Question

In plants, the transpiration pull theory for ascent of sap was first proposed by
A. Dixon
B. Dixon and jolly
C. J.C. Bose
D. Strasburger

Answer 1

Hint: Ascent of sap is the upward movement of water and minerals from roots to the top. This theory is based on cohesion and adhesion.

Complete Answer:
- Dixon along with Jolly proposed the theory of movement of water and minerals from the roots to top based on cohesion and adhesion in 1894.
- J.C. Bose proposed the vital force theory. According to these theories the forces required for ascent of sap are generated in living cells of the plant. These theories are not supported by experimental evidence hence they have been discarded.
- Strasburger proposed that cytokinesis is present in both plants and animal cells.

So, the correct option is B as Dixon and jolly worked in collaboration with each other leading to the proposing of the transpiration theory for ascent of sap.

Note: Transpiration pull is the negative pressure developing at the top of the plant due to the evaporation of the water. Transpiration is the process of losing water from the leaf’s surfaces. This starts through the roots and ends up at the tip points of the leaves. This causes the movement of water against gravity.