Question

Commelina species produce two different types of bisexual flowers “A” and “B”. Select the correct option regarding types of flowers and modes of pollination from the Table given below:

• A. Both A and B are Chasmogamous
• B. A is Chasmogamous and B is Cleistogamous
• C. Both A and B are Cleistogamous
• D. A is Cleistogamous and B is Chasmogamous

Hint:

Examples of plants showing both chasmogamous and cleistogamous flowers include: \[ \text{Commelina, Viola and Oxalis} \] Remember: Chasmogamous $\rightarrow$ Open flowers $\rightarrow$ Usually cross-pollination Cleistogamous $\rightarrow$ Closed flowers $\rightarrow$ Guaranteed self-pollination

Answer 1

The Correct Option is B

Concept: Some flowering plants possess two different types of flowers to ensure reproductive success under varying environmental conditions. Commelina is a well-known example that produces both chasmogamous and cleistogamous flowers.
• Chasmogamous flowers are open flowers in which anthers and stigma are exposed. These flowers generally promote cross-pollination.
• Cleistogamous flowers remain closed throughout their life and ensure self-pollination. The presence of both flower types helps the plant achieve genetic variation through cross-pollination while also guaranteeing seed production through self-pollination when pollinators are absent.

Step 1: Understand Chasmogamous flowers.
The word “chasmogamous” means open-flowered. Characteristics: \[ \begin{aligned} &\text{Flowers open completely} \\ &\text{Anthers and stigma become exposed} \\ &\text{Pollinating agents can easily access the flower} \end{aligned} \] Therefore, these flowers commonly undergo: \[ \boxed{\text{Cross-pollination}} \] although self-pollination may also occur in some cases.

Step 2: Understand Cleistogamous flowers.
The word “cleistogamous” means closed-flowered. Characteristics: \[ \begin{aligned} &\text{Flowers never open} &\text{Pollen is transferred within the same flower} &\text{Pollinators are not required} \end{aligned} \] Hence: \[ \boxed{\text{Self-pollination is compulsory}} \] in cleistogamous flowers.

Step 3: Apply the concept to Commelina.
Commelina produces two kinds of bisexual flowers: \[ \begin{aligned} A &\rightarrow \text{Chasmogamous flower} \\ B &\rightarrow \text{Cleistogamous flower} \end{aligned} \] The chasmogamous flowers facilitate cross-pollination and genetic recombination, whereas the cleistogamous flowers guarantee seed formation through assured self-pollination.

Step 4: Verify the options.
\[ \begin{array}{|c|c|} \hline \text{Option} & \text{Status} \\ \hline \text{A} & \text{Incorrect} \\ \text{B} & \text{Correct} \\ \text{C} & \text{Incorrect} \\ \text{D} & \text{Incorrect} \hline \end{array} \] Thus the correct statement is: \[ \boxed{\text{A is Chasmogamous and B is Cleistogamous}} \] Hence, the correct answer is \[ \boxed{\text{(B) A is Chasmogamous and B is Cleistogamous}} \]