Ontogenesis and Ontogenetic Structure of Local Populations of the Astragalus holargyreus Bunge (Fabaceae) of the Narrow-Local Endemic Of Kyzylkum
Аннотация
Astragalus holargyreus Bunge is a narrow-local endemic of Kyzyl Kum. It grows in the outlier mountains of Bukantau. It has status 1 in the Red Book of the Republic of Uzbekistan (2019). The purpose of the article is to assess the current state of local populations. When describing ontogenesis, we used the method of Rabotnov (1950), Uranov (1975), and Local Plant Populations (1976). The structure of local populations was studied with the generally accepted method (Uranov, 1975; Tsenopopulyatsiya rastenii…, 1976). Local populations were characterized according to the classification of ontogenetic structure proposed by Uranov and Smirnov (1969); age and effectiveness were characterized according to L.A. Zhivotovsky (2001). The ecological density was determined according to W. Odum (1986). Relevés were carried out according to the standard technique on 100-m2 areas (Polevaya geobotanika, 1964). Astragalus holargyreus is a monocentric, vegetatively nonmotile, tap-root, herbaceous polycarpic with sympodially renewing, monocyclic shoots. The ontogenetic spectrum of the first local population is typical and reflects the biological characteristics of the species: a gradual increase in the life span in the pregenerative and generative periods, which culminates in the middle-aged state, and rapid aging with an absolute maximum in individuals of a middle-aged generative state. The proportion of individuals with an absolute maximum occurs in individuals of the middle-aged generative state (29.06%). The ontogenetic spectrum in the second local population does not coincide with the characteristic one, which is unimodal with an absolute maximum for virginal individuals (23.40%). The average density of individuals is 0.86 pcs. per 1 m2 in local population 1 and 1.17 pcs./m2 in CP2. The ecological density ranges from 1.28 to 2.76. According to the sum of the points of organism and population characteristics, all surveyed local populations are in a stable state. It is recommended that the habitats of the species(Bukantau ridge) should be introduced into the system of protected natural areas of the republic in order to preserve the natural population of Astragalus holargyreus.