外源赤霉素（GA₃）对羊草生长发育及生物量的影响

【作者】 崔爽；

【导师】 穆春生；

【作者基本信息】 东北师范大学 ， 生态学， 2004， 硕士

【摘要】 本文以松嫩草甸草原优良禾本科牧草羊草为研究对象，系统地研究了不同时期不同浓度外源赤霉素对羊草种子萌发、幼苗生长、羊草生长发育过程、产草量和粗蛋白产量的影响，以期得出外施赤霉素产生最优效应的施用浓度与使用时间，阐明其在羊草各生长发育阶段中的作用，揭示其对羊草生长发育及生物量的影响规律，为今后进一步研究和利用提供基础数据和参考依据。 实验结果表明，恰当的赤霉素浓度及浸种时间对打破羊草种子的休眠，提高发芽率效果较好。用300 mg/L赤霉素浸种48小时发芽的效果最好，发芽率达到了16.7%，比对照提高7倍多；发芽指数在浓度为300mg/L赤霉素浸种72小时时最高，说明该处理的种子出芽的整齐度最好；用200mg/L的赤霉素浸种72小时的活力指数最大；当浸种浓度为300mg/L，浸种48小时的相对电导率最低；本实验中200mg/L的赤霉素溶液浸种72小时的处理幼根最长，幼叶在用浓度为300mg/L的赤霉素溶液浸种48小时最长，浸种24和48小时处理的幼苗根叶比随着赤霉素浓度的增加，均呈现先增加后减小的趋势。从整体上看，用300 mg/L的赤霉素浸种48小时，成株抗旱性较差，建议在草地管理过程中，应注意适时灌水。如在干旱或灌溉条件不足的地区，可采用200mg/L的赤霉素浸种72小时的处理。 不同时期用不同浓度的赤霉素处理羊草，对羊草的生长发育过程影响很大。有利于株高、总叶长和总叶宽增长的最佳处理时间均为返青期，最佳处理浓度分别为75mg/L 、25 mg/L和50 mg/L；适当浓度的赤霉素虽增加羊草单株的绿叶数，但各处理在刈割期与对照间均无显著差异。外源赤霉素对抽穗率无显著影响，有利于羊草结实。 返青期外施赤霉素对单株地上干物质的积累效果最好，最佳处理浓度为50 mg/L。返青期50 mg/L和乳熟期25 mg/L、50 mg/L三个处理单位面积产草量比对照提高了20%左右。返青期50 mg/L处理的羊草单位面积粗蛋白产量最高。从单位面积产草量和粗蛋白的产量上看，返青期外施50mg/L的赤霉素增产的效果最好。更多还原

【Abstract】 In this thesis, the effects of exogenous gibberellin (GA3) on seeds germination, seedlings growth, plants development, grass and protein yield of Leymus chinensis, a fine perennial grass species that grows in the Songnen Plain, were carried out. These experiments were designed to determine the role of GA3 in the established stages of Leymus chinensis, to find out the proper applied concentration and time, and to provide theoretical foundation for further research and utilization.Seeds of Leymus chinensis were soaked in GA3 at 0, 50, 100, 150, 200, 300, 500mg/L for 24, 48 and 72 hours. Effects of GA3 on germination rate, germination index, vigor index, relative conductance ratio of seeds and root length, shoot length, root/shoot ratio of seedlings were studied. The results showed that the maximum germination rate was 16.7% when seeds were soaked in GA3 at 300 mg/L for 48 hours, and the relative conductance ratio of seeds was the lowest and shoots of seedlings were the longest in this treatment. Treated with GA3 at 300 mg/L for 72 hours, the germination index was the highest. The vigor index was the highest and roots of seedlings were the longest by soaking the seeds for 72 hours in 200 mg/L GA3. Treated with GA3 for 24 hours or 48, the root/shoot ratio of seedlings increased firstly and then decreased with the enhancement of the GA3 concentration. Treated with GA3 of 300mg/L for 48hours, the drought resistance of seedlings was poor, so it is suggested to irrigate properly. The treatment of 200 mg/L GA3 for 72hours will be more suitable for arid regions.The effects of exogenous GA3 on plants development, grass and crude protein yield of Leymus chinensis were also investigated. GA3 was sprayed on the grass with concentrations of 0, 25, 50, 75 and 100 mg/L at four different stages. Applied at returning green stage, the plant height, total leaf length and total leaf width per plant were larger than those applied at other stages. The highest plant height, the longest total leaf length and total leaf width appeared <WP=7>at concentrations of 75, 25 and 50 mg/L, respectively. The green leaf numbers increased in some treatments, but had no significant differences in contrast with control. Exogenous gibberellin had no significant effects on heading rate, but was helpful for seeds setting.The maximum of individual biomass occurred at the GA3 concentration of 50 mg/L applied at returning green stage. The grass yield per area increased by 20% applied with 50 mg/L at returning green stage or applied with 25 mg/L and 50 mg/L at milky stage. The highest crude protein yield appeared at the GA3 concentration of 50 mg/L applied at returning green stage. Treatment with 50 mg/L GA3 at returning green stage was the best way to improve grass and crude protein yield per area.更多还原