Affecting the activity of enzymes. Q10 = 2 or 3. Optimum temperature is 20 - 30°C. At high temperature the rate of respiration declines with time and at very low temperature, the respiration rate is insignificant.
Increase in CO2 concentration and absence of O2 adversely affect the rate of aerobic respiration.
Control respiration by raising the temperature of an organism.
4. O2-Extinction point:
i.e., minimum oxygen concentration at which aerobic respiration takes place which is 3 - 10% of oxygen. In some cases a direct relation between the respiration rate and oxygen concentration has been reported.
Very low water content in dry seeds and stored tubers is responsible for very feeble rate of respiration. In wilted tissues the stored starch converted into sugars which increase the rate of respiration while in well hydrated plants the rate of respiration is not likely to be affected much by slight changes in the water content.
6. Respiratory substrates:
Higher availability of respiratory substrates increases the rate of respiration upto a certain limit.
Mechanical disturbance, injury or infection increases respiration. Hopkins (1927) found that in wounded plant tissue the sugar content is suddenly increased which is responsible for temporary increase in the respiration rate.
8. Climacteric fruits:
Such fruits have high rate of respiration during their ripening e.g.. Banana, Apple.
A number of chemicals inhibit respiration e.g., azide, cyanide, malonate, carbon monoxide etc.
10. Protoplasmic factor:
Young growing cells exhibit high rate of respiration as compared to mature cells.