蔗糖对水稻幼苗叶片谷氨酰胺合成酶和1,5-二磷酸核酮糖羧化酶/加氧酶的影响

报道了在光照和暗处培养下，不同的浓度的蔗水稻幼苗叶片GS及其同工酶、1，5－二磷酸核酮糖羧化酶／加氧酶（Rubisco）的影响。无论是在光照或在暗处，蔗糖对GS活性均有抑制作用，尤其是在较高蔗糖下作用更为明显；虽然Rubisco及可溶性蛋白的水平在光照和暗处有显著的差别，但蔗糖对其未见明显影响。NativePAGE与活性染色表明，在光照下或在暗处，蔗糖对GS2的抑制蔗糖浓度升同而加强，但对GS1未有明显影响。这些结果提示，在水稻幼苗生长中，蔗糖不能象不光一样诱导叶水GS活性及其同工酶表达。

Effect of Sucrose on Glutamine Synthetase and Ribulose-1,5-bisphos-phate Carboxylase/Oxygenase in Leaves of Rice Seedlings

In the current report, we have investigated that the effect of sucrose on GS and its isozymes as well as ribulose 1,5 bisphosphate carboxylase/oxygenase(Rubisco) of the leaves of rice seedlings. GS activity was decreased with the increase of sucrose concentrations whether the illumination of light or the dark. The levels of the soluble proteins and Rubisco were not obviously influenced by sucrose at the illumination of light or the dark although their changes were diffe rent . Native PAGE and activity staining showed that the inhibition of sucrose to GS2 expression was strengthened with sucrose concentrations but GS1 was not clearly affected in the illumination of ligh or the dark. These results suggested that sucrose can not induce the expression of GS in leaves of rice seedlings as light.