章节大纲

  • Young plants growing towards a light source, illustrating the concept of phototropism.

    Why are these plants turning sideways?
    ::为什么这些植物会转弯?

    Plants respond to their environment in how they grow. In this picture, the light source is probably off to the left side. As a result, the plants grow in this direction to get more light.
    ::植物在生长方式上对环境作出反应。在这个图中,光源可能向左偏移。结果,植物朝这个方向生长,以获得更多的光。

    Tropisms
    ::花原主义

    Plants may not be able to move to another location, but they are able to change how they grow in response to their environment. Growth toward or away from a stimulus is known as a tropism ( Table ). , a class of plant , allow plants to curve in specific directions as they grow. The auxin moves to one side of the , where it starts a chain of events that cause rapid growth on just that one side of the stem. With one side of the stem growing faster than the other, the plant begins to bend.
    ::植物可能无法迁移到另一个地方,但是它们能够改变它们如何因环境而成长的方式。 刺激的向向或向外增长被称为三对立方(表 ) 。 一种植物的种类,允许植物在生长时向特定方向曲线。 助产剂移到另一侧,它引发一系列事件,导致仅一端的干茎快速增长。随着干茎的一面比另一边的生长速度加快,植物开始弯曲。

    Name Stimulus
    Phototropism Light
    Gravitropism Gravity
    Thigmotropism Touch

    Phototropism
    ::光花主义

    You might have noticed that plants bend toward the light. This is an example of a tropism where light is the stimulus, known as phototropism ( Figure ). To obtain more light for , leaves and stems grow toward the light. On the other hand, grow away from light. This is beneficial for the roots, because they need to obtain and nutrients from deep within the ground.
    ::植物可能注意到植物向光向倾斜。 这是光是刺激的三对立体的例子, 光是光( 图表 ) 。 为了获得更多的光, 树叶和根向光生长。 另一方面, 从光上长出来。 这对根部有利, 因为它们需要从地下深处获取营养。

    Seedlings bending toward light, demonstrating phototropism in response to sunlight.

    These seedlings bending toward the sun are displaying phototropism.
    ::这些向太阳倾斜的幼苗 展示了光作物主义

    Gravitropism
    ::重力生物

    So, how do the roots of seeds underground know to grow downward? How do the roots deep in the soil know which way is up? Gravitropism is a growth toward or away from the pull of gravity ( Figure ). Shoots , the new growth of a plant, also show a gravitropism, but in the opposite direction. If you place a plant on its side, the stem and new leaves will curve upward.
    ::那么,地下种子的根子怎么会知道向下生长呢?土壤深处的根子怎么会知道哪里是上升的?重力是走向或远离引力的增殖(图 ) 。 射杀,植物的新生长也显示出重力,但方向相反。如果你把植物放在树的侧面,干叶和新叶就会向上移动。

    A seedling emerging from soil, demonstrating upward growth against gravity's pull.

    This shoot is exhibiting gravitropism: it is growing against the pull of gravity.
    ::这张照片展示了重力人类主义: 与重力的拉力形成对比。

    Thigmotropism
    ::蒂格莫作物主义

    Plants also have a touch response called thigmotropism . If you have ever seen a morning glory or the tendrils of a pea plant twist around a pole, then you know that plants must be able to sense the pole. Thigmotropism works much like the other tropisms. The plant grows straight until it comes in contact with the pole. Then, the side of the stem that is in contact with the pole grows slower than the opposite side of the stem. This causes the stem to bend around the pole.
    ::植物也有一种触摸反应,叫作硫磷。如果你曾经见过一个早晨的光荣或一个铁杆周围的豆子植物的旋律,那么你知道植物必须能够感知到杆子。Thigmotrophicism 和其他对流体一样运作。植物长得直,直到它与极接触。然后,与极接触的干茎的侧比柱子的对面慢。这导致柱子的干茎弯曲。

    Summary
    ::摘要

    • Tropisms are growth toward or away from a stimulus.
      ::人本主义是向或向向刺激增长或向向刺激增长。
    • Types of tropisms include gravitropism (gravity), phototropism (light), and thigmotropism (touch).
      ::高血压类型包括重力作物(重力)、光作作物(光学)和高血压作物(触摸)。

    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。

    • Phototropism and Auxin at (2:13)
      ::光生物和Auxin(2:13)
    1. Explain how scientists determined that the signal for phototropism was occurring in the growing tip of a plant?
      ::科学家们如何确定 植物生长端 正在发生光生物学信号?
    2. Explain how scientists determined the signal for phototropism migrated up and down a plant shoot but did not move across the plant shoot?
      ::科学家如何确定光作物主义的信号 向上和向下移动 植物拍摄,但没有移动 通过植物拍摄?
    3. How did an agar block help scientists determine that some substance moving through the plant was responsible for the phototropic response?
      ::一个圆块如何帮助科学家确定通过该厂的某种物质是光热带反应的责任?
    4. What hormone causes the phototropic response to light?
      ::是什么荷尔蒙导致光对光的光反应?

    Review
    ::回顾

    1. What is a tropism?
      ::什么是对立体?
    2. If you tip a plant on its side, what will happen? Why?
      ::如果你把一棵植物倒在树边,那会怎样?
    3. The tendril of a bean meets a metal pole. What will happen to the tendril? Why?
      ::豆子的弯曲会碰到金属杆 旋律会怎样?
    4. Why do leaves and stems grow towards light?
      ::为什么树叶和树枝会长成光芒呢?