外源γ-氨基丁酸对芥蓝生长及品质的影响

Effects of exogenousγ-aminobutyric acid on growth and quality of Chinese kale

为揭示γ-氨基丁酸(GABA)对芥蓝(Brassica albograbra L.H.Bailey)生长与品质影响的生理机制,本研究采取盆栽试验的方式,研究叶面喷施不同浓度GABA(0 mmol/L、25 mmol/L、50 mmol/L、75 mmol/L、100 mmol/L、125 mmol/L)对芥蓝生长、营养品质、光合特性及内源激素影响。结果表明,不同浓度的GABA均能不同程度地提高芥蓝叶片叶绿素含量、净光合速率(P_(n))、蒸腾速率(T_(r))以及PSⅡ最大光化学效率(F_(v)/F_(m)),降低非光化学淬灭系数(NPQ)。适宜浓度GABA(75 mmol/L)显著增加芥蓝的株高、茎粗、鲜质量和干质量,显著增加叶片中可溶性糖、维生素C、可溶性蛋白质、游离氨基酸、总硫代葡萄糖苷、总酚及类黄酮含量,显著增加花茎中可溶性糖、维生素C、游离氨基酸及总硫代葡萄糖苷含量,显著降低叶片及花茎中硝酸盐含量,显著增加芥蓝叶片中玉米素(ZT)、赤霉素(GA_(3))、生长素(IAA)和脱落酸(ABA)等内源激素含量。同时,外源喷施GABA可以显著诱导芥蓝叶片和花茎中内源GABA和谷氨酸的积累,提高谷氨酸脱羧酶(GAD)的活性。本研究结果将为提高芥蓝产量和品质的化控技术运用提供理论参考。

To reveal the physiological mechanism ofγ-aminobutyric acid(GABA)in influencing the growth and quality of Chinese kale(Brassica albograbra L.H.Bailey),pot experiment was adopted to study the effects of different concentrations of GABA(0 mmol/L,25 mmol/L,50 mmol/L,75 mmol/L,100 mmol/L,125 mmol/L)on growth,nutritional quality,photosynthetic characteristics and endogenous hormone of Chinese kale by foliar spraying.The results showed that under different concentrations of GABA,the chlorophyll content,net photosynthetic rate(P_(n)),transpiration rate(T_(r))and the maximum photochemical efficiency(F_(v)/F_(m))of PSⅡof the Chinese kale leaves could be enhanced inordinately,and the non-photochemical quenching coefficient(NPQ)could be reduced.Compared with CK,appropriate concentration of GABA(75 mmol/L)could increase plant height,stem thickness,fresh weight and dry weight of Chinese kales significantly,and could significantly increase contents of soluble sugars,vitamin C,soluble proteins,free amino acids,total glucosinolates,total phenols and flavonoids in leaves.Besides,contents of soluble sugars,vitamin C,free amino acids and total glucosinolates in the flower stalks were significantly increased,while nitrate contents in the leaves and flower stalks were significantly reduced,contents of endogenous hormones such as zeatin(ZT),gibberellin3(GA_(3)),auxin(IAA)and abscisic acid(ABA)in Chinese kale leaves were significantly increased.Exogenous spraying of GABA could significantly induce the accumulation of endogenous GABA and glutamic acid in Chinese kale leaves and flower stalks and enhance the activity of glutamic acid decarboxylase(GAD).The study results will provide theoretical reference for the application of chemical control technology used to improve the yield and quality of Chinese kale.