镧对汞胁迫下豌豆(Pisum sativumL)幼苗生长及汞积累的影响

Effect of Lathanum on Hg Accumulantion and Growth in Pisum Sativum L Seedlings Under Hg Stress

以培养 5d的豌豆 (PisumsativumL)幼苗为实验材料 ,研究了 10和 5 0mg·L- 1 的Hg胁迫下不同浓度La对豌豆幼苗生长的生理效应 ,测定并分析了La对Hg胁迫下豌豆幼苗根和叶细胞中Hg吸收及积累的影响。结果表明 ,合适浓度 (≤ 0 .0 10mg·L- 1 La)的La能在一定程度上缓解Hg胁迫所导致的叶绿体叶绿素和可溶性蛋白含量、光合速率和叶绿体Mg2 + ATPase、光合膜电子传递链活性及PSII活性的降低 ,减轻Hg胁迫对光合膜室温下吸收光谱和荧光光谱的影响 ;能有效增强或保护Hg胁迫下叶片细胞总抗氧化能力 ,降低细胞内Hg胁迫诱导超氧阴离子(·O2 - )产生的速率和膜脂过氧化产物 (MDA)的积累 ,延缓膜透性的增加。La对 10mg·L- 1 Hg胁迫的缓解能力较强 ,而对 5 0mg·L- 1 Hg的缓解效果较弱。最佳作用浓度为 0 .0 10mg·L- 1 。该浓度的La能有效的减少细胞对Hg的吸收和积累 ,特别是增加根细胞壁对Hg的束缚效应。超过一定浓度范围的La(≥ 0 .0 3 0mg·L- 1 )则加剧Hg的毒害作用。

To study the physiological effect of La under Hg stress, Pisum sativum L seedlings were cultivated for 5 d in solution containing different concentration of Hg and La. The results show that La lessens the absorbability and accumulation of Hg; alleviates the reduction of chlorophyll and soluble protein content, thereby increases the seedlings length and bio-masses, lightens the hurt on photosynthesis. It also increases the total antioxicatability, deletes ·O 2- and MDA, and reduces the relative membrane permeability. La is more effective against 10 mg·L -1 Hg treatment than 50 mg·L -1 one. 0.010 mg·L -1 La is most optimum. However, La which under the concentration exceeds certain limit(≥0.030 mg·L -1) aggravates the stress of high Hg concentration.