冻融过程对荒漠短命植物种子萌发的影响

荒漠区冻融交替显著改变土壤温度和水分条件,并进一步影响荒漠植物种子萌发.为解析荒漠土壤冻融过程对植物种子萌发的影响,本研究以古尔班通古特沙漠4种典型短命植物[东方旱麦草(Eremopyrum orientale)、卵果鹤虱(Lappula patula)、尖喙拢牛儿苗(Erodiumoxyrrhychum)和条叶庭荠(...

Effects of freezing and thawing cycle on seed germination of desert ephemeral plants

The alternation of freezing and thawing in desert area significantly changes soil temperature and water conditions,with consequences on seed germination of desert plants.Here,we examined the effects of freezing and thawing process on seed germination of four typical ephemeral plant species,Eremopyrum orientale,Lappula patula,Erodium oxyrrhynchum and Alyssum linifollum,in the Gurbantunggut Desert.We measured the seed germination parameters(germination rate,germination potential,germination index,and seed vigor)of those four species under the treatments of different temperatures,soil moisture,and freezing-thawing cycles.The results showed that temperature did not affect seed germination parameters of the four species,whereas water condition,cycle number of freezing and thawing,and their interaction showed significant effects(except for the effects of soil moisture on A.linifollum).In addition,increased freezing and thawing times promoted seed vigor and seed germination after the freezing and thawing treatments,especially under low moisture condition.High soil moisture in the freezing and thawing period significantly reduced the seed germination rate of E.orientale,but such effects on other species depended on day temperature and numbers of freezing and thawing cycles.Under the same soil moisture condition,high temperature during the freezing and thawing period usually promoted seed germination.In general,freeze-thaw process had a significant species-specific effect on seed germination of desert ephemeral plants,which would lead to species-specific variation in seedling growth after the freeze-thaw period and thus affect plant community structure in the desert.