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The morphology and composition of seeds of desi and kabuli chickpea ('Cicer arietinum' L.) genotypes were studied using light microscopy with differential staining for protein, starch, β-glucans, and nonfluorescing compounds. Kabuli seeds had a thinner seedcoat due to thinner palisade and parenchyma layers which contained fewer pectic polysaccharides and less protein. The outer palisade layer varied in thickness from one to two cells, leading to a textured and sometimes wrinkled appearance of the seed surface. In contrast, the desi palisade layers were rigid and extensively thickened. Hourglass cells were homogeneous for both seed types, but not in an interspecific desi line (containing 'Cicer echinospermum' parentage), which had heterogeneous cells. The inner surface of the seedcoat contained both pectic and proteinaceous materials. The cotyledon comprised a single outer epidermal layer of protein-filled cells devoid of starch, with thickened outer cell walls; cell size and shape differed on abaxial and adaxial faces. Subepidermal cells on the abaxial face were similar to epidermal cells. These findings help explain differences in the processing behavior between the major chickpea seed types. |
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