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.

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

9. 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

10. 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.

11. 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

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

13. 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

14. 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.

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

16. 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.

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

18. 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.

19. • 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

20. • 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.

21. • 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.

22. • 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’

23. • 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.

24. 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

25. • 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

26. 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