Characteristics Of Photosynthesis And Assimilates' Transportation And Distribution In Super Hybrid Rice

The characteristics of photosynthesis and assimilates' transportation and distribution and their physiological foundations in super hybrid rice Liangyou 293,Zhunliangyou 527 were studied with ¹⁴C-isotope tracer technique and regular technology, and common hybrid rice Shanyou 46 were used as the control. The results are as follows:1. During the different growth stages, photosynthesis capabilities of the two super hybrid rice combinations were different with that of Shanyou46. Pn,Cond,Tromml, SPAD and WUE of flag leaf of the two super hybrid rice combinations were significantly higher than those of Shanyou 46 after heading stages, photosynthesis capabilities of the two super hybrid rice combinations are also stronger than the control.2. The total amount of photosynthetic products of one- plant of the two super combinations were remarkably more than those in Shanyou 46 at different growth stages.The proportions of ¹⁴C-assimilate distribution to grains in the two super hybrid rice combinations were higher than those in Shanyoua46 at filling stage,and the speeds of ¹⁴C-assimilate transported to spikes in the two combinations were significantly faster than that in Shanyou 46. Meanwhile, the reserves of ¹⁴C- assimilates in stems of the two super hybrid rice are less than those in Shanyou 46.3. The proportions of ¹⁴C-assimilate distribution from flag leaves, 2nd top leaves and 3rd top leaves to grains in the two super hybrid rice were higher than those in Shanyou 46 at later growing stage,and the proportions of ¹⁴C-assimilates' distribution from flag leaves to grains in the three combinations are the highest, the least is from 3rd top leaves.4. Activities of sucrose phosphate synthetase and phytohormone (Z+ZR, IAA, ABA)contents of the two super hybrid rice are higher than those in Shanyou 46 at different growth stages, These result in high proportions of ¹⁴C-assimilates' distribution to grains in super hybrid rice.