Effects of Nitrogen Forms on the Nitrogen Metabolism of Alfalfa ‘Gannong No.3’ Varity at Different Growth Stages
To explore the law of demand for nitrogen at different growth stages of alfalfa,the influences of 3 nitrogen forms (NO3--N,NH4+-N and NO3--N ∶ NH4+-N was 1 ∶ 1) and 3 nitrogen levels (0,105,210 mg · L-1) on nitrogen metabolism at different growth stages of ‘Gannong No.3’ alfalfa was studied with sand culture method.The results showed that the nodule number,nodule weight,nitrogenase activity,nitrate nitrogen content,ammonium nitrogen content,nitrate reductase activity and nitrogen content of ‘Gannong No.3’ Varity under different treatments of nitrogen forms were significantly higher than those of CK.The mixed nitrogen had the best effect on alfalfa nodule number,nodule weight,nitrogenase activity and nitrogen content,followed by NH4+-N,NO3--N was the worst.The 7 tested indexes of 210 mg ·L-1 nitrogen treatments were higher than those of 105 mg · L-1 nitrogen treatments with all nitrogen forms.The nodule number,nodule weight,nitrogenase activity and nitrogen content of alfalfa were the highest in 210 mg · L-1 mixed nitrogen treatment;the nitrate nitrogen content and nitrate reductase activity of alfalfa were the highest in 210 mg · L-1 NO3--N treatment;the ammonium nitrogen content of alfalfa was the highest in 210 mg · L-1 NH4+-N treatment.All tested indexes increased first and then decreased with the development of reproductive period except the nitrogen content of alfalfa decreased during reproductive period.There were significant positive correlations between nodule number and nodule weight;and among nodule number,nodule weight and nitrogenase activity.
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万方数据
维普
