Thickness of cuticle: Cuticular transpiration depends upon the thickness of cuticle. This is not only because evaporation occurs quickly in warmer air but also because warm air is capable of holding more water vapors than the cold air. This is further influenced by a number of soil factors like soil water, soil particles, soil temperature, soil air etc. The difference between the relative humidity of the leaf -- which is near 100 percent under normal growth conditions -- and the relative humidity of the air determines the strength of the force that drives water vapor from the leaf to the air. Stomata — Stomata are pores in the leaf that allow gas exchange where water vapor leaves the plant and carbon dioxide enters. It reduces the rate of transpiration. The transpiration is faster in mild wind.
Boundary layers increase as leaf size increases, reducing rates of transpiration as well. The volume of water lost in transpiration can be very high. Growing plants absorb soil water through their roots, transport it upward through their stems, and release it as water vapor into the surrounding air through microscopic leaf pores, called stomata. Soil water A plant cannot continue to transpire rapidly if its water loss is not made up by replacement from the soil. In other words the rate of transpiration increases with the decrease in atmospheric pressure. It also increases the capacity of the air to absorb more water. It is a way of getting rid of excess water.
Sunlight Direct sunlight has the same effect as temperature as it warms the leaves up quicker. The environmental factors affecting transpiration in plants include light, relative humidity, temperature, availability of water, and wind. Therefore, plants in hot environments generally transpire more than plants in cooler environments. Age of plant Rate of transpiration is slow at seedling stage, maximum at maturity and gradually decrease near senescence. However, strong wind may cause excessive loss of water from leaves leading to stomatal closure. When atmospheric pressure is high, the rate of transpiration is low.
External Factors Affecting The Rate of Transpiration Light Light affects the rate of transpiration as it is directly involved in the opening and closing of stomata. When there is loner absorption of water. Humidity Humidity is the concentration if water vapour in the air. So it has an indirect influence on the rate of transpiration. Ilms stomata are closed Oen in the presence tn. As such, wind movement on the leaf surface will be reduced so that the boundary layer is retained. Role of stomata: Most of the transpiration takes place through stomata.
First, water transpires from plants and enters the atmosphere as water vapor. Atmospheric humidity The rate of transpiration depends upon the difference in vapour pressure between the internal atmosphere of the leaf and air outside the leaf. But this is only a temporary solution because transpiration is essential for life: plants cannot carry out photosynthesis when their stomata are closed, and reduced transpiration leads to reduced transport of nutrients. This reduces the water loss and helps the plant to survive in adverse conditions. This inadvertently allows some organisms to survive better than others depending on the moisture levels that they need to thrive.
When water is removed from the plant, it can more easily access the carbon dioxide that it needs for. Boundary layer — The boundary layer is a thin layer of still air hugging the surface of the leaf. Internal or Plant Factors: i Root - shoot ratio: If all other conditions are favourable for transpiration, the water absorbing capacity of roo surface and transpiring capacity of the leaf suface regulate the rate of transpiration if transpiration is greater than absorption, a water deficit results, causing reduction in transpiration rate. As a result osmotic pressure of the memmhyll cells increases. Wind Velocity: The velocity of wind greatly affects the rate of transpiration. Plants regulate the rate of transpiration by opening and closing of stomata. It raises the temperature of the lea es and increases the transpiration.
Direct effect of light is on the opening and closing of stomata. Such a condition usually occurs during periods of drought and when the soil is frozen or at a temperature so low that water is not absorbed by roots. At very high temperature, usually beyond 35°C the rate of transpiration gradually falls due to inactivity of the protoplasm. That means when humidity increases, transpiration decreases. Air around the leaf becomes saturated and the rate of transpiration decreases. Temperature as an environmental factor affecting transpiration also relates to water potential and relative humidity.
It has been estimated that over the growing season, one acre of corn maize plants may transpire 400,000 gallons 1. Plants growing in soil with adequate water supply are known mesophytes. Moreover, winds of high velocity bring about a reduction in temperature which undoubtedly affects transpiration. Most of the water absorbed by the roots of a —as much as 99. This video explains how to compare the rate of transpiration between the upper and lower surfaces of a leaf. Plants open their stomata more in hot environments so that water can evaporate, which cools the plant.
Soil Water Content: Availability of soil water greatly affects the rate of transpiration. Reduction in the leaf surface is achieved when leaves are reduced to needles, for example, Pinus or spines for example cacti. High humidity means the air around the leaves is already saturated and has a higher concentration of water molecules than inside the leaves. Function of Transpiration Transpiration occurs because plants take in more water than they actually need at a given time. Therefore, any decease in leaf surface area will reduce transpiration and conserve water absorbed by roots.