油橄榄授粉受精和胚胎发育过程观察

该研究以油橄榄“鄂植-8”为材料,应用压片荧光观察花粉在柱头和花柱中的萌发及生长情况,采用石蜡制片法观察油橄榄的胚珠结构特点和授粉受精过程。结果表明：油橄榄为1子房2心室4胚珠,珠心较发达,由多层细胞构成,属于厚珠心椭圆型胚珠,胚珠直生；花开时花粉粒落到柱头上立刻萌发,随后花粉管在花粉通道中生长,再后进入子房经子房内表面,大部分花粉管不能到达胚珠,仅少数沿胎座生长经珠柄进入珠孔,释放2个精子,2个精核分别进入卵细胞和极核,并与卵核及极核相互融合；观察到合子中雌、雄性核仁融合的过程。授粉受精各阶段经历的时间为花粉落到柱头上立刻萌发；授粉后6d左右,花粉管长入胚珠的珠孔,随后释放精子；10 d左右完成授粉受精,30 d左右形成心型胚,40 d左右胚发育几乎成熟。在进行子房石蜡切片中,共观察到612个完整子房切片,发育完整的子房为97.53％,完成授粉受精的胚珠为15.52％。油橄榄在自然授粉下,约85％的胚珠授粉受精过程不能完成,在一定程度上影响其坐果。该研究结果为油橄榄授粉受精、高效生产等提供了理论依据。

Observation on pollination, fertilization and embryo development process in Olea europaea

The present research was undertaken to better understand the reason of the low fruit setting and gather the basic knowledge of reproductive biology of Olea europaea, the structural characteristics of ovules, pollination and fertili-zation process of ovules to master the various stages of time and the completed percentage of ovary pollination and fertili-zation. Fluorescence microscopy was used to observe pollen tube growth, and the paraffin slice technique was used to ob-serve the ovary pollination and fertilization in olive of‘EZhi-8’ . The results showed that the‘EZhi-8’ is one ovary two ovules four ventricles with developed nucellus, orthotropous and crassinucellate ovule. Pollen grains germinated immedi-ately when they were fallen on stigma, then pollen tubes grew in the transmitting tissue of style, entering ovary and grow-ing on the surface of endocuticle of ovary wall, and passing micropore through placenta and funicle. Pollen tube was re-leased two sperms, one entered egg and another in the secondary nucleus, which was a fusion process of male and female. The performance time of pollination and fertilization was as follows:pollen grains germinated very soon on stig-ma, and the pollen tube grew into the ovule micropyle and released sperm for 60 d after flowering. After flowering, with-in 10 d fertilization was finished , 30 d developed omphalos-embryo and within 40 d maturation occurred. A tatol of 612 ovary slices were observed by treating with a series of paraffin treatments, the highly developed ovaries of‘EZhi-8’ ac-counted for 97.53%, the finishment of pollination and fertilization process of ovules accounted for 15.52%. Our results showed that there were about 85% of ovules were not fertilized in the natural conditions, which affected the fruit setting to a certain extent.