Effect Of Different Nitrate And Ammonium Ratio On Carbon&Nitrogen Metabolism And Nitrogen Metabolism Gene Expression In Vitis Vinifera Cv. Cabernet Sauvignon

In this study, Cabernet Sauvignon (Vitis vinifera L.) cutting-seedlings were used asexperimental materials. Six treatments were conducted according to different NO3--N/NH4+-Nratios:100:0(T1),75:25(T2),50:50(T3),25:75(T4),0:100(T5), and no fertilizer treatmentwas used as control (CK), to study the effects of nitrogen forms on photosynthetic pigmentand carbohydrate content in grape leaves. The results showed blow:(1) Compared with the control (CK), each group treated with nitrate nitrogen had higherlevel of chlorophyll a, b and total chlorophyll content. Among all the treatments, T2(NO3--N:NH4+-N=75:25) showed a maximum increased level, and the difference between T2treatment and the CK was significant (P＜0.05).(2) The contents of reducing sugars, total soluble sugars and soluble starch in eachnitrogen treatment were higher than the control, and T2treatment (NO3--N:NH4+-N75:25)had the largest increase.(3) Nitrate nitrogen and the soluble protein content in leaf sustainedly acculumated. Allthe treatments showed a significant differentce with CK, the increase range arranged indescending order,they were T1＞T2＞T3＞T4＞T5. All then nitrate treatments couldenhance the ammonium nitrogen content, and the increase range arranged in descendingorder,they were T5＞T4＞T3＞T2＞T1.(4) Compared with control, the activities of nitrate reductase(NR), glutaminesynthetase(GS), glutamate synthase(GOGAT) and glutamate dehydrogenase(GDH) in thegrape (Cabernet Sauvignon) leaf were increased in all the treatments. The promotion effect ofnitrogen treatments on the NR activity was arrange in the following order: T1＞T2＞T3＞T4＞T5. Application of nitrogen improved GS activities in an order were T3＞T4＞T2＞T5＞T1. The leaf GOGAT activity was enhanced significantly when applied mixture of nitrogensupply forms50:50(T3) and25:75(T4). The experiment proved that GDH activity wasincreased along with the rise of ammonium nitrogen using proportion, and the highest GDHactivity of T5had significant difference with control (P＜0.05) in Cabernet Sauvignon grapeleaves.(5) The levels of VvNR1and VvGS1expression decreased rapidly after treatment, and then increased. T2treatment could increase VvNR1expression. T4had a more promotiveeffect on the level of VvGS1expression, relative to the T3. Compared with T1and T5, T2, T3and T4showed a significant promotion on VvGOGAT1expression. Moreover, T2and T3brought a forward rise of VvGDH1expression.