【作者】 孙红阳；

【导师】 沈海龙； 张鹏；

【作者基本信息】 东北林业大学 ， 森林培育， 2007， 硕士

【摘要】 对种子萌发过程中生理调控机制进行研究，有助于我们深入了解种子萌发的生理生态特性，指导苗圃育苗生产实践。本实验以已解除初生休眠的水曲柳（Fraxinus mandshurica Rupr．）种子为实验材料，研究水曲柳种子在不同温度下萌发过程中以及解除次生休眠过程中的生理生态特性和生化物质变化。主要研究结果如下：已解除初生休眠的水曲柳种子在变温条件下的种子萌发比恒温条件的好，最佳的变温条件为15℃／10℃，最佳的恒温条件是10℃，20℃以上的恒温会诱导种子产生次生休眠。水曲柳种子的物质转化受阻是其高温下次生休眠产生的主要原因。与最佳的变温条件（15℃／10℃）相比较，在诱导产生次生休眠的温度（25℃）下，种胚和胚乳中GA₃、IAA、ZT的含量降低，ABA含量增加，同时GA₃／ABA、IAA／ABA和ZT／ABA的比值也有所下降；种子中脂肪酶和β-淀粉酶活性受抑制，脂肪和淀粉的分解缓慢，可溶性蛋白和糖的进一步代谢均受到不同程度的抑制；通过对种子25℃萌发过程中各项生理指标的变化相关分析结果表明，ZT／ABA比值与可溶性蛋白含量和淀粉含量分别呈极显著和显著正相关。IAA／ABA比值与脂肪酶活性呈显著正相关。25℃下贮藏物质的代谢变化受到抑制，与几种激素间的比值下降有关。进而造成种子产生了次生休眠。对已产生次生休眠的水曲柳种子于6种不同外源激素浓度条件下进行浸种，其中乙烯利10^-3mol／L处理可有效的解除种子由于高温（25℃）诱导产生的次生休眠。乙烯利可有效促进次生休眠水曲柳种子的物质转化，促进其萌发。乙烯利10^-3mol／L处理增加了种子内源ZT和IAA的水平，并显著的降低了ABA和GA₃的含量，同时使GA₃／ABA、IAA／ABA和ZT／ABA的比值大幅升高；增加了次生休眠种子脂肪酶和β-淀粉酶活性，加速了贮藏物质的动员，提高了可溶性糖和蛋白为幼胚发育提供能量和氮源的能力；通过对乙烯利解除种子次生休眠过程中各项生理指标的相关分析可以看出，种子内β-淀粉酶活性与淀粉含量呈显著负相关，与GA₃／ABA比值呈极显著正相关。脂肪酶活性与IAA／ABA和ZT／ABA比值均呈显著正相关。由此可见，乙烯利通过改变几种促进激素GA₃、IAA、ZT和抑制激素ABA间的比例，使得次生休眠种子本已停滞的贮藏物质代谢活动得以重新恢复，是解除种子次生休眠，促进其萌发的主要原因。更多还原

【Abstract】 The study of the physiological mechanism in process of seed germination can help us to learn physiological and ecological identity of seed germination, and can guide yield in nursery. In the study, seed of Manchurican ash （Fraxinus mandshurica Rupr.）that breaked dormancy for material. We studied the the process of seed germination in different temperatures, and physiological and biochemical change in the process of breaked secondary dormancy. The results were as follow:Seed of breaked first dormancy germinated in different temperatures （ten levels）. Change temperature for seed germination was better than constant temperature. 15℃/10℃was the optimal change temperature, and 10℃was the optimal constant temperature. Seeds were secondary dormant when constant temperature more than 20℃.The material conversion block in Fraxinus mandshurica seeds causes a principal reason which is the secondary dormancy under high temperature. When the temperature was 25℃that can induced secondary dormancy, contents of GA₃, IAA, ZT decreased, content of ABA increased, the ratio of GA₃ and ABA、IAA and ABA, ZT and ABA decreased. And activity of lipase andβ-amylase of seed were restrained, decomposition of fat and starchy slowed, metabolizes of dissoluble albumen and sugar were restrained in different level. We can know that the ratio of ZT and ABA with content of dissoluble albumen and starch were statistically different at the level of p＜0.01 and p＜0.05 respectively by analysis the change of every phyological index in process of seed germination in 25℃. Metabolize of cache were restrained in 25℃, which related to the ratios of several hormones decrease, which induced seeds to secondary dormancy.Soak secondary dormant seeds in six treatments of different concentrations and hormones. Ethephon of 10^-3mol/L breaked dormancy effectively that induced by high temperature （25℃）.Ethephon effect advance materail conversion in secondary dormancy seed and germination. Ethephon of 10^-3mol/L increased endogenetic content of ZT and IAA, and decreased significantly content of ABA and GA, and increased significantly the radios of GA₃ and ABA, IAA and ABA, ZT and ABA, and increased activity of lipase andβ-amylase of secondary dormancy seeds, and accelerated mobilistion of cache, and enhanced the ability of dissoluble sugar and albumen supply energy and nitrogen to immature embryo. The activity ofβ-amylase with content of starch were statistically different at the level of p＜0.05 negatively and with the ratio of GA and ABA were statistically different at the level of p＜0.05 positively by analysis the change of every phyological index in process of breaked secondary dormancy. The activity of lipase with the ratios of IAA and ABA, ZT and ABA were statistically different at the level of p＜0.05 positively. The stagnant metabolism of cache resumed in secondary seed by ethephon changed the ratio of positive hormones of GA₃, IAA, ZT and negative hormones of ABA, which was the important reason of break secondary dormancy and promote germination.更多还原