镧对辣根叶净光合速率和细胞超微结构的影响

Effects of Lanthanum (Ⅲ) on Net Photosynthetic Rate and Ultrastructure in Armoracia rusticana Leaves

摘要:

测定了用稀土镧[La(Ⅲ)] 处理过的辣根(Armoracia rusticana)叶片净光合速率(Pn)和叶绿素(Chl)含量, 并用透射电镜观察了经La(Ⅲ)处理后辣根叶绿体超微结构的变化。 结果表明, 30 mg L^-1 La(Ⅲ)处理24 h, Pn和Chl含量较对照分别提高0.82%、3.69%, 对应的超微细胞结构无明显变化; 48 h处理则抑制辣根光合作用, 细胞结构变化明显,类囊体基粒片层垛叠变薄, 结构松散。而60 mg L^-1 La(Ⅲ) 24h、48h处理对辣根的生理和结构均有明显的抑制和破坏,且时间越长破坏越严重。对Pn和Chl含量进行处理时间、稀土浓度及两者共同作用多因素方差分析得出, 处理时间对Chl含量的影响不显著, 但对Pn的影响极显著,且稀土浓度及二者的共同作用对Pn和Chl含量均达到极显著影响。

Abstract:

Armoracia rusticana leaves treated with lanthanum (Ⅲ) were determined in net photosynthetic rate (Pn) and chlorophyll (Chl) content. Changes in chloroplast ultrastructure were observed under transmission electronic microscopy. After 24-hour treatment with 30 mg/L La(Ⅲ), Pn and Chl content in leaves were increased by 0.82% and 3.69%, respectively, and the ultrastructure of chloroplast varied slightly. After 48-hour treatment with 30 mg L^-1 La(Ⅲ) , photosynthesis was inhibited and granum-thylakoid structure tended to be thinner and loose and incompact. After 24 or 48-hour treatment with 60 mg L^-1 La(Ⅲ) , Pn and Chl content were remarkably decreased and the chloroplast ultrastructure was effectively destroyed. Moreover, the ultrastructure got worse as the treatment time prolonged. The multifactors variance analysis showed that the length of treatment time had a slight effect on Chl content but a significant effect on Pn, whereas the lanthanum level singly or together with the treatment time significantly affected Chl content and Pn.