Scientific publications

We studied the response of light-loving (Quadrille, Courage, Hasbulat) and shade-tolerant (Berendey, Girlyanda, Rafael) hybrids of cucumber (Cucumis sativus L.) to a daily 2 h temperature drop (DROP) to 9°C at the end of the night or at the beginning of the light period. All DROP-treated plants irrespective of their demand for light had a slower growth rate and were more compact than control plants. Light had a significant modifying effect on the plant response to DROP, and although similarity was observed among the hybrids’ responses to this type of low temperature treatment, there was also a certain varietal (ecotypic) specificity. The most pronounced differences between light-loving and shade-tolerant hybrids were related to their ability to adapt to low temperatures. In particular, light-loving hybrids treated by DROP in the light had higher ability to increase chilling tolerance. Besides, in shade-tolerant hybrids, in contrast to the light-loving ones, DROP given in the end of the night did not lead to a decrease in chlorophyll content, while DROP given at the beginning of the light period reduced chlorophyll content in all hybrids. Long-term effect of DROP was manifested in shade-tolerant hybrids only as lower yields(especially in terms of early yields, which were decreased by 50–65 %) in plants treated by DROP at the beginning of the light period.