不同外源植物激素对野苜蓿种子萌发和幼苗生长的影响

Effects of Different Exogenous Plant Hormones on Seed Germination and Seedling Growth of Medicago falcata

【目的】探明不同浓度赤霉素(GA_(3))和生长素(IAA)对野苜蓿种子萌发与幼苗生长、生理指标的影响,为野苜蓿的人工栽培提供科学依据。【方法】使用野苜蓿种子[种子平均长(226.16±22.91)μm、宽(144.15±21.22)μm,种子净度(67.17±0.18)%、千粒重(2.01±0.035)g]为试材,采用培养皿和育苗杯培养方法,以蒸馏水为对照(CK),研究2种外源植物激素GA_(3)和IAA(100 mg/L、200 mg/L、300 mg/L、400mg/L和500 mg/L)对野苜蓿种子萌发特性和幼苗生长性状的影响。【结果】不同浓度GA_(3)处理野苜蓿种子的发芽率、发芽势和发芽指数总体高于IAA处理;300 mg/L GA_(3)对野苜蓿种子发芽率提升较为明显,且发芽势和发芽指数最大,分别为70.00%和10.93。不同浓度GA_(3)处理野苜蓿幼苗的叶片数呈增长趋势、株高均呈先快速增长后平缓趋势,过氧化物酶(POD)活性较CK均下降,以300 mg/L GA_(3)处理野苜蓿幼苗的POD活性和Pro含量最低,分别为993.00 U/g和2803.03μg/g。IAA对野苜蓿种子萌发、叶片数和株高增长具有明显的抑制作用,野苜蓿幼苗的POD活性和Pro含量均呈上升趋势,以100 mg/L IAA处理的POD活性和Pro含量最低,分别为968.00 U/g和4578.79μg/g。【结论】300 mg/L GA_(3)处理可显著促进野苜蓿种子萌发和幼苗生长,不同浓度IAA处理对野苜蓿种子萌发和幼苗生长均表现出明显的抑制作用。

【Objective】The effects of different concentrations of gibberellin(GA_(3))and auxin(IAA)on seed germination,seedling growth and physiological indicators of Medicago falcata were studied to provide scientific basis for the artificial cultivation of M.falcata.【Method】M.falcata seeds[average seed length:(226.16±22.91)μm,average seed width:(144.15±21.22)μm,seed purity:(67.17±0.18)%,1000-grain weight:(2.01±0.035)g]were used as materials and cultured in culture dishes and seedling cups.Taking the distilled water as CK,and different concentrations(100 mg/L,200 mg/L,300 mg/L,400 mg/L,500 mg/L)of two exogenous plant hormones,GA_(3)and IAA,were set up to study their effects on germination properties of seed and growth characteristics of seedling of M.falcata.【Result】The germination rate,energy and index of M.falcata seeds treated with different concentrations of GA_(3)were overall higher than the IAA treatment.300 mg/L GA_(3)had obvious promotion effects on the seed germination rate,and the germination energy(70.00%)and germination index(10.93)were both the largest.The number of leaves of M.falcata seedlings treated with different concentrations of GA_(3)showed an increasing trend,while the plant height showed a rapid increase at first and then flat trend.POD activity decreased compare to CK,and the POD activity and Pro content of M.falcata seedlings treated with 300 mg/L GA_(3)were the lowest with 993.00 U/g and 2803.03μg/g respectively.IAA had obvious inhibition effect on the increase of seed germination,the number of leaves and plant height of M.falcata.POD activity and Pro content of M.falcata both showed increasing trend.POD activity and Pro content treated with 100 mg/L IAA were the lowest with 968.00 U/g and 4578.79μg/g respectively.【Conclusion】300 mg/L GA_(3)treatment can significantly promote the seed germination and seedling growth of M.falcata,while they are obviously inhibited by IAA treatment with different concentrations.