More stomata are predominantly found on the lower surface of a dorsiventral leaf.
Dorsiventral leaves, commonly found in dicotyledonous plants, have distinct upper and lower surfaces. This difference in structure leads to an uneven distribution of stomata. The primary reason for this distribution pattern is to minimize water loss.
Why more stomata are on the lower surface:
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Reduced Direct Sunlight: The lower surface of the leaf receives less direct sunlight compared to the upper surface. This reduces the rate of transpiration (water loss through stomata) from the lower surface.
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Lower Temperature: Due to less exposure to direct sunlight, the lower surface tends to be cooler than the upper surface. Lower temperatures decrease the rate of evaporation, further reducing water loss.
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Protection from Wind: The lower surface is often sheltered from direct wind exposure, which can also exacerbate water loss through transpiration.
Comparison of Stomatal Distribution:
| Leaf Surface | Stomata Density | Primary Reason |
|---|---|---|
| Upper | Fewer | Minimize water loss due to direct sunlight and heat. |
| Lower | More | Facilitate gas exchange while minimizing water loss. |
In summary, the strategic placement of more stomata on the lower surface of dorsiventral leaves is an adaptation to balance the need for gas exchange (carbon dioxide intake for photosynthesis and oxygen release) with the need to conserve water.
