Effects of low potassium stress on mineral nutrient absorption and phytohormone contents of rice seedling

Two low potassium tolerant rice (Oryza sativa L.) genotypes, N18 and N19, and their recipient, N27(control) were used to investigate the effects of low potassium stress on mineral nutrient absorption and phytohormone contents of leaves of rice at the seedling stage using a solution cultivation experiment. The results show that potassium uptake efficiency, potassium utilization efficiency and potassium translocation rate of the 3 genotypes were decreased under the low potassium stress. The decreased values of N18 and N19 are less than those of N27. Furthermore, under low potassium stress, absorption abilities and translocation abilities of Na, P, Mg, Fe and Ca of N18 and N19 are stronger than those of N27. Under low potassium stress, IAA, GA1 and ZR contents of leaves for all genotypes are decreased, and as well as the ratios of IAA/ABA, ZR/ABA and GA1/ABA. The reduced amounts of IAA, GA1 and ZR of N18 and N19 are less than those of N27. While ABA contents are increased, the increased amounts of N18 and N19 are less than that of N27. These results indicate that the characteristics of rice resistance to low potassium stress are related to their abilities to absorb mineral nutrients and the contents of phytohormones.