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Wednesday, 23 September 2015

Short Class Notes On Gymnosperms

GYMNOSPERMS

- Medium sized trees and shrubs.

- Main plant body Sporophyte.

- In some members roots may have fungal association called Mycorrhiza.

- In some (Cycas) coralloid roots present having algal zone with N2-fixingsymbioticalgae.

Root – taproot and leaves of two types -  1)Foliage 2)Sporophylls.

Microsporophyll bears sporangia where microspores are formed.

Megasporophyll bearsovules.

Compact arrangement of Sporophylls is calledConeand loose one iscalled Strobilus.

Microspore i.e. pollens reaches to ovules.

Pollen tubes help to transfer male gametes up to egg of archegonia present in female gametophyte of ovule.

Zygote develops in an embryo inside seed

-e.gCycas, Pinus ,Cedrusetc.


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