Critical tests for determination of microbiological quality and biological activity in commercial vermicompost samples of different origins.

The aim of the present paper was to show that differences in biological activity among commercially produced vermicompost samples can be found by using a relatively simple test system consisting of microorganism tests on six microbiological media and soilless seedling growth tests with four vegetable crop species. Significant differences in biological properties among analyzed samples were evident both at the level of microbial load as well as plant growth-affecting activity. These differences were mostly manufacturer- and feedstock-associated, but also resulted from storage conditions of vermicompost samples. A mature vermicompost sample that was produced from sewage sludge still contained considerable number of Escherichia coli. Samples from all producers contained several potentially pathogenic fungal species such as Aspergillus fumigatus, Pseudallescheria boidii, Pseudallescheria fimeti, Pseudallescheria minutispora, Scedosporium apiospermum, Scedosporium prolificans, Scopulariopsis brevicaulis, Stachybotrys chartarum, Geotrichum spp., Aphanoascus terreus, and Doratomyces columnaris. In addition, samples from all producers contained plant growth-promoting fungi from the genera Trichoderma and Mortierella. The described system can be useful both for functional studies aiming at understanding of factors affecting quality characteristics of vermicompost preparations and for routine testing of microbiological quality and biological activity of organic waste-derived composts and vermicomposts.

Changes of morphogenic competence in mature Pinus sylvestris L. buds in vitro.

The effects of season and cold storage on morphogenic competence in mature Pinus sylvestris buds were investigated. Peroxidase and polyphenol oxidase activity were measured as markers of oxidative metabolism. No growth in vitro was observed on explants detached from the end of January until the beginning of March. Brachioblasts, each with a couple of needles, formed on 11% of the buds without macrostrobili that were detached in early April and introduced immediately into culture. Of the explants detached in late July, 15% formed shoots with brachioblasts and needles. The lowest activity of peroxidase and polyphenol oxidase in pine buds was observed from the end of April until the beginning of June when morphogenic competence of tissues started to increase. Development of bud explants detached in January was achieved by cold storage for 5 months. Low polyphenol oxidase and peroxidase activity coincided with increased morphogenic potential. Results suggest that reduced or stable activity of peroxidase and polyphenol oxidase is associated with an increased ability of tissues to start growth in vitro.