短命植物异喙菊胚胎学研究

STUDIES ON EMBRYOLOGY OF EPHEMERAL PLANT HETERACIAL SZOVITSII FISCH. ET MEY

短命植物异喙菊,直生胚珠,双珠被,薄珠心,合点受精,合点端有帽状珠孔塞,合点端胚胎基部有短柱状装饰物,孢原细胞1个,直接发育成大孢子母细胞,经减数分裂,形成大孢子四分体,合点端大孢子发育成功能大孢子,其他三个退化.合点端、胚囊中都有不定胚发生.

Heteracia Szovitsii Fisch et Mey-Ephemeral Plant with orthotropous, two integuments and tenuinuccellate ovule belongs to chalazogamy. The chalazal has obeturator which looks like a cap. There is a poslament at bottom of the chalazal end embryofenesis. An archesporial cell can grow into sporemother cell directaly. Through meiosis of thesporemother cell, 4 megaspore mecrosporetetrads are formed. Chalazal and megaspore mecrospore, one of the above, grows into functional megaspore mecrosporem, and the other three degenerate. There are adventitious embryos. In embryo sac of chalazal.