plants - one of the five kingdoms of living organisms on our planet.They belong to the eukaryotes, ie beings whose cells contain a nucleus.
structure of plants
They can be unicellular or multicellular.The latter are divided into sections such as green, brown and red algae, spore, gymnosperms and angiosperms.Organism algae may consist of a single cell as well as from many, but absent in their structure bodies solid body - called thallus.In spore, gymnosperms and angiosperms (flowering plants) observed the presence of differentiated tissues and organs.Recent divided into vegetative and generative.The former is an escape (stem and leaves) and root.Many people wonder, "Why are leaves green?" Why this color?Also, many children ask the question: "Why do the leaves green?" And this article we start with this topic.
Why are leaves green?
This color is due to the presence of chlorophyll.In the autumn of this pigment is lost, and green leaf turns red, orange or yellow.Why do you need this stuff?It is simply vital for plants.Without it can not proceed the process of photosynthesis by which nutrients are produced.Organic chemical plants typically obtained only by this process.However, some species that live in the lower layers of the rainforest, do not get enough light for photosynthesis full, so resorted to hunting small insects, thus compensating for the lack of organic compounds.These include the sundew, lady's slipper, and so on. D.
briefly about the structure of the plant cell
It consists of a plasma membrane of the cell wall of cellulose, the cytoplasm, which contains the organelles and the nucleus that contains the DNA.The cytoplasm contains such organelles: the mitochondria, ribosomes, the endoplasmic reticulum, the vacuole (the old cage - one large, in the young - a few small), Golgi apparatus and plastids (chloroplasts, leucoplasts, chromoplasts).Each of them performs its function.Mitochondria produce energy, ribosomes synthesize proteins, endoplasmic reticulum (reticulum) produces lipid vacuoles accumulate unnecessary material as to bring them out because of the hard cell wall is not possible, the chloroplasts of the process of photosynthesis, chromoplasts contain pigments, leucoplasts store spare nutrients (basically, this starch).
How is photosynthesis?
This process is carried out in the chloroplasts, which are located in the cytoplasm.These organelles are odnomembrannymi in their structure consists of thylakoids - thin plate, collected in the granite - stack.It is in them, and contains chlorophyll - which is why leaves are green.Furthermore, chloroplasts contain ribosome participating in protein production, corn starch, and the circular DNA molecule, in which information is recorded on the substances to be synthesized in the cell.In the process of photosynthesis, plants absorb solar energy, water and carbon dioxide and give off oxygen as a by-product reactions.The enzymes that help carry out chemical reactions, are located directly in the matrix of the chloroplast (a substance that fills it).
What leaves consist?
This body can detect several types of plant tissue, they are four.This epidermis, mesophyll, conducting tissue (xylem and phloem), and mechanical tissue.Photosynthesis occurs precisely in the mesophyll, or parenchyma.One can see the green leaf cells under a microscope.This upper ball - the epidermis.The cells are located its close to each other, but in this layer are pores that allow to absorb carbon dioxide and release oxygen, and adjust the temperature and water balance.Parenchyma (mesophyll) is divided into two layers - one of the columnar cells, the other - from the sponge.The first contains a large number of chloroplasts than in the second.Xylem vessels is presented in which the liquid is supplied from the roots to the leaves, that is, up and phloem consists of sitopodobnyh tubes through which water is transported down.Mechanical same fabric sheet provides rigidity and stability, particular shape.