腐植酸对西瓜种子萌发及其生理特性的影响

Effects of Humic Acid on Germination and Physiological Characteristics of Watermelon Seed

以小果型西瓜“黄蜜隆”为试材,采用室内浸种法,研究了不同浓度的腐植酸对西瓜种子萌发及芽苗生长和生理特性的影响,以期探明腐植酸促进西瓜种子萌发作用效果及其生理机制。结果表明:不同浓度腐植酸处理均可不同程度提高根系活力、叶绿素和脯氨酸含量及超氧化物歧化酶(SOD)活性,降低丙二醛(MDA)含量,从而使种子萌发整齐,种子的活力指数提高,芽苗生长粗壮。综合考虑,以1200mg·L^(-1)处理效果最佳,其发芽势、芽苗株高显著高于对照,活力指数、芽苗胚轴粗度、胚轴长度和鲜质量/干质量分别比对照提高43.31%、5.64%、29.96%、25.26%,且均高于其它处理。相关性分析结果表明,种子发芽势、芽苗株高、胚轴长度、胚轴粗度、鲜质量/干质量等指标与腐植酸浓度关系密切,可通过改变腐植酸的浓度调节种子发芽势和芽苗生长;根系活力、超氧化物歧化酶(SOD)活性对腐植酸处理的响应起关键作用,可作为主要的生理调节因子。

The small-type watermelon cultivar‘Huangmilong’was used as experimental material,the seed soaking method was used.Effects of different concentrations of humic acid on germination,bud growth and physiological characteristics by soaking seed were stuided,in order to elucidate promoting effect of humic acid on growth of watermelon seedling and its physiological mechanism.The results showed that the humic acid treatment promoted seed germination and seedling growth,increased root activity,chlorophyll and proline contents,superoxide dismutase activity,and reduced malondialdehyde content so that the germination uniformity improved,the seed vigor index increased and the seedlings grew strongly.The treatment of 1200mg·L^(-1) was optimal,and the germination energy and hypocotyl height were significantly higher than of control,and the vigor index,hypocotyl diameter,hypocotyl length and ratio of fresh weight to dry weight increased by 43.31%,5.64%,29.96%,25.26%,which were higher than other treatments.The results of correlation analysis showed that the relationship between the concentration of humic acid and seed germination energy,seedling height,hypocotyl diameter and length,ratio of fresh weight to dry weight,root activity,superoxide dismutase activity were positively correlated in the way accorded with a polynomial expression.Accord to these results,the seed germination energy and seedling growth of watermelon could be regulated by changing the concentration of humic acid,and that root activity and superoxide dismutase activity could be used as the main factors to regulate physiological response.