水稻钾素营养的基因型特征及分子机制初探

理解水稻(Oryza sativa)的钾素营养特征是提高水稻的钾素利用效率及其生产效应的重要环节.本文针对土壤钾素供应的时空非均匀性,采用水培和分根模拟试验,研究了日本晴(NB)、武育粳18(WYJ18)、南光(NG)及桂单4号(GD4)4个水稻基因型品种的钾素营养特征.结果表明:低钾(0.1 mmol/L K+)或高...

Genotypic Characteristics and Molecular Mechanism of Potassium Nutrition in Rice

Understanding potassium nutrition characteristics of rice is an important step to improve the potassium utilization efficiency and production effect of rice. Aims at the temporal and spatial heterogeneity of soil potassium supply, in this study, Nipponbare (NB), Wuyujing 18 (WYJ18), Nanguang (NG) and Guidan 4 (GD4) four genotypes of rice were used to evaluate the potassium response characteristics by using hydroponic and root division simulation tests. The results showed that insufficient potassium (0.1 mmol/L K⁺) or excess (5 mmol/L K⁺) significantly inhibited rice growth. NB and GD4 maintained high biomass under low and normal potassium (1mmol/L K⁺) supply levels compared with high potassium conditions, possibly attributed to the stronger potassium absorption and transport capacity of NB and GD4. Root division experiment simulated the uneven distribution of potassium showed root lengths and surface areas of the four genotypes were induced on potassium-deficient side, but no significant difference was found between the aboveground biomass compared with the total root potassium supply, indicating the partial potassium supply also can meet the growth requirements of rice. NB was used to study the expression position by using real-time quantitative PCR, and it was found that potassium transport gene OsKAT1;1 in rice roots is mainly located in the roots and inhibited by high and low potassium. The above-ground potassium distribution gene OsAKT2/3 is mainly located in the shoots and induced by high potassium. The root-stem potassium transport system OsSKOR is mainly located in a mature region with a root tip greater than 1.5 cm, and the expression abundance at the root was induced by low potassium. The result of rice injury test showed that the strength and composition of the wound fluid had a good agreement with the expression of root-stem transfer gene OsSKOR under low potassium condition, suggesting OsSKOR may play an important role in root-stem potassium transport.