Variability of the reproductive ability of Lonicera caerulea (Caprifoliaceae) in the seismically active zone of the Altai Mountains (Severo-Chuisky range, Kyzyl-Yaryk valley)
Authors:   Central Siberian Botanical Garden, Siberian Branch of the Russian Academy of Sciences  (Novosibirsk, Russian Federation), Boyarskykh Irina G. , Volkova Lyudmila R. ,   Central Siberian Botanical Garden, Siberian Branch of the Russian Academy of Sciences  (Novosibirsk, Russian Federation)
Published: January 2021

Seismically active areas of tectonic faults create specific inhomogeneous living conditions of plant populations and can thereby determine their structure. Studies of the reaction of plant reproductive structures to geoecological anomalies associated with active tectonic processes are practically absent. The aim of this work was to study the variability of the reproductive characteristics of Lonicera caerulea subsp. altaica plants in the local seismic zone of the Altai Mountains. We carried out studies in 2017 in the valley of the Kyzyl-Yaryk river (Altai Republic, Kosh-Agachsky district) (See Fig. 1), which was formed in the junction zone of seismic-generating faults active in the Holocene that are the boundaries of the North Chuy Range, Kurai intermountain basin and Chagan-Uzun massif and separating the Kurai and Chuysky depressions. We isolated 5 micropopulations of the Altai subspecies of blue honeysuckle - L. caerulea subsp. altaica in areas differing in volumetric activity of the radon emanation field (262-1162 Bq / m3) for research. Fifty fruits were selected in each micropopulation of L. caerulea subsp. altaica from 20 plants. We examined the morphometric characteristics and taste of the fruits, the number of full seeds and immature ovules in the fruits, the ratio of the number of full seeds to the total number of seeds and ovules, the correlation between the characters, as well as the seed germination capacity and germination readiness. The taste of the fruits was evaluated by the organoleptic method on a 5-point scale of taste variations based on the degree of bitterness in the fruits. To determine seed germinating capacity and germination readiness, germination was performed in Petri dishes at room temperature. We evaluated germination readiness on the 5th day, where n is the number of seeds and N is the number of seeds germinated during this period. For each micropopulation, we analyzed data for intragroup homogeneity using the χ2 method. Student’s t-test, Fisher’s exact test and one-way ANOVA analysis were used to test statistically significant differences in reproductive characteristics, as well as to assess the correlation between them. The analysis of variance (ANOVA) showed that the values of the Fisher criterion for the length, width, index, weight of the fruit and the number of seeds in them considerably exceed the critical value, which indicates a reliable effect of the place of plant growth on all these parameters at a 95-99% probability level. For individual test micropopulations, significant differences were found in the morphometric characteristics and seed productivity of plant fruits in comparison to the control micropopulation (the area with the lowest level of radon emanation field) (See Fig. 2, 3, 4 and 5). An analysis of the frequency of occurrence of plants with different weight and seed productivity of the fruits from the studied micropopulations showed a shift in the distribution of these parameters towards larger values, compared to the control micropopulation (See Fig. 6). The seeds collected in the control micropopulation were characterized by the least germination (See Fig. 8) and the shortest germination period (See Fig. 9). In the studied population, the average and close degree of correlation between the weight of the fruit and the number of full seeds was established; the reliability of the correlation varied depending on the place of plant growth. Plants in the L. caerulea subsp. altaica in the valley of the Kyzyl-Yaryk river were characterized by high polymorphism of the fruit shape. The frequency of occurrence of plants with oval fruits was significantly lower than in populations of L. caerulea subsp. altaica in other areas of the Altai Mountains. In micropopulations under the influence of a higher level of volumetric activity of subsoil radon, the variety of fruit shapes (See Fig. 3) and their taste variations (See Fig. 7) increased, including an increase in the expression of the recessive trait L. caerulea, the absence of bitter fruits (bitter-free fruits). The correlation between the level of radon emanation and the frequency of occurrence of plants with bitter fruits was significant at p <0.01. The influence of the level of radon emanation on the variability of morphometric characteristics of the fruit, seed productivity, germination and germination energy of the seeds was not significant. The heterogeneity of the population of the L. caerulea subsp. altaica, according to the features of the generative sphere, suggests a possible influence of a complex of factors associated with active tectonic processes on the formation and development of plant reproductive organs.