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Orchid Mycorrhizae
Orchid mycorrhizae are endomycorrhizal fungi which develop symbiotic relationships with the roots and seeds of plants of the family Orchidaceae. Nearly all orchids are myco-heterotrophic at some point in their life cycle. Orchid mycorrhizae are critically important during orchid germination, as an orchid seed has virtually no energy reserve and obtains its carbon from the fungal symbiont. The symbiosis starts with a structure called a protocorm''.'' During the symbiosis, the fungus develops structures called pelotons within the root cortex of the orchid. Many adult orchids retain their fungal symbionts throughout their life, although the benefits to the adult photosynthetic orchid and the fungus remain largely unexplained. Seed germination Orchids have several life stages. The first stage is the non-germinated orchid seed, the next stage is the protocorm, and the following stage is the adult orchid. Orchid seeds are very small (0.35mm to 1.50mm long), spindle-shaped, and have a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Root
In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the surface of the soil, but roots can also be aerial or aerating, that is, growing up above the ground or especially above water. Function The major functions of roots are absorption of water, plant nutrition and anchoring of the plant body to the ground. Anatomy Root morphology is divided into four zones: the root cap, the apical meristem, the elongation zone, and the hair. The root cap of new roots helps the root penetrate the soil. These root caps are sloughed off as the root goes deeper creating a slimy surface that provides lubrication. The apical meristem behind the root cap produces new root cells that elongate. Then, root hairs form that absorb water and mineral nutrients from the soil. The first root in seed producing plants is the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
