Significance of seed trichome micro-morphology in systematic treatment of Abelmoschus-Hibiscus complex

Abstract

Indian sub-continent is rich in genetic diversity of various species of genus Abelmoschus and Hibiscus. Several of these species exist in wild, semi-wild and cultivated forms due to favorable eco-geographical conditions. Seed morphology (especially trichome structure) of Malvaceae members is known to be diverse, but variation patterns have never been critically studied in these complex genera. In the present paper usefulness of this important character for the generic differentiation between Abelmoschus (13 species) and Hibiscus (10 species) using scanning electron microscopy of seed has been described. Primary generic differentiation has been derived using basic seed trichome morphology i.e. unicellular (un-fused) and multi-cellular (fused) which was spiral or non–spiral, spread evenly or localized in all the studied taxa. The presence of unicellular and un-fused trichomes on seed coat surface in the Abelmoschus species provides an additional and significant micro-morphological differentiation to delineate the boundaries between genus Abelmoschus and Hibiscus.