NCERT Class 11-Biology: Chapter –5 Morphology of Flowering Plants Part 4

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Question 5:

Given below are a few floral formulae of some well-known plants. Draw floral diagrams from these formulae.

(i)

Answer:

(i) The given floral formula shows that the flower from Solanaceae family.

Solanaceae Family

Solanaceae Family

(ii) The given floral formula is a flower from Fabaceae family.

Fabaceae Family

Fabaceae Family

(iii) The given floral formula is a flower from Malvaceae family.

Malvaceae Family

Malvaceae Family

Question 6:

Reticulate venation is found in dicot leaves while in monocot leaves venation is of parallel type. Biology being a ‘Science of exceptions’, find out any exception to this generalization.

Answer:

The arrangement of veins and the veinlets in the lamina of leaf is termed as venation.

When the veinlets form a network, the venation is termed as reticulate.

When the veins run parallel to each other within a lamina, the venation is termed as parallel.

Leaves of dicotyledonous plants generally possess reticulate venation, while parallel venation is the characteristic of most monocotyledons.

There are a few exceptions like Smilax and Discorea are monocots with reticulate venation and Calophyllum and Eryngium are dicots with parallel venation.

Question 7:

You have heard about several insectivorous plants that feed on insects. Nepenthes or the pitcher plant is one such example, which usually grows in shallow water or in marsh lands. What part of the plant is modified into a ‘pitcher’? How does this modification help the plant for food even though it can photosynthesize like any other green plant?

Answer:

Leaves are often modified to perform functions other than photosynthesis. Leaves of certain insectivorous plants such as pitcher plant, venus-fly trap are also modified leaves. In pitcher plant, the leaf is modified into pitcher. The pitcher plant can’t photosynthesize like other green plants so it get its food from the insects as these insects are good source of Nitrogen for the insectivorous plants.

Question 8:

Mango and coconut are ‘drupe’ type of fruits. In mango fleshy mesocarp is edible. What is the edible part of coconut? What does milk of tender coconut represent?

Answer:

Generally, the fruit consists of a wall or pericarp and seeds. The pericarp may be dry or fleshy. When pericarp is thick and fleshy, it is differentiated into the outer epicarp, the middle mesocarp and the inner endocarp.

The edible part of coconut is endosperm. The milk of tender coconut represents the oily endosperm in liquid form. Later it gets deposited along the walls of endocarp and forms edible flesh.

Question 9:

How can you differentiate between free central and axile placentation?

Answer:

The arrangement of ovules within the ovary is known as placentation.

When the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentaion is said to be axile. Examples - china rose, tomato and lemon.

Placenta is Axial

Placenta is Axial

When the ovules are borne on central axis and septa are absent, the placentation is called free central.

Examples - Dianthus and Primrose.

Central Axis

Central Axis

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