根施甜菜碱对镍胁迫下小麦幼苗生长生理的影响

摘要

To explore the influence of the wheat seedling growth under nickel stress with exogenous betaine was studied the effects of root-applying glycinebetaine (GB)with 1.0,2.0,3.0,4.0,5.0,10.0,15.0, 20.0 mmol·L- 1 treatments with 100 μmol·L-1 NiSO4 .And the physiological and biochemical indexes of stress resistance under the stress of 100 μmol·L-1 NiSO4 by solution culture method.The results indica-ted that:(1)under the stress of 100 μmol·L-1 of NiSO4 ,the root length,seedling height,fresh weight and dry weight decreased significantly by 14.7%,11.7%,15.0% and 16.7%,respecticely,as compared with the control.(2)With the increasing concentration of applied glycinebetaine,the root length,seedling height,fresh weight and dry weight increased at first and then descended,compared with the 100 μmol· L-1 of NiSO4 .And the effect of exogenous GB with 4.0 mmol·L-1 treatment was better.(3)Under the concentration of 4.0 mmol·L-1 of GB,the activities of peroxidase (POD),superoxide dismutase (SOD), catalase (CAT)and ascorbate perxoidase (APX)in roots increased by 284.7%,40.3%,82.9% and 20.4%,respectively;Superoxide anion (O-· 2 ),hydrogen peroxide (H2O2 )and malondialdehyde (MDA) contents decreased by 50.6%,38.4% and 40.6%,respectively;soluble sugar and free proline contents decreased by 19.2%,45.4%,respectively;Root activity significantly increased by 358.0%,compared with the 100 μmol·L-1 of NiSO4 .Therefore,the appropriate concentration of root-applying GB could sig-nificantly enhance the antioxidant capacity in root of wheat seedlings,and restore the root activity,so as to effectively reduce the harm of nickel stress on the growth of wheat seedlings.%以普通小麦品种'轮选988'为材料,采用溶液培养法,研究了根施不同浓度甜菜碱(1.0、2.0、3.0、4.0、5.0、10.0、15.0、20.0 mmol·L-1)对镍(100μmol·L-1 NiSO4)胁迫下小麦根系生长的影响,以及4.0 mmol·L-1甜菜碱处理镍胁迫幼苗根系相关抗逆生理生化指标的变化.结果表明:(1)与不施加镍对照相比,镍胁迫下小麦幼苗的根长、株高、鲜重和干重分别显著降低了14.7%、11.7%、15.0%和16.7%.(2)与单独镍胁迫处理相比,小麦幼苗的根长、株高、鲜重和干重均随着根施甜菜碱的浓度逐渐增加且呈先升后降的趋势,并以4.0 mmol·L-1外源甜菜碱处理效果较佳.(3)与单独镍胁迫处理相比较,在4.0 mmol·L-1外源甜菜碱处理下,小麦幼苗根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性分别升高了284.7%、40.3%、82.9%和20.4%,超氧阴离子自由基(O-·2)含量、过氧化氢(H2O2)含量和丙二醛(MDA)含量分别显著降低了50.6%、38.4%和40.6%,可溶性糖含量及游离脯氨酸(Pro)含量分别显著降低了19.2%、45.4%,而根系活力大幅上升了358.0%.研究认为,根施适宜浓度外源甜菜碱可显著增强小麦幼苗根系的抗氧化能力,恢复根系活力,从而有效减弱镍胁迫对小麦幼苗生长的伤害.