Geobotanical and Ecological-Physiological Characteristics of Some Medicinal Species of the Genus Inula L. under Conditions of Uzbekistan

The article presents the geobotanical and some bioecological features of species of the genus Inula L., family Asteraceae (Compositae). The water regime, as well as the water holding capacity, transpiration rate and adaptive ability of plants to drought in the arid zone, is considered. The results of studies on the introduction into the culture based on indicators of the osmotic pressure of cell juice are presented.


Introduction
The Asteraceae family is one of the largest families of dicotyledonous plants, which number from 1150 to 1300 genera and more than 20,000 species in the world. Asteraceae has a large range of plants spread from the tundra to the equator, on the shores of the sea to snow in the alpine region, on sands, on lands with black soils [1]. The genus Inula L. has about 100 species. They are widespread in Eurasia (from the Canary Islands to Japan), as well as in Africa and on the islands of Madakascar. In the CIS countries, 32 species are found. In particular, 9 species grow in Uzbekistan: Inula helenium, Inula grandis Schrenk., Inula salicina, Inula glauca C., Inula caspica Blume., Inula britannica L., Inula macrolepis Bunge., Inula rhizocephala Schrenk., Inula multicaulis Karel [2] [3].
Inula helenium is distributed in the European part of Russia (central and southern regions), Western Siberia (the north of the Altai-Sayan mountain country), Europe, South Asia, the Mediterranean, the Caucasus and Central Asia ( Figure 1).
The root of the Inula helenium plant is used in medicine for the treatment of respiratory diseases. Inula helenium root preparations have the ability to prevent respiratory diseases, inflammation and reduce the secretion of intestinal function, and are also very effective in the treatment of gastrointestinal diseases [4].
The leaves and roots of the Inulahelenium plant contain essential oils (1% -3%), saponins, resins, mucus and bitters. The main ingredient in the root is alantolactone, a mixture of essential oil isoalantolactone. Their mixture was formerly called gelenin. In addition, the roots of digidroalantolactone, fridelin, dammaradienylacetate, dammaradienol, phytomelane and other acetylene compounds, as well as stigmasterine, inulin, and pseuddoinulin have been isolated from the roots [5] [6].
The underlying organs of the Inula helenium plant contain essential oils, bitter and mucous substances, saponins, resins, inulin, alkaloid scars, vitamin E and gum. Tincture of the root of this plant is used in the treatment of respiratory diseases: bronchitis, tracheitis, pulmonary tuberculosis. In addition, the preparations of the Inula helenium plant can cure gastrointestinal diseases [7].
The aim of the research work is to develop a method for introducing promising medicinal plants into the culture of Inula helenium L.-Elecampane high and Inula salicina L.-Elecampane. Beideman [8] and I. V. Borisov [9] were used.

Materials and Methods
The water content was determined using the gravitational method, the water holding capacity in assimilation organs according to A. A. Nichiparovich [10], the osmotic pressure of cell juice according to N. A. Gusev [11] and soil moisture according to the method of T. T. Rakhimova [12].

Results and Discussion
The following changes were observed during 2017: the average air temperature in January was +2.5˚C -7.1˚C. From June to August, the temperature was noted, respectively +27.2˚C -26.7˚C. The average annual air temperature was +16˚C, the average annual relative humidity was 52%. The average air temperature reached +2.5˚C -6.1˚C in January 2018 and +29˚C -31.3˚C in July. The average annual air temperature was +16.4˚C and the average annual relative humidity was 48.7%. During the years of observation, hot days lasted from the third decade of May to the end of September. This period is characterized by an increase in temperature during the day and evening and was also characterized by hot and dry weather ( Figure 2).
Observations showed that soil moisture varies over a year in layers of up to 50 cm ( Table 1). The change in soil moisture at the experimental site in 2017 averaged in April -May, 15.1% -14.5%. In the dry period, from June to September, fluctuations were observed-12.4%, 11.8%, 10.4%, 11.4%. In 2018, changes were recorded in April on average 14.9%, in May-13.2%, in the driest period from June to September, the humidity was 12.4%, 11.8%, 10.4%, 11.4%.
The seeds of Inula helenium sown in early spring at the experimental site be-      Throughout the season, a decrease in the water holding capacity of plants with the onset of the dry period was observed.

N. Y. Kuchkarov
During the season, the average daily increase in water content in the assimila-  Thus, with the beginning of the dry period from June to August, the maximum increase in transpiration intensity was found in both plant species. At the end of the season, with a decrease in illumination, a decrease in air and soil temperature, the intensity of transpiration decreased. During the experiments, it was found that the change in transpiration intensity is also associated with the growth and development of plants throughout the season.

Conclusion
The water-holding capacity, transpiration rate, and osmotic pressure of cell juice in the assimilation organs of Inula helenium change throughout the season depending on temperature, relative humidity, and rainfall. It was established that an increase in the osmotic pressure of plants throughout the season is the main indicator of the adaptation of these species to drought conditions. According to the adaptation properties, these plants were included in the group of xeromesophytes such as mesophytes. In 2018, the water holding capacity of Inula salicina was in the range of 23.8%, which is 10.6% higher than in Inula helenium. Good growth rates, periods of budding, flowering and maturation of Inula helenium and Inula salicina were determined in the hilly terrain of the Tashkent. Ecological and physiological characteristics of plants allow us to conclude that these plant species can adapt to various environmental conditions.

Conflicts of Interest
The author declares no conflicts of interest regarding the publication of this paper.