Chilling injury and chill-hardening in selected tropical foliage plants

Abstract

Chilling susceptibility and symptoms were reported for 31 genera in 18 families, showing widespread sensitivity to chilling injury among foliage plants. Electrolyte leakage was positively correlated (r = 0.97, 0.98) with chilling duration in Scindapsus pictus Hassk., providing a reliable predictor of membrane injury in this species. Electrolyte leakage was not correlated with chilling duration in Maranta leuconeura, E. Morr. var. erythroneura Bunting. Increased concentration of ethane, a by-product of membrane peroxidation, was noted in the internal atmosphere of both species, indicating membrane damage. Increased ethylene concentrations were found in leaves of M. leuconeura, but concentrations were reduced in S. pictus leaves following chilling. Growth of S. pictus, M. leuconeura, and Aphelandra squarrosa was reduced following chilling at 5(DEGREES)C in the dark for 2,4, or 6 days, respectively. Growth of Pilea cadierei was not altered by chilling. Chill-hardening by low-temperature conditioning (15(DEGREES)C) significantly ameliorated the adverse effects of chilling on growth and plant quality in M. leuconeura and S. pictus. Chill-hardening M. leuconeura for 2 days ameliorated the effects of chilling for 4 days at 5(DEGREES)C. Chill-hardening for 9 days effectively ameliorated the effects of chilling for 8 days at 5(DEGREES)C in both species. Measurement of dry wt change demonstrated that chill-hardening alone did not reduce growth in M. leuconeura and S. pictus. Measurement of net CO(,2) exchange in M. leuconeura and S. pictus agreed with dry measurements in three instances: (1) The chill-hardening treatment did not reduce growth; (2) M. leuconeura acclimated to the chill-hardening temperature (15(DEGREES)C) in 9 days; and (3) S. pictus did not acclimate to the chill-hardening temperature (15(DEGREES)C) in 9 days.It is possible that photosynthetic adaptation occurs as a result of, or as a cause of, chill-hardening.