Question

The plant factor which affects the transpiration are (a) Number and distribution of stomata (b) Number of stomata open (c) Water status of plant (d) All of these

Short answer

The correct answer is (d) All of these.

Step-by-step solution

Understanding the role of stomata in transpiration

Stomata are small openings on the plant leaves that allow transpiration. The number and distribution of stomata, as well as how many are open, would naturally impact the rate of transpiration. Therefore, option (a) and (b) are correct.

Considering the water status of the plant

The water status of the plant directly impacts transpiration. If the plant is in a well-watered condition, its stomata tend to open and allow a higher rate of transpiration. Consequently, option (c) is also correct.

Combining all the factors

After examining each of the factors presented independently, we can conclude that all of them - the number and distribution of stomata, the number of open stomata, and the water status of the plant - would play a role in how much transpiration the plant undergoes. Therefore, option (d), which combines all these factors, is the most comprehensive answer.

Key concepts

Stomata and Transpiration

Transpiration is a critical process in plants that involves the movement of water through the plant and its subsequent loss as water vapor from the aerial parts, primarily through structures known as stomata.

Stomata are tiny openings primarily found on the underside of plant leaves that regulate both the uptake of carbon dioxide for photosynthesis and the release of oxygen. However, a critical function they serve is to facilitate the loss of water vapor to the atmosphere in the process of transpiration.

The Role of Stomata in Transpiration

Stomata play a direct role in determining the transpiration rate. When stomata are open, transpiration rates increase because more water can escape from the leaf's internal parts to the external environment. Various environmental conditions such as light, humidity, and the plant's water status can influence whether stomata open or close.

Additionally, the distribution and density of stomata on leaves can affect how much water is transpired. Leaves with a high density of stomata may transpire more water than those with fewer stomata. It is also essential for students to understand that transpiration is not merely water loss but a process that drives the movement of water and nutrients from the roots up through the plant in a system known as the transpiration stream.

Water Status of Plants

The water status of a plant greatly impacts its physiological activities, including transpiration.

The water status can be defined as the balance between water uptake by the roots and water loss through transpiration. Factors that affect the water status include the plant's hydration level, the water content in the soil, and environmental conditions such as temperature and humidity.

Effect of Water Availability on Transpiration

If a plant has sufficient water, the turgidity of the cells, including the guard cells around the stomata, is maintained, leading to the stomata being open. This state promotes higher transpiration rates. Conversely, during water stress, plants will often close their stomata to conserve water, significantly reducing transpiration. This adaptive mechanism helps plants to manage their water economy under different environmental conditions and is crucial for their survival.

Plant Physiology

Plant physiology encompasses the study of how plants function, including processes like photosynthesis, respiration, and transpiration. These complex processes are interlinked and are crucial for plant growth, reproduction, and survival.

Transpiration is a physiological process with both short-term and long-term consequences for the plant. Short-term, it's involved in nutrient uptake and temperature regulation. Long-term, it affects the plant's growth patterns, water-use efficiency, and stress responses.

Big Picture of Plant Physiology

Understanding the physiology of a plant requires looking at how various processes work together synergistically. For instance, transpiration affects the transport of nutrients and maintains the plant's temperature, which in turn affects photosynthetic efficiency and overall plant growth. Students should be able to envision these processes not in isolation but as a complex, finely-tuned system that allows plants to interact with their environment and perform vital life-supporting tasks.