INFLUENCE OF LONG-TERM AND SHORT-TERM TEMPERATURE DROPS ON ACCLIMATION AND DE-ACCLIMATION IN CUCUMBER COLD RESISTANCE

It is known that temperature drop affects plant morphogenesis.
At the same time the drop is usually at cold acclimating temperatures which can cause increase in cold resistance.
In the literature little attention is paid to the effect of DROP on plant thermoresistance.
The aim of our work was to compare phenomenological aspect of the dynamics of cucumber plant cold resistance under short-term (DROP) and long-term temperature decrease on plant acclimation and de-acclimation.
Twenty-two day dynamics of cold resistance of cucumber plants was studied.
The control plants were grown under constant temperature of 20&degC, experimental plants under constant temperature of 12°C for 6 days (long-term treatment) and under conditions of temperature DROP to 12&°C for a 2 and 6 hour period (short-term treatments). To study the de-acclimation under temperature treatments, plants were returned to 20°C for two weeks.
Plant cold resistance was estimated by the LT₅₀ method based on survival.
Under long-term temperature decrease, maximum cold resistance was reached at the end of the 1^st – beginning of the 2^nd day.
Further increase in the exposure up to five days did not influence the resistance.
Under short-term temperature drop, the level of cold resistance doubled by the end of the 5^th day.
After the long-term treatment (after-effect) cold resistance returned to the control level on the 4^th day, but after the shot-term drops on the 9-16^th day.
These results allow concluding that additional ways of elevating plant cold resistance participate in plant response to the effects of diurnal temperature fluctuations.

XXVI International Horticultural Congress: Environmental Stress and Horticulture Crops

E.F. Markovskaya, E.G. Sherudilo, M.I. Sysoyeva

dynamic of cold resistance, daily temperature, greenhouse, shock protein

https://doi.org/10.17660/ActaHortic.2003.618.26