苏打碱胁迫对多年生黑麦草的生理影响

 为研究苏打碱胁迫对多年生黑麦草幼苗的生长和生理特性的影响，采用水培实验，用０．１ ｍｏｌ／Ｌ 的Ｎａ₂ＣＯ₃和ＮａＨＣＯ₃溶液配置ｐＨ＝８．２、ｐＨ＝９．１、ｐＨ＝９．９、ｐＨ＝１０．９四个梯度的处理液，以去离子水ｐＨ＝６．５ 作为对照，探讨ｐＨ 值对黑麦草蒸腾速率、株高、根长、含水量、叶绿素含量、丙二醛（ＭＤＡ）含量以及抗氧化酶系统中超氧化物歧化酶（ＳＯＤ）、过氧化氢酶（ＣＡＴ）、过氧化物酶（ＰＯＤ）活性的影响。结果表明，随着ｐＨ 的升高，幼苗的株高、根长、含水量、相对蒸腾速率及叶绿素含量都显著下降，而根冠比呈先升后降的趋势。随着处理液的ｐＨ 值从８．２递增至１０．９，叶片中的ＭＤＡ 含量从对照的７．０ｎｍｏｌ／ｇＦＷ 逐步上升到３０．０ｎｍｏｌ／ｇＦＷ；而ＳＯＤ 活性先高后低，当ｐＨ＝９．１时，最高含量为８．４Ｕ／ｍｇ蛋白；ＣＡＴ 的活性则从对照的１１８．５Ｕ／（ｍｉｎ·ｇ蛋白）逐步递减至４７．１Ｕ／（ｍｉｎ·ｇ 蛋白）；而ＰＯＤ 活性呈现递增的趋势，当ｐＨ 达到最高时，ＰＯＤ 活性是对照的４倍多。

Effects of saline sodic stress on growth and physiological responses of Lolium perenne

The effects of saline sodic stress on growth and physiological responses of perennial ryegrass(Lolium perenne) were investigated in a greenhouse hydroponics experiment.Relative transpiration rate,shoot height,root length,water content,chlorophyll content,malondiadehyde(MDA) content were measured together with the activities of superoxide dismutase(SOD),catalase(CAT),peroxidase(POD) of perennial ryegrass seedlings treated with one of five pH levels 6.5(The control),8.2,9.1,9.9,and 10.9 mixture of 0.1 mol/L Na2CO3,NaHCO3] and distilled water.As pH values increased,relative transpiration rate,shoot height,root length,water content,and chlorophyll content were significantly reduced compared with the control,while the ratio of root to shoot initially increased but then decreased.MDA contents increased(from 7.0 nmol/g FW to 30.0 nmol/g FW) with an increase of pH.At pH=9.1,SOD activity was the highest(8.4 U/mg protein).CAT activity was highest(118.5 U/min·g protein) at pH=6.5 and then declined at higher pH values.POD was lowest at pH=6.5 but increased as pH values increased.