Comparative study of rates of rates of transpiration in the upper and lower surfaces of leaf, using four-leaf experiment

 

Practical Notebook Biology Standard XII

Biology 

Answeres

Practical Notebook
Standard XII

Class-12th

science

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B. DEMONSTRATION EXPERIMENTS

1. Comparative study of rates of transpiration in the upper and lower surfaces of the leaf, using four-leaf experiment.  7 Loss of excess water in the form of vapor through the aerial parts of the plant is called transpiration.  Aim: To study the comparative rate of transpiration in the upper and lower surfaces of a leaf by conducting four-leaf experiments.  

Requirements: - 

Two stands, thread, four leaves of Calotropis / banyan tree, Vaseline (petroleum jelly), etc.  Fig.  Comparison of transpiration, a demonstration by four-leaf experiment Apply Vaseline to leaf surface in the following manner, 

1. Leaf A: - Petroleum jelly is applied on both surfaces 

Figure: Procedure: 

The leaves selected should be healthy preferably of the same size and showing growth.  Tie the different leaves of the same plant with thread in such a way that they will be equidistant and surfaces will be properly exposed to the sunlight.  Tie the thread to the stand at both ends.  2.  3 41 

2. Leaf B: - Petroleum jelly is applied on the lower surface only.  

3. Leaf C: - Petroleum jelly is applied on the upper surface only 

4. Leaf D: - Petroleum jelly is not applied and then prepare observation table.  

Observe the order of drying of these leaves, 2-3 days after setting off the apparatus Observation table: Sr.  1 Type of leaf Leaf A Leaf B Leaf C Leaf D 69 Observation leaf is fresh and not yet dried leaf look fresh but Silighting dixie leaf is dried or willed portly Ileat is willed completely.