Tema : Climatic Requirements of Plants

Photoperiodism: Response of plant to length daily exposure to the light is known as photoperiodism or relation of the time of flowering formation of tubers, fleshy roots etc. to the daily exposure length of period of light.
The plants are mainly grouped into three according to duration of light required.




1. Long day plant: Those plants which require 16 hours or more of daily exposure of light and short night 8-10 hours of dark period for induction of flowering e.g. radish, cauliflower, cabbage, carrot, spinach.
2. Short day plant: Those plants which require 12 hours or less of daily exposure of light and long night 10 to 14 hours dark period for induction of flowering. e.g. strawberry, potato, sweet potato, chrysanthemum, cosmos, poinsettia etc.
3. Day neutral plants: Day neutral plants are those plants in which flowering are induced irrespective of duration of light. Such plants are also known as photo insensitive plants. e.g. tomato, chilli, okra, carnation, dianthus, African violet.
4. Intermediate plants: Those plants which require definite period of daily exposure of light. e.g. wild kidney bean, Indian grass, broom grass.
Rainfall
This is a very important factor for horticultural crops, and if a garden or orchard is to be established in a new area it is essential that the pattern of rainfall in the region be studied before any decision is taken concerning the types of crop to be cultivated. Well-distributed and consistent rainfall is always desirable for and ideal orchard site. Rain at the time of flowering is not suitable, because most of tropical fruit crops are sensitive to rain.
5 Wind
The effect of high wind on crops can be appreciable. Complete physical destruction may result because little can stand against winds of the order of 100 km/hour, even large trees become uprooted. Some crops have quite low damage even due to high wind speed. In many regions high winds can destroy the