16483.Chlorophyllous cells fewer in number, unique in shape with inner walls thicker are
guard cells
passage cells
subsidiary cells
bulliform cells
16484.The magnitude of root pressure will be minimum in
Rainy season
Fast transpiring angiosperms
Wilting plant
During ascent of sap
16485.Which of the following theory cannot explain the ascent of sap in tall trees.
Root pressure and Transpiration pull
Root pressure and capillarity
Capillarity and Transpiration
Capillarity and physical force theory
16486.Which one gives the most valid explanation for guard cell movements?
Guard cell photosynthesis
Starch hydrolysis theory
Potassium influx and efflux
Transpiration
16487.Stomatal opening is under the control of
Epidermal cells
Palisade cells
Spongy parenchyma cells
Guard cells
16488.Rate of transpiration is highest when
soil is wet and air is dry
soil is wet and air is humid
soil is dry and air is humid
both soil and air are dry
16492.Transpiration differs from evaporation in
rate of water loss
transpiration is a physiological process while evaporation is a physical process
transpiration is a physical process while evaporation is a physiological process
frequency of water loss
16493.Water enters into root hairs from the soil on account of ________.
turgor pressure
osmotic pressure
suction pressure
root pressure
16497.A semipermeable membrane allows the diffusion of
solutes
Solvent
Both solvent and solutes
none of the above
16498.Transpiration rate is dependent upon
Stomatal frequency
Position of stomata
State of stomata
All the above
16500.Transpiration is not helpful in ________.
cooling
Loss of nutrient
Loss of water
Ascent of sap
16501.Transpiration is regulated by movements of
guard cells
subsidiary cells
epidermal cells
mesophyll cells
16503.Exudation of xylem sap on cutting of a shoot is due to
guttation
root pressure
transpiration
none of the above
16504.The loss of water in the form of water droplets is called
Transpiration
Guttation
Evaporation
Bleeding
16506.Rate of transpiration increases ________.
when there is no light
in water
when temperature is high
in rainy season
16507.Transpiration is least in
Good soil moisture
High wind velocity
Dry environment
High atmospheric humidity
16508.Stomata of CAM plants
never open
are always open
open during the day and close at night
open during the night and close during the day
16509.Root pressure is due to
active absorption
passive absorption
increased transpiration
increased photosynthesis
16510.The maximum absorption of water by roots occurs in the (region) zone of
root cap
cell division
cell elongation
root hairs
16512.Water is absorbed from outside solution only when it is
saturated
isotonic
hypertonic
hypotonic
16517.Turgidity of the cell is necessary for
Causes cell elongation
Causes opening and closing of stomata
Prevents wilting of leaves
All the above
16518.Water lost through transpiration is
pure water
rich in organic solutes
rich in dissolved salts
all the above
16519.The water available for plants in soil is ________.
gravitational water
hygroscopic water
capillary water
chemically bound water
16520.Which of the folowing is due to hydrostatic pressure
Osmosis
Plasmolysis
Exeudation
Transpiration
16522.The conditions under which transpiration would be most rapid?
High humidity
Excess of water in soil
Low humidity, high temperature, guard cell are turgid (open) moist soil
Low velocity of wind
16524.Active K+ exchange mechanism for opening and closing of stomata was given by
Darwin
Levitt
Scarth
Khorana
16525.The most widely accepted theory of water translocation in plants is ______.
Root pressure theory
Capillary theory
Cohesion theory
Water pump theory
16526.The following percentage of water absorbed by herbaceous plants is lost in transpiration
80
60
99
40
16527.Which is produced during water stress that brings stomatal closure?
Ethylene
Abscisic acid
Ferulic acid
Coumarin
16530.Transpiration increases by ________.
high temperature
high humidity
wetness in soil
large nuclei
16531.Osmosis is intimately connected with ______ membrane.
permeable
semi-permeable
selectively permeably
impermeable
16532.Root pressure is maximum when
transpiration is high and absorption is low
transpiration is very low and absorption is high
transpiration is very high and absorption is high
transpiration and absorption both are slow.