Effects of temperature on plants health

how plant's growth effected by the temperature. how temperature increase and decrease the plant. how temperature control the plant growth

1. Effects of Temperature on Plants Health

2. TEMPERATUR . The degree of hotness and coldness is called Temperature.It is a means of determining the internal energy contained within a given system. It can be measured with a thermometer . Temperature Scales. Several temperature scales exist. In the United States, the Fahrenheit temperature is most commonly used, though the International System of Units (SI unit) Centigrade (or Celsius) is used in most of the rest of the world. The Kelvin scale is used often in physics

3. Temperature is an ecological factor Temperature is one of the most important ecological factor. It regulates the many physiological processes of plants The metabolic processes are low at minimum temperature. It increases at particular temperature called as Optimum temperature . The plant grows best at optimum temperature . Metabolism again decreases at maximum temperature .the plants cannot survive above this temperature . Both low and high temperature have adverse effects on plants .

4. Warm season plant. Plants that need to warm weather to germinate and actively grow.sometime they also need long day to really get going. They will die when Forest comes . .Example ( beans, tomatoes, lemons) (peaches sweet Cherry s)

5. Cool season plants Cool season crop’s are plants that had adopted to cool climate . Most cool season çrops prefer Temperature 70 . When Temperature start to climb Over they tend to produce seed stalk . Example ( Cabbage, pears , Apples )

6. When High Temperature Above optimum . can kill the plant . can reduce the yield Increase transpiration. Increase evaporation. wind burn seeds and fruits.

7. When Temperature low Blew the Optimum Lower the rate of Photosynthesis and respiration Reduce yield Reduce germination rate Can kill the plants

8. High Temperature Injury. Toxin Injury Anaerobic respiration produces different compounds causing toxicity to plant . . Biochemical lesion Break down of essential compounds like vitamins . Low Temperature Injury. . Frost : This is caused due to sublimation of ice crystals on objects like tree branches .The temperature above 50°C may kill many annual crops

9. Influence of temperature on Crops Temperature is the most important dominating factor influencing the suitability of a crop to a particular region. The yield potential of the crop mainly depends on temperature. More than 50 per cent of variation of crops is determined by climate. The most important climatic factors that influence growth development and yield of crops are solar radiation , temperature and rainfall.

10. Effect of Temperature on Plant Growth Temperature and crop production 1. Important for growth and development 2.Optimum temperature is required for maximum dry matter accumulation. 3. High night temperature _growth of shoot

11. Cardinal temperature points All plants have maximum, optimum and minimum temperature limits. The limits are cardinal temperature points . Optimum temperature range is very important

12. 1) Low temperature: Low temperature affects several aspects of crop growth viz., survival, cell division, photosynthesis, water transport, growth and finally yield Chilling injury If the plants grown in hot temperature are exposed to low temperature, they will be killed (or) severely injured. When the night temperature is below 15°C field crops may show yellowing symptoms ( eg ) Tropical annuals

13. Freezing injury When the plants are exposed to how temperature, water freezes into ice crystals in the intercellular spaces. eg ) Cell dehydration Temperate crops (potato, tea etc.,) Suffocation Formation of thick cover of ice/snow on the soil surface presents the entry of oxygen and crop suffers. This presents the respiration and lead to accumulation of harmful substances.

14. Heaving Lifting of plants along with soil from its actual position by ice, crystals. This is a mechanical lifting

15. Frost damage Low temperature near the canopy due to earth’s re radiation. If the cell size is large the probability of frost damage is high 1) Advective frosts : Advective frosts are due to incursion of large masses of cold air over a region from the colder areas. (2) Radiation frost : Occur on clear calm nights when heat is freely radiated from all exposed objects. 1 Hoar frost (or) white frost : This is caused due to sublimation of ice crystals on objects like tree branches. 2 Black frost : The vegetation is frozen because of reduction of air temperature.

16. Plant management against frost damage: 1. Frost free growing season 2. Adjusting the sowing time 3. Selection of resistant varieties 4. Sprinkler irrigation

17. HIGH TEMPERATURE INJURIES High temperature adversely affects mineral nutrition, shoot growth and pollen development resulting in low yield. 1. The critical temperature above which plants gets killed is called thermal ‘death point’. 2.The temperature above 50°C may kill many annual crops. 3. The limit varies with plants; shade loving plants are killed at lower temperature.

18. Mineral Nutrition 1.High temperature stress causes reduction in absorption and subsequent assimilation of nutrients. 2.Absorption of calcium is reduced at temperature of 28º C in Maize. 3.Nutrient uptake is affected by both soil and air temperature in rice. 4.Nitrate reductase activity decrease under high temperature

19. Shoot growth 1. High temperature, even for short period, affects crop growth especially in temperate crops like wheat. 2. High air temperature reduces the growth of shoots and in turn reduces root growth. 3. High soil temperature is more crucial as damage to the roots is severe resulting in substantial reduction in shoot growth. 4. High temperature at 38º C in rice reduced plant height, root elongation and smaller roots.

20. Pollen development 1. High temperature during booting stage results in pollen abortion. 2. In wheat, temperature higher than 27º C caused under development of anthers and loss of viability of pollen. 3.A temperature of 30º C for two days at reduction division stage decreased grain yield by drastic reduction in grain set.

21. Scorching: High temperature lead to dehydration and leaves are scorched. Physiological activities: High temperature disturbs the photosynthesis and respiration. Injury due to scorching sun: High temperature causes injury on the exposed area of the plant ( eg ) Barcks it is know as ‘Sun sclad ’

22. Burning off: The symptoms are noticed on young seedlings due to high soil temperature. The seedlings are killed. Stem gridle : High soil temperature causes stem scorches at the ground level ( eg ) cotton.

23. OTHER EFFECT OF TEMPERATURE ON CROP PRODUCTION Distribution of plants Temperature Determines Which Species Can Survive In A Particular region. Germination Temperature greatly influences germination of seeds. The Subsequent Phases Of Germination (hydration And Enzyme activation, Enzymatic Degradation Of Storage material, Synthesis And Growth Of embryo) Are Temperature Dependent Due To Biochemical Processes involved

24. Photosynthesis The effect of temperature on photosynthesis is less then on others . According to Mathaie the Rate Of Photosynthesis Increases With The Rise In Temperature From 50 T o 370 C beyond Which There Is A Rapid fall Between 50 To 370 C, The Rate Of Photosynthesis Is Doubled For Every 10 0 C Increase In Temperature . In Desert And C 4 Plants Photosynthesis May Run Relatively At High temperature

25. Respiration The Rate Of Respiration Increases With The Rise Of Temperature Up To a Certain level, But Beyond The Optimum Limit The Respiration Rate Shows Marker Decrease . The Rate Of Respiration Becomes Doubled At The Increase Of 10 0 C above The Optimum Temperatur provided Other Factors Are favorable