镉胁迫对匍匐剪股颖生长及生理生化的影响

Effects of cadmium stress on growth and physiological and biochemical characteristics of creeping bentgrass

本研究分析了镉胁迫对匍匐剪股颖种子萌发、幼苗和植株生长及生理生化的影响。结果表明,1)不同浓度的Cd2+(50~400mg·L-1)对匍匐剪股颖(Agrostis stolonifera)初期生长具有抑制作用,这种抑制作用随着Cd2+浓度的增加而增强。当Cd2+浓度为50mg·L-1时,发芽率、芽长、根长和苗鲜重分别只有对照(0)的47%、87%、54%和83%。当Cd2+浓度为400mg·L-1时,则完全抑制了种子的萌发;2)不同浓度的Cd2+(50~200mg·L-1)对幼苗叶绿素含量、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性和过氧化物酶(POD)活性具有显著影响。随着Cd2+浓度的升高,叶绿素含量逐渐下降,丙二醛含量不断上升,在200mg·L-1的Cd2+胁迫下,叶绿素和丙二醛含量分别是对照的37%和864%;在Cd2+浓度较低时(50 mg·L-1),SOD活性高于对照,达到1 314U·h-1·g-1,更高的浓度引起活性降低,但始终高于对照;POD的活性变化与SOD相似,在Cd2+浓度为100mg·L-1时最大值达到225U·s-1·g-1;3)Cd处理(2~100mg·L-1)播种后90d的植株,4个指标的变化趋势和Cd处理幼苗的变化基本一致。随着Cd2+浓度的升高及胁迫时间的延长,叶绿素和丙二醛含量分别不断下降和上升;SOD和POD活性均是先上升后下降。

The physiological and biochemical response of creeping bentgrass to cadmium stress were studied in the present study.The results showed that cadmium stress exhibited inhibitory effects on creeping bentgrass initial growth and the inhibition effects increased with the cadmium ion concentration increased.When cadmium ion concentration was 50mg·L-1,seed germination rate,shoot length,root length and seedling fresh weight were 47%,87%,54% and 83% of that of control,respectively.Seed germination was completely inhibited by 400 mg·L-1 cadmium.Cadmium ion had significant effects on contents of chlorophyll,malonaldehyde(MDA)and activities of superoxide dismutase(SOD),peroxidase(POD).With cadmium ion concentration increased,chlorophyll content decreased whereas MDA content increased gradually.When cadmium ion was 200 mg·L-1,chlorophyll content and MDA content were 37% and864% of that of control,respectively.SOD activity reached maximum of 1 314U·h-1·g-1 with lower cadmium ion concentration of 50mg·L-1.SOD activity decreased with higher cadmium ion concentration although it was still higher than the control.POD activity had similar variations with SOD activity and reached maximum of 225U·s-1·g-1 with lower cadmium ion concentration of 100 mg·L-1.The response of the 90 day old plants germinated from seeds treated with cadmium(2~100mg·L-1)was similar with seedlings.With cadmium ion concentration increased or cadmium stress period extended,chlorophyll content decreased whereas MDA content increased gradually and both SOD and POD activities increased first and then decreased.