|MadSci Network: Botany|
Hello, You asked why the green algae Pleurococcus needs shade and moisture to grow. Plants such as trees and flowers need water and sunlight, among other things, to photosynthesize, and so do less-evolved plants like green algae. The other nutrients, mainly minerals, that plants need are dissolved in the water. Trees and flowers grow roots to absorb water, but green algae have to make do with what moisture comes in contact with them. As well, green algae havenít developed water-saving protection like the higher plants (e.g. waxy leaves and stomata). In fact, what we see as green algae is actually a huge colony of one-celled organisms. These tiny plants would dry out if they grew in full sunlight. As for sunlight, there is enough light in the shade of a tree for Pleurococcus to grow. The green algae contain chlorophylls A and B; these pigments allow the plant to collect light from a wide range of wavelengths, including the wavelengths that pass through the leaves of the tree. To sum it up, Pleurococcus is a green algae that lives in the shade on tree trunks. It gets enough light from sunlight that comes down through the leaves of the tree for photosynthesis, and it receives water from moisture in the air, usually from rain. Thatís why you will often find ≤moss≤ growing on the shady-side of a tree! Keep asking your questions! Evelyn Tsang
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