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THE ORIGIN OF THE LAND PLANT SPOROPHYTE: AN INTERPOLATIONAL SCENARIO
Author(s) -
HEMSLEY By ALAN R.
Publication year - 1994
Publication title -
biological reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.993
H-Index - 165
eISSN - 1469-185X
pISSN - 1464-7931
DOI - 10.1111/j.1469-185x.1994.tb01270.x
Subject(s) - sporophyte , biology , ancestor , multicellular organism , sporangium , gametophyte , evolutionary biology , botany , spore , geography , pollen , biochemistry , archaeology , gene
Summary The origin of terrestrial plants from a charophycean ancestor is assumed as a basis for the consideration of the origin of life histories amongst this group. Charophycean algae are vegetatively gametophytic, thus requiring the interpolation of the multicellular sporophytic stage. The model presented here derives the sporophyte and typical sporangial contents from the zygospore produced from the reproductive structure of a hypothetical charophycean land plant ancestor. The presence of monads, dyads, and various forms of tetrads in the fossil record of presumed land plants add support to this model. In addition, such spore types suggest that the temporal relationship of meiosis to sporopollenin deposition was less strictly controlled than in extant land plants.