Dynamic model of seed germination on the example of a genus Dracocephalum L. based on logistic function

The aim of this paper is to present the use of mathematical model for an assessment of seed germination on the example of a genus Dracocephalum L. based on logistic function. An assessment of the quality of seeds and their species specificity was carried out. For this the method of a mathematical model of seed germination and the "Origin Pro" application package was used. The objects of research were samples of species Dracocephalum L. of different geographical origin from the collection of the I.N.Vavilov named All-Russian Crop Research Institute (VIR). Morphometric parameters of seeds of the studied species of the genus Dracocephalum L. were identified, which were divided into two groups. The first group with small seeds (2.7–3.0 mm long and 1.6–2.0 mm wide) included varieties of the species D. moldavica, and the second group – with very small seeds (2.0 mm in length and 1.0 mm wide) of D. multicaule and D. nutans. To assess the quality of seeds, we used both standard static indicators for germination, germination energy and seed vigour which are also assessed by both known the Grodzinsky bio test, and new ones based on dynamic parameters for evaluating seed germination. The dynamic model presented in the work reproduces changes in the initial phase of plant growth through the dynamics of seed germination. That is, the change in the state of a living object in motion in this model. When processing the results, a logistic function was applied that reflects the dynamics of change or accumulation of quantitative signs with the transition to new qualitative indicators. It was revealed that the shortest germination time of half of the maximum number of germinated seeds (intensity of germination) equal to 44.0 hours had the sample K-6 ('Aroma-2'). This indicates vigourous and friendly germination of the seeds of this variety. For sample K-7 ('Aroma-2'), this figure is 60 hours and, therefore, the germination rate is less than that for K-6. Similar in these parameters and the intensity of germination in the sample K-8 'Zeya' equal to 53 hours. Sample K-10 ('Arhat') was characterized by a relatively high germination rate, intensity of germination equal to 46 hours. Samples at 32 (D. nutans) and at 20 (D. multicaule) had approximately the same intensity of germination was equal to 61 and 54 hours, respectively. As a result, comparing the similarly different age characteristics of the seed material, a certain species and variety specificity in the dynamics of growth processes in the seeds of various types of snake head was revealed. The novelty of these studies was the search for new patterns and phenomena in assessing the quality of seeds and their species specificity.