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Plant Science: Inside the Plant

Up to now we've been looking at the exterior of plants.是时候深入研究一下了。

当你仔细观察一片树叶时,你看到了什么??

平行叶脉拿这片夹竹桃叶,例如。You can see that is is green,but there are also lighter yellow or white areas.中间的灯线叫做midrib.It is the main vein of the leaf for moving water and nutrients in and out.中脉通常也会增加叶片的刚度或结构。

与中脉垂直的是许多较小的静脉。In the oleander leaf they are lined up parallel to each other.最小的静脉形成网状图案。

叶脉百香藤The veins in this passion vine plant are more complex because some come to a V and others are curved.

The leaves of certain plants will have some features not found in all plants.For example,the yellow bumps on the leaves above are specialized glands called nectaries.在这种情况下,它们出现在花的外面,so they are also called"花外蜜腺。”“

oil-glands-citrus-leafThe bright specks in this lemon leaf are glands filled with citrus oils.这些斑点有时被称为pellucid dots"因为当阳光透过树叶照射时,它们就会发光。

其他植物可能有许多毛或毛状体。

叶脉如果我们能靠近树叶,we might see something like this leaf cross section diagram:

Leaf_anatomy(来自的公共域映像Wikimedia)

叶子是由不同类型的细胞组成的。在图的右边是一组xylem(带水)和phloem(carry food) cells labeled as the vascular bundle.Those are the elements of the veins.

标记为“的两种类型的单元格mesophyll,“the栅栏海绵状的,are the cells that contain the chloroplasts and are responsible for the majority of photosynthesis that occurs in the plant.我们将在以后的文章中广泛讨论光合作用。

在底部有一个开口叫做stoma(plural stomata),这就是气体进出树叶的地方。因为开口也会让一些水流失,under certain conditions the cells around the stomata,theguard cells,膨胀并关闭开口。

Plant_cell_structure(广义植物细胞的公共领域图像Wikimedia)

如果我们能深入研究,我们可以看到单个植物细胞的组成。Plant cells have some features in common with those of other organisms,比如核的存在,endoplasmic reticulum,and mitochondria.其他特征只在植物中发现,such as the cell wall made up of cellulose.

看看这个交互式植物细胞模型了解更多.

活动建议1.仔细观察植物

Gather:

  • Fresh plant material (non-allergenic and non-toxic)
  • 解剖显微镜或手镜
  • 适合年龄的切割工具,解剖销

在显微镜或手镜下检查植物材料。Dissect stems and leaves into sections to see structures more clearly.Draw and label what you see.

活动建议2.Make a model plant cell.

利用多种材料制作植物细胞的二维和三维模型已成为中学生的经典科学活动。网上有很多例子。Start at this植物细胞模型试验页for ideas,as well as the diagram above and the interactive website.

活动3:植物用水

We all know we must water our houseplants,草坪,and gardens,但是植物对水有什么作用呢?主要是植物的叶子中含有能利用阳光的化学物质,water,and carbon dioxide to make food in the form of sugars.这叫做光合作用.植物也利用水来运输营养物质,为了增加对其结构的支持,保持凉爽。All that water moves from the roots through the stems to the leaves via the xylem.

Gather:

  • Clear plastic bag big enough to hold a few leaves
  • Twist-tie or chenille
  • Tree or shrub (with leaves close enough to the ground to put a bag over)

On a warm sunny day,把一个透明的塑料袋套在树枝末端的叶子上。用麻绳或雪尼尔把袋子紧紧地系在树枝上,把树叶困在里面,防止空气外泄。十五分钟后去看那棵树,半小时后再来看一次。What is happening inside the bag??

植物蒸腾作用

你应该看到袋子里开始装满冷凝水。Why??

树木在炎热的日子里通过一个被称为蒸腾作用.Much of the water comes out of the stomata.You are capturing the water that is being released.当它接触到塑料时就会凝结。一些数据表明,从植物蒸腾中进入空气的水多于从海洋表面蒸发的水。

Transpiration cools the plant on a hot day and is also involved in helping the plant move water to the chloroplasts.

How to make this activity an experiment:

  • compare the rate of transpiration at different times of the day or at different temperatures (by measuring the amount of water produced in a given time)
  • compare transpiration rates between different trees and shrubs

相关:

迷幻学习集叶解剖活动,包括要贴标签的叶子的横截面图。

第二章

想了解更多信息吗?请在评论中留下问题。


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Plant-Science-Lessons

为了看到我们完整的植物科学课程,或者访问plant science category(最新的职位到最旧的职位)或我们的植物科学部门必威体育 (links to posts in order).

Looking for books about plants for children?Be sure to visit our growing园艺与植物科学书籍目录对孩子们来说,as well as ourlist of children's books about seeds.

更多活动,try ourGardening/Plant Science for Kids Pinterest board.

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