In an experiment, a student removes all the leaves of a geranium plant. Several days later, the student notices new leaves growing from the stem.
Which source of energy is needed for the new leaves to grow?
A. starch stored in the roots
B. water absorbed by the roots
C. fertilizer absorbed by the roots
D. photosynthesis occurring in the roots
The correct answer is A. starch stored in the roots. When the leaves are removed, the plant can rely on the stored starch in the roots as an energy source for new leaf growth. Water absorbed by the roots is important for overall plant health, but it is not specifically needed for new leaf growth. Similarly, fertilizer absorbed by the roots contributes to plant nutrition, but it is not the direct source of energy for leaf growth. Photosynthesis occurs in the leaves, not the roots, and is responsible for producing glucose, which is then converted into starch and stored in the roots.
The correct answer is D. photosynthesis occurring in the roots.
Photosynthesis is the process by which plants convert sunlight into energy, allowing them to produce their own food in the form of glucose. In this case, since the leaves have been removed, the plant cannot perform photosynthesis using its leaves. However, some plants are capable of photosynthesis occurring in other parts, such as the stem or roots. The new leaves that the student observes are most likely growing as a result of photosynthesis happening in the roots.
To determine which source of energy is needed for the new leaves to grow in this experiment, we need to understand the process of photosynthesis in plants.
Photosynthesis is the process through which plants convert light energy from the sun into chemical energy in the form of glucose, or sugar. This chemical energy is crucial for plant growth and is used for various functions, including the development of new leaves.
Since the student removed all the leaves from the geranium plant, it means that the leaves are not present to carry out photosynthesis. Therefore, the source of energy for the new leaves to grow cannot be photosynthesis occurring in the roots (option D) because photosynthesis primarily occurs in the leaves, not the roots.
Next, let's evaluate the remaining options:
A. Starch stored in the roots: Starch is a carbohydrate that serves as a storage form of glucose in plants. While starch can be broken down into glucose to provide energy for growth, it is not the primary source of energy for new leaves to grow. Additionally, plants often store starch in structures other than the roots, such as tubers or bulbs.
B. Water absorbed by the roots: Water is essential for a plant's growth, and it plays a vital role in many physiological processes. However, water alone does not provide the necessary energy for new leaves to grow.
C. Fertilizer absorbed by the roots: Fertilizers are compounds that provide essential nutrients to plants to support their growth. While fertilizers contribute to various metabolic processes in plants, they are not the direct source of energy for new leaves to grow.
Given the options provided, the most likely correct answer is option A. Starch stored in the roots. Although starch is not the primary source of energy for new leaves to grow, it can be broken down into glucose, which is then used for energy during the growth process.
It's important to note that while this explanation provides a logical answer, the experiment and its variables might play a significant role in determining the actual answer.