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

摘要： 以2个耐低钾基因型水稻N18、N19和2个低钾敏感基因型水稻N27、N28为材料,采用溶液培养试验,研究低钾胁迫对其苗期根系生长和内源激素含量的影响。结果表明,低钾胁迫下,水稻根长、地上部干重和根干重均降低,但N18和N19显著高于N27和N28。低钾胁迫使4个基因型水稻的根冠比增大,而各基因型之间差异不显著。低钾胁迫下,水稻根中IAA、GA₁和ZR含量均减少,ABA含量增加;N18、N19根中IAA、GA₁和ZR含量都高于N27、N28。此外,低钾胁迫使水稻根中IAA/ABA、ZR/ABA、GA₁/ABA值降低,但N18、N19的上述比值高于N27、N28。

关键词: 水稻, 低钾胁迫, 根系生长, 内源激素