PLANT MORPHOLOGY AND PHYSIOLOGY:
Plants capture solar energy and convert it into food substances for their own use and for the use of animal through photosynthesis. The physiological process by which plants grow and morphological changes that take place during growth are pre-requisite for range mgt. the survival of the plant depends upon:
- Its ability to manufacture and store food for plant’s functioning
- From vegetative structure for the renewal of top growth.
- Maintain a healthy root system
- Produce reproductive organs
Food synthesis takes place in green parts where chlorophyll bearing cells in the presence of sunlight, combine the carbon from air obtained through stomata with water mineral nutrients obtained from the soil to form carbohydrates.
Important factors for photosynthesis:
Photosynthesis is a process in which light energy is converted to chemical energy to produce organic compounds.
In plants, photosynthesis occurs within the chloroplasts, consists of two stages, the light reactions and the dark reactions which are utilized in carbon fixation. The light reactions convert light into energy (ATP and NADPH) and the dark reactions use the energy and carbon dioxide to produce sugar which is utilized for the proper functioning of the plant processes.
The formation of photosynthesis is cited by the following seven factors:
- The physiological efficiency of the plant
- Amount of CO2 in the air and freedom with which it enters the leaves through stomata.
- Leaf surface area.
- Intensity and quantity of light
- Water supply (Soil moisture)
- Soil nutrients
Most important of these are leaf area and water, as water is necessary chemical constituent for the reaction. It keeps the plant turgid and stomata, opened and functioned thus to ensure carbon dioxide entry in the leaves. It carries mineral nutrients taken by the roots from the soil. Leaf area exposed determines the rate of food manufacture eg the average rate of photosynthesis is b/w 0.8 – 1.8 gm of sugar for each square meter of leaves per hour depending upon the spp.
Food storage takes place in the roots and stem bases of perennial herbaceous pants; in the stem, branches and roots of woody plants and in the seed on annual plants. The food reserves are used for respiration during dormancy, re-growth following winter or drought dormancy and reproduction. It is essential that range plants be allowed to manufacture and store sufficient food during the period of active growth to fulfill these needs.
Stages of Photosynthesis:
For details please check out the Photosynthesis Topic.