[Photo credit: Estreya]
Plant wastes products include water, carbon dioxide oxygen, acids, resins, mucilage, latex, alkaloids, crystals of salts, oils, gum and anthocyanin.
But the main waste products are water, carbod dioxide and water. The main excretory organs of flower plants are the:
- stomata in the leaves, and
- lenticles in the stem.
The excretory products and how they are excreted are:
(i) Carbon dioxide: Carbon dioxide is excreted by diffusion through the stomata or lenticles.
(ii) Oxygen: Oxygen produced during photosynthesis is also removed or eliminated by diffusion through the stomata or lenticles.
Carbon dioxide and oxygen diffuse through the intercellular spaces in the tissues and pass through the stomata in leaves and young stems to the exterior. In old stems, gases escape through lenticles. In roots, gases pass out through the general root surface.
(iii) Water: Water is excreted in plants by diffusing out of the stomata or lenticles. It is also excreted by the process of transpiration. It is also excreted as water vapor by the process of transpiration. In certain plants like tomato and potato, droplets of water resembling dew-drops often form at the tips and margins of leaves. They enlarge and eventually drop off, a process known as guttation.
Water is lost continuously from all parts of a plant above the soil. Therefore, the water absorbed by the roots must be enough:
- for the plant's needs; and
- to make up for the water lost through transpiration.
This water must be balanced. Plants living in a desert face dehydration and must develop some mechanisms to slow down or prevent water loss by transpiration.
(iv) Latex: Latex is stored in tube-like system in tissues and kept harmless until they ooze out of the plant when thje part of it is damaged.
(v) Other waste products: Some waste products like tannins, mucilage, gum, crystals, alkaloids and anthocyanin are converted into insoluble compounds and deposited in dead tissues like the bark of trees, leaves and petals, which are shed periodically. Some of the stored products are of commercial importance, while others are poisonous. Such products are normally removed during leaf-fall.
Read also: EXCRETORY SYSTEM OF MAMMALS: Structure and Mechanism of Excretion of the Kidney and Urinary Tubule
Plant Oils That Are Commercially Important
Oil
|
Source
|
Cinnamon
|
Bark of cinnamon
|
Eucalyptus
|
Leaves of eucalyptus tree
|
Turpentine
|
Resin of pine tree
|
Camphor
|
Wood and leaves of camphor tree
|
Common Alkaloids
Alkaloids
|
Action
|
Source
|
Morphine
|
Anesthetic(Anaesthetic)
|
Young fruits of opium poppy plants
|
Quinine
|
Anti-malaria
|
Bark of cinchona tree
|
Cocaine
|
Narcotic
|
Leaves of coca shrub
|
0 comments:
Post a Comment