模拟四季温度层积对南方红豆杉种子生理性状的影响

Effects of Simulated Seasonal Temperature Stratification on Physiological Changes of Taxus chinensis var. mairei Seeds

摘要:

为了解濒危物种南方红豆杉(Taxus chinensis var. mairei)种子内含物含量受温度和湿度层积的影响，设置4个季节、2种湿度(16%和24%)基质层积处理，对种子的可溶性糖、淀粉、可溶性蛋白和脂肪等内含物质的变化进行研究。结果表明，不同层积处理下种子贮藏物质的含量有显著变化，春季层积9个月后，可溶性蛋白含量达到最高值；可溶性糖含量呈现降低-升高-降低的变化趋势；淀粉和脂肪含量均随层积逐渐减少。秋季层积9个月后，淀粉含量降至最低。相比于24%湿度，16%湿度的春季、秋季、冬季层积9个月后，脂肪含量均减少较多，说明16%湿度下种子代谢活动更强。春季和秋季的暖温更能促进种子代谢，促进种子形态后熟。夏季温度过高，导致种子生活力下降，夏季层积处理3个月后，种子已经发霉和腐烂。层积过程中，种子内含物在相关酶的作用下，降解为可溶性蛋白、可溶性糖等，为种子萌发提供物质与能量。种子层积时间、温度和湿度及交互作用可作为种子内含物的调控因子。

Abstract:

In order to understand the effects of temperature and humidity stratification on seed content of Taxus chinensis var. mairei, the seeds were treated under four seasons and two humidity (16% and 24%) stratifications for 12 months, and then the changes in soluble sugar, starch, soluble protein and fat of seeds were studied. The results showed that the contents of seed storage substances changed significantly under different stratification treatments. The soluble protein content reached the highest after stratification for 9 months in spring, and the soluble sugar content showed a trend of decreasing-increasing-decreasing. Starch and fat contents decreased gradually with stratification. The starch content decreased the lowest after stratification for 9 months in autumn. Compared with the 24% humidity, the fat content decreased in the spring, autumn and winter after stratification for 9 months under 16% humidity, indicating that the metabolic activity of seeds was stronger under 16% humidity. The warm temperature in spring and autumn could promote seed metabolism and post-ripening. High temperature in summer caused the decrease of seed viability. After summer stratification for 3 months, the seeds had become moldy and rotten. In the stratification process, seed contents were degraded into soluble proteins and soluble sugars under the action of related enzymes, which provide material and energy for seed germination. Therefore, seed stratification time, temperature and humidity and their interactions could be used as regulators of seed contents.