灌水量与氮素形态对西兰花生产和氮代谢的影响

以西兰花品种碧绿为试材,采用双因素交互试验设计,设置3个灌水量水平——W1(田间最大持水量的80%)、W2(田间最大持水量的60%)、W3(田间最大持水量的40%)和3种氮素形态——N1(全硝态氮)、N2(硝态氮与铵态氮的比例为7∶3)、N3(硝态氮与铵态氮的比例为5∶5),研究不同灌水量与氮素形态对西兰花干物质积累(干重)、产量、水氮利用效率和氮代谢的影响。结果表明:总的来看,在相同氮素形态下,西兰花干重、产量、氮肥偏生产力随着灌水量的减少呈现先升高后降低的趋势;在相同的灌水量下,西兰花的谷氨酰胺合成酶、谷氨酸合成酶活性和叶片可溶性蛋白含量随着铵态氮比例的增加而升高,而硝酸还原酶活性的变化与此正好相反。综合来看,本试验条件下,当灌水量为田间最大持水量的60%、硝态氮与铵态氮的比例为5∶5时,西兰花的产量、水氮利用效率、干重等性状均表现较优,是适宜当地西兰花生产的水氮组合。

Effects of irrigation amount and nitrogen forms on production and nitrogen metabolism of broccoli

In the present study, broccoli cv. Bilyu was selected as experimental material, and a two-factor interactive experimental design was adopted. Three irrigation amounts, namely, W1 (80% of the maximum field capacity), W2 (60% of the maximum field capacity), W3 (40% of the maximum field capacity) and 3 nitrogen forms, namely, N1 (pure$NO^{-}_{3}-N$), N2 (proportion of $NO^{-}_{3}-N$ to $NH^{+}_{4}-N$ was 7∶3), N3 (proportion of $NO^{-}_{3}-N$ to $NH^{+}_{4}-N$ was 5∶5) were set. The effects of different irrigation amounts and nitrogen forms on dry matter accumulation (dry weight), yield, water and nitrogen use efficiency and nitrogen metabolism of broccoli were studied. It was shown that under the same nitrogen form, the dry weight, yield, and partial factor productivity from applied nitrogen of broccoli exhibited a trend of increase first and decrease later with the decreasing irrigation amount. Under the same irrigation amount, the glutamine synthetase (GS) activity, glutamate synthase (GOGAT) activity and soluble protein content of broccoli increased with the elevated proportion of $NH^{+}_{4}-N$, while the changes of nitrate reductase (NR) activity was the opposite. All in all, under the experiment condition, the performance of yield, water and nitrogen use efficiency, dry weight of broccoli was the best under W2N3 treatment. In other words, it was a suitable combination for local broccoli production when the irrigation amount was 60% of the maximum field capacity, and the proportion of $NO^{-}_{3}-N$ to $NH^{+}_{4}-N$ was 5∶5.