MORPHOLOGICAL AND BIOCHEMICAL CHANGES INDUCED BY COLD-HARDENING IN TOMATO

Tomato seedlings were chill-hardened by using a split-night temperature regime (low temperature during the second half of the night). Some morpho-physiological and biochemical parameters were monitored during the hardening period (15 days). At the end of the hardening treatment, plants were subjected to chilling stress (3°C for 52 hours, in continuous light), and relative water content, and abscisic acid levels were measured.
The results obtained indicate that the split-night temperature regime adopted in this study was effective in inducing chilling resistance in tomato seedlings.
The increased cold resistance was associated to changes in plant habitus (reduced height, reduced total and specific leaf area) due to differences in dry matter distribution.
No significant differences were observed in soluble sugars, free aminoacids and proline content.
Plant water relations were slightly affected.
Levels of free abscisic acid differed significantly from control plants only after the first cycle of split-night.
SNTR represent an efficient technique for raising tomato transplants as it allows energy saving in greenhouse management and an improvement in seedling quality without reducing growth rate.

Protected Cultivation, XXIII IHC

P. Vernieri, A. Pardossi, F. Tognoni

https://doi.org/10.17660/ActaHortic.1992.303.17