Question
Question: Match the following and choose the correct combination from the options given below. Placentation ty...
Match the following and choose the correct combination from the options given below. Placentation types and Represented in Column I and Column II respectively.
| Column 1 | Column 2 |
|---|---|
| A. Basal. | 1. Dianthus |
| B. Free central. | 2. Pea |
| C.Parietal | 3. Lemon |
| D.Axile | 4. Marigold |
| E.Marginal. | 5.Argemone |
A-1, B-2, C-3, D-4, E-5
A-2, B-3, C-4, D-5, E-1
A-4, B-1, C-5, D-3, E-2
A-4, B-3, C-5, D-1, E-2
A-5, B-4, C-3, D-2, E-1
Solution
In plants, the term placentation refers to the arrangement of ovules within the ovary and it is frequently of any economic value. In plants, there are mainly five types of placentation which are explained below.
Complete step by step answer: Basal placentation- In this type of placentation there is only a single ovule present and it is present at the base of the ovary and in this ovary is unilocular. This type of placentation is seen in the Asteraceae family including Sunflower and marigold.
Free central- In this type of placentation also the ovary is unilocular and ovules are found to be borne on the central axis in the center of the ovary. It is found in Syncarpous gynoecium. There, they lack septum. For example, they are present in the Caryophyllaceae family including Dianthus and Primrose.
Parietal- It is seen in the unilocular syncarpous ovaries. The ovule is seen to be developed on the inner wall or periphery of the ovary. The ovary is seen to be bilocular or multilocular due to the formation of the septa which is the false septum. For example, it includes the Cruciferae family having Mustard and also includes Cucurbita.
Axile- Axile type of placentation is seen in multicarpellary syncarpous gynoecium. It is seen the fusion margin of carpets grows and they meet in the center of the ovary. Therefore it leads to axis formation in the center of the ovary and the ovary becomes multi-chambered. It is seen that the number of these chambers is equal to the number of carpels. It is seen in lemon, tomato, orange, potato and china rose, etc.
Marginal- Marginal type of placentation is mostly seen in the unilocular ovary. The placenta seems to form a ridge along with the ovary and ovules are seen to be borne on this ridge forming two rows of it. Examples include Family Leguminosae.
So, the correct answer to this question is the option"C".
Note: The placentation pattern helps to differentiate between different species of the plants. The placentation differs greatly among various plant families. Its main function is to transfer nutrients, respiratory gases, and water from maternal tissue to the embryo.