Section outline

  • Mosses and ferns in a forest, showcasing non-flowering plants reproducing via spores.

    Do all plants have flowers ?
    ::所有的植物都有花吗?

    No, plants do not all have flowers. For example, the mosses and ferns pictured here are both types of plants. However, they never produce flowers. They don't produce seeds , either. They do, however, make tiny spores to reproduce.
    ::不,植物并不都有花。例如,这里所描绘的苔稼和幼苗都是两种植物。然而,它们从不生产花朵,也不生产种子。它们的确制造小颗粒来繁殖。

    Plant Reproduction and Life Cycle
    ::植物生殖和生命周期

    The life cycle of a plant is very different from the life cycle of an animal . Humans are made entirely of diploid cells (cells with two sets of chromosomes , referred to as ''2n''). Our only cells that are haploid cells (cells with one set of chromosomes, ''n'') are and egg cells. Plants, however, can live when they are at the stage of having haploid cells or diploid cells. If a plant has a haploid chromosome number of 20, what is the diploid chromosome number? If the diploid chromosome number is 20, what is the haploid number?
    ::植物的生命周期与动物的生命周期大不相同。 人类完全由浸泡细胞组成( 两组染色体的细胞,称为“ 2n ” ) 。 我们唯一的细胞是杂交细胞( 一组染色体的细胞, “ n ” ) 和蛋细胞。 但是, 当植物处于有杂交细胞或浸泡细胞的阶段时, 植物可以活下来。 如果植物有20个杂交染色体, 什么是染色体数? 如果染色体的染色体数是20个, 什么是杂交细胞数? 如果染色体的染色体数是20个, 杂交细胞数是多少?

    Plants alternate between diploid-cell plants and haploid-cell plants. This is called alternation of generations , because the plant type alternates from generation to generation. In alternation of generations, the plant alternates between a sporophyte that has diploid cells and a gametophyte that has haploid cells. 
    ::植物在浸泡细胞植物和薄荷细胞植物之间交替生长。这被称为代代相传,因为植物类型代代相传。 在代代相传的交替中,植物在含有浸泡细胞的花生植物和含有薄荷细胞的花生植物之间交替生长。

    Alternation of generations can be summarized in the following four steps: follow along in the Figure as you read through the steps.
    ::代代相传可归纳为以下四个步骤:从各个步骤看,在图中依次可见。

    1. The haploid gametophyte produces the gametes , or sperm and egg, by . Remember, gametes are haploid, having one set of chromosomes.
      ::手动游戏植物产生调子, 或精子和蛋, by 。 记住, 调子是杂交, 有一套染色体 。
    2. Then, the sperm fertilizes the egg, producing a diploid zygote that develops into the sporophyte, which of course, is diploid.
      ::然后,精子使蛋受精, 产生一种低脂的zygote 发展成, 当然,它就是低脂的。
    3. The diploid sporophyte produces haploid spores by .
      ::
    4. The haploid spores go through mitosis, developing into the haploid gametophyte.
      ::胡椒颗粒经过了分裂, 发展成杂草的游戏植物。

    As we will see in additional Plants concepts, the generation in which the plant spends most of its life cycle is different between various plants. In the plants that first evolved, the gametophyte takes up the majority of the life cycle of the plant. During the course of evolution, the sporophyte became the major stage of the life cycle of the plant.
    ::正如我们从更多的植物概念中可以看到的那样,植物大部分寿命周期的一代是不同的。 在最初进化的植物中,植物植物占了植物生命周期的大部分。在进化过程中,脊椎植物成为植物生命周期的主要阶段。

    Alternation of generations in ferns, showing diploid and haploid stages.

    In ferns, the sporophyte is dominant and produces spores that germinate into a heart-shaped gametophyte.
    ::在胎儿体内,脊髓灰质素占主导地位,并产生发芽成心形草药的螺旋。

    Summary
    ::摘要

    • Plants undergo alternation of generations, meaning they alternate between diploid-cell plants and haploid-cell plants.
      ::植物代代相传,意思是它们交替在底栖细胞植物和杂栖细胞植物之间。
    • During the course of evolution, the sporophyte (diploid) became the major stage of the life cycle of the plant.
      ::在演化过程中,脊椎植物成为植物生命周期的主要阶段。

    Explore More
    ::探索更多

    Use the resource below to answer the questions that follow.
    ::利用以下资源回答以下问题。

    • Plant Reproduction at (2:23)
      :sad2:23) 植物繁殖时间(2:23)
    1. When does meiosis occur during a plant's life cycle?
      ::植物的生命周期中什么时候会发生肾上腺素中毒?
    2. When does mitosis occur during a plant's life cycle?
      ::植物寿命周期内何时会发生分裂症?
    3. How do gametophytes with both male and female parts avoid self-fertilization?
      ::男女部分的博生植物如何避免自我受孕?
    4. Describe the fertilization process for an Angiosperm.
      ::描述血管的授精过程。

    Review
    ::回顾

    1. What is the difference between a haploid and diploid cell?
      ::杂交细胞和低潮细胞有什么区别?
    2. What does "alternation of generations" mean?
      ::"代代相传"是什么意思?
    3. What part of the plant life cycle is made of haploid cells, the sporophyte or the gametophyte?
      ::植物生命周期的哪一部分 是由杂交细胞、或草药构成的?
    4. What process is used by the sporophyte to produce spores?
      ::脊髓灰质素用什么过程来生产颗粒?