沙棘果实成熟模式研究

STUDIES ON RIPENING PATTERN OF SEABUCKTHORN (HIPPOPHAE) FRUITS

本文对乌鞘岭地区天然分布的中国沙棘和西藏沙棘物候期进行了系统观察,对两种沙棘果实生长与成熟期间的呼吸速率、内源植物激素IAA、ABA、乙烯含量的变化进行了系统测定,结果表明果实发育前期IAA含量与呼吸速率都很高,果实变色期时降至极小值,ABA恰在此时出现,9月末(花后135—139天)果实完熟时,ABA达到最高水平。果实完熟后果肉与种子中IAA又有增长趋势。中国沙棘、西藏沙棘分别于9月中旬末(花后133天)和9月上旬(花后115天)种子完熟时出现呼吸升高现象。果实生长后期有微量乙烯生成。根据沙棘果实ABA在变色期出现,完熟衰老前达到高峰值与呼吸速率及IAA的变化状况,有理由认为ABA在沙棘果实生长阶段的转化与成熟过程中起有重要的调节作用。按照其成熟模式,沙棘应属于非跃变果实,但成熟时却伴有呼吸升高现象,又有别于其它非跃变果实。

The phenological stages of seabuckthorn ( Hippophae rhamnoides L. subsp. sinensis rousi and H. thibetana Schlechted ) distributed natura-lly over an area of Wushao ridge were observed.The respiratory rate, and the changes in the levels of endogenous phytphormones-IAA, ABA and ethylene were investigated during the developing and ripening periods of these two species of fruits. The results showed that both the respiratory rate and IAA levels were very high during the early stages of fruit growth, decreased to a minimum at color changing phase and just at this time, ABA first appeared. ABA reached a maximum in the last ten days of Sep. ( 135 139 days after anthesis ) during full ripening stage of fruits.After the full ripening stage, IAA levels increased once more both in the flesh and in the seeds. An increase in respiratory rate apeared at the earlier last ten days of Sep. (133 days after anthesis) in Hippophae sinensis and at the first ten days of Sep. ( 115 days after anthesis) in H. thibetana when the seeds reached the full ripening phase. But only trace of ethylene was detected in the ripening stages. Based on the above facts, it is reasonable to consider that it is ABA which plays an importent regulating role in the changes of developing stages and ripening process of seabuckthorn fruits. According to its ripening pattern, the seabuckthorn fruits seems to belong to the nonclimacteric fruits, but with an increase in respiratory rate during the ripening period, which is different from other nonclimacteric fruits.