镧对镉胁迫下豌豆幼苗根部细胞内离子平衡及膜质子泵的影响

Effect of Lathanum on Ion Balance and Proton Pump in Pisum Sativum L Seedlings under Cadmium Stress

以水培豌豆(PisumsativumL)幼苗为材料,研究了La3+对Cd2+胁迫下豌豆幼苗生长、叶部与根部细胞对Cd2+的吸收、根部细胞内无机离子平衡体系及膜H+-ATPase,H+-PPase活性的影响。结果表明:Cd2+胁迫下喷施适宜浓度的La3+(0.50mg·L-1)可使豌豆幼苗相对生物量、苗长、叶绿素含量以及光合速率受到的毒害明显缓解,有效减少叶部与根部细胞对Cd2+的吸收,显著减轻了Cd2+胁迫导致的离子平衡系统的紊乱,明显缓解Cd2+对质膜及液泡膜H+-ATPase,H+-PPase活性的抑制作用。10mg·L-1Cd2+胁迫下La3+的保护效应比30mg·L-1Cd2+胁迫下更为显著。样品中La3+的测定和分析结果还表明,外源La3+处理后,La3+主要结合于细胞膜外,进入原生质体的仅占很小部分,但30mg·L-1Cd2+处理样品中La3+进入细胞的量则明显多于10mg·L-1Cd2+处理的样品。

To study the physiological mechanism of La^3＋ under Cd^2＋ stress, Pisum Sativum L seedlings were cultivated for 7 d in solution containing different concentration of Cd^2＋ and sprayed with La^3＋. The results show that La^3 ＋ alleviates the reduction of relative biomass, length, chlorophyll and photosynthesis; lessen the absorbability and accumulation of Cd^2＋ and kept ion balance. La^3＋ also increase the activity of TM-H^＋-ATPase, TP-H^＋ -ATPase and H ＋-PPase which reduce under Cd^2＋ stress. La^3＋ is more effective against 10 mg· L^-1 Cd^2＋ treatment than 30 mg· L^-1 one. Besides, the results show that most of La^3＋ sprayed to seedlings stayed outside of protoplasts.