关键词: 水稻, 低钾胁迫, 根系生长, 内源激素

Abstract: Two low-K tolerant rice genotypes named N18 and N19, and two low-K sensitive rice genotypes named N27 and N28 were used in this experiment to investigate the effects of low potassium stress on the root growth and contents of endogenous phytohormone in roots of them at seedling stage. The results showed that under low potassium stress, root length and dry weight of all genotypes were decreased, which were longer and higher significantly of N18 and N19 than those of N27 and N28. Furthermore, low potassium stress increased the ratio of root/shoot, but the differences in it were inconspicuous among the four genotypes tested. Under low potassium stress, contents of IAA, GA₁ and ZR in roots of all genotypes were decreased, which were higher in N18 and N19 than those in N27 and N28, while contents of ABA in roots of all genotypes were increased. Furthermore, under low potassium stress, the ratios of IAA/ABA, ZR/ABA and GA₁/ABA in roots of all genotypes were reduced, which were higher in N18 and N19 than those in N27 and N28.

Key words: rice, low potassium stress, root growth, endogenous phytohormone