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. The osmotic potential increases and … Concentration gradient: The rate of diffusion is directly proportional to the concentration gradient. Water potential (Ψw) is expressed as the sum of solute potential (Ψs) and pressure potential (Ψp).Ψw = Ψs + Ψp. Creates transpiration pull for the absorption and the transport of water in plants.ii. can reduce the rate of … Stomata: the number of stomata per unit area affect the stomatal transpiration. 13 min. 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. Thus, windy conditions lead to an increased rate of transpiration. On the other hand, still air builds up a shell around the leaf reducing the steepness of vapour gradient. It is the system of interconnected protoplasts. X. Light or Illumina­tion 3. 2.Thickness of cuticle - Thick cuticle layer lowers the rate of transpiration. 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. Your email address will not be published. Any liquid can evaporate. Example Definitions Formulaes. These factors also affect the stomatal movements. © Sign in. Delhi - 110058. TThe water potential of pure water is always taken as zero at standard temperature and pressure. Light; Temperature; Wind velocity; Atmospheric humidity; Atmospheric pressure; Available water; Leaf area; Leaf structure; Stomatal frequency; Root-shoot ratio. In plants, the water is lost in the form of water vapour from the stomata of the leaves. 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. 4. Factors affecting the water potential are as followwing:i. Solute concentration - The dissolution of solute in water decreses its water potential. 2020 Zigya Technology Labs Pvt. Atmospheric Pressure 6. Soil Factors. Temperature. Rate of transpire varies greatly geographically and over time. Has a cooling effect on the leaf surface. Most alpine plants show xeromorphic features which help reduce water loss. External factors: (i) Light: Light regulates the transpiration directly and indirectly by two ways. Wind speedInternal factorsi. supplies water for photosynthesis.iii. Humidity of Air: The factors are: 1. It is not aided by streaming movement of cytoplasm. It occurs through cell wall and intercellular spaces. Distribution of stomata plays an important role in preventing loss of water vapour. For example, the rate of transpiration is higher in Sorghum as compared to Corn since, it possesses secondary roots which increase its absorption surface. Pressure - If pressure greater than the atmospheric pressure is aaplied to a pure water or solution, its water potential increases. Guttation. 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. Factors Affecting Transpiration - Internal. Transpiration is useful to the plants in the following way:i. Type # A. 2. This reduced uptake of water slows down the rate of transpiration. (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. 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. Intensity of sunlight; Temperature; Velocity of wind; Humidity; Carbon dioxide; Atmospheric pressure; Internal factors. 1. 5. Movement of Water Through Leaves. 232, Block C-3, Janakpuri, New Delhi, 1. STUDY. Canopy structure. 1. It is very essential for transpiration. ii) Rate of transpiration is directly proportional to the surface area of leaf. Water potential : This term was given by Slatyer and Taylor (1960). Light : Light is very important factor of transpiration . Internal Factors. 12 min. internal factors affecting the rate of transpiration - root to shoot ratio - surface area of leaves - stomatal frequency - structure of leaf. The list below gives the factors which affect the transpiration rate. Notify me of follow-up comments by email. More permeable the mebrane more will be the diffusion. Internal Factors:-i) Rate of transpiration is directly affected by the thickness of cuticle covering on leaf surface. Atmospheric Humidity: The rate of transpiration is roughly inversely proportional to atmospheric humidity. There are different factors that can affect the rate of transpiration as discussed below. (a) External Factors: Light: Photosynthesis takes place in presence of light and as a result stoma opens. The humidity of the atmosphere the gradient the sub-stomatal cavity and air outside the leaf. Permeability of the membrane separating the solutions. Percent of open stomataiii. 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 … Briefly describe water potential. what does rate of transpiration refer to. An increase in the air temperature warms the water inside the leaves more quickly causing it to evaporate quicker. Humidityiii. Water vapour from transpiring surfaces rapidly moves into the atmosphere which is at low pressure. It is dependent upon anatomy of root, stem and leaves. Light: Light induces photosynthesis in guard cells leading to sugar synthesis. Internal factors. Both these factors increase the vapour gradient between sub-stomatal cavity and external atmosphere. The efficiency of absorbing (roots) and evaporating surfaces (shoots) affect the rate of transpiration. The higher the number of stomata, the greater the rate of 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. Temperature : The rate of diffusion is directly proportional to the temperature. 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. Low atmospheric pressure increases the rate of transpiration. Various forces such as vapour pressure, diffusion pressure, osmotic pressure, etc. They, in turn, take water from the xylem. Download the PDF Question Papers Free for off line practice and view the Solutions online. Factors affecting transpiration. 4. 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. The following points highlight the six main factors affecting transpiration in plants. This is largely because light stimulates the opening of the stomata . Rolling, twisting and curling of leaves also reduce transpiration because the amount of radiation received by the leaf is decreased. Storage of water in the soil leads to wilting of plants and closure of the stomata. Internal water conditions. 3. In xerophytes, the number of stomata are reduced and sunken, thus the rate of transpiration is lesser. Differentiate between apoplast pathway and symplast pathway. 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. 9 min. It is aided by streaming movements of cytoplasm. 4. Ltd. Download books and chapters from book store. The water vapours diffuse through cucticle or through the stomata. In dark stomata are closed and stomatal transpiration is checked. The rate of transpiration is directly proportional to leaf surface area and surface area to volume ratio. More transpiration process occurs from the lower surface of a dorsiventral leaf as compared to upper surface. So light is the main factor, which influences transpiration. Factor # 1. 6. Factors which affect transpiration rate both external and external are discussed here . Different environmental conditions trigger both the opening and closing of stomata. The environmental factors affecting the rate of transpiration are: Light, For this reason transpiration takes place in daytime. Deficiency of water in the plants will result in decrease of transpiration rate. 2.Thickness of cuticle - Thick cuticle layer lowers the rate of transpiration. Transports minerals and nutrients to the plants.iv. Advantages of Transpiration. There are, however, a number of external factors that affect the rate of transpiration, namely: temperature, light intensity, humidity, and wind. The internal factors that control the rate of transpiration are the leaf structure, root-shoot ratio, leaf area, age of plants. 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. It is a physical process and occurs on any free surface. As a result, the water present in the xylem is pulled as a single column from the stem. Internal factors affecting transpiration : 1.Surface area of leaf - Leves having larger surface are have more transpiration. 1. We are going to be discussing about each one of these in brief. 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. 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. 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. 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. Transpiration is the loss of water from the plant surface into the atmosphere. Transpiration rate depends on the same factors which affect the evaporation rate. v. Maintains the shape and structure of the plants cells by keeping them turgid. Humidity of Air 2. The external and internal factors affecting the rate of transpiration are as follows: the amount of water lost from a plant per unit time. 1. 9.1 Factors affecting the rate of transpiration. is termed as transpiration. more will be the thickness less will be the transpiration. Factors affecting the Transpiration Rate. Water vapour pressure decreases as the atmospheric pressure decreases with increasing altitude. Water status of the plantiv. Revise with Concepts. Required fields are marked *. Types of Transpiration. The loss of water in the form of vapor from the living tissues of aerial parts of plant such as leaf, stem, leaves etc. Related Questions to study. 6 min. High winds may result in closure of stomata. 1.Surface area of leaf - Leves having larger surface are have more transpiration. Lightiv. This is called the cohesion-tension model of water transport. During daytime, the water lost through transpiration (by the leaves to the surroundings) causes the guard cells and other epidermal cells to become flaccid. It can occur from both living and non-living surfaces. B. Temperature: With the increase of temperature water vapourises rapidly and increased the humidity in the atmosphere. So light is the main factor, which influence transpiration It has been observed that rate of transpiration increases with increase in root shoot ratio The cohesion and adhesion forces of the water molecules and the cell walls of the xylem vessels prevent the water column from disrupting. Leaf Surface Area & Surface Area to Volume Ratio. Water content of the leaves; Learn with Videos. The factors affecting the transpiration include. In most plants stomata open during the day. Cell membrane is not crossed. The rate of transpiration is affected by several factors. In dicots, the stomata are confined to lower epidermis usually, therefore not in, contact with environment directly and the rate of transpiration is lesser. Internal Affecting factors of transpiration. Light affects transpiration indirectly. influence the rate of transpiration. 5. Transpiration of a plant increases with its total leaf surface area and with leaf surface area to volume ratio. It is independent of anatomy of leaf, stem and roots. Stomata tend to be open in the light, therefore, the rate of transpiration increases in the light than in the dark. Continuity of protoplasm from one cell to another cell is through plasmodesmata. 2. 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. Pressure - Increase in the pressure increase diffusion rate. 3. 6. The living epidemis and stomata are not required. 3. The number, size, position and the movement of stomata affect the rate of transpiration. Temperature 4. Environmental factors that affect the rate of transpiration. Firstly, stomata open in the presence of light and close in the absence of light. Number of stomata - more the number of transpiration more will be the transpiration. The rate transpiration is affected by a number of environmental (external) and plant (internal) factors. 2. 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. It is a physiological process and occurs in plants. This is because of the fact that more stomatal openings are present on the under surface. 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. atmospheric humidity, temperature, wind velocity, light, water supply, atmospheric pressure, sprays and dusts and vital activities) As the soil dries out the remaining soil water becomes more concentrated solution and becomes bound to soil particles more tightly. https://www.zigya.com/share/QklFTjExMDA3MTg4. More the solute more negative will be the water potential.ii. Also light helps in increasing the temperature of atmosphere. As the temperature increases the rate of diffusion increases. Factors affecting transpiration. Surface area : More the surface area more will be the rate of diffusion. The factors affecting rate of transpiration can be categorized under two groups: External or Environmental factors (eg. Factors affecting Transpiration : Affecting factors of transpiration are of two types; External and Internal. Wind 5. External or Environmental factors: 1. (A) Internal factors : Number and distribution of stomata,ii. are involved. Sunken stomata help … However, in CAM plants the stomata open in dark and remain closed in light. Root-Shoot Ratio The efficiency of absorbing (roots) and evaporating surfaces (shoots) affect the rate of transpiration. The lower the atmospheric pressure, the greater is the rate of evaporation of water from leaves. Environmental Factors. 3. Factors Affecting Transpiration - External. 2. 1. It is denoted by Psi or Ψw and is expressed in Pascals (Pa). 9 min. These include: temperature; humidity; air movement; light intensity Differences between Transpiration and Guttation. Several structural features of plants like leaf area, structure of leaf and its orientation, root-shoot ratio, age of the plant, etc. Light Plants transpire more rapidly in the light than in the dark. 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. If rate of transpiration exceeds rate of absorption, a water stress condition develops and rate of transpiration is reduced. Sunken stomata - lowers the rate 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. Low humidity outside the leaf favors transpiration because it increases the gradient. PLAY. 5. Factors affecting transpirationThe rate of transpiration depends on the following factors: External factors - i. Temperatureii. 2. All mixtures have a water potential less than zero. The external and internal factors that affect transpiration are as follows: External factors. Affecting factors of transpiration are of two types; External and Internal. 3. The internal or plant factors affecting the rate of transpiration has been explained in this video. Leaf structure: The structural modification such as presence of thick cuticle, epidermal hairs, frequency of stomata, sunken stomata, developed palisade tissue etc. Any factor in the plants’ environment that is less than optimum, whether it is deficient or in excess, will limit plant growth (17). Number of stomata - more the number of transpiration more will be the transpiration. Light is also the chief source of heat energy for the plant, enhancing evaporation. Light also speeds up transpiration by warming the leaf. Apoplast is the system of adjacent walls and continuous through the plant except at casparian strips. The various environmental factors affecting transpiration, particularly the rate of transpiration, are briefly discussed below. In xerophytes cuticle is extremely thick and prevent transpiration through it. 2. Describe internal factors affecting transpiration. External Factors: Light: Photosynthesis takes place in presence of light and as a result stomataopens. 10 min. Leaf shape, thickness of cuticle and number and distribution of stomata influence the rate of transpiration. Factors affecting Transpiration Rate of Transpiration is affected both by the Internal and External Factors. The opening and closing of stomata. Factors affecting the rate of transpiration : Intensity of light, temperature, atmospheric humidity, wind velocity, availability of soil water, etc. Structural features If the rate of transpiration exceeds the rate of absorption, the stomata get closed the cells lose their turgidity and the plant wilts. external factors affecting plant growth Plant growth and development are influenced by physical, chemical and biological components in the plants environment. The water movement into the root cells by osmosis is reduced. K+ ion and Sugar Concentration Theory. The transpiration regulatory factors are of two types: External factors and Internal factors.. 1. Following factors affecting transpiration are external and internal factors like light air and temprature 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. In most plants stomata open during the day. 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