Q.12:- Describe the important characteristics of gymnosperms.
→ The seeds of these plants are not enclosed in fruits.
→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.
→ The root system consists of tap roots. The coralloid roots present in Cycas are associated with nitrogen-fixing cyanobacteria.
→ The stem can be branched (as in Pinus and Cedrus) or un-branched (as in Cycas).
→ 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.
→ Gymnosperms are heterosporous. They bear two kinds of spores – microspores and megaspores.
→ Flowers are absent. The microsporophylls and megasporophylls are arranged to form compact male and female cones.
→ Pollination occurs mostly through wind and pollen grains reach the pollen chamber of the ovule through the micropyle.
→ The male and female gametophytes are dependent on the sporophyte.
→ The seeds contain haploid endosperms and remain uncovered.