连续增氧对不同基因型水稻分蘖期生长和氮代谢酶活性的影响

为明确氧对不同基因型水稻生长和氮素代谢的作用机理，以籼稻、粳稻和旱稻品种为材料，采用营养液培养，考察根际连续增氧水稻分蘖期生长和氮代谢状况。结果表明，连续增氧后，各水稻品种叶绿素含量均有所下降，国稻1号(籼稻)地上部分和根系干物质重分别降低44%和40%，巴西陆稻(旱稻)和秀水09 (粳稻)降低不显著。国稻1号和巴西陆稻的氮积累量分别降低35.8%和36.0%。各基因型水稻叶片NRA (硝酸还原酶活性)显著提高，GSA (谷酰胺合成酶活性)下降。秀水09，叶片NRA增加较少(P>0.05)。连续增氧提高了水稻根比表面积和氧化强度；但降低了叶片叶绿素含量和GSA，不利于水稻氮素吸收和干物质积累。不同基因型水稻对连续增氧的响应存在差异。

Effect of Continuous Aeration on Growth and Activity of Enzymes Related to Nitrogen Metabolism of Different Rice Genotypes at Tillering Stage

In order to clarify the role of oxygen in the growth and development of rice and its mechanism of nitrogen,three rice genotypes,i.e.,"Guodao 1"(indica),"Xiushui 09"(japonica),and "Brazilian upland rice"(upland rice),were cultured in nutrient solution with continuous aeration to measure the growth-related parameters and the activity of enzymes related to nitrogen me-tabolism at tillering stage.The results showed that,compared with the control,lower chlorophyll content in leaves was found in all the genotypes.The dry weights of shoots and roots were decreased by 44% and 40% for "Guodao 1" under continuous aeration,respectively,whereas no significant effects were observed for the "Brazilian upland rice" and "Xiushui 09".The root length,spe-cific surface area,and the intensity of α-naphthylamine oxidation of roots were increased significantly by continuous aeration,irrespective of the genotypes.The nitrogen accumulation in the "Guodao 1" and "Brazilian upland rice" under aeration was re-duced by 35.8% and 36%,respectively.Therefore,the nitrate reductase activity(NRA) in leaves was significantly increased,while the glutamine synthetase activity(GSA) was decreased under aeration.The NRA in leaves of "Xiushui 09" under continu-ous aeration tended to increase(P > 0.05) in comparison to the control.Thus,continuous aeration could increase the surface area and oxidation intensity in rice roots,and reduce the chlorophyll content and GSA in rice leaves,which may reduce nitrogen ab-sorption and dry matter accumulation.In addition,these were significant differences in responses of rice genotypes to continuous aeration.