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

Seed Infection by Viruses 213floretsspikeinfected plant(+)rachis (+)lemma (+)palea (+)fertileappendagesantherprimordia (+)pistilprimordia (+)antherwallepidermis (+)middle layers (+)tapetum (+)malearchesporium (+)microsporemother cells (+)seedling(+)seedendosperm (+)pericarpseed coat (+)endosperm (+)embryo (+)ovule—primary endopermcell (+)integument (+)nucellus (+)femalearchesporium(+)megasporemother cell (+)dyad, tetrad &functionalmegaspore (+)2-, 4-, 8-,nucleate (+)embryo sacsorganisedembryo sacdyad (+)tetrad (+)microspores (+)vegetative cell(+)cytoplasm(+)antipodalcells (+)central cell(+)synergids (+)egg (+)pollen grainssperms(+)nucleus(+)embryo (+)—zygote (+)fertilized embryo sacpollination andfertilizationFIGURE 7.3 Schematic representation of infection cycle of BSMV seed-transmitted strainin barley. (+) = presence of virus. (-) = absence of virus. (Based on the publications of Carrolland co-workers.)antigen has been observed in the ovule, microspores, pollen grains, and anthertapetum, but not in the embryo sac (Pesic, Hiruki, and Chen, 1988) and seed coat(Pesic and Hiruki, 1986). Baillis and Offei (1990) have concluded that AMV invadesthe female reproductive organs of most flowers systemically.Similarly, southern bean mosaic virus (SBMV) and soybean mosaic virus (SMV)occur in all flower parts, green pods, immature seeds, and seed coat and embryo ofmature seeds (Cheo, 1955; Bowers and Goodman, 1979). According to Yang andHamilton (1974) tobacco ringspot virus (TRSV) particles are contained in the pollen,integuments, nucellus, embryo sac wall, and cells in soybean. Earlier Athow andBancroft (1959) found TRSV in embryo, but not in the seed coat of soybean seed.