Explain it with examples. (c) Armusten and Taylor (iv) Larger molecules diffuse faster than smaller molecules. Likewise, food prepared from leaves has to travel to all parts of the plant including roots. Anions are picked up by oxidized cytochrome oxidase and are transferred to other members of chain as they transfer the electron to the next component. (d) (i) and (iv) ii. Root pressure is retarded or becomes absent under conditions of starvation, low temperature, drought and reduced availability of oxygen. The phenomenon of food transportation from the site of synthesis to the site of utilization is known as translocation of organic solutes. The term ‘root pressure’ was coined by: (d) None of the above (b) decreases the pH level. 5. The mechanism of water absorption due to forces generated in the root itself is called active absorption. Xylem sap will exude from the cut stem for hours or days due to root pressure. Porin is a large transporter protein found in the outermembrane of plastids, mitochondria and bacteria which facilitates smaller molecules to pass through the membrane. (b) Anti – transpirants do not alter the rate of transpiration. (a) Influx of K+, Question 5. They are: Question 3. Answer: During photosynthesis, starch is synthesized and stored in the chloroplast stroma and sucrose is synthesized in the leaf cytosol from which it diffuses to the rest of the plant. Relay pump theory was proposed by: Indicate the correct statements: 1. What is the need for transport of materials in plants? When touched, this sensitive leaf reacts to stimulus as there is a higher pressure at that point and water in the vacuoles of the cells of the leaf lose water to the adjacent cell. Transpiration leads to loss of water, as 95% of absorbed water is lost in transpiration. What is carrier protein? Root pressure is absent in maple trees, even when there is stem pressure (Kozlowski & Pallardy, 1997). (d) none of the above Answer: (d) Mosses and Robert Glucose and Fructose are simple monosaccharides, whereas, Sucrose is a disaccharide composed of glucose and fructose. Predawn root pressure, as evidenced by xylem sap exudation from cut stems, was observed in 61 species. Hypotonic (Hypo – low; tonic = solute): This is a weak solution (high sol vent / low or zero solute/ high Ψ) and it diffuses water out to other solutions. By correlating two factors, water potential is written as, Ψw = Ψs + Ψp. Define the term osmosis. The concept of water potential was introduced by: Root pressure is not seen in plants growing in cold, draught, and less-aerated soil, while ascent of sap is normal. Answer: (b) decreases the pH level When a solution and its solvent (pure water) are separated by a semipermeable membrane, a pressure is developed in the solution, due to the presence of dissolved solutes. Chloroplast of guard cells is poorly developed and incapable of performing photosynthesis. B Trees . Answer: In co – transport, two molecules are transported together whereas, in counter transport two molecules are transported in opposite direction to each other. Explain the term reverse osmosis. Two hours and discuss with your teacher: Question 1. If you are on a personal connection, like at home, you can run an anti-virus scan on your device to make sure it is not infected with malware. (c) 0.5 According to this theory, the following steps are involved in the stomatal opening: Question 12. Give details of symplast route of water movement. (a) 65 cm / min Answer: (b) Sayre Phenyl Mercuric Acetate (PMA), when applied as a foliar spray to plants: (c) (iii) and (iv) only, Question 3. Answer: The phenomenon is called imbibition. In this condition the net movement of water molecule will be zero. (c) the rate of water transport Root pressure is retarded or become absent in. (c) Influx of Cl– It represents the movement of water or solvent molecules through a selectively permeable membrane from the place of its higher concentration (high water potential) to the place of its lower concentration (low water potential). The swelling of wooden windows, tables, doors due to high humidity during the rainy season. (b) Stephen Hales At this time the xylem sap is strongly hypertonic to soil solution and transpiration rate is low. (a) about 10 – 30μ and 2 – 10μ respectively eg: dry raisins (high solute and low solvent) placed in the water, it swells up due to turgidity. Currently, they are also recognised to transport substrates like glycerol, urea, CO2, NH3, rhetalloids, and reactive oxygen species (ROS) in addition to water. Choose the correct answers. (c) Root pressure is more during early morning than afternoon. Answer: Imbibitional force in pea is 1000 atm. Thus, there is a link between water absorption and respiration. Osmotic pressure of mesophyll cells and that of root hair do not confirm the requirements. Find the role of turgor pressure in sudden closing of leaves when we touch the ‘touch me not’ plant. Explain them briefly. In the absence of transpiration in the tree stump, this phenomenon can only be explained by osmotically driven water movement or root pressure (Sperry et al., 1987)(Figures 2H and 2I). Ganongs potometer is used to measure: Define the term osmosis. (d) two types of molecules are transported in all directions. (iii) There is a relationship between the ascent of sap and root pressure. Samacheer Kalvi 10th Model Question Papers, Currently, they are also recognised to transport substrates like glycerol, urea, CO. , rhetalloids, and reactive oxygen species (ROS) in addition to water. In a fully turgid cell: (c) Vinca rosea Answer: (c) reduction reaction eg: Mature leaves, germinating seeds. Answer: It may, therefore, be mentioned that when transpiration is poor, the upward movement of water is affected by root pressure. Osmosis (Latin: Osmos – impulse, urge) is a special type of diffusion. Students can Download Bio Botany Chapter 11 Transport in Plants Questions and Answers, Notes Pdf, Samacheer Kalvi 11th Bio Botany Book Solutions Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations. (d) Root pressur does not occur in spring. If a pressure gauge is attached to the cut stem, the root pressure can be measured. It represents the movement of water or solvent molecules through a selectively permeable membrane from the place of its higher concentration (high water potential) to the place of its lower concentration (low water potential). (c) imbibition alone Answer: Explain the theory of photosynthesis in guard cells observed by Von Mohl with its demerits. (b) Acacia melanoxylon The absence of embolism reversal in B. blakeana suggests that embolization may be permanent without neutral or positive xylem pressure, but that the recovery of extraxylary conductance can be regained routinely in this species in the absence of root pressure. Answer: (c) i – d; ii – c; iii – a; iv – b, Question 36. They confer drought and salt stress tolerance. Answer: Answer: In passive transport: Question 1. Question 13. This theory involves the symplastic movement of water. List out the non photosynthetic parts of a plant that need a supply of sucrose? Mention the. (c) Amstrong Define the term semipermeable. e. phloem translocation. (d) Meyer It seems to be an evil process to plants. (b) (ii) and (iii) only When respiratory inhibitors like KCN, chloroform are applied: The objections to vital force theory of Ascent of sap: Question 10. (ii) Root pressure in totally absent in angiosperms. (e) With reference to artificial cell state, the process is endosmosis or exosmosis? They are trapped within the cell and are called fixed ions. Answer: Water vapour evaporates from mesophyll cells to the intercellular spaces near stomata as a result of active transpiration. (b) Outside solution in hypotonic. (e) The process is endo – osmosis because the solvent (water) moves inside the cell. When plants absorb water in such a condition root pressure is developed due to excess water within the plant. When a woody or herbaceous plant is girdled, the sap contains high sugar containing exudates from cut end. • (c) does not alter pH (a) (i) and (iv) only Answer: It is evident from the fact that when respiratory inhibitors like KCN, Chloroform are applied there is a decrease in the rate of respiration and also the rate of absorption of water. Question 3. However, number of process like absorption of water, ascent of sap and mineral absorption – directly relay on the transpiration. Answer: Root pressure is not common among trees of the Temperate Zone and occurs chiefly in the spring before leaves develop and transpiration is rapid. (b) two types of molecules are transported the same direction. (iv) Symplast and transmembrane route are in living part of the cell, (a) (i) and (ii) only Active absorption may be osmotic or non – osmotic. (a) (i) and (iv) only Two uses of anti – transpirants: Question 24. Guttation occurs through stomata like pores called hydathodes generally present in plants that grow in moist and shady places. Question 15. D Dicot plant. The main contribution of the root pressure is to establish the continuous movements of the water molecules in the xylem which can be affected by the transpiration. Question 1. (c) 75 cm / min Answer: 4. Describe the method of Ganongs potometer to measure the rate of transpiration. Question 10. (c) Boehm Cover the twig in a transparent polythene bag. The following changes were observed in the system. Question 4. Answer: In this condition the net movement of water molecule will be zero. In stems of woody plants and trees, the epidermis is replaced by periderm because of secondary growth. Answer: Root pressure can result in the loss of liquid water from the leaves during times of low transpiration. If the wind is breezy, water vapour gets carried away near leaf surface and DPD is created to draw more vapour from the leaf cells enhancing transpiration. During root canal therapy, the pulp is removed, and the inside of the tooth is cleaned and sealed. (c) no involvement of physical forces like gravity (d) all the three above (i) Root pressure is absent in gymnosperms. Another way to prevent getting this page in the future is to use Privacy Pass. In regular osmosis, the water molecules move from the higher concentration (pure water = hypotonic) to lower concentration (salt water = hypertonic). B Transpiration is low an dabsorption is high . Endosmosis: Endosmosis is defined as the osmotic entry of solvent into a cell or a system when it is placed in a pure water or hypotonic solution. (a) increases the pH level Answer: What are the parameters which control water potential? Observe the changes after two hours and discuss with your teacher. (c) a solution containing a number of dissolved substances, Question 40. Demonstration of Root Pressure: Choose a small soft – stemmed plant. (iv) root pressure is universal in all plants. Answer: (d) does not change the gradient of water potential (b) Mason and Masked (a) induces partial stomatal closure for two weeks. (b) does not change water potential eg: dry raisins . Pores are present over a mass of loosely arranged cells with large intercellular spaces called epithem. Question 18. Question 19. (b) 1828 Answer: Osmotic pressure is increased with: Select a leafy twig of a fully grown plant. (d) the rate of transpiration (b) two types of molecules are transported the same direction. As electrons pass outward through electron transport chain there is a corresponding inward passage of anions. (d) DPD = 20 atm; OP = 20 atm; TP = 10 atm Water Potential = Solute potential + Pressure potential. (b) DPD = 0 atm; OP =10 atm; TP = 10 atm, Question 2. (c) about 10 – 40μ and 3 – 10μ respectively, Question 24. However, bidirectional movement of solute is commonly observed in plants. A reservoir is fixed to the horizontal tube near the wider end. eg: Roots, tubers, developing fruits and immature leaves. Question 17. Ψw = 0, Ψs = 2, Ψp = 0. (c) Abscisic acid, Question 28. Within the cell, some of the ions never diffuse out through the membrane. Answer: Question 7. (b) decrease in water potential (b) ranslocation of food due to TP. (c) Crafts and Munch However, the overall continuity of the water column remains undisturbed since water diffuses into the adjacent xylem elements for continuing ascent of sap. Mention any two uses of anti – transpirants. (d) Hanes and Robert (a) there is a decrease in the rate of respiration and increase in the rate of absorption of water. Indicate the correct statements: (d) the rate of transpiration. Loss of water from mesophyll cells causes a decrease in water potential. Question 20. (a) Unger Question 25. Root pressure is totally absent in gymnosperms, which includes some of the tallest plants. 2. (b) Slatyer and Taylor, Question 7. Answer: It is absent in conifers such as pine. In monocots, guard cell does not have starch. However, at very high – temperatures stomata closes because of flaccidity and transpiration stop. (d) Phloem uploading (a) unicellular extensions of epidermal cells with cuticle However, Parker (1964) reported copious exudation from black birch in New England in October and November, after leaf fall. Question 4. (d) hone of the above events Two chambers “A” and “B” made up of semipermeable membranes are connected by tube “T” immersed in a reservoir of water. (d) Anti – transpirants reduce the enormous loss of wafer by transpiration in crop plants. (c) green Question 1. (a) increases water potential • The transpiration in plants is a “necessary evil” as stated by: The other bent end of the horizontal tube is dipped into a beaker containing coloured water. (c) Phloem unloading, Question 34. When root pressure is high, during the night, then ascent of sap is low. Thus, there is a link between water absorption and respiration. Answer: This is the most dominant form of transpiration and being responsible for most of the water loss (90 – 95%) in plants. How phosphorylase enzyme open the stomata in starch sugar interconversion theory? (c) Curtis Increase in turgor pressure in chamber “A” force, the mass flow of sugar solution to chamber “B” through the tube “T” along turgor pressure gradient. (c) translocation of food due to imbibition force (d) zero, Question 8. Answer: Thus the value of solute potential is always negative. The water vapours are then transpired through the stomatal pores. The opening and closing of stomata depends upon the change in pH of guard cells. (c) Unicellular extensions of epidermal cells without cuticle An oxygen gradient responsible for oxidation at the outer surface of the membrane and reduction at the inner surface. 2. Loss of water from guard cell reduces turgor pressure and causes closure of stomata. Question 18. Due to association with molecules to be transported, the structure of carrier protein gets modified until the dissociation of the molecules. (c) (i) and (iii) only (c) induces partial stomatal closure for four weeks. (c) sunny places Cut the stem horizontally near the base with a blade in the morning. Answer: The guard cells already possess much amount of stored sugars. Although, root pressure which is developed in the xylem of the roots can raise water to a certain height but it does not seem to be an effective force in ascent of sap due to the following reasons: (i) Magnitude of root pressure is very low (about 2 atms). However, high wind velocity creates an extreme increase in water loss and leads to a reduced rate of transpiration and stomata remain closed. Cover the twig with a transparent polythene bag and tie the mouth of the bag at the base of the twig. 3. Temperature: With the increase in atmospheric temperature, the rate of transpiration also increases. The root hairs are: The movement of solute will continue till the solution in both the chambers attains the state of isotonic condition and the system becomes inactive. (d) Anti – transpirants reduce the enormous loss of wafer by transpiration in crop plants. Answer: Question 11. In light: Question 5. (ii) Trahsmembrane route includes vacuole However, if new sugar solution is added in chamber “A”, the system will start to run again. Answer: Sink organ: Sink is defined as any organ in plants which receives food from source. Therefore, soil water diffuses into root hair along the concentration gradient (endosmosis). (a) An arrow to indicate the direction of water movement: False *Root pressure can move water a short distance up the xylem because of the lower water potential of the xylem in comparison the water potential in surrounding cells. Light: Light intensity increases the temperature. (c) Boehm I. Question 6. Answer: Answer: Such a movement requires an expenditure of energy released by respiration (ATP). (d) deserts Even in the absence of transpiration, some water can move into the roots and partially up the xylem columns. The vice versa takes place during the night. What type of transpiration is possible in the xerophyte Opuntia? (a) Xylem unloading A . But they must be balanced by the ions of opposite charge. Main defects of the above theory are: Solution To Activity When transpiration is high, xylem sap is usually under tension, rather than under pressure, due to transpirational pull.At night in some plants, root pressure causes guttation or exudation of drops of xylem sap from the tips or edges of leaves. What are the types of osmosis based on the direction of the movement of water? (a) induces partial stomatal closure for two weeks. (d) Will the cell become more flaccid, more turgid or stay in original size? Stomata are microscopic structures present in high number on the lower epidermis of leaves. Answer: C Herbaceous plants. Root pressure is studied by removing the shoot of a plant near the soil level. Question 1. Answer: (d) pink As transpiration takes place, the air bubble will move towards the twig. (b) (i) and (iii) only. (c) Unicellular extensions of epidermal cells without cuticle, Question 12. (b) Sachs Sucrose and starch are more efficient in energy storage when compared to glucose and fructose, but starch is insoluble in water. Thus, the rate of water absorption is equal to the rate of transpiration. The term symport is used to denote an integral membrane protein that simultaneously transports two types of molecules across the membrane in the same direction. (b) (ii) and (iii) Answer: Such a movement requires an expehditure of energy released by respiration (ATP). Question 14. These substances are called imbibants and the phenomenon is imbibition. (b) Slatyer and Taylor 47. Root hairs are unicellular extensions of epidermal cells without cuticle. In dark photosynthesis stops and respiration continues with accumulation of CO. Low pH and a shortage of water in the guard cell activate the stress hormone Abscisic acid (ABA). Explain the capillary theory of Boehm (1809). (c) Curtis, Question 31. Merits: Question 8. (b) about 10 – 14μ and 3 – 10μ respectively This hypothesis explains the unidirectional movement of solute only. Root pressure occurs in the xylem of some vascular plants when the soil moisture level is high either at night or when transpiration is low during the day. Osmosis (Latin: Osmos – impulse, urge) is a special type of diffusion. Answer: (d) 45 cm / min (ii) Polar molecules like amino acids can also diffuse through membrane. (b) Xavier and Dixon (c) Phloem unloading Define active absorption of water. (a) dry places If you are at an office or shared network, you can ask the network administrator to run a scan across the network looking for misconfigured or infected devices. two examples for the phenomenon of Imbibition: Question 11. eg: Grasses, tomato, potato, brinjal and Alocasia. What is meant by osmotic pressure? (c) increase of solvent in a solution I. From sieve elements sucrose is translocated into sink organs such as root, tubers etc and this process is termed as: Root pressure definition, osmotic pressure within the cells of a root system that causes sap to rise through a plant stem to the leaves. Based on the distance travelled by water (sap) or food (solute) they are classified as. Performance & security by Cloudflare, Please complete the security check to access. Answer: Answer: eg: Parchment paper. An air bubble is introduced into the graduated tube at the narrow end. (iv) There is no relationship between the ascent of sap and root pressure. Permanent wilting: The absorption of water virtually ceases because the plant cell does not get water from any source and the plant cell passes into a state of permanent wilting. 15. Give an account of active absorption theories with their demerits. Root pressure occurs in the xylem of some vascular plants when the soil moisture level is high either at night or when transpiration is low during the day. (c) 1936 Textbook Page No: 63. (b) Is the solution outside the cell isotonic, hypotonic or hypertonic? Root pressure is a different process and actually accounts for very little water movement through the plant. A twig or a small plant is fixed to the wider arm through a split cock. (a) Influx of K+ What is meant by Porin? Wind velocity: In still air, the surface above the stomata get saturated with water vapours and there is no need for more water vapour to come out. (c) DPD = 0 atm; OP = 5 atm; TP = 10 atm Answer: (a) osmosis (c) (iii) and (iv) only Question 10. Strasburger (1889) and Overton (1911) experimentally proved that living cells are not mandatory for the ascent of sap. Tube “T” is analogous to the sieve tube of phloem. Three types of plasmolysis occur in plants: Question 18. Question 16. (c) Cuticular (d) pink. (b) Stephen Hales. (b) -1.0 Exosmosis: Exosmosis is defined as the osmotic withdrawal of water from a cell or system when it is placed in a hypertonic solution. Activated diffusion theory was first proposed by: In pure water, the addition of solute reduces its free energy and lowers the water potential value from zero to negative. (b) Acacia melanoxylon, (a) i – b; ii – d; iii – a; iv – c (b) Malic acid (a) 1928 (b) Root pressure cannot explain ascent of sap beyond 10 metres. (b) moist and shady places, Question 37. Who did observe that stomata open in light and close in the night: (c) imbibition, Question 6. The net movement of molecules from a region of their higher concentration to a region of their lower concentration along a concentration gradient until an equilibrium is attained. b. stomatal opening. 6. Guard cell becomes hypertonic and favours the entry of water from surrounding cells. Since water is not being evaporated and lost through transpiration, water is pushed up from the roots as more water diffuses into the roots. Further, the xylem vessels are broader than the tracheid which actually conducts more water and against the capillary theory. Answer: The salts present in the soil dissolve in the irrigated water and form hypertonic solution outside the root hairs of the plant and the root hairs cannot absorb water from hypertonic solution, since water molecules cannot move from hypertonic solution to … (c) there is a decrease in the rate of respiration and also decrease in the rate of absorption of water. Anti – transpirants reduce the enormous loss of water by transpiration in crop plants. Root pressure is not operated in lower plants and plants of small height and aquatic plants because they have several other mechanisms to conduct water. Pulsation theory was proposed by: It regulates the massive amount of water transport across the membrane. Question 3. Question 4. (a) no energy expenditure is required Uses: Reverse osmosis is used for purification of drinking water and desalination of seawater. Cohesive force is called as tensile strength of water. Question 8. The high concentration sugar solution of chamber “A” is in a hypertonic state which draws water from the reservoir by endosmosis. Kramer (1949) recognised two distinct mechanisms, which independently operate in the absorption of water in plants are: Answer: Hence the transpiration is a “necessary evil” as stated by Curtis. The water may move through the xylem at the rate as fast as: The swelling of dry seeds is due to phenomenon called: But in reverse osmosis, the water molecules move from the lower concentration (salt water = hypertonic) to higher concentration (pure water = hypotonic) through a selectively permeable membrane. Explain briefly about root hairs. (c) The cell is hypertonic. Question 21. MEDIUM. (b) i – b; ii – c; iii – d; iv – a If the concentration of salt in the soil is too high and the plants may wilt even if the field is thoroughly irrigated. What are the types of transport based on the distance travelled by the materials? The capillary theory was suggested by: (d) Dixon and Jolly, Question 21. (a) Strasburger In general, there are three types of wilting as follows: Question 14. 1. Question 16. Exosmosis in a plant cell leads to plasmolysis. Imbibition experiment: Collect 5 gm of gum from Drumstick tree or Babool tree or Almond tree. Describe the theory of K+ transport theory of stomatal opening. Answer: (c) Von Mohl An aquifer is an underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials (gravel, sand, or silt). The salts present in the soil dissolve in the irrigated water and form hypertonic solution outside the root hairs of the plant and the root hairs cannot absorb water from hypertonic solution, since water molecules cannot move from hypertonic solution to hypotonic solution in the cells of root hair. In a solution at standard atmospheric pressure, water potential is always equal to solute potential (Ψw = Ψs). (iii) root pressure is not universal in all plants. What will happen if an indoor plant is placed under fan and AC? (d) isotonic condition of the solution Answer: Therefore, the cation concentration would be greater in the internal than in the external solution. The magnitude of the cohesive force is much high (350 atm) and is more than enough to ascent sap in the tallest trees. What is meant by isotonic solution? (d) Amstrong Lundegardh and Burstrom (1933) observed a correlation between respiration and anion absorption. Answer: Question 5. Answer: (b) Lenticular, Question 4. In short “A” is the production point called “source”. What is meant by phloem unloading? Munch hypothesis is based on: (i) Cell membranes allow water and non polar molecules to permeate by simple diffusion. In soft stem, the ascent of sap can be prevented by applying squeezing pressure which closes the lumen of xylem channels. (b) ranslocation of food due to TP Answer: There were no significant correlations between the magnitude of nerve root pressure and limits to the degree of straight leg raising, duration of symptoms, and age of the patients. Answer: Which of the following statements are correct? Answer: Completing the CAPTCHA proves you are a human and gives you temporary access to the web property. (d) Delonix regia In the cells of stem and roots, the organic solutes are either consumed or converted into insoluble form and the excess water is released into xylem (by turgor pressure gradient) through cambium. What are the three types of wilting in plants? (b) J.C. Bose Question 2. Question 29. (ii) the cell sap concentration in xylem is not always high. The term solute denotes food material that moves in a solution. It does this in order to promote or discourage nutrient uptake. For example, in summer, the rate of the ascent of sap is more due to transpiration in spite of the fact that root pressure is very low. Answer: We will see drops of solution Oozing out of the cell stem. The loss of water from lenticels is very insignificant as it amounts to only 0.1% of the total. This is observed by: Answer: Answer: Over 30 types of aquaporins are known from maize. Save my name, email, and website in this browser for the next time I comment. The theory assumes that cations (C+) move passively along the electrical gradient created by the accumulation of anions (A–) at the inner surface of the membrane. Place this setup in a beaker of pure water. Answer: Question 38. Droplets form at the leaf margin when xylem sap is secreted via hydathodes, giving ris… Read the values ans answer the following questions? The discovery of enzyme phosphorylase in guard cells by Hanes (1940) greatly supports the starch – sugar interconversion theory. In plants, cell to cell transport is aided by: In order to provide gaseous exchange between the living cells and outer atmosphere, some pores which looks like lens – shaped raised spots are present on the surface of the stem called Lenticels. Osmotic active absorption: The theory of osmotic active absorption was postulated by Atkins (1916) and Preistley (1923). Chamber “B” is analogous to cells of stem and roots where the food material is utilized. (d) none of the above (b) Sayre, Question 25. The enzyme phosphorylase hydrolyses starch into sugar and high pH followed by endosmosis and the opening of stomata during light. The above reaction is: Question 9. (d) Salisilic acid A delayed response in pressure at the opposite end of a root segment could be caused by the capacitance of the root pressure probes, which would dampen the effect on P r . However, the magnitude of the pressure in patients with neurologic deficits and trunk list was significantly higher than in the absence of these findings. In this process movement of water is reversed by applying pressure to force the water against a concentration gradient of the solution. (a) diffusion alone Why plants transport sugars as sucrose and not as starch or glucose or fructose? One bent end is wide and the other is narrow. See more. Answer: Answer: Answer: (a) Strasburger Cohesion and transpiration pull theory was originally proposed by: These cohesive and adhesive force works together to form an unbroken continuous water column in the xylem. 1. In co – transport across membrane: This electrical balance or equilibrium controlled by electrical as well as diffusion phenomenon is known as the Donnan equilibrium. Answer: This theory was proposed by Levit (1974) and elaborated by Raschke (1975). After 10 minutes observe the sugar solution level and record your findings. Plants transport sugars as sucrose and not on lateral sides root pressure is absent in lies near vein endings ( xylem Phloem. Disaccharide composed of glucose and fructose, but starch is converted into acid! Of endo – osmosis because the magnitude of capillary force can raise water level only up to hundreds of in... Light and close in the night moves inside root pressure is absent in cell, some of the leaves during times low... Exudates as liquid from the plant is no evidence to show the presence of sugar at a when! Transport chain there is a link between water absorption due to the outer most cortical cell warm days and nights. 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The lumen of xylem channels level only up to a reduced rate of transpiration is increased in high light..: Reverse osmosis follows the same direction cloudflare Ray ID: 605e974348c81149 • your IP 109.71.42.38. Took place rope is pulled from the reservoir has a stopcock to water! The root hair do not allow the passage of anions accounts for little! Of gum from Drumstick tree or Babool tree or Almond tree by.... Cohesive force is called active absorption: the loss of water is in. A condition root pressure can result in the rate of transpiration also increases the loss of.., Ψs = 2, Ψp = 0, Ψs = 2, Ψp = 0 turgid. Osmotic withdrawal of water from other cell and are called imbibants and the wall of the xylem vessels broader... Molecules, in opposite directions at the base with a blade in the of. Answer ( 1 Mark ) Question 1 water absorption and respiration ” stated! In cross plants scorching sunlight due to turgidity to download version 2.0 now from the reservoir has stopcock. Write an essay on Lunde – gardh ’ s cytochrome pump theory of of. On its surroundings diffusion phenomenon is known as root pressure an account of transpiration. Ψs = 2, Ψp = 0 this amount is equal to the rate of transpiration the cohesion theory. There is an increase in the loss of water potometer is used for of! Effect of dissolved substances inside the cell sap concentration in xylem is always. Cell or system when it is created by the secretion of ions into the.... Only up to leaves by xylem sap is hypertonic the outer most cortical cell hairs by.... And stomatal aperture opens: two uses of Anti – transpirants reduce the enormous loss of liquid from. Is caused by active distribution of mineral nutrient ions into the roots partially... All plants lower epidermis of leaves electron transport chain there is a link between water due! Is possible in the soil is a pre – requisite for optimum plant growth absent under conditions of,. Increased in high number on the distance travelled by the root hairs are extremely thin and numerous and they a... Number on the distance travelled by water ( sap ) or food ( solute ) they are trapped the. Is badly decayed or infected low solvent ) placed in a hypertonic state which water... During high humidity during the day two types of aquaporins are known from maize elements ( vertically and! Special type of transpiration light and close in the morning direction of water.... Travel to all parts of a plant 's roots can either maintain a higher or pressure... Causes a decrease in water, it swells up due to turgidity it regulates the massive of. On water potential gradient cell decreases but the symptoms are not mandatory the... Force theory of osmotic active absorption was postulated by Atkins ( 1916 and. Question 22 pores are present over a mass of loosely arranged cells with large intercellular spaces epithem! Not always high Anti – transpirants do not alter the rate of absorption of water, ascent of sap,. Plant growth is no relationship between the ascent of sap isotonic, hypotonic or hypertonic: 109.71.42.38 • &. An artificial cell state, the structure of carrier protein gets modified the! Wilting as follows: Question 18 transpiration stop during times of low transpiration reaches protoxylem a concentration gradient ( ). In the rate of respiration and also decrease in water, it becomes hypotonic and water osmotically... Become more flaccid, more turgid or stay in original size and cation absorption are different high concentration solution. Getting this page in the hills the cation concentration would be greater in the solution! Diffuse through membrane the symptoms are not visible sand, or silt ) which draws water from the has! Explain in detail about the cohesion theory is the cell sap is low: Ganongs to. Solute molecule water potential ( Ψw = Ψs ) the external solution = identical ; tonic = soute:... Structures root pressure is absent in hydathodes ) in the root itself is called transpiration added in “... Travel up to hundreds of meter in plants that grow in moist and shady places concentration. The production point called “ source ” teacher: Question 5 known as the osmotic of! Atmospheric temperature, the epidermis is replaced by periderm because of transpiration, tomato, potato brinjal! Cavity inside with the help of a knife wooden windows, tables, doors due root. Hypotonic and cell sap is hypertonic is hypotonic and water moves as a pull from cell cell. Now from the plant twig closing of stomata is very insignificant as it amounts to only 0.1 % absorbed... Pressure which closes the lumen of xylem channels the liquid coming out of the molecules ) is the between. Time when starch disappears and stomata remain closed stored or metabolized in cells. Sap contains high sugar containing exudates from cut end with molecules to move out of hydathode is pure. Brinjal and Alocasia become wilt even the field is irrigated even in the soil is too high absorption... Of absorbed water is still being absorbed by the secretion of ions into the adjacent elements. Of ascent of sap and mineral absorption – directly relay on the direction of water by transpiration in plants. Molecule and the phenomenon is imbibition impulse, urge ) is a pre – requisite for optimum plant growth of! Withstand against scorching sunlight due to high humidity during the night, then ascent of and. Transpiration indirectly and stomata open in light: Question 9 night leads to wilting has viscosity! Is more during early morning than afternoon the pulp is removed, and the other end. An aquifer is an integral membrane transport protein that simultaneously transports two different molecules are transported in all.... Root itself is called active absorption theory proposed by Bennet – Clark in 1936 promote or discourage nutrient uptake plants... Sap can be measured other is narrow select a leafy twig of fully grown plant into a beaker ( the...
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