孕穗期干旱胁迫下外源γ-氨基丁酸对寒地粳稻籽粒氮素形成及产量的影响

Effects of Exogenous γ-aminobutyric Acid on Grain Nitrogen Formation and Yield in Cold-region Japonica Rice under Drought Stress at Booting Stage

为探究孕穗期干旱胁迫下外源γ-氨基丁酸(GABA)对寒地粳稻籽粒氮素及产量形成的调控效应,以东农425和松粳6为试验材料,设置6个GABA浓度(0,0. 25,0. 50,1. 00,2. 00,4. 00 mmol/L),以正常灌溉为对照(CK),分析孕穗期干旱胁迫下外源GABA对寒地粳稻籽粒干物质量、全氮含量及氮代谢酶活性的影响。结果表明,与对照相比,孕穗期干旱处理下寒地粳稻产量、产量构成因素、籽粒干物质积累量(除齐穗后7 d)显著降低;籽粒谷草转氨酶(GOT)和谷丙转氨酶(GPT)酶活性降低,籽粒谷氨酰胺合成酶(GS)活性升高(齐穗后7,14 d),籽粒全氮(除松粳6齐穗后21～35 d)和内源GABA含量(齐穗后7,14 d)显著升高。与干旱处理相比,施用不同浓度GABA能够显著提高寒地粳稻籽粒产量、产量构成因素以及籽粒干物质积累量、氮代谢关键酶活性、全氮和内源GABA含量,随着喷施GABA浓度的增加,东农425和松粳6的产量、产量构成因素、籽粒干物质量积累、氮代谢关键酶活性、全氮和内源GABA含量均表现为先升高后降低,通过回归分析得出,孕穗期干旱胁迫下东农425和松粳6喷施外源GABA的最适浓度分别为0. 54,1. 22 mmol/L。

To investigate the regulation effect of exogenousγ-GABA on the formation of nitrogen and yield of Japonica rice in cold region under drought stress at booting stage,Dongnong 425 and Songjing 6 were used as experimental materials,and 6 GABA concentrations(0,0.25,0.50,1.00,2.00 and 4.00 mmol/L)were set up.The effects of exogenous GABA on dry matter amount,total nitrogen content and activity of nitrogen metabolism enzyme of Japonica rice were analyzed under drought stress at booting stage with normal irrigation as control(CK).The results showed that compared with the control,the yield and the yield components,dry matter accumulation of grains(in addition to 7 days after full bloom)decreased significantly,the activity of straw transaminase(GOT)and glutamine pyruvic transaminase(GPT)decreased,the activity of glutamine synthetase(GS)increased(7 and 14 days after full bloom),the content of total nitrogen(in addition to 21-35 days after panicle of Songjing 6)and endogenous GABA increased significantly.Compared with the drought treatment,using different concentrations of GABA could significantly improve grain yield,yield components and dry matter accumulation of grains,nitrogen metabolism key enzyme activity,total nitrogen and endogenous GABA content,and with the increased of GABA concentration.The yield and yield components of Dongnong 425 and Songjing 6,and the accumulation of grain dry matter quality,the activities of nitrogen metabolism key enzymes,and the content of total nitrogen and endogenous GABA increased first and then decreased.And the optimum concentrations of exogenous GABA in Dongnong 425 and Songjing 6 sprayed by drought stress at booting stage were 0.54,1.22 mmol/L.