赤霉素和生长素浸种对野牛草种子萌发及幼苗生长生理的影响

为研究外源激素对野牛草(Buchloe dactyloides)种子破除休眠和幼苗生长生理的作用,本研究分别设置3个浓度的赤霉素(GA3)和生长素(IAA)对野牛草进行浸种处理,浸种后进行发芽试验,对浸种后种子的萌发及幼苗生长情况、非结构性碳水化合物和内源激素进行测定。结果表明,1)赤霉素浸种可以有效增强野牛草种子发芽力,提高发芽势、发芽率、发芽指数和种子活力指数,其中,2 000mg·L-1的赤霉素处理效果最显著(P0.05);适当浓度的生长素浸种可以有效增强野牛草种子的生活力。2)赤霉素处理有助于野牛草幼苗地上部的生长;生长素处理对野牛草幼苗地下部和根冠比有显著(P0.05)的增强作用,其中较低浓度(250mg·L-1)处理效果最明显。3)1 500mg·L-1赤霉素与450mg·L-1生长素浸种均可显著(P0.05)提高野牛草幼苗可溶性糖与淀粉的积累。4)较高浓度的外源赤霉素和生长素浸种处理会使野牛草幼苗内源生长素、赤霉素、脱落酸(ABA)含量上升,其中,2 000 mg·L-1的赤霉素和450mg·L-1的生长素浸种效果最佳。综上所述,打破野牛草种子休眠、促进地上部生长及其幼苗内源赤霉素含量的最佳试剂和浓度为2 000 mg·L-1的赤霉素,增加可溶性糖和淀粉在野牛草幼苗期积累的最佳试剂和浓度是1 500mg·L-1的赤霉素;促进野牛草幼苗地下部生长的最佳试剂和浓度是250mg·L-1的生长素,增加野牛草幼苗内源生长素和脱落酸含量的最佳试剂和浓度是450mg·L-1的生长素。

Seed soaking in exogenous gibberellin and auxin and their impact on seed germination and seedling physiology of Buchloe dactyloides (Nutt.) Engelm.

In order to study the effects of exogenous hormones on breaking seed dormancy,and seedling growth of buffalo grass,seeds were soaked in three concentrations of gibberellic acid(GA3) and auxin(IAA) separately.After soaking,seed germination,seedling growth,non-structural carbohydrates,and endogenous hormone levels were measured.Our results showed:1) Seed germination GA3 increased germination vigor and increased germination,germination rate,germination index and seed vigour index.Based on the treatment effects,gibberellin at 2 000 mg · L-1 had the most significant impact.Auxin also effectively enhanced the viability of the seeds,of which 450 mg · L-1 auxin yielded the best results.2) Seedling growth GA3 treatment promoted the growth of aerial parts.IAA effectively increased buffalo grass seedling root length and root to bud ratio,at a low concentration of 250 mg · L-1,which yielded the best results.3) Seedling non-structural carbohydratesoptimal GA3 concentration was 1 500 mg · L-1 while for IAA it was 450 mg · L-1,which could effectively increase the content of soluble sugars and starch in buffalo grass seedlings.4) Seedling endogenous hormones ——IAA,GA3 and ABA,all increased with the treatment with exogenous gibberellin and auxin,of which GA3 at 2 000 mg · L-1 and IAA at 450 mg · L-1 provided best results.In summary,the best phytochemical to break dormancy in buffalo grass seeds and promote the growth of seedlings,buds and endogenous gibberellin is GA3 at a concentration of 2 000 mg · L-1.The best reagent to enhance soluble sugars and starch content in buffalo grass seedlings is also GA3 at a concentration of 1 500 mg · L-1.The best reagent to promote the growth of the buffalo grass seedlings and shoot growth is IAA,when applied at a concentration of 250 mg · L-1.Auxin at a concentration of 450 mg · L-1 was found to be the best hormone to increase endogenous IAA and ABA levels in buffalo grass.