Question

Match Colum-l with Column-ll and selec the corred oction from the codes given below. Column-I Column-II A. Dixon and jalig (0) Poct pressure B. Stomata (i) Orly water avalable to plants C Mancmeter (iii) Trensciration D. Capillary water (iv) Transpiration pull E. Potometer (v) Rate of transpiration (a) A-(iv), B-(iii), C-(v), D-(ii), E-0) (b) \(A-(i), B-(i i i), C-(i v), D(i), E-(v)\) (c) \(A-(i v), B-(i i i), C-(i), D-(i), E(v)\) (d) \(A-(v), B-(i v), C-(i i i), D-(i i), E-(i)\)

Short answer

The correct option is (c) A-(iv), B-(iii), C-(0), D-(i), E-(v).

Step-by-step solution

Understanding the Concepts

To match the terms in Column-I with the correct options in Column-II, understand what each term represents:A. Dixon and Joly refers to scientists who proposed the cohesion-tension theory explaining the transpiration pull.B. Stomata are the pores in plant leaves through which transpiration occurs.C. Manometer is an instrument used to measure pressure, often related to gas pressure.D. Capillary water is water held in the soil that can be absorbed by plant roots.E. Potometer is an instrument used to measure the rate of transpiration in plants.

Matching Column-I with Column-II

Match each term in Column-I with its corresponding concept in Column-II:A. Dixon and Joly though indirect but they are related to (iv) Transpiration pull.B. Stomata is directly related to (iii) Transpiration.C. Manometer, although used for various pressures, is not related to transpiration directly, but the choice (i) Only water available to plants does not make sense, so the next option is (0) Root pressure related to water movement in plants.D. Capillary water is correctly matched with (i) Only water available to plants because it is the water accessible to the root system.E. Potometer measures the (v) Rate of transpiration.

Select the Correct Option

Based on the matched terms, find the appropriate answer from the given options:A-(iv), B-(iii), C-(0), D-(i), E-(v). The correct option that matches this arrangement is (c) A-(iv), B-(iii), C-(0), D-(i), E-(v).

Key concepts

Transpiration Pull

Transpiration pull helps plants draw water upwards from the roots to the leaves, even defying gravity. Imagine drinking with a straw – as you suck the air out of the straw, the liquid rises. Similarly, when water vapor exits through the stomata during transpiration, it creates a tension (a 'pull') on the water molecules below. This is all thanks to water’s cohesion property (the attraction between water molecules) and adhesion (attraction between water molecules and other surfaces). Water molecules stick together and form a continuous stream from the roots to the leaves, moving upwards in the xylem vessels as one unit.

Let's remember that transpiration isn't just water loss; it is a vital process that drives the upward transport of nutrients and maintains plant turgor, which is essential for keeping the plant upright and growing. The understanding of transpiration pull is crucial for students as it explains how water can travel through the plant against gravity without the need for a pumping mechanism.

Stomata Function

Stomata are tiny openings on the surfaces of leaves, commonly on the underside to reduce water loss. Each stoma (singular of stomata) is flanked by a pair of guard cells that swell or shrink to open or close the pore.

Let's use a relatable analogy: stomata are like windows in a house. When it gets too warm inside, you might open a window to let some air out. Similarly, stomata open to release water vapor and oxygen into the atmosphere and at the same time, they take in carbon dioxide necessary for photosynthesis. It's a delicate balance – the plant wants to let in enough CO2 without losing too much water. This stomatal function is a textbook example of plant adaptation as they help regulate the plant’s water balance and gas exchange.

Measuring Transpiration

Have you ever wondered how scientists measure the seemingly invisible process of transpiration? They use a tool called a potometer! It's designed to measure the rate at which a plant absorbs water, which is directly related to the rate of transpiration.

A simple potometer consists of a tube filled with water and is connected to a plant's stem. As the plant transpires, water is absorbed to replace the lost water, and the movement of water in the tube can be measured. By monitoring how quickly the water level in the tube decreases, scientists can quantify the rate of transpiration. This measurement helps them understand various factors influencing transpiration rates, including temperature, humidity, and light intensity. Measuring transpiration with a potometer is an excellent practical exercise that can help students visually grasp the concept and effects of transpiration.

Cohesion-Tension Theory

The cohesion-tension theory is fundamental in understanding how water moves up plants. This scientific concept explains that water molecules are cohesive (they stick to each other), and they are under tension (a negative pressure) because of transpiration.

Think of it like a team effort in tug-of-war. Water molecules stick together just like the team members’ hands, and when transpiration pulls on the chain of water molecules, the whole 'team' of molecules moves upwards through the xylem vessels. This upward pull is the 'tension' part. Moreover, adhesion of water molecules to the walls of the xylem vessels helps resist the force of gravity pulling them down. Without this process, trees wouldn't be able to transport water from their roots to their leaves, which can sometimes be over 100 meters aboveground. Understanding the cohesion-tension theory is essential for students because it explains how plants can move nutrients and maintain structure without any mechanical pump.