Sunday 22 April 2012

HYPOSTASE: Meaning, occurance, feature, structural details & function.


Hypostase is one of the unusual features present at the chalazal region of the embryo sac and situated immediately below it. It represents an irregularly outlined group of nucellar cells which are poor in cytoplasmic contents but have their walls partially lignified or suberized.
The name Hypostase to this group of unusual cells was first given by Van Tieghem. According to him the hypostase forms a barrier or boundary to prevent the further growth of the embryo sac.
Even though hypostase is limited to basal region of the embryo sac occasionally they may cover the embryo sac extending up to the micropylar half.
Hypostase has been reported from a number of families Amaryllidaceae, Villiaceae, Zingiberaceae, Euphorbiaceae, Crossomataceae, Theaceae and Umbelliferae.
At the stage of the organized embryo sac the cluster of hypostase cells appear like a beard at the chalazal region of the embryo sac.

HYPOSTASE OF PLANT (ANATOMICAL VIEW)

FUNCTIONS:
       I.            It prevents excessive growth of the embryo sac of the chalazal region acting as a barrier.
    II.            It plays a role in the water balance of the resting seed.
 III.            It serves as a link between the vasculature of the funicle and the embryo sac facilitating the rapid transport of the nutrients.
 IV.            It may acts as secondary storage tissue.
    V.            It produces certain enzymes or hormones and has a role to play in the protection of the seed.










7 comments:

  1. We seek your permission to use the image for educational purposes at university of delhi. www.vle.du.ac.in

    ReplyDelete
    Replies
    1. Kindly give your opinion to improve the blog content.
      Follow the blog for regular update or follow my official Facebook page https://www.facebook.com/biologywriteup?ref=aymt_homepage_panel

      Delete
  2. Great tips, many thanks for sharing. I have printed and will stick on the wall! I like this blog. Knee Supplements

    ReplyDelete