油菜角果SPS活性变化对其碳氮代谢及油分形成的影响

Effects of SPS activity variation on carbon and nitrogen metabolism,and oil formation in rape silique

【目的】探明油菜角果蔗糖磷酸合成酶(Sucrose phosphate synthase,SPS)活性变化对其碳氮代谢产物及油分含量的影响,为进一步研究油菜SPS表达调控机理、改良油菜品质和产量的矛盾提供理论依据。【方法】以氮低效和氮高效油菜品种为试验材料,在正常供氮和氮胁迫条件下进行土培试验。角果发育中期涂抹SPS抑制剂,以涂抹蒸馏水为对照,处理后第3 d上午测定角果皮及籽粒的SPS活性、可溶性糖和游离氨基酸含量,成熟期测定籽粒油分含量。【结果】角果涂抹SPS抑制剂后,不同氮水平条件下不同氮效率油菜品种的SPS活性均明显下降,其差异达显著水平(P<0.05)。氮胁迫条件下,氮低效品种的SPS活性受抑制较明显,而在常氮条件下,氮高效品种的SPS活性受抑制较明显;角果发育期的SPS活性表现为正常供氮处理高于氮胁迫处理,氮高效品种高于氮低效品种;可溶性糖含量的变化规律与SPS活性一致;游离氨基酸含量在不同氮水平间和品种间的差异与SPS活性一致,而对SPS抑制剂的反应与SPS活性和可溶性糖含量不同,即在SPS活性受抑制条件下呈升高趋势。籽粒油分产量也与SPS活性的变化趋势相同,在SPS抑制剂处理下明显下降,氮胁迫和常氮水平下氮低效和氮高效品种的籽粒油分含量分别降低5.00%、13.13%、17.57%和21.88%,表现出氮高效品种的籽粒油分产量高于氮低效品种、常氮处理高于氮胁迫处理。【结论】无论氮水平如何,氮低效和氮高效油菜品种油菜角果的SPS活性受抑制时,角果皮和籽粒的碳代谢减弱、氮代谢增强,最终导致油分产量降低。

【Objective】Effects of sucrose phosphate synthase(SPS)activity variation in rape silique on carbon and nitrogen metabolite and rapeseed oil content were studied to provide reference for revealing the expression regulation mechanism of SPS,and contradiction between quality and yield of improved rape varieties.【Method】Rape varieties with low nitrogen use efficiency and high nitrogen use efficiency were used in this experiment,and soil culture test under normal nitrogen supply and nitrogen stress was carried out.During silique development period,rape siliques were smeared with SPS inhibitor,and those smeared with distilled water were set as control.SPS activity,soluble sugar content and free amino acid content in husk and grain were determined in the morning on day3after treatment,and grain oil yield at maturity stage was measured.【Result】After smearing SPS inhibitor on silique,under different nitrogen supply conditions,SPS activity of rape varieties with different nitrogen use efficiencies decreased greatly,and the differences were significant(P<0.05).Under nitrogen stress,SPS activity of varieties with low nitrogen use efficiency was greatly inhibited,but under constant nitrogen condition,SPS activity of varieties with high nitrogen use efficiency was greatly inhibited.As for SPS activity of silique during development period,those in constant nitrogen condition were higher than those in nitrogen stress,and those of varieties with high nitrogen use efficiency were higher than those of varieties with low nitrogen use efficiency.The change of soluble sugar content was consistent with that of SPS activity.The difference of free amino acid content between different nitrogen levels and varieties was consistent with SPS activity,but its reaction to SPS inhibitor was different from SPS activity and soluble sugar content.That is,it increased when SPS activity was inhibited.Grain oil yield had the same variation trend with SPS activity.Under SPS inhibitor treatment,grain oil yield decreased greatly.Under nitrogen stress,grain oil content of varieties with low nitrogen use efficiency and high nitrogen use efficiency reduced by5.00%and13.13%;under constant nitrogen condition,grain oil content of varieties with low nitrogen use efficiency and high nitrogen use efficiency reduced by17.57%and21.88%.Grain oil yield of rape varieties with high nitrogen use efficiency was larger than those with low nitrogen use efficiency,and grain oil yield under constant nitrogen condition was larger than that under nitrogen stress.【Conclusions】Regardless of nitrogen level,when silique SPS activity of rape varieties with low and high nitrogen use efficiencies is inhibited,carbon metabolism of silique and grain weaken,nitrogen metabolism strengthens,and eventually grain oil yield reduces.