Caryopsis micromorphological survey of Sorghum (Poaceae)—Taxonomic implications

Abstract

Caryopsis micromorphological characters of 25 Sorghum species were studied using stereoscopic microscopy and scanning electron microscopy. There are three caryopsis shapes, including obovate-elliptic, ovate-elliptic and subulate; two patterns of stylopodia, including with or without an apical tuft of unicellular microhairs; and five spermoderm sculpture patterns, that is, reticulate with wavy cell walls, reticulate with straight cell walls, substriate, undulating and rugose in Sorghum. Caryopsis size and stylopodium persistence pattern have limited taxonomic application at the infrageneric level, while the caryopsis shapes show a certain taxonomic significance at the infrageneric level and spermoderm sculpture patterns are important diagnostic characters at the interspecific level in Sorghum. The separation of Sorghum sudanense from S. × drummondii is supported by our result of caryopsis size and spermoderm sculpture patterns. Consistent micromorphological characters of stylopodium persistence, dorsoventral compression, embryo proportion (the ratio of embryo to caryopsis length) and hilum proportion (the ratio of hilum to caryopsis length) are firstly found in Sorghum. Caryopsis micromorphological characters provide evidence that Sorghum is a highly heterogeneous genus at the micromorphological level.

Detailed macro and micromorphology of grasses caryopsis using scanning electron and light microscopy

“…Such types of caryopsis were also reported by Morgado, Gonçalves‐Esteves, Resendes, and Ventura (2015) in their study for various species of family Poaceae. These results are also in accordance (in partial) with Liu, Hu, Liu, and Liu (2015) as they also observed such types of caryopsis in their study of the Sorghum (Poaceae) genus. In general, the results revealed that different patterns of caryopsis (regarding morphology and others) were of immense importance in distinguishing various species.…”

“…For example, traditional taxonomists (De Wet, 1978) have always been considered Sorghum sudanese and S. drummondii as synonym because of similar ventral surface. Based on sculpture pattern, Sorghum sudanese and S. drummondii with substriate spermoderm sculpture and reticulate spermoderm sculpture, respectively, were distinguished as independent species (Liu et al, 2015). Other techniques (phylogenetic analysis of nuclear Pepc4 and GBSSI sequence data) also supported that they, that is, Sorghum sudanese and S. drummondii, are genetically distinct species (Liu, Zeng, & Liu, 2014).…”

“…But still, it is useful to diagnose the closely related species (Aguilar‐García, Figueroa‐Castro, & Castañeda‐Posadas, 2012; Bonhomme, Prasad, & Gaucherel, 2013; Liu et al, 2015; Morozowska & Idzikowska, 2004). Caryopsis size (in length) of Sorghum halepense (2.36 mm) was the same measured by Liu et al (2015) as we found (2.65 mm) in our study; however, the width in their study was as more than double (1.45 mm) that of our results (0.32) for Sorghum halepense . In another study, Morgado et al (2015) reported as “small size” of caryopsis in their investigated species of Poaceae.…”

Cytogenetics and fertility of an induced tetraploid Sorghum bicolor x S. propinquum hybrid

“…While these findings revealed extensive homology, there are nonhomologous regions with significant divergence as indicated by the increased incidence of rod bivalents. This is further supported by cytological (Celarier, 1958), molecular (Dillon et al, 2004), and micromorphological taxonomic (Liu et al, 2015) findings reported by others. Because the S. propinquum accession used in this study is rhizomatous and the S. propinquum accession (PI 653737) is nonrhizomatous under our conditions, we were interested in confirming that the accession we used is S. propinquum.…”

Interação de agroecossistema consorciado com palma-sorgo em ambiente semiárido: uma revisão

“…Most species have a habit of growing caespitose, perennials, polyploids and feathery inflorescences of whitish color, having as main representative the genus Sorghum. This genus has a striking characteristic of its inflorescences, to the panicles (Watson & Dallwitz, 1992;Filgueiras et al, 2012;Liu et al, 2015;Upadhyaya et al, 2017).…”