PLANTS
PLANT RESPONSES TO STIMULI
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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a wilted stem to return to an upright position.
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leaves to fall off a tree in the autumn.
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the roots of a plant to grow downward.
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a seedling to be carried by the wind.
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Detailed explanation-1: -As turgor pressure increases more water is pushed against the cell wall causing the plant to stand up straight. When turgor pressure decreases, the cells begin to shrivel, and the plant will begin to wilt. How does gravity affect a plant’s growth? Plants stems grow upward, and roots grow downward due to geotropism.
Detailed explanation-2: -turgor, Pressure exerted by fluid in a cell that presses the cell membrane against the cell wall. Turgor is what makes living plant tissue rigid. Loss of turgor, resulting from the loss of water from plant cells, causes flowers and leaves to wilt.
Detailed explanation-3: -Turgor pressure provides structural integrity to each cell and to the tissue as a whole (Fig. 1). At the cellular level, turgor pressure pushes the plasma membrane against the cell wall and causes in-plane mechanical tension within the cell wall (Fig. 1A).
Detailed explanation-4: -One significant function of the turgor pressure is to promote cell volume expansion (Kazuyuki et al., 1997), and the higher the turgor pressure is, the larger the leaf expansion will be (Liu et al., 2002). The magnitude of turgor pressure is determined by water potential and osmotic potential. Zou et al.