Answer : (d)

The influx and efflux of potassium and chlorine regulate the opening and closing of stomata. Efflux of K+ and Cl will cause closure of stomata Answer : (a)

The exudation of water on cutting stem is known as bleeding. And is occur due to root pressure. Guttation is also occur due to rooty pressure and in guttation water droplets comes out from hydathodes present in leaf margins. . Transpiration is the evaporation of water from the upper surface of the leaves. Explanation is provided by Mr Sunil Gurjar Answer : (b)

When the osmotic concentration of the guard cells increases, they absorb water from the surrounding epidermal cells and become turgid. Increased turgidity causes the outer elastic wall of the guard cells to stretch towards outside. The inner thick and inelastic wall also gets pulled along with it and assumes a concave shape. The stomatal pore between the two guard cells opens in this condition. When guard cells lose water and become flaccid, the stomata close. Answer : (d)

Ringing or girdling experiment is a strategy was first performed by Hartig (1837) in which the outer tissues (bark) of a stem are detached, and leaving only the xylem and pith unharmed Answer : (a)

The process of guttation occurs when the roots of a plant absorb water from the soil and loss of water through transpiration is less. This creates a pressure inside the plant, and the water is forced out through the hydathodes. Answer : (d)

As the relative humidity of the air surrounding the plant rises the transpiration rate falls. It is easier for water to evaporate into dryer air than into more saturated air. Wind and air movement: Increased movement of the air around a plant will result in a higher transpiration rate Answer : (d)

Root pressure, in plants, force that helps to drive fluids upward into the water-conducting vessels (xylem). It is primarily generated by osmotic pressure in the cells of the roots and can be demonstrated by exudation of fluid when the stem is cut off just aboveground. Answer : (a)

If a cell is placed in a hypertonic solution, water will leave the cell, and the cell will shrink. Answer : (a)

Increased temperature. and presence of wide open stomata increase the rate of transpiration. Light is the most important factor in the regulation of transpiration. As the relative humidity of the air surrounding the plant rises the transpiration rate falls. It is easier for water to evaporate into dryer air than into more saturated air. Answer : (d)

Answer : (b)

Answer : (d)

when there are more water molecules in the system, water potential is expected to be higher, e.g., under conditions of low transpiration in leaf tissue the water potential is expected to be positive. When transpiration is low, considerably more water molecules will be stuffed up inside leaf in the intercellular spaces giving rise to a positive water potential Answer : (a)

The apoplast pathway facilitates the transport of water and solutes across a tissue or organ. Symplast Pathway: The inner side of the plasma membrane is the symplast. Answer : (c)

Demonstration of Osmosis process by Thistle Funnel Method. Since the egg membrane is semi-permeable, water can move in but proteins cannot move out, egg membrane is used insted of parchment paper Answer : (c)

Answer : (c)

When there is the rise in pH it causes hydrolysis of starch into sugar which accumulates in guard cells which results in the opening of cells. For this mechanism, cytokinins and cAMP are required. Abscisic acid is the stress hormone which results in the closing of stomata. Answer : (d)

Cells gain or lose water among themselves on the basis of their water potential or DPD and not their solute or osmotic potentials only. Movement of water (solvent) takes place from lower DPD to high DPD or form higher water potential to lower water potential. Answer : (b)

Diffusion is the net movement of a substance from a region of high concentration to a region of low concentration. A gradient is a change in the value of a quantity (e.g., concentration, pressure, temperature) with the change in another variable (e.g., distance). The uniformly sweet taste of coffee or tea is also an example of diffusion. Here, when added tea or coffee powder to milk/water, movement of substance takes place from high concentration to lower concentration. Answer : (d)

Girdling experiment experiment proves that phloem is responsible for translocation of organic material. a- s Cobalt chloride paper method is performed to demonstrate unequal transpiration on two surfaces. As lower surface have more stomata than upper surface so transpiration is more on the lower surface b - r An atmometer or evaporimeter is a scientific instrument used for measuring the rate of water evaporation from a wet surface to the atmosphere. c - p Bell jar experiment demonstrate Transpiration d - q Answer : (b)

The apoplast pathway is where water takes a route going from cell wall to cell wall, not entering the cytoplasm at any point. Answer : (d)

Root pressure is due to various ions from the soil are enter the root by active absorption and ions are actively transported into the vascular tissues of the roots, water follows (its potential gradient) and increases the pressure inside the xylem. Answer : (a)

Answer : (a)

When water is plentiful, the seed fills with water in a process called imbibition. Answer : (c)

The cell wall of most plant cells is completely permeable to small proteins (size- 30-60 kilodaltons), water and other molecules etc. Answer : (c)

Answer : (b)

As ions accumulate in the root xylem, the osmotic potential of the xylem solution falls causing the passive uptake of water from the soil by osmosis into the xylem. As pressure builds up within the xylem due to osmotic water uptake, the xylem solution is forced upward to the leaves by mass flow. Answer : (b)

The force which determines the flow of water from one cell to another is diffusion pressure deficit. Diffusion pressure deficit (DPD) is the amount by which two solutions differ in their diffusion pressure Answer : (b)

Answer : (d)

Curtis (1926) called transpiration as necessary evil because it provides some beneficial aspects but on the other hand, many functioning and energy gets wasted from absorption of water upto the stage of transpiration. Answer : (d)