3. They, in turn, take water from the xylem. 2. Wind 5. 2. 9 min. The higher the temperature the greater the rate of transpiration since high temperature provides latent heat of vaporization and lowers the relative humidity of air. Humidity of Air: So light is the main factor, which influences transpiration. More transpiration process occurs from the lower surface of a dorsiventral leaf as compared to upper surface. Water status of the plantiv. 2.Thickness of cuticle - Thick cuticle layer lowers the rate of transpiration. The external and internal factors affecting the rate of transpiration are as follows: 2. 6 min. Light also speeds up transpiration by warming the leaf. External or Environmental factors: 1. As the soil dries out the remaining soil water becomes more concentrated solution and becomes bound to soil particles more tightly. The osmotic potential increases and … In xerophytes cuticle is extremely thick and prevent transpiration through it. When the water potential of the soil water is lower than the cells of the root the permanent wilting, point has been reached and plants die quickly. Internal factors affecting transpiration : 1.Surface area of leaf - Leves having larger surface are have more transpiration. The root-shoot ratio, leaf surface area and surface area to volume ratio and leaf structure are the major internal factors affecting the rate of transpiration. The rate of transpiration is directly proportional to leaf surface area and surface area to volume ratio. 3. (A) Internal factors : (adsbygoogle = window.adsbygoogle || []).push({}); Factors Affecting the Rate of Transpiration, environmental factors that affect the rate of transpiration, how does light intensity affect transpiration, Chloroplast Structure and Function Detailed, Seed Dispersion And Seed dispersal methods. The cellular factors affecting the rate of transpiration are: The orientation of leaf, The water status of the plant, Structural Peculiarities of the leaf, Total number and distribution of stomata in a leaf. There are different factors that can affect the rate of transpiration as discussed below. 1.Surface area of leaf - Leves having larger surface are have more transpiration. STUDY. As the temperature increases the rate of diffusion increases. K+ ion and Sugar Concentration Theory. External Factors: Light: Photosynthesis takes place in presence of light and as a result stomataopens. 5. It is the difference in free energy or chemical potential per unit molal volume of water in a solution over its pure state at same temperature and pressure. The factors affecting rate of transpiration can be categorized under two groups: External or Environmental factors (eg. Light : Light is very important factor of transpiration . The higher the number of stomata, the greater the rate of transpiration. 5. It is independent of anatomy of leaf, stem and roots. PLAY. Different environmental conditions trigger both the opening and closing of stomata. More permeable the mebrane more will be the diffusion. Humidityiii. Stomata tend to be open in the light, therefore, the rate of transpiration increases in the light than in the dark. Movement of Water Through Leaves. Humidity of Air 2. What are the factors affecting it ? The factors affecting the rate of transpiration can be categorized into two groups: (A) External or Environmental Factors and (B) Internal or Structural or Plant Factors. Notify me of follow-up comments by email. If rate of transpiration exceeds rate of absorption, a water stress condition develops and rate of transpiration is reduced. Also light helps in increasing the temperature of atmosphere. Water vapour from transpiring surfaces rapidly moves into the atmosphere which is at low pressure. Factors affecting Transpiration : Affecting factors of transpiration are of two types; External and Internal. The living epidemis and stomata are not required. what does rate of transpiration refer to. Both these factors increase the vapour gradient between sub-stomatal cavity and external atmosphere. Internal Affecting factors of transpiration. Sunken stomata - lowers the rate of transpiration. Leaf shape, thickness of cuticle and number and distribution of stomata influence the rate of transpiration. internal factors affecting the rate of transpiration - root to shoot ratio - surface area of leaves - stomatal frequency - structure of leaf. atmospheric humidity, temperature, wind velocity, light, water supply, atmospheric pressure, sprays and dusts and vital activities) The efficiency of absorbing (roots) and evaporating surfaces (shoots) affect the rate of transpiration. Percent of open stomataiii. external factors affecting plant growth Plant growth and development are influenced by physical, chemical and biological components in the plants environment. The Environmental Factors Affecting Transpiration In general, plants transpire fastest under the following climatic conditions: (a) bright day, (b) dry air, (c) moist soil, (d) warm temperature, and (e) windy day. Factors affecting Transpiration Rate of Transpiration is affected both by the Internal and External Factors. Firstly, stomata open in the presence of light and close in the absence of light. © In most plants stomata open during the day. 12 min. Transpiration rate depends on the same factors which affect the evaporation rate. Canopy structure. Factor # 1. For this reason transpiration takes place in daytime. Environmental factors that affect the rate of transpiration. Any liquid can evaporate. Various forces such as vapour pressure, diffusion pressure, osmotic pressure, etc. 6. Light; Temperature; Wind velocity; Atmospheric humidity; Atmospheric pressure; Available water; Leaf area; Leaf structure; Stomatal frequency; Root-shoot ratio. The internal or plant factors affecting the rate of transpiration has been explained in this video. Transpiration - Factors Affecting Rates of Transpiration PLANT PARAMETERS – These plant parameters help plants control rates of transpiration by serving as forms of resistance to water movement out of the plant. There are, however, a number of external factors that affect the rate of transpiration, namely: temperature, light intensity, humidity, and wind. 2. It is a physiological process and occurs in plants. Water vapour pressure decreases as the atmospheric pressure decreases with increasing altitude. As a result, the water present in the xylem is pulled as a single column from the stem. The factors are: 1. In dark stomata are closed and stomatal transpiration is checked. 1. can reduce the rate of … Continuity of protoplasm from one cell to another cell is through plasmodesmata. For example, the rate of transpiration is higher in Sorghum as compared to Corn since, it possesses secondary roots which increase its absorption surface. Affecting factors of transpiration are of two types; External and Internal. It has been observed that rate of transpiration increases with increase in root shoot ratio supplies water for photosynthesis.iii. The cohesion and adhesion forces of the water molecules and the cell walls of the xylem vessels prevent the water column from disrupting. The number, size, position and the movement of stomata affect the rate of transpiration. Factors which affect transpiration rate both external and external are discussed here . Pressure - Increase in the pressure increase diffusion rate. This creates a negative pressure or tension in the xylem vessels, from the surfaces of the leaves to the tips of the roots, through the stem. Any factor in the plants’ environment that is less than optimum, whether it is deficient or in excess, will limit plant growth (17). An increase in the air temperature warms the water inside the leaves more quickly causing it to evaporate quicker. In dicots, the stomata are confined to lower epidermis usually, therefore not in, contact with environment directly and the rate of transpiration is lesser. Differences between Transpiration and Guttation. The transpiration regulatory factors are of two types: External factors and Internal factors.. Internal factors Root - Shoot Ratio : Transpiration shows a direct relation with the amount of water absorbed by the roots and the water lost through leaves. Required fields are marked *. The humidity of the atmosphere the gradient the sub-stomatal cavity and air outside the leaf. Light: Light induces photosynthesis in guard cells leading to sugar synthesis. The external and internal factors that affect transpiration are as follows: External factors. Most alpine plants show xeromorphic features which help reduce water loss. The list below gives the factors which affect the transpiration rate. This is because of the fact that more stomatal openings are present on the under surface. Temperature: With the increase of temperature water vapourises rapidly and increased the humidity in the atmosphere. (a) External Factors: Light: Photosynthesis takes place in presence of light and as a result stoma opens. Types of Transpiration. Moving air, especially the low speed wind, sweeps away the water vapour in the air outside the stomata, speeding up diffusion of water vapour by making a steeper gradient between stomatal cavity and the air. Thus, windy conditions lead to an increased rate of transpiration. 6. Light or Illumina­tion 3. influence the rate of transpiration. 5. The factors affecting the transpiration include. Temperature also helps opening of stomata since stomata remain open up to about 30° C. in fact, in the presence of light, the temperature has the greatest effect on the rate of transpiration. Transpiration is useful to the plants in the following way:i. It is a physical process and occurs on any free surface. are involved. High winds may result in closure of stomata. Rate of transpire varies greatly geographically and over time. The root-shoot ratio, leaf surface area and surface area to volume ratio and leaf structure are the major internal factors affecting the rate of transpiration. 4. is termed as transpiration. https://www.zigya.com/share/QklFTjExMDA3MTg4. It is dependent upon anatomy of root, stem and leaves. It is aided by streaming movements of cytoplasm. 1. On the other hand, still air builds up a shell around the leaf reducing the steepness of vapour gradient. Describe internal factors affecting transpiration. 4. The internal factors that control the rate of transpiration are the leaf structure, root-shoot ratio, leaf area, age of plants. the amount of water lost from a plant per unit time. In most plants stomata open during the day. It is not aided by streaming movement of cytoplasm. The rate of transpiration is affected by several factors. TThe water potential of pure water is always taken as zero at standard temperature and pressure. Internal Factors. On the other hand, in monocots, the leaves are vertical and stomata are distributed on both surfaces equally, thus the rate of transpiration is higher. Example Definitions Formulaes. Your email address will not be published. Factors affecting the rate of transpiration : Intensity of light, temperature, atmospheric humidity, wind velocity, availability of soil water, etc. Following factors affecting transpiration are external and internal factors like light air and temprature Ltd. Download books and chapters from book store. Lightiv. 232, Block C-3, Janakpuri, New Delhi, B. Light Plants transpire more rapidly in the light than in the dark. 3. Leaf structure: The structural modification such as presence of thick cuticle, epidermal hairs, frequency of stomata, sunken stomata, developed palisade tissue etc. Root-Shoot Ratio The efficiency of absorbing (roots) and evaporating surfaces (shoots) affect the rate of transpiration. 2. Low humidity outside the leaf favors transpiration because it increases the gradient. Download the PDF Question Papers Free for off line practice and view the Solutions online. Factors affecting the Transpiration Rate. Stomata: the number of stomata per unit area affect the stomatal transpiration. Type # A. Light is also the chief source of heat energy for the plant, enhancing evaporation. Factors affecting transpiration. Intensity of sunlight; Temperature; Velocity of wind; Humidity; Carbon dioxide; Atmospheric pressure; Internal factors. Environmental Factors. 3. All mixtures have a water potential less than zero. 9.1 Factors affecting the rate of transpiration. Factors Affecting Transpiration - External. Deficiency of water in the plants will result in decrease of transpiration rate. Soil Factors. Water potential (Ψw) is expressed as the sum of solute potential (Ψs) and pressure potential (Ψp).Ψw = Ψs + Ψp. Temperature : The rate of diffusion is directly proportional to the temperature. The environmental factors affecting the rate of transpiration are: Light, So light is the main factor, which influence transpiration ii) Rate of transpiration is directly proportional to the surface area of leaf. This reduced uptake of water slows down the rate of transpiration. This is largely because light stimulates the opening of the stomata . The various environmental factors affecting transpiration, particularly the rate of transpiration, are briefly discussed below. Apoplast is the system of adjacent walls and continuous through the plant except at casparian strips. Guttation. Briefly describe water potential. Water content of the leaves; Learn with Videos. Factors affecting transpirationThe rate of transpiration depends on the following factors: External factors - i. Temperatureii. 3. These include: temperature; humidity; air movement; light intensity In plants, the water is lost in the form of water vapour from the stomata of the leaves. The opening and closing of stomata. Sunken stomata - lowers the rate of transpiration. Has a cooling effect on the leaf surface. Revise with Concepts. External factors: (i) Light: Light regulates the transpiration directly and indirectly by two ways. 1. Factors affecting the water potential are as followwing:i. Solute concentration - The dissolution of solute in water decreses its water potential. Cuticle: if the cuticle is thin the rate of transpiration is higher, for example in ferns 30%-45% water loss is cuticular since the cuticle is thin. Water potential : This term was given by Slatyer and Taylor (1960). For example, conifers, the leaves are reduced to needles and the rate of transpiration is reduced, while the shade plants with large leaf surface area lose much water vapour. Storage of water in the soil leads to wilting of plants and closure of the stomata. v. Maintains the shape and structure of the plants cells by keeping them turgid. 1. It is very essential for transpiration. Structural features 1. 1. However, in CAM plants the stomata open in dark and remain closed in light. Structure of leaf: Compact arrangement of leaf cells, presence of hairs, cuticle, and hydrophilic substances such as gums and mucilage reduce the rate of transpiration; Orientation of leaf: Leaves arranged transversely on the shoot have higher rates of transpiration compared to those arranged perpendicularly ; Number of leaves: More the number of leaves in a … The following points highlight the six main factors affecting transpiration in plants. The water movement into the root cells by osmosis is reduced. 13 min. 4. Internal water conditions. 6 min. Differentiate between apoplast pathway and symplast pathway. The loss of water in the form of vapor from the living tissues of aerial parts of plant such as leaf, stem, leaves etc. Temperature. Pressure - If pressure greater than the atmospheric pressure is aaplied to a pure water or solution, its water potential increases. Factors affecting the rate of transpiration Many environmental factors, such as intensity of light, temperature, atmospheric humidity, wind, availability of soil water, etc., greatly affect the rate of transpiration. We are going to be discussing about each one of these in brief. 2. These factors also affect the stomatal movements. 9 min. It can occur from both living and non-living surfaces. The rate transpiration is affected by a number of environmental (external) and plant (internal) factors. 10 min. There are a lot of internal and external factors which affect the rate of transpiration in plants which is as follows: External factors: External factors affecting transpiration - Light, atmospheric moisture, wind velocity, air temperature, solar radiation and soil environment. Atmospheric Humidity: The rate of transpiration is roughly inversely proportional to atmospheric humidity. It is the system of interconnected protoplasts. Transpiration in plants: types, mechanism, affecting factors and significance Define Transpiration and its significance? During daytime, the water lost through transpiration (by the leaves to the surroundings) causes the guard cells and other epidermal cells to become flaccid. As the film of water is continuous over the cells, thus a transpirational pull is generated by the loss of water from the stomatal pores of leaves. Atmospheric Pressure 6. Sign in. It is denoted by Psi or Ψw and is expressed in Pascals (Pa). 1. Cell membrane is not crossed. Transpiration is the loss of water from the plant surface into the atmosphere. X. The lower the atmospheric pressure, the greater is the rate of evaporation of water from leaves. In xerophytes, the number of stomata are reduced and sunken, thus the rate of transpiration is lesser. Distribution of stomata plays an important role in preventing loss of water vapour. Factors affecting transpiration. Sunken stomata help … Creates transpiration pull for the absorption and the transport of water in plants.ii. Transpiration of a plant increases with its total leaf surface area and with leaf surface area to volume ratio. If the rate of transpiration exceeds the rate of absorption, the stomata get closed the cells lose their turgidity and the plant wilts. More the solute more negative will be the water potential.ii. Rolling, twisting and curling of leaves also reduce transpiration because the amount of radiation received by the leaf is decreased. Concentration gradient: The rate of diffusion is directly proportional to the concentration gradient. Advantages of Transpiration. The environmental factors such as humidity (vapour pressure), temperature, air movements (wind), atmospheric pressure, light and availability of soil water influence the rate of transpiration most. Internal factors. Factors Affecting Transpiration - Internal. This is called the cohesion-tension model of water transport. 4. Number and distribution of stomata,ii. Temperature 4. Increase rate of transpiration containing for longer periods often create internal water deficit in plants because absorption of water does not keep pace with it. how does temperature affect transpiration how does light intensity affect transpiration factors affecting transpiration ppt plant factors affecting transpiration Factor Effecting the Transpiration 9th Class Biology Chapter 9 Transport Online Videos Lecture. Wind speedInternal factorsi. Transports minerals and nutrients to the plants.iv. Delhi - 110058. Related Questions to study. It occurs through cell wall and intercellular spaces. Number of stomata - more the number of transpiration more will be the transpiration. Internal Factors:-i) Rate of transpiration is directly affected by the thickness of cuticle covering on leaf surface. Light affects transpiration indirectly. 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