摘要
以水稻"中早 39"为试验材料,采用盆栽试验,研究在控水增氧条件下不同施氮水平对水稻根系形态、根系活力、根系氮素代谢酶活性、植株光合特性和植株干重的影响.结果表明,在相同的控水增氧条件下,随施氮量的增加,水稻同一生育期的总根长、根表面积、根体积和平均根直径、根系活力、根系硝酸还原酶(NR)活性和谷氨酰胺合成酶(GS)活性、叶片净光合速率(Pn)、叶片蒸腾速率(Tr)、叶片叶绿素含量(SPAD)、根系及秸秆干重均呈先增后降的趋势,以施氮量180 kg/hm2控水增氧处理为峰值;同一施氮水平的控水增氧处理较不控水增氧处理,水稻同一生育期的上述指标均显著增加;施氮量 180 kg/hm2 控水增氧处理较施氮量 0 kg/hm2 控水增氧处理、施氮量 180 kg/hm2 不控水增氧处理开花期的根系活力分别增加 127.6%、26.4%,孕穗期根系NR活性分别增加 41.2%、88.7%,黄熟期根系干重分别增加 257.2%、20.0%,黄熟期秸秆干重分别增加 161.2%、16.4%.
Abstract
A pot experiment was conducted with the rice cultivar'Zhongzao 39'to study the effects of different nitrogen application levels on the root morphology,root vitality,activities of nitrogen-metabolizing enzymes in the root,photosynthetic characteristics,and plant dry weight under controlled irrigation and oxygen enrichment conditions.The results showed that under the same controlled irrigation and oxygen enrichment conditions,with the increase in nitrogen application level,the total root length,root surface area,root volume,average root diameter,root activity,root nitrate reductase(NR)and glutamine synthetase(GS)activities,leaf net photosynthetic rate(Pn),leaf transpiration rate(Tr),leaf chlorophyll content(SPAD),and root and straw dry weights of rice plants at the same growth stage first increased and then decreased,with the peak values at the nitrogen application level of 180 kg/hm2.At the same nitrogen application level,controlled irrigation and oxygen enrichment significantly increased the above indicators at the same growth stage of rice plants compared with the treatment without controlled irrigation and oxygen enrichment.The treatment of nitrogen application at 180 kg/hm2,controlled irrigaion,and oxygen enrichment increased the root vigor during the flowering stage by 127.6%and 26.4%,the root NR activity during the booting stage by 41.2%and 88.7%,the root dry weight during the yellowing stage by 257.2%and 20.0%,and the straw dry weight during the yellowing stage by 161.2%and 16.4%,respectively,compared with the treatment of nitrogen application at 0 kg/hm2,controlled irrigation,and oxygen enrichment and the treatment of nitrogen application at 180 kg/hm2 and without controlled irrigation and oxygen enrichment.
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