水分胁迫下肥料配比对葡萄光合速率与氮代谢的影响

Effects of fertilizer ratio on the photosynthetic rate and the nitrogen metabolism of grape under water stress

以无核白鸡心葡萄为试材，设置3个水平的水分处理和3个肥料配比，研究水分胁迫下肥料配比对无核白鸡心葡萄叶片叶面积、叶绿素含量、光合速率及氮代谢相关酶活性的影响。结果表明：萌芽期和坐果期土壤水分含量为田间持水量的55％～60％、施肥配比为N∶P∶K＝2∶5∶3的水肥处理能有效促进叶面积增加，提高光合速率，是较好的水肥处理组合；转色期和采收后需维持正常含水量和适当增施钾肥可提高光合速率；土壤水分含量为田间持水量的55％～60％、施肥配比为N∶P∶K＝2∶5∶3的水肥处理无核白鸡心葡萄硝酸还原酶活性较高，能有效促进氮肥的吸收利用；水分胁迫处理使谷氨酰胺合成酶活性先升高后降低，且使谷丙转氨酶活性升高。在生长期中轻度水分胁迫、适当增施钾肥能明显提高硝酸还原酶、谷氨酰胺合成酶与谷丙转氨酶活性，提高氮肥的转化利用。

To investigate the effects of fertilizer ratio on leaves area ,chlorophyll content ,and key enzymes of nitro-gen metabolism under water stress in grape ,Centennial Seedless was used with three different water treatment levels and three kinds of fertilizer ratios .The results showed that at the germination and fruit-set stages ,a water treatment using 55% ~60% that of the field capacity and a fertilizer ratio of N∶P∶K=2∶5∶3 could effectively increase the leaves area and the chlorophyll content of grape leaves ,and could also effectively improve the photosynthetic rate .At the color-changing and post-harvesting stages ,maintenance of normal water content and proper increase of potassium could improve photosynthetic rate .A water treatment using 55% ~60% that of the field capacity and a fertilizer ratio of N∶P∶K=2∶5∶3 could effectively enhance the NR activity and promote the absorption and utilization of nitrogen fertilizer .The GS ac-tivity became increased first and was then decreased by water stress ,whereas the GPT activity kept increased .At mild stress level ,increase of potassium fertilizer could lead to the elevation of NR ,GPT and GS activities ,improving the transformation and utilization of nitrogen fertilizer .