Problem 65 - Objective Biology for NEET

Question

Sepals or petals in a whorl just touch one another at the margin, without overlapping is found in (a) China rose (b) Pea (c) Cassia (d) Calotropis

Step-by-Step Solution

Answer

(b) Pea

Step 1: Research Botanical Characteristics

First, gather information about the botanical characteristics of the given plants. Specifically, look for information about the configuration of their petals or sepals. The plant in question should have sepals or petals that just touch one another without overlapping.

Step 2: Compare Characteristics to Given Description

Then, compare the information collected in step 1 with the description provided in the exercise.

Step 3: Identify the Matching Plant

The plant that matches the given description is the correct answer. In this case, the petals or sepals of Pea (Pisum sativum) are known to touch each other at the margin without overlapping. So, the correct answer is (b) Pea (Pisum sativum).

Key Concepts

Sepals

Sepals are an integral part of a flower's anatomy. They are leaf-like structures that encase and protect the floral bud before it blooms. These structures usually form the outermost part of a flower, creating a layer often referred to as the 'calyx'. The primary function of sepals is to shield the developing flower from harsh conditions and external threats.

• They are typically green, though sometimes can be colorful, adding to the visual appeal of the bloom.
• In some plants, sepals can resemble petals, a condition known as 'tepals', where differentiation is unclear.

In the context of the exercise, understanding the behavior of sepals—whether they overlap or simply touch at the margins—helps identify the correct plant species.

Petals

Petals are often the most noticed part of a flower due to their vibrant colors and varying shapes. They play a crucial role in attracting pollinators such as bees, birds, and insects. Petals together form what is known as the 'corolla'. The aesthetic and functional aspects of petals highlight their importance in plant reproduction.

• They can vary greatly among species in color, size, and number.
• Petals are generally more delicate than sepals and serve primarily to invite pollinators.

In the question, the arrangement of petals—whether touching without overlapping—can be a key differentiator among plant species. Recognizing such formations aids in identifying plants like Pisum sativum, which bears closely arranged petals.

Whorl

Whorl refers to a circular arrangement of sepals, petals, leaves, or branches that emanate from a single point around a stem. This configuration is vital in classifying and identifying plants by their floral pattern.

• From a floral perspective, a whorl consists of one or more circles of floral organs.
• The mutual arrangement—whether overlapping or merely touching their neighbors—is crucial for identifying specific plant species.

In Pisum sativum, the configuration of the petal whorl is such that the petals just touch as opposed to overlapping. Recognizing these subtle arrangements facilitates plant identification.

Pisum sativum

Pisum sativum, commonly known as the garden pea, is a member of the legume family. This plant is known for its agricultural importance and distinct morphological features.

• It exhibits flowers that are generally pink, white, or purple, depending on the variety.
• The petals and sepals are arranged such that they merely touch each other at the margins without overlapping.

Understanding these features of Pisum sativum helps distinguish it from other plants in botanical exercises and reinforces its role in plant morphology studies.