甜菜氮营养对蔗糖积累转化及有关酶活性的调节

试验表明，甜菜块根中蔗糖含成酶（ＳＳ）活性和蔗糖磷酸合成酶（ＳＰＳ）活性高于叶片，随植株氮营养增加，可溶性蛋白含量增加，ＳＳ活性较ＳＰＳ活性提高得更快些，叶片中转化酶活性与氮素供应量呈显著正相关，导致块根，叶片蔗糖和己糖含量下降，叶片转化酶活性是ＳＳ活性的１７０倍左右，转化酶在蔗糖降解中起关键作用，表明氮营养通过影响蔗糖的合成与降解过程，调节蔗糖的实际积累量。放线菌素Ｄ对可溶性蛋白质含量，ＳＳ活性

Regulating of Nitrogen to Sucrose Synthesis and Sucrose Degradation and Some Enzymes Activities in Beet

Expriment showed that the activities of sucrose synthean and sucrere phosphate Synthetue were higher in sugarbeet roots than in blade. The soluble prutein content of plants increased and sucrose synthetase activity rose faster than the activity of sucrose phosphate synthetase, but the amount of accumulation of sucrose and hexose in the root and in the blade reduced with the incrase of amount of nitrogen application. The activity of invertase in the blade showed a strong positive correlation with amount of nitrogen application. In blade , the activity of invertase was 170tAnes of the activity of sucrose phosphate synthetase.Actinomyctri D had very higher inhibition to soluble protein content,to the activities of sucrose synthetase and sucrose phocphate synthetase than chloramphenicol; the both inhibtors showed higher inhibitiun tu sucrase phusphate sythetase than sucruse synthetase, the role to the express of the both enzymy was dominited by capyon gene.Since lush growing stage of folight to sugar content accumulating stage. the percentage of nitrogen application. N uptake rate by Per day (mg/plant)showed a strong opitive correlation with amount of nitroge application nitrate reductase activity (NRA) in the blade and soluble protein content in the plants were increased with the amount of nitrogen application increased but the content of sucrese and hexose dropping in the roots and blades.The characteristies of the metabolisms uf nitrogen and sugar in different stage were reflected, which come from the law of the NRA varied with various stage of vegetation growth:significant affects of ultrate in assay medium on the NRA in the blades were observed in the sugar content accumulating stage.