The purpose of this work is to comparatively assess pollen viability of five plant species growing in different areas of the city of Aktobe, Kazakhstan (N 50Њ18¢, W 57Њ10¢). Pollen viability was assessed through iodine staining on the samples of pollen grains harvested between April and June 2017 from 100 plants of 5 species growing in the industrial zones, parks, and along highways: Ulmus laevis Pall., Ulmus pinnato-ramosa Dieck., Acer negundo L., Syringa vulgaris L., Populus tremula L. The minimum percentage of fertile pollen grains that was found in Ulmus laevis species has been detected in samples from the industrial zones, up to 68%. For Ulmus pinnato-ramosa, the minimum proportion of fertile pollen grains was 30%. For Acer negundo and Syringa vulgaris, similar trends were obtained. All plant species except Ulmus laevis (0.42) and Populus tremula (0.37) showed no relationship between the size of pollen grains and the intensity of their color change. Among all plant species under study, two (Ulmus laevis and Populus tremula) had the potential to act as model plant species and bioindicators of urban pollution. All five plant species demonstrated the highest proportion of defective pollen grains in the industrial zones, up 98%.

Dendroflora of Aktobe city consists of 71 species and forms belonging to 40 genera and 18 families. The predominant number of species are Rosaceae, Salicaceae, and Pinaceae. Their total participation in the dendroflora of Aktobe city is 56.3%. The basis of the city greening forms some 7 tree species: aspen, elm, smooth, rough, ash-leaved maple, yellow acacia, Syringa vulgaris. Among the bushes the most common are dog-rose bushes and cherry shrubs. During the research we revealed infectious diseases of trees and shrubs that have been identified. We registered 17 fungi species on 12 species of trees and shrubs. The most common diseases are powdery mildew, rust and spot, the most vulnerable tree species were Ulmus pinnato-ramosa, Acer negundo, Fraxinus pennsylvanica, Populus nigra.

The article presents the results of identification of fungal diseases among the trees and shrubs in Aktobe City (Kazakhstan). The most common diseases were powdery mildew, rust, spots, and leaf curl. Three species of fungal diseases were identified in genus Ulmus, two species – in genus Acer, four species in Populus, two species in genus Fraxinus, and the genera Salix, Rosa, Malus, Padus, and Crataegus had one fungi species each. The study revealed an uneven distribution of the identified fungal diseases. We determined that there were fewer types of fungal diseases in the gardens and parks than in the suburbs. We also registered a decrease in powdery mildew together with increase of the leave rust in urban environments. The regularity in reducing the number of fungal diseases toward the city center from periphery was defined.

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The article presents the results of long-term studies of useful plants of Aktobe region, located at the junction of Europe and Asia and therefore of special interest in the botanical-geographical aspect. Seven groups of useful plants were identified: forage, medicinal, food, honey, technical, decorative, and poisonous plants. According to our results, 876 species with certain properties are used by humans, accounting for 59.4% of the total number of flora species in the Aktobe region. We revealed that the following groups represent the largest number of species: medicinal plants-593 species (40.2%), forage plants -428 species (29.0%), ornamental plants -253 species of flora of the region or 17.2% of the total number of species, and the smallest group of poisonous plants -114 species. Some species like Agropyron cristatum, Bromopsis inermis, Eremopyrum orientale, Festuca valesiaca, Phleum phleoides, and Poa pratensis, are the most abundant in the Aktobe region. Agropyron cristatum and Secale sylvestre shoud have potential interest for breeding.