超干种子的膜功能与糖组分的研究

采用两相法分离种子质膜,研究超干处理对种子质膜ATP酶活力及膜流动性的影响.结果表明,白菜(Brassica pekinensis(Lour.)Rupr.)、榆树(Ulmus pumila L.)种子经超干处理后,在人工老化和自然老化条件下,与在-20℃条件下贮藏的种子比较,超干贮藏种子质膜ATP酶活力和微粘度无显著变化,过于贮藏种子的效应虽有所下降,但仍比高含水量室温贮藏的对照种子为好.此结果与超干种子具较高活力水平完全一致,说明超干贮藏种子保持了质膜的生理功能,因此提高了种子的耐藏性.高效液相色谱分析结果显示超干种子中还原糖/非还原糖的比值低于高含水量种子,积累的蔗糖、水苏糖含量与超干种子的耐干力有关.玉米(Zea mays L.)种子中不含水苏糖,这可能是玉米种子较其他种子耐干力下降的原因之一.

Studies on Membrane Function and Sugar Components of Ultradried Seeds

The series Variantia Ching et S.H.Wu mainly occur in China and its members are highly variable in morphology. The denomination on this group of Asplenium is very confused in the herbaria. We hope by means of a biosystematic study to find out their genetic relationships in the reticulate evolution, and to raise a suggestion on their taxonomic treatment. Evidence from cytology, allozyme, morphology, and palynology shows that three ancestor diploids have formed Asplenium sarelii complex comprising 13 members. A. sarelii Hook. Should be typified as a diploid. The so_called tetraploid “A. sarelii" before is an allotetraploid that comes from the doubled hybrid between diploid A. sarelii and A. tenuicaule Hayata, which should be treated as a new species A. wudangense Z. R. Wang et X. Hou. A. pekinense Hance is an autotetraploid that comes from the doubled diploid ancestor A. sarelii. A. lushanense C. C hr., a diploid species and the only ancestor of A. yunnanense group, should not been sunk as a synonym of tetraploid A. yunnanense Franch. Most probably, A. varians Wall. E x Hook. Et Grev. Is an autotetraploid of A. tenuicaule Hayata. Three new natural tetraploid hybrids and their origins have been found out: they are A.×longmenense (= A. pekinense × varians), A. × jingyunense (= A. pekinense × yunnanense) and A. × kidoi (=A. pekinense × wudangense). Three other new natural triploid hybrids have been found and their origins have been inferred: they are A. × huawuense (=A. sarelii × wudangense), A. × luyunense (=A. Lushanense × yunnanense) and A. × tenuivaians (=A. tenuicaule × varians). The method of allozyme comparion combined with cytological observation is employed to reveal the complicated relationships among the members of Asplenium sarelii complex in reticulate evolution and proved to be a highly effective tool to investigate the origin of polyploid and hybrid.