| Summary: | 碩士 === 中國文化大學 === 生物科技研究所 === 93 === Sweet potato (Ipomoea batatas (L.) Lam) is one of important economical crops of the world. The unstable climate in Taiwan affects the growth, quality, yield and economic value of sweet potato. The chlorophyll fluorescence parameters of sweet potato exposed in high and low temperature, drought and flooding stress were measured to realize if chlorophyll fluorescence be the stress indicator of sweet potato.
Three cultivars of sweet potato ‘Tainung 57’ (TN57), ‘Tainung 66’ (TN66) and ‘Taoyuan 2’ (TY2) were utilized as experimental materials. Four experiments of high temperature (45℃ in dark) for 2 days, low temperature (7/7℃) for 2 days, drought (24/20℃, no water supply), and flooding (water to medium level, in screen-house) were executed. Completely randomized design (CRD) with three replicates and four potted plants per replicate was applied. In each timing of each stress experiment, 0, 3, 6, 12, 24 hr, 1, 2, 3 day, till dying, fluorescence parameters were measured and calculated.
The results showed that Fv/Fm and Fm were decreased, Fo increased under high temperature, low temperature and flooding stress. ETR and qP changed in same pattern under drought and flooding stresses. Under low temperature, qN and NPQ decreased, but increased under high temperature stress. Fv/Fm, Fm, ETR and qP were higher under flooding stress than other stresses, while Fo, qN and NPQ were lower. On the other hand, correlation relationship existed between existed chlorophyll fluorescence parameter and temperature in flooding stress experiment. These results demonstrate the sensitivity of chlorophyll fluorescence to temperature and the flooding-tolerance of sweet potato. Fv/Fm is regarded as a stress indicator of sweet potato.
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