Germination and the Initial Seedling Growth of Lettuce, Celeriac and Wheat Cultivars after Micronutrient and a Biological Application Pre-Sowing Seed Treatment.

Seed treatments with zinc, boron, biostimulant Coveron and MIX (zinc + boron + Coveron) were applied to three lettuce and three celeriac cultivars. Seeds of three wheat cultivars were treated under laboratory conditions with Trichoderma harzianum and eight Bacillus spp. Seed germination, seedling growth, and the presence of the following pathogens were determined: Fusarium sp., Alternaria sp., Penicillium sp., and Mucor sp. The Coveron treatment was the most effective on lettuce seeds tested in the germination cabinet. Seed germination was higher by 4% than in the control. Alternatively, germination of seeds treated with boron in the greenhouse was higher by 12% than in the control. The Coveron treatment had the highest effect on the shoot length, which was greater by 0.7 and 2.1 cm in the germination cabinet and the greenhouse, respectively. This treatment was also the most effective on the root length. Zn, B, and MIX treatments increased celeriac seed germination by 14% in the germination cabinet. The Zn treatment was the most efficient on seeds tested in the greenhouse. The germination was higher by 15%. A significant cultivar × treatment interaction was determined in both observed species under both conditions. The maximum effect on wheat seed germination (8%) was achieved with the T. harzianum treatment in the Salazar cultivar. A significant interdependence (p ≤ 0.01 to p ≤ 0.001) was established between seed germination and the seedling growth. The interrelationship between seed germination and pathogens of all cultivars was negative.

Occurrence and Identification of Pectobacterium carotovorum subsp. brasiliensis and Dickeya dianthicola Causing Blackleg in Some Potato Fields in Serbia.

Blackleg outbreaks were noticed on three fields (about 100 ha total) in 2 consecutive years (2018, 2019) in one of the main potato growing areas in Serbia (Backa region, Vojvodina). The percentage of infected plants reached 40 to 70%, with 10.5 to 44.7% yield reductions. From the three fields, out of 90 samples Pectobacterium carotovorum subsp. brasiliensis was most frequently identified and diagnosed as causal agent of potato blackleg in Serbia for the first time (29 isolates). Dickeya dianthicola was a less frequently causative bacterium, which was also noticed for the first time (nine isolates). A total of 38 isolates were characterized based on their phenotypic and genetic features, including a pathogenicity test on potato. The repetitive element PCR (rep-PCR) using BOX, REP, and ERIC primer pairs differentiated five genetic profiles among 38 tested isolates. Multilocus sequence analysis (MLSA) of four housekeeping genes, acnA, gapA, icdA, and mdh, revealed the presence of three so far unknown P. c. subsp. brasiliensis multilocus genotypes and confirmed clustering into two main genetic clades as determined in other studies. MLSA also revealed the presence of a new genotype of D. dianthicola in Serbia.

Molecular Characterization of Pseudomonas syringae pv. coriandricola and Biochemical Changes Attributable to the Pathological Response on Its Hosts Carrot, Parsley, and Parsnip.

Bacterial leaf spot caused by the plant pathogenic bacterium Pseudomonas syringae pv. coriandricola (Psc) was observed on carrot, parsnip, and parsley grown on a vegetable farm in the Vojvodina Province of Serbia. Nonfluorescent bacterial colonies were isolated from diseased leaves and characterized using different molecular techniques. Repetitive element PCR fingerprinting with five oligonucleotide primers (BOX, ERIC, GTG5, REP, and SERE) and the randomly amplified polymorphic DNA-PCR with the M13 primer revealed identical fingerprint patterns for all tested strains. Multilocus sequence analysis of four housekeeping genes (gapA, gltA, gyrB, and rpoD) showed a high degree (99.8 to 100%) of homology with sequences of Psc strains deposited in the Plant-Associated Microbes Database and NCBI database. The tested strains caused bacterial leaf spot symptoms on all three host plants. Host-strain specificity was not found in cross-pathogenicity tests, but the plant response (peroxidase induction and chlorophyll bleaching) was more pronounced in carrot and parsley than in parsnip.

Microelements and Heavy Metals Content in Frequently Utilized Medicinal Plants Collected from the Power Plant Area.

The effectiveness of medicinal plants is mainly associated with their active constituents, but one of the major quality problems frequently encountered is their high trace metals content that can be associated to extensive pollution of the environment where medicinal plants grow. Therefore the aim of this research was to evaluate the content of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn and As in selected and frequently used medicinal plants, including chicory, broadleaf, common comfrey and dandelion. The plant material was collected from their wild habitats in the area of highly developed power plant activity during the summer of 2015. Plant analyses were done according to ICP methodology, using ICAP 6300 ICP optical emission spectrometer. The obtained results showed that the content of As, Cd, Co, Mn, Ni and Zn in the investigated medicinal plant species was below the maximum permissible concentration, while in all parts of all studied plants the concentration of Cr was toxic. The toxic concentrations of Cu were determined in root and aerial parts of chicory and common comfrey, and the toxic concentrations of Fe in root and aerial parts of dandelion and broadleaf plantain, and in aerial parts of common comfrey. However, high but not toxic content of Pb was found in aerial parts of chicory. It can be concluded that medicinal plants from the studied growing site are not appropriate for use in alternative medicine and that a determination of trace metals content in these plants must become a standard criterion for evaluation of their quality.