Measurement of Heat Sensitivity in Cucumber Leaves by ChlorophyII Fluorescence Method

Tropical agriculture research series : proceedings of a symposium on tropical agriculture researches
ISSN 03889386
NII recode ID (NCID) AA00870529
Full text

Usefulness of the chlorophyll fluorescence measurement at room temperature (Fr) to detect and quantify heat sensitivity was examined. Seedlings with 2 to 3 true leaves, detached leaves placed in polyethylene bags or leaf discs floated on distilled water were subjected to 38-48°C temperatures for 5-40 min in the dark at 100% relative humidity. The Fr value decreased depending on the heating temperature and exposure time to heat. When leaves and roots of the seedlings were heated separately, the decrease of the Fr value was pronounced in the seedlings in which both leaves and roots had been subjected to heating, but not in those in which only roots had been exposed to heating. After the seedlings were returned to normal growth conditions, leaf growth continued to be depressed. The depression rates of the Fr value and leaf growth were positively correlated with each other in a quadratic curve. Cucumber seedlings grown under a high temperature (26°C day/2l°C night), with a high optimal temperature for oxygen exchange rate, were resistant to heating with regard to Fr and leaf growth compared to those under a low temperature regime (20°C day/15°C night). Heat sensitivity was ranked in cucumber varieties. Based on these results, it was considered that heat sensitivity can be easily assessed by the Fr measurement.

Date of issued
Creator Satoshi Aoki
Publisher Japan International Research Center for Agricultural Sciences
Volume 23
spage 239
epage 247
Language eng

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