干旱胁迫下外源ABA对鼓粒期大豆产量及氮代谢关键酶活性的影响

Effect of Exogenous ABA on Yield and Key Enzyme Activities of Nitrogen Metabolism of Soybean Under Drought Stress

通过研究鼓粒期外源脱落酸(ABA)在干旱胁迫条件下与氮素同化关键酶的关系,为大豆产量在实际生产中提供理论依据。采用2种不同类型的大豆为材料,在15%聚乙二醇(PEG-6000)模拟干旱条件下,于鼓粒期进行干旱胁迫处理(PEG)和干旱胁迫+喷施脱落酸处理(PEG+ABA),研究外源ABA在干旱胁迫下对大豆硝酸还原酶(NR)、谷氨酰胺合成酶(GS)和谷氨酸合成酶(GOGAT)活性的调控效应。试验结果表明,从鼓粒始期到鼓粒末期,在正常供水(CK)情况下,供试2个品种大豆叶片中NR和GS活性急剧降低,GOGAT活性呈先下降再上升趋势。与对照相比,PEG处理均降低叶片中NR、GS、GOGAT活性,在鼓粒后21天与CK、PEG+ABA处理产生显著差异,导致大豆籽粒产量较低。PEG+ABA处理叶片NR、GS和GOGAT活性高于PEG处理,差异显著;在鼓粒后28天和35天,其活性大小急剧上升,有利于大豆籽粒产量的形成。由此说明,外源ABA可以缓解逆境胁迫带来的伤害,同时可以促进氮代谢反应,从而控制叶片的衰老速度,提高籽粒产量。

The main purpose of this paper is to study the relationship between key enzymes of nitrogenassimilation and exogenous abscisic acid（ABA）, and provide a theory basis for soybean production underdrought stress during seed-filling period. The drought resistance was studied in two different cultivars atseedling stage under a simulated drought stress condition by using 15% concentration of polyethylene glycol（PEG） in vitro in order to investigate and analyze the effect of exogenous ABA under drought stress on activitiesof NR, GS and GOGAT activities of soybean leaf during seed-filling period. The results showed that NR andGS activity of soybean leaves decreased sharply during the seed-filling period, GOGAT activity first decreasedand then increased under the condition of normal water supply. Compared with the control, PEG treatmentdecreased the activity of NR, GS and GOGAT, and produced significant differences compared with CK andPEG＋ABA treatment on the 21 d after the beginning of seed-filling, which led to the lower yield of soybean.PEG ＋ ABA treatment increased the activity of NR, GS and GOGAT, which were higher than that of PEGtreatment and the difference was significant; their activity increased sharply on the 28 d and 35 d after thebeginning of seed-filling, and promoted the formation of soybean seed. The results indicate that exogenoushormones improve soybean tolerance under drought stress and promote the nitrogen metabolic reaction, therebyslow down the senescence of soybean leaves and improve the grain yield.