商陆钾离子吸收特性研究

Characteristics of K^+ uptake in Phytolacca acinosa

采用K+浓度分别为50、200和800μmol/L的Hoagland营养液培养商陆和水稻,观测商陆的形态和生理指标,比较商陆和水稻的K+吸收动力学参数米氏常数(Km)、最大吸收速率(Imax)和钾离子吸收最低临界浓度值(Cmin)。结果表明,各处理的商陆能正常生长,光合速率、蒸腾速率、株高和根冠比等的差异不显著;在低钾(50μmol/L)条件下,商陆的Km小于水稻,Imax大于水稻,说明商陆比水稻更具耐低钾特性,对钾的亲和力更强。

Phytolacca acinosa Roxb. and Oryza sativa L. were cultured in modified Hoagland medium containing 50, 200 and 800 μmol/L K^＋ respectively to analyze the morphological and physiological characteristics of Phytolacca acinosa. The results were as follows： The photosynthetic rate, transpiration rate, plant height and the root to shoot ratio exhibited no significant difference between the two plants, and Phytolacca acinosa grew normally in medium with different K^＋ concentrations. The Km was lower but the Imax was higher in the Phytolacca acinosa than those in the rice under K^＋ concentrations of 50 and 200μmol/L. These results indicated that Phytolacca acinosa was more tolerable to low K^＋ stress and had higher potassium affinity than Oryza sativa.