Describe the important characteristics of gymnosperms.
Important features of gymnosperms:
1. The term gymnosperm refers to plants with naked seeds (gymnos – naked, sperma – seeds), i.e., the seeds of these plants are not enclosed in fruits.
2. The plant-body ranges from medium to tall trees and shrubs. The giant redwood tree Sequoia is one of the tallest trees in the world.
3. The root system consists of tap roots. The coralloid roots present in Cycas are associated with nitrogen-fixing cyanobacteria.
4. The stem can be branched (as in Pinus and Cedrus) or un-branched (as in Cycas).
5. The leaves can be simple (as in Pinus)or compound (pinnate in Cycas). The leaves are needle-like, with a thick cuticle and sunken stomata. These help in preventing water loss.
6. Gymnosperms are heterosporous. They bear two kinds of spores – microspores and megaspores.
7. Flowers are absent. The microsporophylls and megasporophylls are arranged to form compact male and female cones.
8. Pollination occurs mostly through wind and pollen grains reach the pollen chamber of the ovule through the micropyle.
9. The male and female gametophytes are dependent on the sporophyte.
10. The seeds contain haploid endosperms and remain uncovered.
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