Question 1: Define transpiration and explain its significance in the water cycle of plants.

Answer: Transpiration is the process by which water vapor is lost from the plant, primarily through the stomata in leaves. It helps in cooling the plant, transporting minerals, and maintaining water flow from roots to leaves.

Question 2: Describe the mechanism by which water moves from the roots to the leaves during transpiration.

Answer: Water moves from the roots through the xylem vessels by capillary action and root pressure, aided by cohesion and adhesion between water molecules. Evaporation of water from the stomata creates a negative pressure that pulls water upward.

Question 3: Calculate the transpiration rate if a plant loses 0.5 grams of water over 2 hours. Express your answer in grams per hour.

Answer: Transpiration rate = Total water lost / Time = 0.5 g / 2 hours = 0.25 g/hour

Question 4: Which of the following factors does NOT affect the rate of transpiration? A) Light intensity B) Humidity C) Soil pH D) Wind speed

Answer: C) Soil pH

Question 5: Fill in the blank: The tiny pores on the surface of leaves through which transpiration occurs are called __________.

Answer: stomata

Question 6: Explain how environmental conditions such as humidity and temperature influence transpiration rates.

Answer: Higher temperature increases transpiration by enhancing evaporation, while higher humidity decreases transpiration by reducing the vapor gradient between the inside and outside of the leaf. Conversely, low humidity accelerates transpiration.

Question 7: Identify and describe two practical applications of understanding transpiration in agriculture or industry.

Answer: Understanding transpiration helps in optimizing irrigation techniques to prevent water wastage and in developing drought-resistant crops by modifying traits that control water loss.

Question 8: Describe an experiment to measure the effect of wind speed on transpiration rate, including variables to control and safety precautions.

Answer: An experiment can involve placing identical potted plants in areas with different wind speeds or using a fan to simulate wind. The independent variable is wind speed, while the dependent variable is water loss measured by weighing the pots. Control variables include plant type, soil moisture, and light exposure. Safety precautions include handling electrical equipment safely and avoiding exposure to moving fans for extended periods.

Question 9: Data Scenario: A plant loses 1.2 grams of water in 3 hours under conditions of low humidity. Predict how the rate of transpiration might change if humidity increases, and justify your answer.

Answer: The rate of transpiration would decrease because higher humidity reduces the vapor gradient between the inside of the leaf and the external environment, leading to less water vapor loss.