Consider a plant exhibiting guttation. Which of the following statements regarding the xylem sap at night is MOST accurate?
Transpiration pull generates negative pressure in the xylem
Root pressure generates positive hydrostatic pressure in the xylem
Cohesion-tension theory is the primary driver of xylem sap movement
Xylem sap movement ceases entirely at night
Related Questions
Attraction of water molecules to polar surfaces is known as
    Cohension
Capillarity
Surface tension
Adhesion
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
I, III and V
II, IV and VI
    Guard cells control
    Intensity of light entering
Photosynthesis
Closing and opening of stomata
Change in green color
Water is lost in a liquid state in some plants through hydathodes. These hydathodes
    Remain closed at night
    Remain closed during day
    Remain always open
    Do not show any specificity in opening and closing
Scotoactive stomata are seen in?
Succulent plants
Mesophytic grass
Hydrophytes
Mesophytic trees
    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
Guard cells help in
Transpiration
Guttation
Fighting against infection
Protection against grazing
In land plants, the guard cells differ from other epidermal cells in having
    Mitochondria
Endoplasmic reticulum
Chloroplasts
Cytoskeleton
The force responsible for the water movement against gravity even up to a 130 m of tall free comes from
    Root pressure
Transpiration pull
Diffusion pressure
Pulsation
