Meir, S., Dept. Postharvest Sci. Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel Ronen, R., Dept. Postharvest Sci. Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel Lurie, S., Dept. Postharvest Sci. Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel Philosoph-Hadas, S., Dept. Postharvest Sci. Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
Chlorophyll (Chl) fluorescence analysis by pulse-amplitude modulation (PAM) measurements was performed to assess the extent of chilling injury (CI) in stored sweet basil (Ocinum basilicum L.) leaves. Changes in three photosynthetic characteristics, in relation to visible CI rating, were monitored in leaves following modification of their chilling susceptibility by varying storage temperature and duration in two basil cultivars, or by soil application of triazole. Basil leaves developed severe or moderate visible symptoms of CI after 4 days of storage at 4 or 8°C, respectively, but remained undamaged when stored at 12°C. The chilling-dependent changes obtained in the ratios of variable to maximal fluorescence (F(v)/F(m)), represented chilling sensitivity rather than membrane damage. The photochemical quenching coefficient (qP) was unaffected by low temperatures and did not seem to be correlated with CI. On the other hand, changes in the non-photochemical quenching coefficient (qNP) were positively correlated with the appearance of visual CI symptoms in leaves of the two cultivars at all storage temperatures and durations. Similarly, the chilling-alleviating effect of triazole was accompanied by a corresponding reduction in the chilling-induced decrease of qNP. Therefore, qNP may be associated with an irreversible transition step in the CI process, which precedes the appearance of visual symptoms. As such, changes in qNP may provide a suitable, rapid and non-destructive criterion for estimation of chilling damage in green tissues.
Assessment of chilling injury during storage: Chlorophyll fluorescence characteristics of chilling-susceptible and triazole-induced chilling tolerant basil leaves
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Meir, S., Dept. Postharvest Sci. Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel Ronen, R., Dept. Postharvest Sci. Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel Lurie, S., Dept. Postharvest Sci. Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel Philosoph-Hadas, S., Dept. Postharvest Sci. Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
Assessment of chilling injury during storage: Chlorophyll fluorescence characteristics of chilling-susceptible and triazole-induced chilling tolerant basil leaves
Chlorophyll (Chl) fluorescence analysis by pulse-amplitude modulation (PAM) measurements was performed to assess the extent of chilling injury (CI) in stored sweet basil (Ocinum basilicum L.) leaves. Changes in three photosynthetic characteristics, in relation to visible CI rating, were monitored in leaves following modification of their chilling susceptibility by varying storage temperature and duration in two basil cultivars, or by soil application of triazole. Basil leaves developed severe or moderate visible symptoms of CI after 4 days of storage at 4 or 8°C, respectively, but remained undamaged when stored at 12°C. The chilling-dependent changes obtained in the ratios of variable to maximal fluorescence (F(v)/F(m)), represented chilling sensitivity rather than membrane damage. The photochemical quenching coefficient (qP) was unaffected by low temperatures and did not seem to be correlated with CI. On the other hand, changes in the non-photochemical quenching coefficient (qNP) were positively correlated with the appearance of visual CI symptoms in leaves of the two cultivars at all storage temperatures and durations. Similarly, the chilling-alleviating effect of triazole was accompanied by a corresponding reduction in the chilling-induced decrease of qNP. Therefore, qNP may be associated with an irreversible transition step in the CI process, which precedes the appearance of visual symptoms. As such, changes in qNP may provide a suitable, rapid and non-destructive criterion for estimation of chilling damage in green tissues.