干旱胁迫对破除硬实的苦马豆和披针叶黄华种子萌发影响

Impacts of Drought Stress upon Broken Hard Seeds of Swainsonia salsula and Thermopsis lanceolata

随胁迫的加剧,2种豆类种子的吸水速率和累计吸水率显著下降,萌发起始天数推迟,发芽率、发芽指数和活力指数显著下降,萌发最低渗透势阈值分别为10%（PEG6000）和20%（PEG6000）;2种种子萌发于48 h累计吸水率的回归方程为：y=4.881x2-57.622x＋162.71（R2=0.896 7）,y=-4.666 7x2＋19.67＋79.286（R2=0.882 9）;随模拟干旱的加剧,幼苗高度、根长、次生根个数和鲜重受到抑制,5%的PEG可促进苦马豆根长、次生根的生长;随胁迫的加剧,幼苗干重、子叶养分转化率和幼苗饱和含水量降低,幼苗根干重和根冠比先升高后降低;吸胀的苦马豆受到干旱胁迫后复水不再萌发,受到20%~30%PEG胁迫的披针叶黄华吸胀种子复水后萌发率随干旱胁迫的加剧而增加。

Impacts of drought stress upon broken hard seeds of Swainsonia salsula and Thermopsis lanceolata were investigated.With the increment of the intensity of drought stress,the rates of water absorption and accumulated rate of water absorption of the two seeds decreased significantly.The starting time of seed germination delayed.The germination rate,index of germination and vigor index declined greatly.The lowest germination osmotic potential threshold the two seeds were 20%（PEG6000） and 10%（PEG6000） respectively.Quadratic equation fitted by the germination rate of T.lanceolata seeds and 48 h accumulated absorbing water rate was y=-4.666 7x2＋19.67＋79.286（R2=0.882 9）,and that of S.salsula was y=4.881x2-57.622x＋162.71（R2=0.896 7）.Seedling height,root length,adventitious root amount and fresh weight of the two seeds were inhibited with the increment of drought stress.5% PEG could promote the root length and adventitious root growth of S.salsula.Seedling dry weight,cotyledon nutrition convert rate and seedling saturated water content decreased with increment of drought stress.Seedling root dry weight and root/shoot ratio increased firstly,and then decreased.S.salsula seed under drought stress couldn＇t germinate after rewatering.Germination of T.lanceolata seed simulated with 20%-30% PEG after rewatering increased with increment of drought stress.