摘要
在荔枝和龙眼种子发育过程中，内源ＡＢＡ水平先是上升，至大约７８～８０ＤＰＡ时出现高峰，之后两者ＡＢＡ含量均不断下降。果实成熟时采收的种子，ＡＢＡ含量比高峰时分别下降近６倍。另外，随着种子的发育，种子及其胚轴对外源ＡＢＡ的敏感性（ＳＡＢＡ）亦持续下降。１０－４ｍｏｌ／ＬＡＢＡ可以完全抑制９０ＤＰＡ前的荔枝和龙眼种子的萌发，但对成熟种子１０－２ｍｏｌ／ＬＡＢＡ亦不能抑制其萌发。龙眼种子离体胚轴的ＳＡＢＡ高于荔枝。ＡＢＡ含量与敏感性的这种变化可能是两种顽拗性种子成熟时萌动，进而不耐脱水贮藏的重要原因之一。
ABA contents, measured by enzyme linked immunosorbent assay(ELISA), increased obviously duringearly developttiental stagal of lycheeand longan seeds (Fig. 1). When itPeaked at 78 ￣ 80 days pet anthesis(DPA), ABA content was 986 ng/gDW in lychee seeds, and 1128 ng/gDW in longan seeds, then declinedmarkedly in both species. At harvest,ABA content of lychee and longanseeds was 144, 169 ng/g DW, respectively. Moreover, the sensitivity toABA (SABA ) of seeds (Fig. 2 ) andtheir isolated embryonic axes (Fig. 3)decreased during development. 10-4mol/L ABA could completely inhibitthe germination of lychee and longanseeds before 90 DPA; however, even10-2 mol/L ABA failed to completelyinhibit the germination of seeds harvested at full maturity. For young embryonic axes, 10-7 mol/L ABA inhib-ited their germination incubated onwoody plant medium (WPM), wheras10-4 mol/L ABA could hardly inhibitthe germination of embryonic axes iso-lated from mature seeds. The SABA oflongan embryonic axes was higher thanthat of lychee ones. The ABA contentand sensitivity in relation to seed reCalcitrance was discussed.
基金
国家自然科学基金
关键词
荔枝
龙眼
种子发育
顽拗性种子
脱落酸
Litchi chinensis,Euphoria longan, seed development, ABA contsnt, sensitivity to ABA, redcitrant seed
