铅对叶菜用甘薯根系生长及植株光合作用的影响

Effects of Pb on root growth and plant photosynthesis of sweetpotato

利用砂培设置5个不同浓度Pb处理,研究Pb对叶菜用甘薯根系生长及光合作用的影响。结果表明,随着Pb处理浓度的上升,植株根系生长受到抑制,当处理浓度大于300 mg/kg,不仅植株生根的数量显著减少,新根的活力也明显减弱。Pb处理也降低了植株的光合能力,表现为光合速率下降,光效率减低。从光合色素影响因素上看,叶绿素a含量降低最为关键,其次为叶绿素b,而胡萝卜素含量变化相对较小。

The leaves and vines of sweetpotato （cv. Fushu7-6） are used as vegetable. This paper studied effects of different Pb concentrations on root growth and plant photosynthesis of sweet potato （cv. Fushu7-6） in a sand culture experiment. The results showed that root growth of sweetpotato was inhibited with increasing Pb concentration. When Pb concentration was greater than 300 mg/kg, not only the nanabers of the root significantly decreased, but also activities of new roots was reduced. Pb treatment reduced photosynthesis rate and photosynthesis efficiency, which resulted in decreases in plant photosynthesis. Inhibiting effect of Pb on photosynthesis pigments was in the following order： chlorophyll a 〉 chlorophyll b 〉 carotenoid.