摘要
The stigmas of five species, Populus euphratica Oliv., P. alba L., P. simonii Carr., P. lasiocarpa Oliv. and P. nigra L. have been studied. Scanning electron microscopy re veals that exudates are present in the intercellular spaces, in the clefts between the multicel lular papillae and on the receptive surface. Release and movement of exudates can be visual ized when the fresh stigmas are stained with sudan Ⅲ and auramine O. Paraffin and semi thin resin sections of stigmas after glutaraldehyde osmium fixation evidence the lipidic nature of the exudates. Transmission electron microscopy reveals the glandular features of the stigmatic papillae cells, such as abundance of rough and smooth endoplasmic reticulum, polyribosomes, and well developed dictyosomes with secretory vesicles. Pellicle and epicuticular lamellate layers which have been considered as typical features of the dry type stigmas are also present in the species where stigmas appear extremely wet. It is concluded that stigmas in all of the five species are secretory at the receptive stage. Well developed generative and sperm cells were observed in the pollen tubes penetrating through the deep layers of the stigmatic tissue in the reciprocal crosses between P. euphratica and P. simonii, which indicated that there is no significant barrier in the stigma.
研究了胡杨（Ｐｏｐｕｌｕｓ ｅｕｐｈｒａｔｉｃａ Ｏｌｉｖ．）、银白杨（Ｐ． ａｌｂａ Ｌ．）、小叶杨（Ｐ． ｓｉｍ ｏｎｉｉＣａｒｒ．）、大叶杨（Ｐ． ｌａｓｉｏｃａｒｐａ Ｏｌｉｖ．）和欧洲黑杨（Ｐ． ｎｉｇｒａ Ｌ．）的柱头． 扫描电镜显示∶分泌物存在于胞间隙、多细胞乳突的缝隙和接受表面． 用苏丹Ⅲ和金胺Ｏ染新鲜柱头可见分泌物的释放和运动． 戊乙醛－锇酸固定柱头，石蜡和半薄切片显示分泌物的脂类性质． 透射电镜显示柱头表面乳突细胞的腺质特征——丰富的粗糙和光滑内质网、多聚核糖体、发育良好的具分泌泡的高尔基体． 曾被认为是干型柱头典型特征的表膜和上角质膜片层出现于极湿型的柱头中． 观察结果表明，在接受期，５ 个种的柱头都是分泌柱头． 在胡杨和小叶杨正反交中，穿入柱头组织深层的花粉管内有发育良好的生殖细胞和精子细胞。
基金
the NationalNaturalScience Foundation ofChina (NNSFC)
