花粉和花蜜
花是高度特化的生殖枝。一朵典型的花在茎上有4个轮,一个接一个。茎可以长也可以短。两个较低的轮不直接参与繁殖。因此,它们被称为副轮。上面两个轮直接参与繁殖。因此,它们被称为生殖轮。生殖轮由小孢子叶和大孢子叶组成。小孢子叶被称为雄蕊,大孢子叶被称为心皮。有些花在同一花上既有雄蕊又有心皮,有些花既有心皮又有雄蕊。 Third whorl is known as the androecium, which is the male whorl. Fourth whorl is known as the gynoecium, which is the female part of the flower. Reproductive structures give rise to megaspores and microspores or pollens. A main way to disperse microspores or pollens is by insects. In order to attract insects, nectar is very useful.
花粉
雄性孢子被称为小孢子。小孢子也被称为花粉粒。在开花植物中,花粉囊或小孢子囊内可发现小孢子。小孢子是非常小的、微小的结构。它们几乎就像尘埃颗粒。每个小孢子有一个细胞和两层表皮。最外层的被毛是外壁,内层的被毛是内壁。外壁是一种坚硬的角质层。通常它含有棘状突起。有时也会很顺利。 The intine is smooth, and it is very thin. It is mainly made up of cellulose. The extine contains one or more thin places known as the germ pores through which the intine grows out to form the pollen tube. The pollen tube elongates through the gynoecium tissues carrying two male gametes in it. Pollen tube grows down and enters the ovule through the micropyle. Then the apex of the pollen tube degrades and the two male nuclei are released in to the ovule. The double fertilization takes place by the fusion of the one male nucleus with the egg cell nucleus, giving rise to the diploid zygote and fusion of the other male nucleus with the diploid secondary nucleus, giving rise to the triploid primary endosperm nucleus.
花蜜
花蜜是一种被称为花油桃的特殊腺体或器官分泌出来的有用物质。油桃生长在花和营养部位。花油桃可以在花的不同位置找到。花蜜的分泌组织位于表皮。秘书细胞具有非常密集的细胞质。它们可能是像栅栏细胞一样的细长细胞。花蜜被一层角质层覆盖。维管组织与油桃密切相关。油桃的糖来自韧皮部。花蜜可以通过细胞壁和破裂的角质层排出,有时也可以通过气孔排出。
花粉和花蜜有什么区别? •花粉是单倍体细胞,而花蜜只是细胞分泌的。 •花粉参与有性繁殖,花蜜不参与有性繁殖。 花粉由小孢子母细胞形成,花蜜由蜜腺内的分泌组织分泌。 |
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