1.

Enumerate any five characteristic features of Gymnosperms

Answer»
  • The gymnosperms are naked seeded plants 
  • Gymnosperms include medium-sized trees or tall trees and shrubs. 
  • Roots in some genera have fungal association in the form of mycorrhiza (Pinus), while in some others (Cycas) small specialized roots called coralloid roots are associated with N2- fixing cyanobacteria. 
  • The stems are unbranched (Cycas) or branched (Pinus, Cedrus). 
  • The leaves may be simple or compound. 
  • The leaves in gymnosperms are well-adapted to with stand extremes of temperature, humidity and wind.
  • In conifers, the needle-like leaves reduce the surface area. 
  • Their thick cuticle and sunken stomata also help to reduce water loss. 
  • The gymnosperms are heterosporous; they produce haploid microspores and megaspores. 
  • The two kinds of spores are produced within sporangia that are borne on sporophylls which are arranged spirally along an axis to form lax or compact strobili or cones. 
  • The strobili bearing micros porophylls and micros porangia are called micros porangiate or male strobili. The micros pores develop into a male gametophytic generation which is highly reduced and is confined to only a limited number of cells.  
  • The cones bearing megasporophylls with ovules or megasporangia are called macros porangiate or female strobili.


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