地下滴灌条件下水氮耦合对黄瓜氮代谢的影响

In this paper, cucumber "Jinyou 35" was used to investigate the effects of irrigation and nitrogen fertilizer coupling on enzyme activities related to nitrogen metabolism under subsurface drip irrigation in solar greenhouse. The results showed that irrigation amount and nitrogen application had significant effects on enzyme activities related to nitrogen metabolism. Under the same nitrogen fertilizer level, the activities of nitrate reductase and glutamine synthetase increased with the increase of irrigation, but as for glutamate synthase activity, there was no significant difference existed between I2 and I3 irrigation treatments. The contents of nitrate nitrogen and soluble protein in leaves of cucumber decreased with increase of irrigation water in fruiting stage, whereas there was no significant difference between I2 and I3 treatments. Under I2 and I3 irrigation level, the activities of nitrate reductase, glutamine synthetase and glutamate dehydrogenase in N2 treatment were significantly higher than those in N3 treatment, while there were no significant difference on the glutamate synthase activity and the contents of nitrate nitrogen and soluble protein between N2 and N3 treatments. According to enzyme activities related to nitrogen metabolism, the optimum irrigation level and nitrogen fertilizer application level for cucumber under subsurface drip irrigation were 0.8 Ep and 450 and 600 kg ha-1, respectively.