浮动弯角藻有性生殖和生殖生态

Sexual Reproduction and its Ecology in Eucampia zoodiacus Ehr.

在浮动弯角藻卵配生殖中发现两种特殊的形态发生;糖原孢囊里形成一个长椭圆形薄膜和原初细胞由复大孢子变形产生。在有性细胞大小范内常发生分段生殖和由此产生两次细胞复大现象。在低温(12℃)低光(1000 1x)和22.5‰盐度条件下,该藻呈最适的性化效应。

Morphogenetic process of oogamous reproduction are described in Eucampia zood-iacus Ehr.. Within the spermatogonangium, the contractive protoplasm is enclosed by a thin elongate-elliptical membrane . Small naked sp-irmatogonia are produced in the membrane which will disappear during the meiotic prophase of spermatocytes , In the spermatogonangia each give 64 or 128 uniflagel-late sperms. Each of oogonium contains only an egg. After fertilization, the zygotc swells considerably , and develops an auxosporc in big spheroid. The initial cell is not developed inside the auxospore membrane and is formed by deformation of whole auxospore without any abandoned residual membranes.The cell size of sexual phase gives between 10 and 31 urn in widths,in most cases in both size ranges of 10-17 um 23-31 μm, so that the auxospores and initial cells of two size ranges are frequently observed in a same cultured material.The different effects of temperature, light intensity and salinity on sexualization are observed in E. zoodiacus. Low temperature(12℃) and light intensityd 000 1x)were found to be optimal for male formation, and the sexualization will be reduced correspondingly with increasing temperature and light intensity. More male cells have been produced under the condition with photoperiod of 12 hours daily. A strong sexual reaction appear in 22. 5‰ salinity.