If the mass flow hypothesis were entirely accurate, which scenario would be LEAST likely to occur in a plant?
Movement of sucrose from a leaf to a developing fruit.
Higher turgor pressure in phloem sieve tubes near a photosynthesizing leaf compared to those near a root tip.
Simultaneous bidirectional transport of different organic molecules within the same sieve tube element.
Changes in phloem sap composition based on the source and sink tissues involved.
Related Questions
    Choose the false statement
    If bark of tree is girdled from main stem, the plant dies because ascent of sap is stopped
    If xylem is girdled from main stem, wilting of leaves tales place
In the flowerering plant food is transported in the form of dissacharide sucrose
    In Girdling experiment, in a plant, root dies first
The 'Girdling Experiment' is conducted by plant physiologists to identify the tissue responsible for:
Translocation of food
Translocation of water
Transpiration
Absorption of water
Loading of sucrose in sieve tube elements is
Simple diffusion
Active process
Facilitated diffusion
Osmosis
According to the mass flow hypothesis, what is the main driving force for the translocation of organic solutes in phloem?
Transpiration pull
Root pressure
Capillary action
Osmotic pressure gradient between source and sink
    Which of them is/are correct regarding pressure flow model for translocation?
I.    Sugar is transported through phloem as glucose
II.    Movement of sugar is carried out through sieve tube near the source region
III.    Concentration of sugar is always highest near the sink region
IV.    Water from the adjacent xylem moves into phloem by osmosis
I and III only
II and IV only
I, II, and III only
II, III, and IV only
Unloading of minerals in leaves is?
Active process
Passive process
Simple diffusion
None of these
    Choose the correct statements regarding the uptake of mineral nutrients and food in plants
    Even a little amount of exchange of material does takes place between xylem and phloem
    Most of the minerals enter the root through active absorption
    Due to variable relationship between source and sink direction of sap flow in phloem is
bidirectional
All of the above
    Arrange the following events of mass flow of organic material in sequence
I.    Sugars are transported from cell to cell in the leaf
II.    Food is synthesised in form of glucose by leaf cells
III.    Movement of water takes place into sieve tube elements
IV.    Downward movement of sugar occurs in the stem
V.    Solutes are actively transported into the sieve elements
I, II, III, V, IV
II, I, V, III, IV
II, III, I, V, IV
I, II, V, IV, III
If the mass flow hypothesis were entirely accurate, which scenario would be LEAST likely to occur in a plant?
Movement of sucrose from a leaf to a developing fruit.
Higher turgor pressure in phloem sieve tubes near a photosynthesizing leaf compared to those near a root tip.
Simultaneous bidirectional transport of different organic molecules within the same sieve tube element.
Changes in phloem sap composition based on the source and sink tissues involved.
A plant is exposed to for a short period. After 5 minutes, the radioactive carbon is detected in the phloem sieve tubes near the source. After 20 minutes, it's found further down the stem in the phloem. Which observation MOST directly contradicts the mass flow hypothesis?
Sucrose moves bidirectionally in the phloem, sometimes against the concentration gradient.
ATP is required for active loading of sucrose into the sieve tubes.
The concentration of sucrose is higher in the source than in the sink.
Water moves from xylem to phloem at the source and from phloem to xylem at the sink.
