HORTICULTURE

HORTICULTURE SCIENCE

PLANT BIOLOGY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What causes a plant to wilt?
A
response to gravity
B
negative homeostasis
C
excessive humidity
D
lack of turgor pressure
Explanation: 

Detailed explanation-1: -Wilting is the loss of rigidity of non-woody parts of plants. This occurs when the turgor pressure in non-lignified plant cells falls towards zero, as a result of diminished water in the cells. Wilting also serves to reduce water loss, as it makes the leaves expose less surface area.

Detailed explanation-2: -turgor, Pressure exerted by fluid in a cell that presses the cell membrane against the cell wall. Turgor is what makes living plant tissue rigid. Loss of turgor, resulting from the loss of water from plant cells, causes flowers and leaves to wilt.

Detailed explanation-3: -Without adequate water in the extracellular fluid water molecules will tend to move out of the cell and thus cause a neutral or negative net water movement, thus a relatively low turgor pressure. A plant cell in an isotonic fluid could lose its turgor pressure and become flaccid.

Detailed explanation-4: -The loss of turgor causes the violent detachment of the living protoplast from the cell wall. The plasmolytic process is mainly driven by the vacuole. Plasmolysis is reversible (deplasmolysis) and characteristic to living plant cells.

Detailed explanation-5: -Plants wilt when roots are unable to supply sufficient moisture to the stems and leaves. Wilting for short periods of time does not harm plants. Sometimes a plant wilts on a hot day because moisture is evaporating from the leaves faster than the roots can take it up.

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