HORTICULTURE SCIENCE
ULTRA STRUCTURE OF PLANT CELLS AND ORGANS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The pressure in the plant cells is stronger than the force of gravity.
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The force of gravity is stronger than the pressure in the plant cells.
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The soil exerts an upward force on the seedling.
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The air in the soil exerts an upward force on the seedling.
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Detailed explanation-1: -Seedlings can only emerge from the soil when they push upward, exerting a force on the soil that is greater than the downward force of gravity. The turgor pressure inside of the plant cells must be high in order to have enough force to push up on the soil.
Detailed explanation-2: -Gravity perception is important to plants because they need to send their roots downwards towards water and nutrients and their shoots upwards towards light. Plants are known to detect gravity using statoliths, which are small starch-filled packets that settle at the bottom of gravity-sensing cells.
Detailed explanation-3: -Gravity affects the ecology and evolution of every living organism. In plants, the general response to gravity is well known: their roots respond positively, growing down, into the soil, and their stems respond negatively, growing upward, to reach the sunlight.