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Sporogenesis and gametogenesis of some Boraginaceae
Author(s) -
Rao B. Hanumantha,
Rao P. S. Prakasa
Publication year - 1992
Publication title -
feddes repertorium
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.24
H-Index - 25
eISSN - 1522-239X
pISSN - 0014-8962
DOI - 10.1002/fedr.19921030106
Subject(s) - tapetum , biology , megaspore , ovule , sporogenesis , botany , gametophyte , stamen , boraginaceae , pollen , microspore , spore
Embryological details pertaining to the development and structure of anther and ovule, sporogenesis, gametogenesis and gametophytes of 9 species of 7 genera belonging to Boraginaceae are described. Anther is tetrasporangiate with ‘Dicotyledonous type’ of wall development. The wall includes the epidermis, endothecium, single middle layer and secretory type tapetum. Cytokinesis is simultaneous. Tetrahedral, decussate and isobilateral tetrads are formed. Pollen grains are mostly dumb‐bell shaped and 3‐celled at shedding stage. Ovules are unitegmic, tenuinucellate and hemianatropous or anatropous. Megaspore tetrads are linear or ‘T’ shaped. The female gametophyte development conforms to Polygonum type except in Lycopsis and Anchusa where it is predominantly of Allium type. The mature embryo sac consists of two pear‐shaped synergids with filiform apparatus, an egg cell, two polars and three ephemeral antipodals.