Tema : Climatic Requirements of Plants

Tema : Climatic Requirements of Plants

Climate is the principal factor controlling plant growth. It refers to the average condition of the atmosphere over along period, where as the term weather is used to describe the current and temporary atmospheric conditions. For successful growing of horticultural plants, various components of climate like temperature, humidity, wind, light, rainfall, hail and frost should be carefully studied.

Man can not control these environmental factors. It is not possible to make any change in it. But the effect of these factors can be altered. For these we can take certain steps to increase or decrease its effects. i.e. effect of high or low temperature can be altered, additional moisture can be given, high wind velocity can be reduced by growing wind break around the orchard.
Climate of a region is mainly influenced by the factors viz. a) latitude b) altitude c) topography d) position related to continents and oceans e) large scale atmospheric circulation patters.
Almost all components of the climate influence horticultural crops. All are closely interrelated. The effect of each is modified by others. All crops have certain natural threshold limits of the climatic components beyond which they do not grow normally, but breeding and selection are gradually extending the threshold for many crops.
Following is a brief account on important climatic components which are affecting the production of horticultural crops.





Temperature
Temperature is one of the most important components of climate. It plays vital role in the production of horticultural crops. The different activities of plant like growth and development, respiration, photosynthesis, transpiration, uptake of nutrients and water and reproduction (Such as pollen viability, blossom fertilization fruit set etc.), carbohydrate and growth regulators balance, rate of maturation and senescence, and quality, yield and shelf life of the edible products. The above function of the plant should be well when the temperature at the optimum range. During high temperature plant does not perform proper functions of growth, where in low temperature physiological activities of the plant are stopped.
According to different temperature range in the tropics, the specific trees are grown in different location e.g. apple, pear, peach, almond are successfully grown in the regions of low temperature known as temperate fruits. In warm winter areas, due to insufficient chilling temperature fruit trees fail to complete their physiological rest period or meeting their chilling requirement. As a consequence, buds remain dormant, and leave and blossoms do not appear on the trees in the following spring. For this reason temperate fruit like apple, apricot, pear and plums are not considered suitable for tropical or subtropical regions. For tropical and sub tropical fruits the minimum temperature must be within the limit of tolerance of the fruit species. The fruit grown in tropical and sub tropical climate is known as tropical fruit and sub tropical fruits. Mango, chiku, papaya, banana are successfully grown in high temperature regions also known as tropical fruits.
The plant performs well in optimum temperature range. The activities of the plant are affected by very high or very low temperature. The temperature range for plant is
Minimum 4.5° to 6.5° C (40° - 43° F)
Optimum 24° to 27° C (75° - 85° F)
Maximum 29.5° to 45.4° C (85° - 114° F)