金鱼草珠被绒毡层壁囊的分离与鉴定

由金鱼(Antirrhinum majus L.)草开花后的胚珠中分离出抗乙酰解、抗酶解、对强氧化剂有一定抗性但不抗二乙醇胺的细胞壁囊状结构。切片原位观察表明,它是珠被绒毡层的内壁,能被苏丹 IV 染色与金胺 O 荧光染色。它全面地包围胚囊内正在发育的胚和胚乳,仅在合点与珠孔两端开口,而在此二处分别有胚乳吸器与胚柄与外相通。这一结构的功能可能是保证营养物质定向导入胚囊以及防止珠被绒毡层分泌的水解酶侵蚀胚囊等。

ISOLATION AND IDENTIFICATION OF INTEGUMENTARY TAPETAL WALL SAC IN ANTIRRHINUM MAJUS L.

Sac-shaped wall structures were isolated from post-anthesis ovules of Antirrhinum majus treated with acetic anhydride-H_2SO_4(9:1),50% cold chromic acid,80% H_2SO_4-30% H_2O_1 (5:1)or cellulase-pectinase solution.This means that the wall sac is acetolysis-resistant as well as enzyme-iesistant and has some resistance to strong oxidizers.Observations on paraffin and ultrathin sections confirmed that the isolated wall sac was just the inner wall of integumentary tapetum,which enclosed the embryo sac from all side but leaves an aperture at each pole.This wall showed positive reaction to Sudan IV staining and auramine O fluorescence staining but negatively reacted to phloroglucinol,indicating that it was likely to be composed of highly stable lipid substances,preferably cutin or sporopollenin.Based on all these results,it is sup- posed that the wall sac functioned as a dam for preventing damage of young embryo and endo- sperm from the hydrolytic enzymes secreted by integumentary tapetum and also for chanaliz- ing nutrient flow through the chalazal and micropylar apertures into embryo sac.