The botanical magazine = Shokubutsu-gaku-zasshi

, Volume 99, Issue 3, pp 241–266 | Cite as

Ovule and seed ontogeny inGnetum gnemon L.

  • Tokushiro Takaso
  • Ferdinand Bouman


The ovule ofGnetum gnemon has three envelopes around the nucellus. The outer one forms two clear swellings at the lateral sides during the early developmental stages. The middle envelope also shows two swellings in many cases arranged decussately with respect to those of the outer one. All these swellings become obscure or disappear later. The inner envelope arises as an annular primordium and forms several manifest lobes at the stage of pollination. it develops two proliferating structures from its middle portion, viz., a flange and a micropyle-closing tissue. The three envelopes differentiatiate into the fleshy outer, sclerenchymatic middle and compressed inner layers of the seed coat, respectively. The inner one, however, remains restricted to the apical part of the seed owing to endochalazal growth. The outer envelope is derived from both dermal and subdermal cells of the ovule primordium and, therefore, is of dual origin. The middle and inner envelopes are subdermal in origin. The present study has cleared up some conflicting reports in the previous publications.

Key words

Gnetum Gymnosperms Integument Morphology Ovule Seed coat 


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Copyright information

© Botanical Society of Japan 1986

Authors and Affiliations

  • Tokushiro Takaso
    • 1
  • Ferdinand Bouman
    • 1
  1. 1.Hugo de Vries LaboratoriumUniversiteit van AmsterdamAmsterdam

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