著者

Agarie Sakae Hanaoka Naomi Ueno Osamu Miyazaki Akira Kubota Fumitake Agata Waichi Kaufman Peter B.

出版者

日本作物学会

雑誌

Plant production science (ISSN:1343943X)

巻号頁・発行日

vol.1, no.2, pp.96-103, 1998-06

参考文献数

54

被引用文献数

9

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To evaluate the positive effects of silicon on the stress tolerance of rice plants, we measured the electrolyte leakage (El) from leaf tissue caused by desiccation with polyethylene glycol (PEG) and by high temperature to estimate the integrity of cell membranes. The El caused by 30% and 40% solutions of PEG decreased with the increase in the level of Si in leaves. In leaves of plants grown with 100 ppm SiO_2, the level of polysaccharides in cell walls, which is one of the factors related to tolerance to desiccation, was 1.6-fold higher than that in leaves of plants grown without Si. Ultrastructural observations of leaves revealed that polymerized Si accumulated in the walls of epidermal cells but not in those of the mesophyll cells, which are probably the main sites of El. These findings suggested that silicon in rice leaves is involved in the water relations of cells, such as mechanical properties and water permeability and plays a role in preventing El through the synthesis and functions of cell walls. The El caused by high temperature (42.5℃) was also lower in the leaves grown with Si than in the leaves grown without Si, suggesting the involvement of silicon in the thermal stability of lipids in cell membranes. These results suggested that silicon prevents the structural and functional deterioration of cell membranes when rice plants are exposed to environmental stress.

著者

Agarie Sakae Kawaguchi Akiko Kodera Akiko Sunagawa Haruki Kojima Hide Nose Akihiro Nakahara Teruhisa

出版者

日本作物学会

雑誌

Plant production science (ISSN:1343943X)

巻号頁・発行日

vol.12, no.1, pp.37-46, 2009-01

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We measured the concentration of polyols (pinitol, ononitol, and myo-inositol), which are known to have health-promoting and/or disease-preventing functions, in the common ice plant (Mesembryanlhemum crystallinum L.) cultured under salt- and drought-stressed treatments. In NaCl-treated plant the concentration of pinitol/ononitol increased with increasing NaCl concentration in culture solution. The maximal concentration was 3.6mg g^<-1> FW, which was found in the shoot top, followed by small side shoots (2.1mg g_<-1> FW) of mature plants grown with 400mM NaCl for 35 ds. The drought stress also accelerated the accumulation of pinitol/ononitol. The maximal concentration was 1.2mg g^<-1> FW, which was found in the shoot top of plants under the stress for 25 ds. The myo-inositol increased in salt-stressed plants at 3 ds after the start of the treatment and then decreased with the lapse of time during stress. The concentration of polyols in the ice plant was comparable to that in the other species reported to accumulate polyols at high levels. Radical scavenging activity evaluated by DPPH assay was increased two-fold by 400mM NaCl treatment, which was twice as high as that in the leaves of lettuce (Lactuca sativa L.). These results indicated the high potential of the ice plant as a polyol-rich high-functional food.