ВЛИЯНИЕ КРАТКОВРЕМЕННОГО ТЕМПЕРАТУРНОГО СТРЕССА НА ПРОРАСТАНИЕ СЕМЯН УКРОПА

Abstract

New data on the process of germination of dill seeds of the first and second orders after short-term heat stress (40 ° C) have been obtained. Seed germination was carried out in a thermostat. Swollen seeds (four repetitions of 100 seeds) were exposed to a temperature of 40 ° C in accordance with the scheme of the experiment: 0 (control); 1; 2; 3; 4 and 5 days. After incubation, the seeds were transferred to standard (t = 20 ° C) conditions and germinated in Petri dishes on filter paper with-out access to light for 21 days. Methods of analysis of seed germination in dynamics are used. Log-logistic regression with three parameters was used to construct the seed germination curve: b, d, e. All statistical analyses were performed in R version 3.4.3. The duration of the action of high temperature, which has an inhibitory effect on the germination rate and the number of germinated seeds, was revealed. Seeds of the first order in the control and after incubation for 1-3 days germi-nated in a similar way, and with an increase in the incubation period to 4-5 days, the rate of ger-mination decreased sharply. The seeds of the second order were even less resistant to the action of a short high-temperature stressor, and when the seeds were incubated for 3 days and then trans-ferred to standard temperature conditions, germination did not occur. The germination time of 50% of seeds (T50) of the first order as a result of a sequential increase in the incubation period at 40 ° C increased from 0.92 ± 0.11 to 6.4 ± 0.49 (p<0.001) days, respectively. Seeds of the second order during incubation for 1-2 days also germinated significantly slower compared to the control, and in the future germination did not occur. The curves of changes in the index of maximum seed germination, especially for the second order of branching, had a sharp bend when the critical dose of the temperature factor was exceeded. After that, there was a sharp decrease in the speed of seed germination up to a complete stop. The maximum incubation time (at 40 ° C), after which germi-nation is possible under standard temperature conditions, was 3.69 ± 0.06 days for the first order, and 2.00 ± 0.19 days for the second order. The difference was significant at the significance level of p<0.001.