Photosynthesis occurs mainly in the leaves of plants. Leavers are specially efficiency.
During Photosynthesis - Carbon dioxide diffuses in through the stomata. Oxygen diffuses out through the stomata. And water is absorbed through the root hair cell.
A leaf has four distinct layers:
- The upper epidermis - is transparent to allow the sunlight through to the layer below.
- The palisade layer
- The spongy mesophyll - contains a lots of air spaces connected to the stomata to allow the optimum exchange of gases.
- The lower epidermis.
Osmosis is the diffusion of water from high concentration of water to low concentration of water through a partially-permeable membrane.
Water in Plants:
Plants use water to...
- keep their leaves cool
- transport minerals
- keep cell firm and the plant supported.
Two adaptation reduces the rate of water from the leaves:
- A waxy cuticle on the surface of the leaf.
- Having the majority of the stomata on the lower surface of the leaf.
Stomata open and close to allow the diffusion of gases and also to control the water loss.