mean ± SE) .1 ＝ Juncaceae 　 2 ＝ Rosaceae 　 3 ＝ Caryophyllaceae 　 4 ＝ A steraceae5 ＝ Polyonaceae　 6 ＝ Amaranthaceae 　 7 ＝ Ranunculaceae8 ＝ Plantaginaceae 　 9 ＝ Brassicaceae 　 10 ＝ A piaceae11 ＝ Primulaceae 　 12 ＝ L iliaceae 　 13 ＝ Gentianaceae14 ＝ Geraniaceae 　 15 ＝ Scrophulariaceae 　 16 ＝ Lamiaceae17 ＝ Fabaceae　 18 ＝ Cyperaceae 　 19 ＝ Campanulaceae20 ＝ DipsacaceaeFigure 3 Final p roportion dormancy o f seed f rom ３ f amilies at ５ temperature regimes(Mean ± SE) .Discussion Based on the results of this study , alternating temperature has proved to be an important factor for breaking seed dormancy .It indicates that temperature may have played an important role in determining seed germination . The response to temperature amongfamilies differed significantly , and as a scale of temperature , the differentiation of proportion dormancy was presented . Low proportiondormancy occurred at higher (１０ /２５ ℃ ) or lower temperature (５ /１５ ℃ ) for all seeds , especially in Asteraceae .

The Effect of Temperature on Seed Dormancy in an Alpine Meadow on the Eastern Tsinghai‐Tibet Plateau

University of Kentucky UKnowledge International Grassland Congress Proceedings XXI International Grassland Congress / VIII International Rangeland Congress Effects of Seed Size and Temperature on Seed Dormancy in an Alpine Meadow on the Eastern Tsinghai‐Tibet Plateau Wenlong Li Lanzhou University, China Jing Xu Lanzhou Commercial College, China Guozhen Du Lanzhou University, China Zizhen Li Lanzhou University, China Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/14-1/44 The XXI International Grassland Congress / VIII International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　 瞯 ]593　 瞯Grasslands/Rangelands Production Systems——— Seed Science and TechnologyEffects of seed size and temperature on seed dormancy in an alpine meadow on the easternTsinghai‐Tibet plateauWenlong L ia倡 , Jing Xub , Guoz hen Duc , Ziz hen L ica School o f Pastoral A griculture Science and Technology , L anz hou University , L anz hou 730000 ,China ; b Institute o fEnv ironmental and Ecological Economics , L anz hou Commercial College , L anz hou , 730020 ; China ; c K ey L aboratory o fA rid and G rassland A groecology , L anz hou University , L anz hou 730000 ,China .Key words : seed dormancy ,alpine meadow ,temperature treatment ,seed size ,Tsinghai‐Tibet plateauIntroduction As a complex phenomenon , dormancy is an important persistence mechanism for many weeds in temperate regions( Baskin and Baskin １９９８ ) . Although germination could be influenced by lots of factors , temperature is one of the mostimportant environmental factors influencing the induction of seed dormancy ( Strand ,１９８０ ) . Meanwhile most studies haveconcentrated on demonstrating intraspecific variation in seed size with respect to their fitness . However , studies dealing withvariation in seed size among species are few ( Foster １９８５ ; Murali KS １９９７) . In this research , we aimed to assess correlationsbetween seed size and proportion dormancy of ５３４ plants in a whole community and whether these correlations changedepending on temperature treatments .Material and method In this experiment , ５ /１５ ℃ , ５ /２０ ℃ , １０ /２５ ℃ were chosen . Seeds were sorted by weight into ９２ , ２１ and１１size classes , on the basis of ０ .０５mg , ０ .５mg and １mg intervals respectively ( because some mass classes were missing or hadonly fewer species when seed mass ＞ ３ .０mg , not all size classes were sorted by fixed interval) . Data from this study wereanalyzed using SPSS １３ .０ software . After conducting an analysis of variance ( General Linear Model) , the LSD was used todetect significant differences among the treatments with a probability of ９５％ ( α ＝ ０ .０５) .Results Both seed size and temperature had strong influences on the proportion dormancy , but no interaction was found betweentemperature and seed size ( Table １ ) . High proportion dormancy occurred at ５ /２０ ℃ , compared with ５ /１５ ℃ and １０ /２５ ℃( Figure １) . We also found a significant positive relationship between seed mass and dormancy percentage . With the decline ofthe classification number , the correlation between seed mass and proportion increased ( Figure ２ ) .Table1 Results o f GLM f or the e f f ects o f temperature andseed size on the p roportion dormancy .Source df F pCorrect model ２４７ 洓１ 揶.５０ ＜ ０ 葺.００１Seed size ９１ 剟１ 揶.６６ ＜ ０ 葺.００１Temperature ２ m７ 揶.２４ ０ �.００１Seed size × Temperature １５４ 洓０ 揶.７８ ０ 破.９８Figure 1 The mean ( ± SE)p roportion dormancy at ５ /１５ ℃ ,５ /２０ ℃ and １０ /２５ ℃ .Figure 2 Simp le linear regressions o f mean p roportion dormancy against seed massDiscussion Seed dormancy pattern and germination preferences help to explain and predict the spatial and temporal distributionof a species . According to our results , relatively larger seeds showed higher proportion dormancy . Similar to our study , manyresearches have found significant correlations between seed mass and dormancy ( Thompson and Grime １９７９) .Rees and Juradofound a negative relationship between seed mass and dormancy in １９９６ and ２００５ respectively . This different result may stemfrom the fact that important factors co‐varying with seed size and/or seed dormancy may have been left out of consideration( Jurado and Flores ２００５) . Furthermore , percentage germination of larger seeds would lower because of their usual opacity ofthick and hard seed coats ( Pearson et al . ２００２) . In addition , the seed sizes are various at different flora . In the Tsinghai‐Tibetalpine meadow , small‐seeded species had a numerical advantage , so the decision of seed size has the quality of relativity . Theinteresting pattern observed in this study is the higher proportion dormancy occurred at ５ /２０ ℃ , neither the hightemperature１０ /２５ ℃ , nor the low one ５ /１５ ℃ .

Effects of Seed Size and Temperature on Seed Dormancy in an Alpine Meadow on the Eastern Tsinghai‐Tibet Plateau

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The Effect of Temperature on Seed Dormancy in an Alpine Meadow on the Eastern Tsinghai‐Tibet Plateau

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