I. Which of the following statements is TRUE or FALSE for state 1 and state 2 ?
(a) State 1 is observed specifically on the adaxial surface of mesophytic leaf during day time
(b) State 2 is obtained when guard cells absrob moisture from- stomatal space.
(c) Uneven thickness of guard cell wall favours the stomatal movement.
II. Consider the above figures and fill in the blanks.
The labeled region designated as 'A' in the figure above is/are the epidermal cell(s) with (i) ________ (chloroplast / rhodoplast / leucoplast). In daylight (the region labeled as 'A') makes carbohydrates by the process of (ii)_______(chemosynthesis / photosynthesis / respiration). This (iii)________(increases /decreases) the water potential of (the region ‘A’). Water enters cell by (iv) _______(endosmosis / diffusion / pinocytosis) where by water moves from (v)_________(higher / lower) water potential to(vi)______(higher / lower) water potential. Now, The region ‘B’ reaches state 1 due to(vii)_______(increase / decrease) in turgidity.
III. Closing of stomata is likely to cause the following physiological changes EXCEPT.
(a) Decrease in the rate of photosynthesis.
(b) Decrease in the rate of transpiration
(c) Decrease in the rate of nitrogen fixation.
(d) Decrease in the rate of water uptake
IV. Which one of the following represents the correct statement about the tonicity of environment around cell A in state 1 ?
(a) The environment is hypertonic with respect to cell A.
(b) The environment is hypotonic with respect to cell A.
(c) The environment is isotonic with respect to cell A.
V. Water Potential is the difference in the free energy or chemical potential per unit molar volume of water in a system compared to that of pure water at the same temperature and pressure. Water potential of pure water at normal temperature and pressure is zero. This value is considered to be the highest. The presence of solid particles reduces the free energy of water and decreases the water potential. Therefore, water potential of a solution is always less than zero or it has negative value. If the water potential ( ψ) of guard cell placed in distilled water is measured as 0.0 MPa and the water potential ( ψ) of O.lM glucose solution is - 0.23 MPa, what will be result if guard cells are placed in O.lM glucose solution.
(a) Glucose will flow into guard cells
(b) Water will flow into the guard cell
(c) Water will flow out from the guard cell
(d) Nothing will happen as the process will also depend on energy input.
VI. When chemical “X” is sprayed on plants, it results in wilting. The probable explanation for this is:
(a) Stoma remains in state 1 for an extended period of time.
(b) Stoma remains in state 2 for an extended period of time.
(c) The stomatal pore gets blocked by the chemical.
