Excretion in Plants
Plants also excrete waste products like animals. But here product excreted is different and many time it is found beneficial for humans and other organisms. For example, oxygen is used up by animals for respiration; medicines like quinine, morphine are used as medicines.
These waste products are the result of various metabolic processes like photosynthesis, respiration, protein metabolism etc. Various excretory wastes are Oxygen, Excess water, tannin, ammonia etc. Plants have developed specific mechanisms for different excretory wastes. They are:
- Stomata: Plants have specialized cells for gaseous exchange and excess water called stomata. Oxygen produced during photosynthesis is dispersed into the air through diffusion and excess water is evaporated by the process called transpiration.
- Dead cells of plants: Plant contains many cells which are dead. Examples are Bark, Heartwood. Heartwood contains old xylem. Old xylem provides structural support to plant and store excretory waste.
- Leaves: Plant shades their leaves regularly. During shading of leaves, useful components like chlorophyll and starch are moved to new leaves, and waste material like resin, tannin, volatile oil are dumped into cell vacuole of these leaves. When the leaves fall, waste product is removed.
- Roots: Some plant store waste materials like oxalate crystals in their root.