Pollen mother cell ( pmc ) in angiosperms and gymnosperms , a somatic cell that gives rise to four haploid pollen grains by meiosis 花粉母细胞（ pmc ） ：指在被子植物和裸子植物中，能通过减数分裂产生4个单倍体花粉粒的体细胞。
Gymnosperms lack endosperm and the precise double fertilization characteristic of the angiosperms , although some show a primitive form of it 尽管裸子植物还保留有某些被子植物的基本形态，但它没有被子植物所特有的胚乳以及双受精现象。
Angiosperms are divided into two major classes , the monocotyledons ( monocotyledonae ) and dicotyledons ( dicotyledonae ) , with a small basal group known as primitive dicotyledons 被子植物可以划分为两个纲，单子叶植物纲和双子叶植物纲。
Funicle ( funiculus ) the stalk attaching the ovule ( later the seed ) to the placenta in angiosperm ovaries . nutrients pass through the funicle to the ovule and seed 珠柄：被子植物子房中连接胚珠（之后的种子）和胎座的柄。营养物质通过珠柄传递到胚珠和种子。
One fuses with the egg cell to form a zygote while the other either degenerates or , in certain angiosperms , fuses with the polar nuclei to give the primary endosperm nucleus 一个与卵细胞结合形成受精卵，另一个要么退化，要么在某些被子植物中与极核结合形成初生胚乳核。
We transferred the hetero - logous gene into toreniafournieri successfully . this method laid a foundation for study of double fertilization of angiosperm by transgenic tecnology 我们将外源基因成功地导入蓝猪耳，为利用转基因的手段研究被子植物受精和胚囊发育打下基础。
He also observed that gymnosperm ovules were not enclosed in an ovary wall , leading to the establishment of one of the basic differences between angiosperms and gymnosperms 他还观察到裸子植物的胚珠并不是被子房壁包围，这个发现直接导致了被子植物和裸子植物之间最根本的几点区别的建立。
These genera and ephedra also hve advanced tracheids with a structure reminiscent of angiosperm vessels , whereas in other gymnosperms the xylem is composed solely of more primitive tracheids 这些属以及麻黄属植物和被子植物一样有进化的管胞，而其他的裸子植物的木质部只由很多导管组成。
Obstacles to progress are : ( 1 ) the double fertilization of most angiosperms occurs internally , deep within ovary tissues , as a result it is very difficult to investigate the truth 这方面的研究之所以比较滞后，一方面是由于大多数被子植物胚囊深藏于子房内，为处理和观察带来很大困难。
Heteranthery exists in several angiosperm families , such as melastomataceae , solanaceae , lytbraceae , leguminosae and pontederiaceae , but the aspects and extent of differentiation often vary in taxa 异型雄蕊在野牡丹科、茄科、千屈菜科、豆科、雨久花科等多个科中都有分布，但其分化与程度常随类群而异。
