Choose correct statements regarding the flow of sap in xylem?
I. Flow is driven by higher concentration of sugar in the vessel elements
II. Flow from root to twigs and leaves would be reduced if leaves are removed
III. In the morning, sap begins to flow first in the twig then in trunk
IV. Rapid flow of water put tissues under pressure much more than atmospheric pressure
I and IV
II and III
I, II, III and IV
No one is correct
Related Questions
What is the main driving force for transpiration?
Root pressure
Capillary action
Difference in water potential
Photosynthesis
Which of the following processes directly contributes to the opening of stomata?
Release of abscisic acid (ABA) by guard cells
Active transport of potassium ions into guard cells
Decreased turgor pressure in guard cells
Movement of water out of guard cells
Lenticels on woody stems help in?
Transpiration
Exchange of gases
photosynthesis
1 and 2
Read the following statement carefully and choose the right answer from the codes given below
I. PMA and silicon oil of low viscosity are considered as antitranspirant
II. BAP, NAA and cobalt chloride is also used as antitranspirant
III. Abscisic acid affects the mechanism of opening and closing of stomata
IV. Starch of guard cells is converted into PEP ions by the process of hydrolysis
V. Potometer works on the principle of potential difference between the tip of the tube and that of plant
VI. Transpiration rate is directly proportional to the relative humidity
I and III
II and IV
III and V
IV and VI
In land plants, the guard cells differ from other epidermal cells in having
Mitochondria
Endoplasmic reticulum
Chloroplasts
Cytoskeleton
Which one of the following is the reason for higher rate of transpiration in Sorghum as compared to maize?
Increased shoot/root ratio
Increased rate of respiratory quotient
Increased rate of phototsynthesis
Decreased shoot/root ratio
Stoma opens, when
Guard cells swell due to an increase in their water potential
Guard cells swell by endosmosis due to influx of hydrogen ions (protons)
Guard cells swell by endosmosis due to efflux of potassium ions
Guard cells swell due to a decrease in their water potential
Cohesion force, a feature of cohesion theory is also called
Tensile strength
Adhesion force
Capillary action
Surface tension
Which one of the following is the reason for higher rate of transpiration in Sorghum as compared to maize?
Increased shoot/root ratio
Increased rate of respiratory quotient
Increased rate of phototsynthesis
Decreased shoot/root ratio
The sugarcane plant has
Dumb bell-shaped guard cells
Pentamerous flowers
Reticulate venation
Capsular fruits
