云南油杉受精过程中新细胞质及蛋白泡的动态观察

云南油杉(Keteleeria evelyniana Mast)在受精前,精核与卵核周围的细胞质鞘不明显。受精后,合子核周围出现细密的新细胞质。应用孚尔根核染色法,可以较清晰地将新细胞质染出,呈现较弱的正反应,而合子的核质及受精前的精核与卵核染色极弱。卵细胞质及其中的蛋白泡均为负反应。原胚形成后,除上层外,其余几层细胞质内开始积累淀粉粒。此时胚原细胞核的孚尔根染色深度有所增加。幼胚形成后,在顶端的胚原细胞群中核的孚尔根染色反应已恢复正常。在原胚及幼胚胚原细胞质中也呈现很弱的正反应。在电镜下,胚原层细胞质及新细胞质中均含有核样电子致密小体或称作染色质小体,而原胚莲座层细胞质及四周套细胞质中的线粒体则不含这种核样小体。因此,大蛋白泡在卵核形成的早期数量不多,当合子形成时含量最高,而随着游离核的分裂进程,蛋白泡以及原卵质均逐渐地解体,在原胚形成后全部消解。

OBSERVATIONS ON THE NEOCYTOPLASM AND PROTEID VACUOLES DURING THE FERTILIZATION OF KETELEERIA EVELYNIANA

Distributions and dynamics of the neocytoplasm and proteid vacuoles during the fertilization of Keteleeria evelyniana were studied by histochemical meth- ods.Before fertilization cytoplasmic sheath surrounding the male and female gametes was indistinct.After fertilization,the dense neocytoplasm appeared around the zy- gote.Part of the neocytoplasm is invaded by mitochondria of maternal origin which had collected in large numbers in the perinuclear zone.The mitochondria contain ele- ctron compact little body which looks like a nucleus in the cytoplasm,but not observed in the rosette tier cell of proembryo and jacket cells.Hence,it was showed that the ncocytoplasm participated in the development of embryo by all these observations.By using Feulgen reaction,the staining reaction of neocytoplasm was positive,the egg nucleus or zygote nucleus was weaker in positive reaction,while the proteid vacuoles were negative.When the proembryo developed,there were a few starch grains accu- mulated in the other three tiers except the upper tier.The Feulgen reaction was in- creased in intensity in the suspensor tier and embryonal cell tier nuclei.When the young embryo developed,Feulgen reaction became normal in the nuclei of the embryo initials.The embryo initials and suspensor cells showed very weak Feulgen positive reaction in the proembryo and young embryo.The development of the large proteid vacuoles was from plastid.During the early stage of egg nucleus,contents of large proteid vacuoles were less.When the zygote was formed,they reached the highest. However,after the zygote produced,the proteid vacuoles and egg cytoplasm were gett- ing disintegrated following the course of fission of free nuclei.After the proembryo formed,the proteid vacuoles were wholly disintegrated.