| 研究実績の概要 |
Strawberry plants (Fragaria × ananassa Duch. var. “Benihoppe”) when experiences autotoxicity under recycled hydroponics exudates benzoic acid as their potential allelochemical. Root is the first organ that comes into contact with allelochemicals and cause oxidative damage and inhibition of uptake water and mineral nutrients. Therefore, we applied benzoic acid exogenously in the nutrient solution growing strawberry plantlets. We used 25% “Enshi” nutrient solution at 0, 1, 5, 10, 25, 50, 100, 200 and 400 μ M/L benzoic acid. After two weeks of culture, strawberry roots were collected for the following phenotypic observation and enzymatic analysis.
1.Observation of strawberry cell integrity under Scanning Electron Microscope: After two weeks benzoic acid treatment, strawberry roots were collected and stored in FAA solution for subsequent microscopic observation.
2.Generation of O2- (NBT test) and H2O2 (DAB test) in allelochemical (benzoic acid) inducted in strawberry roots (Zhi-Fang et al. 2011).
3.Determination of peroxidase activity and measurement of protein content (Bradford methods) were conducted following procedures described by Hammerschmidt et al. (1982).
Results indicated that, strawberry root injury occurred from 25 μM/L benzoic acid in the nutrient solution. Roots showed black discoloration and lower activity after this concentration.
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| 今後の研究の推進方策 |
In further experiment, strawberry plant will be cultured in nutrient solution either renewed or non-renewed. Plantlets will be ncubated in the controlled-environment room set at 25/20 °C (day/night). The concentrations of the main nutrients in the culture solution will be adjusted every three weeks following chemical analysis using a C-141 ion meter for NO3－, a UV mini 1240 spectrophotometer for PO43－, and a Z-5010 atomic absorption spectrophotometer for K+, Ca2+, Mg2+, and Fe3+. Strawberry plants will be cultured until root become brown to black in order to evidence the allelochemical stress in non-renewed culture solution. The root samples will be collected for further analysis.
Observation of root oxidative damage and enzyme activity:
1.Observation of strawberry cell integrity under Scanning Electron Microscope: Strawberry roots samples will be collected at different stages (anthesis, fruiting and final harvest) and stored in FAA solution for subsequent observation under SEM.
2.Generation of O2- (NBT test) and H2O2 (DAB test) due accumulated allelochemicals (in non-renewed nutrient solution) in strawberry roots will be measured.
3.Peroxidase activity and protein content will be measured following Bradford method.
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