Ultrastructure of the sporoderm in megaspores of some Indian Selaginellas

Abstract

Megaspores of six species of the genus Selaginello were studied under light microscope and Scanning Electron Microscope. In general, the sporoderm of all the species investigated shows a tuberculate sculpture, intervening areas have fine reticulum. The sporopollenin units could also be examined in some megaspores by fracturing the spore wall.
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Taxonomic significance of megaspores in some species of Selaginella from Arunachal Pradesh in India

“…The description of the megaspores of Selaginella in the present work agrees with the prior research (Bajpai, 2000; Liu et al, 1989; Minaki, 1984; Shalimov & Zhang, 2022; Singh et al, 2014; Taylor, 1989; Wang et al, 2018; Zhang, 2015; Zhou et al, 2016; Zhou & Zhang, 2015). Our examination of megaspores of some species was found to have indistinguishable features as described by earlier workers in S .…”

“…The description of the megaspores of Selaginella in the present work agrees with the prior research (Bajpai, 2000;Liu et al, 1989;Minaki, 1984;Shalimov & Zhang, 2022;Singh et al, 2014;Taylor, 1989;Wang et al, 2018;Zhang, 2015;Zhou et al, 2016;. Our examination of megaspores of some species was found to have indistinguishable features as described by earlier workers in S. biformis, S. bisulcata, S. bryopteris, S. ciliaris, S. decipiens, S. helferi, (S. indica, S. involvens, S. monospora, S. pennata, Selaginella inequalifolia (S. inequalifolia), Selaginella reticulata (S. reticulata) and…”

“…A dense spinulose micro sculpture resembling spiky flower is noted in S. helferi. The presence of dense irregular verrucae micro sculpture in S. decipiens contradicts the report of fine spinulose micro sculpture byBajpai (2000) andWang et al (2018). Mega-At the micro sculptural level, the presence of interwoven networks of tubular muri of unequal thickness in S.vaginata and such interwoven networks forming numerous tiny pores in S. wallichi are features, which were not reported earlier.Such differences from previous studies are either due to spores being in different developmental stages or variations within species at the micro sculptural level.Many species of the genus Selaginella show similar morphological characteristics, which makes it difficult to identify.…”

“…reticulata ) and Selaginella wallichi ( S . wallichi ) (Bajpai, 2000; Liu et al, 1989; Liu et al, 2003; Liu et al, 2006a, 2006b; Shalimov & Zhang, 2021; Singh et al, 2014; Singh et al, 2020; Wang et al, 2018; Zhou et al, 2015a; Zhou et al, 2016).…”

“…Most of the previous observation of megaspores of the genus was based on light microscopic study (Dixit, 1983; Dixit, 1992; Panigrahi & Dixit, 1967). Bajpai (2000) and Singh et al (2014) carried out the megaspore morphology of six species and 20 species, respectively, from India. The state of Arunachal Pradesh lies in the North eastern region of India with an area of 83.743 km 2 .…”