NUTRITION IN PLANTS
- In 1648 a Belgian scientist Jan Baptiste Von Helmont conducted an experiment on willow tree.
- Von Helmont arrived at a result that-
- Stephen Hales described the leaves as organs of transpiration.
- According to Priestly, if animals were making air impure, plants were making it pure.
- Ingenhouz explained that green plants exposed to sunlight purify the air.
- The green substance in the leaves is called chlorophyll.
- The main nutrients needed for the plants are nitrogen, phosphorous and potassium.
- Plants are Autotrophic organisms; they prepare their own food.
- Plants prepare their food by photosynthesis.
- The process in which chloroplasts present in green plants using CO, and water in presence of sunlight prepare carbohydrates is called photosynthesis.
- Sunlight
- CO, + H,O Chlorophyll Glucose + Oxygen
- Cuscuta takes food from the plant on which it is climbing; it is a stem parasite.
- Plants exchange gases through leaf pores called stomata.
- Lenticles present in the bark of stem also exchange gases.
- Saprophytes grow on dead decaying matter. Ex : Fungi.
- Leaves of some plants are specially modified to trap insects. These are called insectivorous plants.
- These plants grow in areas deficient in nitrogen.
- Drosera, Utricularia, Venusblytrap, Dionea are examples for insectivorous plants.
- Algae and fungi live together in a symbiotic relationship. Ex : Lichens.
- Preservation of plant parts like leaves, flowers or whole plant is known as Herbarium.