Mechanisms of rice adaptation to low potassium stress in soil

摘要

Five lowland rice genotypes with different potassium use efficiency (KUE) were used to study the physiological and genetic mechanisms of K use efficiency. The results indicated that K use efficiency is associated with K uptake affinity in roots and the minimal K~+ concentration in the culture medium, rather than with the maximum K~+ uptake rate. A determination of rhizosphere K depletion suggested that a K-efficient rice genotype profited mainly from the readily available K pool under both K-deficient and K-sufficient conditions, while genotypical differences in the ability to utilize slowly-released K in the soil showed no consistent difference. A F_2 population derived from a cross between a variety with high K use efficiency, Fujiandao, and a variety with low K use efficiency, 81394, was generated. Investigating the relative whole-plant K accumulation of each F_2 plant indicated that KUE in rice is a quantitative trait and controlled by multiple genes.