Ultrastructural study on the stylar transmitting tissue in Japanese pear

Abstract

The stylar transmitting tissue in the mature pistil of the Japanese pear consists of its component cells and intercellular heterogeneous secretions. The cytoplasm of the periplasmic region contains two different organelles that are characteristic of floral bud development. One of these is the vesicle, which is derived from rough ER and transferred to the periplasmic region of the cell during an early stage of the floral bud. The other one is the lipid droplet, which reacts to polysaccharidic staining and is seen throughout floral bud development. The lipid droplets are closely associated with the Golgi bodies and seem to be dissolved in the vacuole. The materials found in the vacuoles appear to diffuse and pass through the cell walls as intercellular substances,

Ultrastructure of receptive stigma and transmitting tissue at anthesis in two pear species

“…Generally, the results of our observations on the ultrastructure of TT in P. pyrifolia var. culta are consistent with those carried out by Nakanishi et al (1991) on cv. Nijuseiki and with data on TT in Malus (Cresti et al, 1980).…”

“…e most characteristic features of the TT protoplast ultrastructure noticed in this study are the prominent endoplasmic reticulum and numerous leucoplasts and their close spatial relationship with other organelles. Similar ultrastructure has been reported for Malus communis (Cresti et al, 1980) and Asiatic pear 'Nijuseiki' (Nakanishi et al, 1991), although in the latter species we do not confirm the presence of either that much periplasmic fibrillar secretion or fusion of vacuolar and periplasmic compartments. Interpretation of such an ultrastructure should be made in relation to the function of TT consisting in the secretion of components of the ECM, which generally include mostly carbohydrates (mainly pectins), amino acids, glycoproteins, glycolipids, and phenolic compounds, incl.…”

“…; however, in a cultivar of Malus × domestica, the individual TT strands of the free styles form a compitum in the basal (fused) part of the style (Sheffield et al, 2005), thus facilitating pollen tube growth redirection between carpels. e ultrastructure of TT was studied in Japanese pear 'Nijuseiki' (Nakanishi et al, 1991). e deposition of a fibrillar substance in the periplasmic space of TT cells, proliferation of Acta Agrobotanica / 2023 / Volume 76 / Article 169344 Publisher: Polish Botanical Society the rough endoplasmic reticulum (RER), and presence of large lipid "droplets" were indicated as the most characteristic features of the TT cells.…”

Style-specific and developmentally regulated accumulation of a glycosylated thaumatin/PR5-like protein in Japanese pear ( Pyrus serotina Rehd.)

“…The thaumatin/ PR5-like proteins have been considered to be involved in defensive functions by mediating membrane permeabilization of fungi (Roberts and Selitrenniko 1990;Vigers et al 1992). The style of Japanese pear is of the solid type, like those of the Solanaceae, and the intercellular space of the transmitting tissue, the path of pollen tube growth, is ®lled with secretions (Nakanishi et al 1991) that are considered to serve as nutrients for pollen tube growth and are expected to make the style highly susceptible to infection by pathogens. It is possible that PsTL1 is involved in defensive functions in the style, as expected for other PR proteins in styles (Ori et al 1990;Wemmer et al 1994;Harikrishna et al 1996;van Eldik et al 1996), although the antifungal activity of PsTL1 is not clear.…”

Integrated physiological analyses, transcriptome, and DNA methylation reveal superiority of pear stigma-style complex development regulation

“…Both style and stigma secreted an extracellular fluid necessary for the pollen grain germination and pollen tube growth. 15 As a self-incompatible fruit tree, both compatible and incompatible pollen can hydrate and then germinate into the stigma after falling on the stigma. The incompatible pollen tubes stopped growing due to the action of a self-incompatible factor, S-RNase, in style.…”