Rhizoctonia solani was isolated from 91 % of alder and birch seedlings with stem rot symptoms and 2-3% of seeds. Sowing of seeds to substratum infested with R. solani resulted in pre-and postemergence damping off. On leaves and stem parts of alder and birch, inoculated with 3 isolates of R. solani, necrosis spread from 0.22 to 0.52 mm/hr.

Phytophthora cambivora was isolated from the bark lesions of two 10- and 15-year-old of analysed alder trees. Additionally, Botrytis cinerea, 3 Fusarium species, Mucor spp., P. alni and Trichoderma spp. were recovered from diseased tissues. Isolates of P. cambivora from six plant species, used for inoculation of alder seedlings and plant parts, cause dthe development of necrosis. Isolate from Chamaecyparis lawsoniana was the weakest pathogen whereas those from Abies alba, Acer pennsylvanicum and Alnus glutinosa were the strongest.

Six isolates of Trichoderma spp. (belonging to species; Trichoderma harzianum and T. longibrachiatum) were applied as seed or soil treatments to suppress damping-off of seedlings of ten cotton cultivars under greenhouse conditions. In most cases, cultivar x isolate interaction was a highly significant (p < 0.01) source of variation in the tested seedling growth parameters: incidence of disease, seedling height, and seedling dry weight. This interaction implies that a single isolate of Trichoderma can be highly effective in controlling the disease on a cotton cultivar but may have minimal efficiency in controlling the disease on another cultivar. It was also found that, in most cases, cultivar x isolate x application method was a highly significant source of variation (p < 0.01) in the tested growth parameters. Cotton cultivars showed differences in the disease reaction to the biocontrol agents. In the experiments evaluating the Trichoderma antagonists and their effect on seedling disease, a highly significant (p < 0.01) experimental treatment interaction was found. This interaction suggests that the outcome of cultivar x isolate interaction is markedly affected by the application method. Thus, the application method should be chosen to maximize the outcome of this interaction. The degree of the control of seedling disease in cotton differed according to the isolates of antagonists, the application method and cultivars.

Isatis cappadocica Desv. is a newly found As-hyperaccumulator showing very high remediation efficiency in polluted soils. We studied the effects of arsenic at 0-1400 μM concentrations on seed germination, relative root length, relative shoot height, and root and shoot biomass in young seedlings of I. cappadocica. The seeds were from Iranian arsenic-contaminated mine spoils and from a non-contaminated population. The control for reference was brassica (Descurenia sofia). Germination decreased significantly versus the control with increasing arsenic concentrations. The response to arsenic exposure differed between the I. cappadocica populations and D. sofia. I. cappadocica from mine spoil seeds showed strong resistance to the highest As concentration, with no adverse effects until the 1000 μM dose. Germination from non-mine seeds of I. cappadocica decreased to 89.6% at 1400 μM As. D. sofia germination was completely inhibited at 400 μM As. Relative root length (RRL) and relative shoot height (RSH) decreased with increasing As concentration. Overall, RRL correlated with RSH. Shoot height and root length were more sensitive to arsenic than other endpoints, and might be used as arsenic toxicity indicators. I. cappadocica showed more As tolerance than the reference brassica.

The aim of the research was to determine the factors defining the growth and development of Lolium perenne and Trifolium repens upon petroleum contamination. The top layer of clay soil contaminated with petroleum products resulting from an oil pipeline failure was collected for the tests. The control was the same type of uncontaminated soil with the addition of, under laboratory conditions, tissue paper. The research was conducted in two stages. The first concerned the germination process and seedlings parameters (Petri dishes). The germination energy ( GE) and the germination capacity ( GC) of seeds were determined. The seedling’s development was also evaluated based on ‘WinRhizo PRO 2009’ software. Then, in the second stage, pot tests were carried out, where the growth and development of species in the first year after sowing were temporarily measured. The parameters studied were the number, height, green and dry masses of the plants.
A Gompertz regression model describing seed species germination and number species as time dependent dynamic was applied. The data were analysed statistically using variance analysis (ANOVA) and the PCA (principal component analysis) method. The results of our study indicated that admixture of petroleum into the soil does not seriously affect the development dynamics of Lolium perenne seedlings. The diesel oil contamination mostly affects the germination of the Trifolium repens by a statistically significant increase of the maximum value of germination and increasing the maximum growth rate.

We examined the response of plants of various crop and weed species to cyanamide in order to evaluate allelochemical- mediated interactions between the species. We studied germination and seedling growth in the common weeds Galium aparine L. and Amaranthus retroflexus L., and the crops Zea mays L., Triticum aestivum L., Lactuca sativa L., Solanum lycopersicum L. and Sinapis alba L. as acceptor plants. Concentration-dependent phytotoxic effects of cyanamide were noted during seed germination and in the root and shoot growth of the tested plants. The monocotyledonous plants generally were less sensitive to cyanamide treatment. Seed germination and seedling growth of the dicotyledonous plants were strongly inhibited by the allelochemical at both tested concentrations (1.2 mM, 3 mM). We conclude that cyanamide has potential for use as a natural herbicide only in specific field systems of cyanamide-tolerant monocotyledonous crops accompanied by cyanamide-sensitive dicotyledonous weeds.