2,4-D处理对大百合种子休眠解除及内源激素变化的影响

Effects of 2,4-D on Dormancy Release and Endogenous Hormone Changes in Cardiocrinum giganteum Seeds

在筛选最佳浓度的基础上,利用液质联用色谱法,测定不同层积时期种子赤霉素、生长素和脱落酸的含量,分析3种激素及其相互作用在种子休眠解除中的动态变化,探索内源激素在大百合种子休眠解除中的作用机理。结果表明:随着层积时间的增加,大百合胚的长度随之增长,层积135 d时,5 mg/L 2,4-D处理的胚长高出CK 9.03%。在5 mg/L 2,4-D处理下胚生长率最高,达到82%,发芽起始时间最早,为4℃下14 d后;发芽率最高,达75.33%。在层积过程中,CK和2,4-D处理脱落酸含量的变化总体呈下降趋势,在生长素、赤霉素含量上均表现为先上升后下降的趋势,生长素含量在层积60 d时达到峰值,CK比2,4-D处理高出516.66 ng/g,赤霉素含量在层积120 d时达到峰值,2,4-D处理比CK高出52.17 ng/g。生长素与脱落酸、赤霉素与脱落酸之间的比值呈先上升后下降的趋势,在层积60 d时,生长素与脱落酸的比值达到峰值,CK比2,4-D处理高了49.24,层积120 d时,2,4-D处理的生长素与脱落酸的比值比CK高出10.53,在层积120 d时,赤霉素与脱落酸的比值达到峰值,2,4-D处理高于CK处理1.63。可见,5 mg/L 2,4-D处理为最佳浓度,有利于种子休眠解除和萌发。脱落酸含量的变化与大百合种胚的发育呈负相关,生长素和赤霉素可能是促进大百合种子休眠解除的主要调节物质。

On the basis of screening the optimal concentration, the content of gibberellin, auxin and abscisic acid in different layering stages were determined by LC-MS. The dynamic changes of three hormones and their interactions in seed dormancy were analyzed, and the mechanism of endogenous hormones in dormancy release of Cardiocrinum giganteum seeds was explored. Results show that the length of C. giganteum embryo increases with the increase of the stratification time. When the layer is 135 d, the embryo length of 5 mg/L 2,4-D is 9.03% higher than CK. Under 5 mg/L 2,4-D treatment, the growth rate of the embryo is the highest, reaching 82%, and the germination initiation time is the earliest, after 14 days at 4℃;the germination rate is the highest, reaching75.33%. In the process of stratification, the changes of abscisic acid content in CK and 2,4-D treatments show a general downward trend, and both auxin and gibberellin content show a trend of increasing first and then decreasing. The auxin content peaks at 60 d, CK is 516.66 ng/g higher than 2,4-D treatment, gibberellin peaks at 120 d,and 2,4-D is 52.17 ng/g higher than CK. The ratio of auxin to abscisic acid, gibberellin to abscisic acid increase first and then decrease. When the layer is 60 d, the ratio of auxin to abscisic acid peaks, and CK is 49.24 times higher than 2,4-D. When the layer is 120 d, the ratio of auxin to abscisic acid treats by 2,4-D is 10.53 times higher than that of CK. When the layer is 120 d, the ratio of gibberellin to abscisic acid peaks, and 2,4-D treatment is1.63 times higher than CK. It can be seen that 5 mg/L 2,4-D treatment is the best concentration, which is beneficial to seed dormancy release and germination. The change of abscisic acid content is negatively correlated with the development of C. giganteum embryo. The auxin and gibberellin may be the main regulators to promote the dormancy release of C. giganteum seed.