Yong, Jean W.H
- Department of Biosystems and Technology, Swedish University of Agricultural Sciences
Abstract
Premise Unique among vascular plants, some species of Selaginella have single giant chloroplasts in their epidermal or upper mesophyll cells (monoplastidy, M), varying in structure between species. Structural variants include several forms of bizonoplast with unique dimorphic ultrastructure. Better understanding of these structural variants, their prevalence, environmental correlates and phylogenetic association, has the potential to shed new light on chloroplast biology unavailable from any other plant group.Methods The chloroplast ultrastructure of 76 Selaginella species was studied with various microscopic techniques. Environmental data for selected species and subgeneric relationships were compared against chloroplast traits.Results We delineated five chloroplast categories: ME (monoplastidy in a dorsal epidermal cell), MM (monoplastidy in a mesophyll cell), OL (oligoplastidy), Mu (multiplastidy, present in the most basal species), and RC (reduced or vestigial chloroplasts). Of 44 ME species, 11 have bizonoplasts, cup-shaped (concave upper zone) or bilobed (basal hinge, a new discovery), with upper zones of parallel thylakoid membranes varying subtly between species. Monoplastidy, found in 49 species, is strongly shade associated. Bizonoplasts are only known in deep-shade species (
Keywords
bilobed chloroplast; chloroplast diversity; cup-shaped chloroplast; monoplastidy; shade-adapted Selaginella; Selaginellaceae; Stachygynandrum; ultrastructure
Published in
American Journal of Botany
2020, volume: 107, number: 4, pages: 562-576
SLU Authors
UKÄ Subject classification
Evolutionary Biology
Botany
Biological Systematics
Publication identifier
- DOI: https://doi.org/10.1002/ajb2.1455
Permanent link to this page (URI)
https://res.slu.se/id/publ/103964