Flora of the natural monument «Cape Plaka» (Southern Coast of the Crimea): preliminary analysis

As a result of long standing research, 116 species from 88 genera of 36 families of vascular plants have been registered on the territory of the “Cape Plaka” nature monument. A preliminary analysis of the systematic, geographic and biomorphological structure of the flora was carried out, which showed that it belongs to the flora of the Mediterranean type. A list of habitats of the Cape has been compiled according to the EUNIS habitat classification. It was found that six native plant species ( Asphodeline lutea , Avena barbata , Hedypnois rhagadioloides , Juniperus excelsa , Pistacia mutica , Rhus coriaria ) and five types of biotopes have a conservation status, which confirms the high conservation value of the territory. It is proposed to include two more rare taxa in the list of protected species in the Crimea: Fumaria petteri and Misopates orontium . High invasive activity of Cheiranthus cheiri and two representatives of the genus Opuntia was revealed. It is recommended to combine two natural monuments - “Cape Plaka” and “The Coastal Aquatic Complex at Cape Plaka” - into a single protected area.

Identification and Origin of Xanthomonas campestris pv. campestris Races and Related Pathovars

One hundred sixty-four isolates of Xanthomonas campestris pv. campestris and other X. campestris pathovars known to infect cruciferous hosts (X. campestris pvs. aberrans, raphani, armoraciae, and incanae) were inoculated onto a differential series of Brassica spp. to determine both pathogenicity to brassicas and race. Of these, 144 isolates were identified as X. campestris pv. campestris and grouped into six races, with races 1 (62%) and 4 (32%) being predominant. Other races were rare. The remaining 20 isolates from brassicas and other cruciferous hosts were either nonpathogenic or very weakly pathogenic on the differential series and could not be race-typed. Five of these isolates, from the ornamental crucifers wallflower (Cheiranthus cheiri), stock (Matthiola incana) and candytuft (Iberis sp.), showed clear evidence of pathovar-like specificity to the hosts of origin. A gene-for-gene model based on the interaction of four avirulence genes in X. campestris pv. campestris races and four matching resistance genes in the differential hosts is proposed. Knowledge of the race structure and worldwide distribution of races is fundamental to the search for sources of resistance and for the establishment of successful resistance breeding programs.