洋葱种子种质超干保存的效果及其对膜系统的影响

洋葱超干种子室温下抗老化能力增强，耐储性提高。能明显延缓衰老。超干种子直接吸胀会引 起胚根断裂和种子活力下降。但吸胀前回水处理可以减轻吸胀过程中造成的损伤；超干处理大大增加了 苏氨酸（Ｔｈｒ）的渗漏，回水处理可恢复到原来水平。经回水处理的老化超干种子较未超干的对照老化种 子氨基酸和无机离子泄漏量减少，洋葱种子漏失的氨基酸以组氨酸（Ｈｉｓ）和苏氨酸（Ｔｈｒ）为多，外渗离子 以钾最多，超干还增加Ｃａ２＋和Ｍｇ２＋的渗漏，但回水后恢复到超干前的水平。

Effects of ultradry on seed germplasm preservation and biomembrane system in onion.

The storability of onion seed at ambient temperature was enhanced by ultra-drying , which was indicative of slower decrease in seed vigor. It was shown that the aging process of short-lived onion seed was delayed by ultradry storage. Imbibitional injury of ultradried .seeds,i. e. , breakage of embryonic root was alleviated by rehumidification before soaking. Histidine and Thrinine were the major components of amino acids leaked from ultradried onion seeds. Leakage of thrinine greatly increased induced by ultradry but the leakage of Thrinine and total amino acids were cut down obviously by rehumidification. Potassium was prevalent in the leakage of ions from ultradried seeds, which was less affected by rehumidification. However the leakage of calcium and magnesium from ultradried onion .seeds was much less compared to potassium. Leakage of calcium and magnesium increased by ultradry but it droped down to original level after rehumidification. Moreover , the integrity of biomembrane in ultradried onion seeds was still kept in a perfect situation after aging compared to that in non-ultradried seeds.