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How the plant ben
Plants have developed a number of strategies to capture the maximum amount of sunlight through their leaves. As we know from looking at plants on a windowsill, they grow toward the sunlight to be able to generate energy by photosynthesis. Scientists have provided definitive insights into the driving force behind this movement – the plant hormone auxin.
The growth of plants toward light is particularly important at the beginning of their lifecycle. Many seeds germinate in the soil and get their nutrition in the dark from their limited reserves of starch and lipids. Reaching for the surface, the seedlings rapidly grow upwards against the gravitational pull, which provides an initial clue for orientation. With the help of highly sensitive light-sensing proteins, they find the shortest route to the sunlight – and are even able to bend in the direction of the light source.
EXPLANATION: We know that green plants make their food by the process of photosynthesis. The leaves of the green plants contain a green pigment called chlorophyll. Chlorophyll converts water from the soil and carbon dioxide from the air into oxygen and sugar.
Oxygen is then released into the air and sugar is taken as food by the plant. But this entire process of making food can only be done in the presence of sunlight. The leaves, therefore, lean towards the light for photosynthesis. Without sunlight green plants cannot survive.
Plant cells contain a substance called auxins. This substance has a tendency to move away from the light. Auxins make the cells on the darker side grow faster than the cells on the lighter side.
This causes the stems and the leaves to bend or lean towards the lighter side. The concentration of auxins on the dark side may be due to the fact that sunlight slows or kills these auxins molecules when light fall on them. However, as long as one part of the plant gets sunlight, it can make food and the whole plant survives.
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