低温胁迫和赤霉素对花生种子萌发和幼苗生理响应的影响

低温是影响我国广大花生产区春花生发芽的主要因素之一。本文以不同生态区的30个花生品种为实验材料,研究了倒春寒天气诱导的低温胁迫对花生出苗的影响,以出苗率为标准筛选出4个耐低温的花生品种(阜花17、阜花12、冀花16、冀花18)和4个不耐低温的品种(鲁花11、白沙1016、正农黑花生1号、白玉)于温室测定了4℃低温和赤霉素(GA_3)处理后种子发芽相关指标和幼苗生理指标。结果表明, 4℃对耐低温花生品种发芽率、发芽指数影响不显著,但种子活力指数和芽长呈现下降趋势;4℃处理后,不耐低温品种幼苗相对膜透性和MDA含量上升幅度更高,耐低温品种幼苗的可溶性糖和游离脯氨酸含量上升幅度更大。GA_3显著促进4℃低温处理后花生种子萌发和种子活力,抑制了花生幼苗在低温处理后相对膜透性和丙二醛的上升,提高了可溶性糖、可溶性蛋白、游离脯氨酸含量。研究表明,赤霉素促进低温胁迫下种子萌发和幼苗生长的最佳浓度是300μmol L~(–1)。发芽率与相对膜透性和丙二醛含量显著负相关,与可溶性糖、脯氨酸含量显著正相关。温度影响发芽率的品种间差异较大,常温下赤霉素对不同耐低温品种的发芽率影响较小。本研究为耐低温花生种质资源创新和新品种培育提供了理论依据,为研究赤霉素对不同花生品种耐低温性影响的生理机制提供了基础。

Effect of low-temperature stress and gibberellin on seed germination and seedling physiological responses in peanut

From 30 peanut cultivars, we screened four cultivars with strong low-temperature-resistance (Fuhua 17, Fuhua 12, Jihua 16, Jihua 18) and four cultivars with weak low-temperature-resistance (Luhua 11, Baisha 1016, Zhengnongheihuasheng 1, Baiyu), and measured related indicators of seed germination and physiological indexes of seedlings under low temperature (4oC) and GA₃ treatments. There was no significant difference in rate of emergence and germination index of strong low-temperature- resistant cultivars with or without 4oC treatments, but decrease in hypocotyl length and seed vigor under low temperature. The relative membrane permeability and MDA content of four cultivars with weak low-temperature-resistance had higher ascensional range. The contents of soluble sugar, soluble protein and free proline of cultivars with strong low-temperature resistance had smaller reduction. GA₃ facilitated the rate of emergence and seed vigor of all peanut seeds, as well as promoted the contents of soluble sugar, soluble protein and free proline of seedlings, but suppressed the uptrend of relative membrane permeability and MDA content of peanut seedlings under low temperature. The best concentration of GA₃ promoting seed germination and seedling growth of peanut with low temperature treatment is 300 μmol L ^-1. The rate of emergence had significantly negative correlation with relative membrane permeability and MDA, and obviously positive correlation with the contents of soluble sugar or free proline. The temperature had greater influence on germination rate, but the effect of gibberellin on difference of germination rate between different varieties was smaller. This study provided a theoretical basis for germplasm resources innovation and breeding new peanut cultivars with strong low-temperature resistance, as well as for studying the physiological mechanism of gibberellin on chilling tolerance of different peanut varieties.