Morphology of Flowering Plants's Question 27 | Biology XI | NCERT Exemplar Questions

Botany

The Living World Biological Classification Plant Kingdom Morphology of Flowering Plants

Zoology

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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 photosynthesise like any other green plant?

Explanation

In insectivorous plant, e,g., Nepenthes, the leaf lamina gets modified in the form of pitcher and anterior part of petiole coils like tendril which keeps the pitcher in a vertical direction. Posterior part of the petiole remains flattened like a leaf. The apex of lamina forms a lid. Pitcher contains digestive enzyme which digest the trapped insects.

All these modifications and adaptation are developed to make up the nitrogen deficiency in the plant because these plants are found in $\mathrm{N}_2$ deficient soil, (marshy/swamp soils)

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?

Explanation

Mango and coconut are drupe fruits. They develop from monocarpellary superior ovaries and are one seeded. It is differentiated into outer thin epicarp, middle fleshy mesocarp and inner stony endocarp.

The edible part of coconut (Cocos nucifera) 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.

How can you differentiate between free central and axile placentation?

Explanation

Placentation is the arrangement of ovules on the walls of ovary with the help of special kind of tissue called placenta. Plants show different types of placentation, central and axile are among them.

They have the following differences

Free Central Placentation	Axile Placentation
Ovary contains only one chambers the placenta bearing. The ovules are borne on the central axis and less free inside the ovary. The septa are absent.	Ovary is syncarpous and multi-carpellary, i.e., contain many chambers. Placenta arise from the central axis where the septa fuse to form axile column to which ovules are attached.

Tendrils are found in the following plants. Identify whether they are stem tendrils of leaf tendrils.

(a) Cucumber (b) Peas (c) Pumpkins (d) Grapevine (e) Watermelon

Explanation

(a) Cucumber (Cucums sativus), have stem tendril from axillary bud.

(b) Peas (Pisum sativum) leaf gets modified into tendril for climbing.

(d) Grape wine (Vitis), stem tendril from axillary bud.

(e) Water melon (Citrullus lanatus), stem tendril from axillary bud.

Why is maize grain usually called as a fruit and not a seed?

Explanation

The maize grain is usually known as fruit because it is infact a ripend ovary which contains a ripened ovule, e.g., a single seed. This fruit is known as caryopsis in which the pericarp is fused with the seed coat. The maize grain occurs attached to a thick cob or peduncle.

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