Biology Questions and Answers

Biology Questions and Answers

6. How do plants control the
   opening and the closing of the
   stomata?

The opening and the closing ostomata depend upon the necessity off the (^)
the plant to lose transpiration (exit of water water and heat thrvapor meansough (^)
elimination of heat). When the plant has
excessiveturgid and the ostiole op water the guard cells becomeens. When little (^)
water is available the guard cells
become flaccid and the ostiole closes.
Water enters anby osmosis. d goes out the stomata
Other factorscarbon dioxide concentration in like light intensity andthe
leaves influence the opening and the
closing is high the photosynthesisof the stomata. When luminosity rate
increases and the stomata open to
absorb menvironment and release hore carbon dioxide from theeat; when
luminosity is low the stomata tend to
close. Wconcentration ihen the carbon dioxiden the photosynthetic (^)
parenchyma is low the stomata open to
absorb mphotosynthore of the gas and makeesis possible; when such (^)
concentration is high the stomata tend
to close.

7. Do plants placed under an
   environment drier than the
   habitat where they are used to
   living have an increase or a
   reduction in the time during
   which their stomata remain
   open?

If plants from a moister region were

transferred to a drier region probablytheir stomata would remain closed for a (^)
longer time, i.e., the time during which
stomatalower the loss of are open will bwater be reduced toy transpiration.

8. Why do some plants
   adapted to a dry environment
   open their stomata only at
   night?
   During the day in dry habitats the guardcells become flaccid and the stomata
   close; concurrently carbon dioxide is

disallowed to diurnal photosynthesis.pass to participate i Some plantsn (^)
from dry regions solve this problem
through the method of nocturnal carbondioxide fixation. At night, when water
loss by transpiration is lower, the
stomataand it is store open, carbon d within the parenchymaldioxide enters (^)
tissues. During the day the stored gas is
mobilized to be used in photosynthesis.

9. How has the position of the
   stomata changed in some
   plants to prevent excessive
   water loss by transpiration?
   In some plants that have leaves that

receive concentrate itoo mucn the inferior eh sunlight the stomatapidermis, so (^)
their heating is lower and less water is
lost by plants of dry environments the stomatastomatal transpiration. In other (^)
group in some the surface of these areas the wateregions of the leaf; overr
concentration of the air is higher
comparing to the environment and the
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