Histopathology of Seed-Borne Infections - Applied Research Center ...

56 Histopathology of Seed-Borne InfectionsscendcotepsmucembmlepiiiendABCepsmlepiDiiEFIGURE 3.4 Structure of seed of Brassicaceae. A to C, Eruca sativa. A, B, Ls and Ts seed.C, Ts part of seed coat, cells of epidermis are full of mucilage and cells of inner epidermis(epi) of outer integument thick-walled. D, Ls part of seed coat of Brassica juncea. E, Ls partof seed coat of B. campestris var. yellow sarson. (Abbreviations: cot, cotyledon; emb, embryo;end, endosperm; epi, inner epidermis of outer integument consisting of characteristic thickwalledcells; eps, seed epidermis; ii, inner integument; ml, middle layers; muc, mucilage; sc,seed coat.) (A to C, From Prasad, K. 1974. J. Indian Bot. Soc. 53: 24–33; D, Sulbha, K. 1957.J. Indian Bot. Soc. 36: 292–301; E, Rathore, R.K.S. and Singh, R.P. 1968. J. Indian Bot. Soc.47: 341–349.)internal mucilage (Eruca sativa); mesophyll of outer seed coat thin-walled, the nextlayer formed by the inner epidermis of the outer integument is of cuboid or shortradially elongated cells, thick-walled — inner and radial walls lignified forming themain mechanical layer (endotestal); the inner seed coat of thin-walled, compressedcells with protein bodies and pigmented material. A three-tiered basal body occursin hilar region, subhilar tissue constitutes the solid core of the basal body and innerand outer integument after invagination forms the other parts. The basal body istwo-tiered due to the obliteration of the lower (middle) tier in Eruca sativa.Mucilage may diffuse or break through the outer wall and cuticle of the seedcoat during seed maturity. When seeds are soaked in water, mucilage collects on theseed surface (Eruca).Embryo: Bent, radicle dorsal or lateral, extend along the margin of seed; radiclelying along the edges of cotyledons or along the back of one cotyledon, cotyledonsconduplicated or folded; reserve food material predominantly oil.