氮素形态对水稻蔗糖分配的影响

目的]为了对NH4+和NO3-互作在水稻氮素代谢中的作用做出合理的解释。方法]以南光水稻种子为试验材料,研究NH4+和NO3-影响水稻碳水化合物代谢的某些过程,特别是蔗糖代谢。结果]NH4+处理水稻根部生物量较NO3-处理明显下降,NH4+处理水稻叶片中蔗糖含量明显高于NO3-处理,而叶片中蔗糖磷酸合成酶、蔗糖合酶的活性以及根部酸性转化酶的活性低于NO3-处理;与NO3-相比较,NH4+对根部酸性转化酶的活性有明显的抑制作用,而对中性转化酶几乎没有影响。结论]由根部酸性转化酶活性较低所导致的对蔗糖利用能力的降低可能是叶片中积累较多蔗糖的原因之一,也是供NH4+处理时根部生长明显受到抑制的重要原因。

Influence of Different Nitrogen Forms on the Sucrose Partitioning Characteristics of Rice (Oryza sativa L.)Plants

Objective]The study aimed to provide a reasonable explanation for the interaction effect of NH4 and NO3-in rice nitrogen metabolism.Method]In this paper,carbon partitioning characteristics especially the sucrose metabolism in rice "Nan Guang" were studied when supplying different forms of N fertilizers NH4 and NO3-.Result]Dry matter production was depressed strongly by ammonium nutrition in roots relative to plants grown on nitrate.Greater allocation of sucrose contents occurred in NH4 compared to NO3-fed plants.SPS,SS in leaves and acid invertase activities in roots by nitrate were greater compared to NH4 fed rice.The acid invertase activities were depressed strongly by NH4 compared to NO3-,No obvious changes were observed in neutral invertase activities.Conclusion]The results indicate that the lower acid invertase enzyme activities in roots lead to inefficient utilization of sucrose,which is one of the causes of sucrose accumulation in leaves as well as roots growth suppression when supplying NH4 .