Tag: botany

Questions Related to botany

Ascent of sap will be maximum during

botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

  1. Daytime

  2. Night time

  3. Early morning

  4. None of the above

Show answer
Correct Option: A
Explanation:

Cohesion transpiration pull theory was put forward by Dixon and Jolly in 1894. It is also known as Dixon's theory of ascent of sap. During day time, there will be maximum water loss due to transpiration, hence, transpiration pull will also be maximum during day time. Consequently, maximum ascent of sap will occur during day time.

The rate of transpiration ........... the process of ascent of sap.

botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

  1. Increases

  2. Decreases

  3. Do not affect

  4. Increases and then decreases

Show answer
Correct Option: A
Explanation:

Transpiration causes the development of a pull or a negative pressure region which created a suction force to aid the ascent of sap. It increases the process of ascent of sap.

So the correct answer is 'Increases'.

The root pressure theory considers ........... responsible for the ascent of sap.

botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

  1. Gravitational pull

  2. Hydrostatic pressure

  3. Capillary force

  4. None of the above

Show answer
Correct Option: B
Explanation:

The root pressure theory considers that hydrostatic pressure developed in the roots is responsible for pushing the water through the column. It depends on the active accumulation of minerals in the root cells which then causes passive absorption of water creating a high pressure.

It neglects the effect of gravity.
Capillary force is not the driving force in this theory.
Many small herbaceous plants only depend on root pressure for ascent of Sap.
So the correct answer is ' Hydrostatic pressure'.

Organic and mineral nutrients undergo______

botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

  1. Unidirectional

  2. Bidirectional

  3. Multidirectianal

  4. Both A and B

Show answer
Correct Option: D
Explanation:

Organic material in plants is transferred by phloem while water and mineral nutrients are transferred by xylem. It is a well-known fact that xylem only has unidirectional transport of water while phloem can exhibit bidirectional transport.

So, the correct answer is 'Both A and B'.

Movement of water and mineral salts in plant is __________.

botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

  1. Osmosis

  2. Absorption

  3. Ascent of sap

  4. Active absorption

Show answer
Correct Option: C
Explanation:

Ascent of Sap : Ascent of sap in the xylem tissue of plants is the upward movement of water from the root to the crown.

Pulsation theory was proposed by

botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

  1. Godlewski

  2. Jagadish Chandra Bose

  3. Dixon and Joly

  4. Arthur

Show answer
Correct Option: B
Explanation:
Sir J.C. Bose proposed a theory of ascent of sap known as pulsation theory. The pulsation theory states that water is absorbed by the plants due to the metabolic activity of living cells which are in constant state of rythmatic pulsation. But it was not accepted as water can be passively absorbed by the roots even the cells were dead.
So, the correct answer is option B.

Which substances do the plants obtain from the soil for the constitution of the body?

botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

  1. Organic substances

  2. Inorganic substances

  3. Complex substances

  4. Insoluble substances

Show answer
Correct Option: B
Explanation:
Soil contains a large number of inorganic substances in the form of ions which are taken up by the plant through process called ascent of sap
So, the correct answer is 'Inorganic substances'

Who found that overlapping cuts do not hinder ascent of sap

botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

  1. Askenasy

  2. Preston

  3. Mac Dougal

  4. Priestly

Show answer
Correct Option: A

Theory of 'Ascent of Sap' was given by Dixon and Jolly. Which of them is against the theory?

botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

  1. Cohesive and adhesive properties of H$ _2$O

  2. Requirement of ATP

  3. Presence of pores in the tracheary elements

  4. All of the above

Show answer
Correct Option: B
Explanation:

Ascent of sap theory is based on transpiration pull of a continuous water column in the xylem elements of plants. The continuous water column is generated because of adhesion and cohesion forces, operating between water molecules and xylem elements and between water molecules respectively. The pull is generated passively due to loss of water during transpiration and does not requires input of energy. Hence, there is no requirement of ATP in ascent of sap and it is a physical process only.

First theory for ascent of sap was proposed by

botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

  1. Westermeier

  2. Godlewski

  3. Bose

  4. Stephen Hales

Show answer
Correct Option: B
Explanation:

The first theories proposed to explain ascent of sap were Vital force theories. These theories believed that living cells are involved in the ascent of sap, e.g., relay pump theory by Godlewski, 1883 and Pulsation theory by Bose, 1923.  

Bose believed that the inner most cortical cells pump water into the interior that contains xylem channels. The vital force theories have been discarded because as proved by Boucherie in 1840 and Strasburger in 1891 water rises up the stem even when all the living cells are killed by poison or heat.