Effect of Potassium on Transport and Distribution of Photosynthate in Hybrid Rice
Xie Xuemin~1, Rao Lihua~2, Shen Yuwei~1, Jiang Dian~2 ('Institute of Nuclear Agricultural Sciences, Plant Physiology Reearch Laboratory, Zhejiang Agricultural University, Hangzhou 310029)
The effects of potassium on the transport and distribution of photosynthate in hybrid rice have been studied by using ~(14)CO_2. The results showed that potassium could stimulate transport of photosynthate out of the photosynthately active leaves. At tillering stage, ~(14)C-Photosynthate of the first completely extended leaf from top transported mainly to rapidly growing leaves. After 24 hours of the introduction of ~(14)CO_2, the amount of ~(14)C-photosynthate transported to the unextended leaf accounted for 32.65% of the total amount of ~(14)C-photosynthate assimilated in the plants cultured in 80ppm-containing Ksolution whereas that in the pants cultured in 80ppm-containing K solution only accounted for 5.92%. At filling stage, the bulk of the ~(14)C-photosynthate assimilated in flag leaf transported to grain. After 8 hours of ~(14)CO_2 introduction, the amount of the ~(14)C-photosynthate transported to grain accounted for 64.4% of the total in the plants treated with 40ppm potassium while that in the plants treated with 1-5 ppm K was only 36.2% of the total. As transport time extended to 36h, the imported ~(14)C-photosynthate increased to 76.6% and 51.6% respectively.