It reduces leaf growth and hence photosynthetic area. Besides, water stress also makes leaves wilt, thus reducing the surface area of leaves and their metabolic activity as well. Chlorophyll Contents: The rate of photosynthesis in two varieties of barley having normal green leaves and yellow leaves was studied. Indirect roles are stomatal movement and hydration of protoplasm. Most effective wavelengths differ with different plants. It reduces the rate of photosynthesis.
Temperature: In general, increase in temperature results in an increase in the rate of photosynthesis when other factors are not limiting. According to this law the rate of chemical reaction doubles for every rise of 10°C. It maintains the turgor of the assimilatory cells. The rate of photosynthesis decreases in the cells which have lost their turgor, The loss of turgor of guard cells closed the stomata. Chloroplast functions decline as the leaves age. Quantity of Light: In plants which are exposed to light for longer duration Long day Plants photosynthetic rate is higher.
Leaves with Kranz anatomy are more efficient in photosynthesis. It increases the temperature of the leaves. Different plants require different intensity of light. Due to decreased amount of internal water the stomata get closed which results in less uptake of carbon dioxide inhibiting the photosynthesis. The decline may be due to one or more of the following causes: i Accumulation of the end products of photosynthesis. Photosynthetic Pigments It is an essential factor and even a small quantity is enough to carry out photosynthesis.
Quality of light: Different wavelengths of light affect the rate of photosynthesis because pigment system does not absorb all the rays equally. There is initial increase in the rate of photosynthesis at this temperature but this is soon followed by a decline. This study is of great importance to farmers. Nitrogen is basic constituent of chlorophyll. · They develop different types of sclerenchyma and vascular tissues. The decline is due to the following reason: · Accumulation of the end products of photosynthesis.
Photosynthesis hardly starts at about 5°C in tropical plants. Therefor, it cannot be a limiting factor directly. There is a point in light intensity where there is no gaseous exchange in photosynthesis. Factors affecting photosynthesis are further grouped into External or Environmental factors and Internal factors. The proportion of the total incident sunlight on earth, absorbed by green plants is generally a limiting factor.
But increasing the intensity of light to a prudent limit will speed up the process. The removal of water from the protoplasm also affects its colloidal state, impairs enzymatic efficiency, inhibits vital processes like respiration, photosynthesis etc. There is a point in light intensity where there is no gaseous exchange in photosynthesis. Keep this setup in sunlight. Higher concentrations have an inhibitory effect on photosynthesis.
Different plants require different intensity of light. Afterwards the rate of photosynthesis begins to decline Fig. What factor most affects the rate of photosynthesis? Oxygen C3 plants show optimum photosynthesis at low oxygen concentration. Red light favours carbohydrate accumulation while blue light stimulates protein synthesis. · They have different sizes, positions and distribution of the stomata.
At a very high oxygen content the rate of photosynthesis begins to decline in all plants. Place the leaf to a dilute solution of iodine. The dark reaction being enzymatic are temperature controlled. Sugar is also converted into starch and the accumulation of starch in chloroplasts reduces their effective surfaces and the process slows down. Less than 1% of the water absorbed by a plant is used in photosynthesis. These components are crucial to overall composition of the plant and its survival.
In summer, some farmers growing crops in glasshouses actually increase the amount of carbon dioxide in the air as all their plants have plenty of water and light and the temperature is near the best possible for photosynthesis. Hormones: Cytokines and gibberellins increase the rate of photosynthesis but abscisic acid reduces the same. This is because the light now becomes the limiting factor. Temperature: A suitable temperature is necessary for photosynthesis. The rate of assimilation per unit area of leaf surface in the two varieties was the same even though the green-leaved variety contained ten times more chlorophyll than the yellow one. Light of wavelength longer than 700 run is not effective for photosynthesis for green plants.
This reduces the rate of photosynthesis. These include size of stomata, their position, amount of intercellular spaces, thickness of epidermis and cuticles. The sun is the main source of light energy. There is an initial increase in the rate of photosynthesis at this temperature. Water deficiency may accumulate sugars and thus increase respiration and decrease photosynthesis.