Calcium oxalate crystal macropatterns in leaves of species from groups Glycine and Shuteria (Glycininae; Phaseoleae; Papilionoideae; Fabaceae)

Abstract

Calcium oxalate crystal macropatterns in leaves were characterized for 69 species (and two Glycine tomentella cytotypes) from 14 of 16 genera in two legume groups, Glycine and Shuteria, to determine whether they share a common macropattern. A leaf clearing method was used to visualize the crystals. All 69 species (and two Glycine tomentella cytotypes) displayed prismatic crystals associated with leaf veins and vein endings. In contrast, mesophyll crystals occurred in 76.8% of 69 species and two G. tomentella cytotypes, and varied from a few to many. Conversely, only 40.9% of 22 Glycine species (in group Glycine) lacked mesophyll crystals, while 8.7% of 23 species of six genera associated with Glycine (in group Glycine) lacked mesophyll crystals. Thus 24.4% of 45 species of seven combined genera in group Glycine lacked mesophyll crystals. With seven genera in group Shuteria, 20.8% of 24 species lacked mesophyll crystals. The consistently present vein crystals varied in size and shape, so their length–width (Stubby versus Long) crystal ratios were determined for primary, secondary, and tertiary veins, and vein endings. Two trends were evident: Long-crystal ratios increased from primary veins to vein endings in species in both groups, and the perennial and annual Glycine species showed this condition to a greater extent than all the non-Glycine species. In some cases, taxonomically closely associated species were quite similar in their macropattern and presence or absence of mesophyll crystals. These results should be of value to future studies dealing with taxonomy and phylogeny of species in these two leguminous groups.