Question

Given above is the diagram of an experimental setup to study the process of transpiration in plants. Study the same and then answer the questions that follow:

(a) Name the color of dry cobalt chloride paper?

(b) Is the experimental leaf a monocot or a dicot? Give a reason to support your answer.

(c) Why are glass slides placed over the dry cobalt chloride papers?

(d) After about half an hour what change, if any, would you expect to find in the cobalt chloride paper placed on the dorsal and ventral sides of the leaf? Give a reason to support your answer.

Answer 1

Part (i): Cobalt chloride paper:

1. The cobalt chloride paper is blue in color.
   
2. It is used because it changes its color indicating the presence of moisture.
   

Part (ii): Type of leaf used:

1. Dicot leaf is used in the experiment.
   
2. This is because the dicot leaves possess reticulate venation and different levels of stomata in the two sides of the leaf.
   

Part (iii): Glass slides:

1. Glass slides are kept over the cobalt chloride paper to keep the moisture contained.
   
2. It does not let the moisture evaporate and maintain the cobalt chloride paper at the same place on the leaf.
   

Part (iv): Changes after an hour:

1. The cobalt chloride paper changes its color to pink due to the presence of moisture that occurs as a result of transpiration.
   
2. The cobalt chloride paper on the dorsal side will turn less pink while on ventral side will turn more pink.
3. The result proves that there are more stomata on the ventral side of the leaf while there are less stomara present on the dorsal side.