Gymnosperm are any of the plants that have seeds unprotected by an ovary or fruit, which includes the conifers, cycads, and ginkgo. The word gymnosperm comes from the Greek root gymnós meaning naked, therefore gymnosperm being, "naked seed". They are characterized mainly by their exposed seeds and cones, and their longelivity along with their many uses in the economy as lumber.
The most notable feature of gymnosperms is that they contain their seeds in cones. Most gymnosperms are evergreens, meaning they retain their green color year round.
The anatomy of gymnosperms are similar to many other types of plants. They have a root which contains ground tissue which provides storage for the plant as well as anchors it to the ground. The trunk is usually covered in bark which is made mainly from dead xylem which has hardened on the outside. The xylem in the trunk of the plant is responsible mainly for transporting dissolved minerals obtained from the ground tissue in the roots to the leaves. Water is mainly carried from the root through the xylem to the leaves so that the leaves may have water to perform photosynthesis to produce food. The phloem in the trunk is made of mostly living cells responsible for carrying the products of photosynthesis down to the roots for continual growth of the root and the trunk. Leaves on the branches of the trees/plants perform photosynthesis for food.(Porch p345-48)
Phylum Coniferophyta is the largest Phylum in the group gymnosperm. They are easily recognizable by the cones that they produce for reproduction found on the stems and branches. In the spring they produce two types of cones, the pollen and seed cones. Pollen produced by the pollen cone contains all the male reproductive gametes and is produced in large quantities by the cone, the reason for this being that the pollen is distributed by wind, which would make fertilization very difficult. The pollen from the pollen cones are carried by the wind to seed cones often found on the branches of the same tree or another tree of the same kind. When the pollen lands on the scales of an immature seed cone, the scales of the cone close tightly and will often point downward to protect the seeds while they mature. When mature, the scales will then open, dispersing the mature seeds to create a new plant. Phylum Cycadophyta is one of the smaller phyla in group Gymnosperm. They bear seeds in cone-like structures and are native to tropical areas. Phylum genetophyta produce seeds in cones that resemble flowers [Porch 341-42].
Gymnosperms are highly diverse and found on every continent of the world with the sole exception of Antarctica. They are easily recognizable by their cones and are most often evergreens, never truly losing their green color. They are among the oldest living things on earth, such as the massive redwood forest in California.
Economical and Ecological Significance
Gymnosperms are among the most essential plants used today. The main importance of them is in their use as lumber. Today most are cultivated from farms due to them almost being completely wiped out from over uses (Porch 340). Other important uses for them include houses paper and furniture. The Greeks and Romans used the pitch obtained from conifers to waterproof their ships. In special importance, the white spruce is prized for its wood because it is essential to the production of musical instruments such as violins and cellos. Conifers also have a very important impact on the environment. Due to their often massive sizes, their trunks make room for many varieties of insects and animals, namely birds. Their massive size usually means they also have large roots, which help hold the soil together, helping deter land erosion and washouts..
- Porch, Thomas E. and DMD, Batford, Brad R. Biology. Greenville, South Carolina: Bju Press, 2005.
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