旱稻和水稻不同基因型根细胞膜特性与氮素吸收的关系

Root Cell Plasmalemma of Upland Rice and Wetland Rice Related to Nitrogen Uptake

对常规粳稻、常规籼稻和巴西旱稻离体根细胞膜的H+-ATP酶活性及泵H+能力进行了测定,并结合根系NO3吸收动力学参数及NH4的影响等对各因素间的关系加以探讨。结果表明,根细胞膜H+-ATP酶活性与-+泵H+能力间表现出较好的一致性。巴西旱稻的H+-ATP酶活性与泵H+能力>武育粳3号>扬稻6号。在NO3-N吸收动力学方面,巴西旱稻的Vmax显著地高于另2个水稻品种,且很少受NH4存在的影响。武育粳3号NO3吸收+-的Vmax值受NH4影响最大。NH4的这种影响很可能是通过降低膜电位从而影响质子驱动力以及抑制NO3载体蛋白++-的合成所造成的,但NH4并不影响根细胞膜载体蛋白与NO3之间的亲和性。

The H+-ATPase activity and its H+-pumping capacity of plasmalemma isolated from a conventional Japonica rice (Wuyujing 3), a conventional Indica rice (Yangdao 6), and an upland rice (Brazil upland rice), were measured, respectively. Combined with the results of nitrate uptake kinetic and effects of ammonium on nitrate uptake of 3 varieties, the relationships between parameters was studied. The results show that the H+-ATPase activities of 3 varieties are in consistent with H+-pumping capacity. The H+-ATPase activities and H+-pumping capacities were in the following order: Brazil upland rice > Wuyujing 3 > Yangdao 6. For nitrate uptake the Vmax of Brazil upland rice was significantly higher than those of other genotypes, and was less affected by ammonium. Ammonium has the largest repressive effect on the nitrate uptake by Wuyujing 3 than on that of other 2 varieties. The effect of ammonium on nitrate uptake may be due to the decreasing membrane potential, which could descend the so-called proton-driving-force, and repressing synthesis of nitrate-carrier in plasmalemma. However, ammonium has no effect on the affinity of carrier to nitrate.