Population status and variation of the rare species Dactylorhiza viridis (L.) R. M. Bateman, Pridgeon & M. W. Chase (Orchidaceae) under anthropogenic load conditions in the meadow phytocenoses of the Central Caucasus

We studied the variation of morphological characters, ontogenetic structure and vitality of seven cenopopulations of Dactylorhiza viridis (L.) R. M. Bateman, Pridgeon & M. W. Chase within the Kabardino-Balkar Republic in 2015–2019. The studies were conducted in the meadow plant communities under different conditions of anthropogenic load (recreation and grazing). The species presents medium phytocenotic plasticity of morphological characters (I p=36–70%) and high variation of morphological characters (CVх–ср=18,55–45,22%) under changeable conditions of growth. The intensification of growth processes in the individuals with the maximum increase of the cenopopulation vitality (IVC = 1,12–1,18) is observed in the composition of undisturbed meadows. The portion of generative individuals is 44,8–52,6% in ontogenetic spectra, and the stable seed reproduction of cenopopulations is registered. Under the intensification of the anthropogenic load, the vitality of cenopopulations (IVC = 0,80–1,04) and the density of individuals (0,47–3,20 ind./m2) are decreased; the portion of generative individuals is increased in ontogenetic spectra (65,4–81,6%). The rate of the seed reproduction of cenopopulations, in which the density of individuals accounts for 28,47 ind./m2, is high on the rubbly substrata with low total projective cover.

Seed propagation of Juniperus foetidissima Willd. in Absheron

The bioecological characteristics of the genus Juniperus L. on the Absheron Peninsula and its resistance to environmental factors are considered. The juniper, which occupies a very important place in the forests of Azerbaijan, is less demanding on environmental factors. At the Institute of Dendrology of Azerbaijan NAS, research on seed reproduction was carried out. Despite the fact that seed propagation is the only way to create new hybrid forms, the structure of the seeds and the growth characteristics of conifers make it difficult to use this propagation method. In the presented work, the influence of various factors on seed reproduction is considered and a model for the complex application of stratification and scarification for seed germination is proposed.

Population dynamics of two endemic species in Aksu-Zhabagly State Nature Reserve

The structure of Allium pskemense and A. karataviense coenopopulations from the Aksu-Zhabagly State Nature Reserve was described. It was established that the ontogenetic spectrum of coenopopulations is left-sided with a maximum on immature individuals. This is due to good seed reproduction, rapid rates of development at the end of ontogenesis. It was shown that over a 10-year period, there is a gradual aging of the coenopopulation, which is reflected in the shift of the peaks in the spectrum to the young generative (A. pskemense) and virginal (A. karataviense) groups. It was concluded that the sustainable development of coenopopulations will be in the case of a decrease in the number of the phytophages and successful regeneration by seed, which leads to a regular turnover of generations.

Seed Reproduction technology of the Magnolia grandiflora from seeds

This article highlights the results obtained on the basis of scientific research carried out in 2019-2020 on the technology of reproduction from the seeds of Magnolia grandiflora plant in the farmer’s farm named “Saydullo Temirov” specialized in the cultivation of landscape trees and shrubs located in the Uighur village of Pakhtaobod District of Andijan region. As a result of the study, determination of seed stratification time, planting time and methods, as well as maintenance work were determined, and conclusions were made.

Effects of Light and Autotoxicity on the Reproduction of Bidens pilosa L.: From Laboratory to the Field

In Taiwan, the good agricultural practices for Bidens pilosa L. (Cobbler’s pegs) had been established due to its pharmacology application. However, the reproduction of this species that may cause phytotoxicity to the subsequent crops has not been investigated extensively. We hypothesized that both the phytotoxicity and canopy shading conditions that were altered by agricultural practices might affect its seed reproduction. Three experiments from laboratory, pot and field were conducted under different light treatments and residue application rates to evaluate the light requirement and phytotoxicity on the germination of Cobbler’s pegs. The results showed that the germination in the laboratory, dark treatments was higher than that of light treatment while it was inhibited in the darkness in the pot experiments (24% of the light treatments). Moreover, some seeds in the pot experiments germinated in the far-red light (FR) pretreated dark treatments. This observation indicated that the germination response of the investigated plant might be a very low fluence response (VLFR). Results also showed that the autotoxicity enhanced the germination reduction in the FR pretreated dark treatment while increasing the residues buried in the field. Accordingly, both autotoxicity and canopy shading may inhibit the reproduction of Cobbler’s pegs, but the application method needs further study.

FEATURES SEED REPRODUCTION OF HEDYSARUM GRANDIFLORUM PALL. EX SITU AND IN VITRO

Hedysarum grandiflorum samples were collected from 7 natural populations of the Volgograd, Samara and Lugansk People's Republic and the features of seed reproduction were studied under ex situ and in vitro conditions. The optimal temperature for seed germination and the dependence of germination and seed vigor on the storage were revealed. We observed the maximum germination rate in the scarified seeds of H. grandiflorum of 2018 collection and it was equal to 70%.It was found that the seed germina-tion and seed vigor are low and quickly decrease with years of storage, while their scarification allows to increase these indicators. It is noted that the relatively low germination of the studied seeds is leveled by the rather high productivity of species in general. The optimal mode of sterilization of H. grandiflorum seeds was experimentally determined - 10% Lysofornin® 3000 solution for 5 minutes. The percentage of sterile seedlings was 60%.