Root Growth, Mycorrhizal Frequency and Soil Microorganisms in Strawberry as Affected by Biopreparations

The aim of the study was to assess the effects of various biopreparations on the growth of the strawberry root system, the number of spores of mycorrhizal fungi, the total number of bacteria in the rhizosphere soil, and the degree of mycorrhizal association in the roots of two strawberry cultivars. The experiment with strawberry plants was established in the spring of 2010 in the Experimental Orchard of the Institute of Horticulture in Dabrowice. The objects of research were “frigo” strawberry plants of the cultivars Elsanta and Elkat. The following experimental combinations were used: control, control NPK (standard NPK fertilization), manure, mycorrhizal preparation Micosat F, Humus UP, Humus Active + Aktywit PM, BioFeed Amin, BioFeed Quality, Tytanit, Vinassa, Florovit Eko, and Florovit Pro Natura. The use of the biopreparation BioFeed Quality resulted in a six-fold increase in root length and a seven-fold increase in root surface area. Compared with NPK fertilization, application of the preparation BioFeed Amin contributed to an eight-fold increase in root volume, and the use of Vinassa increased 24-fold the number of root tips of Elkat strawberry plants. Micosat F and Humus UP caused a five-fold increase in mycorrhizal frequency in the roots of strawberry plants. Micosat F and manure contributed to a two- and four-fold increase, respectively, in the number of spores in the rhizosphere soil. Application of the preparations Humus UP, BioFeed Amin and Florovit Eko doubled the total number of bacteria and filamentous fungi in the rhizosphere soil of strawberry plants of the cultivars Elsanta and Elkat in comparison with NPK fertilization. Fertilization with the biopreparations intensified the growth of the root system and increased the number of spores of AM fungi, mycorrhizal frequency, and the total number of bacteria and filamentous fungi in the soil.

The Influence of Bioproducts on Mycorrhizal Occurrence and Diversity in the Rhizosphere of Strawberry Plants under Controlled Conditions

The new products obtained from natural resources are an alternative to methods based on traditional mineral fertilizers, which are destructive for soil mycorrhizal communities. Our experiment was carried out to evaluate the effect of organic fertilizers and amendments of very diverse composition on mycorrhizal abundance and diversity, as well as on root growth, in strawberry plants cv. “Honeoye”. The plants were grown in rhizoboxes filled with a podsolic soil. The plants were treated with granulated bovine manure, vermicompost extract, humates extract, plant extract, extract from seaweed species reinforced with humic and fulvic acids, a consortium of beneficial soil organisms, a stillage from yeast production and a solution of titanium. Plants treated with products and the microorganisms consortium also received half dose of manure. A standard mineral fertilization (NPK) and an unfertilized control were also included. The bioproducts based on humus-like substances and the yeast stillage had the greatest positive influence on the colonization of roots by arbuscular mycorrhizal fungi (AMF). The different treatments affected the diversity of AMF species present in the rhizospheric soil. All organic products, even though providing a significantly low amount of nutrients, enhanced root growth characteristics in comparison to the mineral fertilization.

Assessment of Mycorrhizal Frequency in the Roots of Fruit Plants Using Different Dyes

The aim of the experimental work was to optimize the previously used Phillips and Hayman (1970) method of staining roots for microscopic assessment of mycorrhizal frequency in the root material. The materials used in the experiment were the roots of strawberry plants of the cultivar “Elsanta” obtained in a greenhouse experiment in May 2012. Morphological features of the roots were assessed using a root scanner, and then attempts were made to stain the roots in four types of dyes: 0.01% methylene blue, 0.01% acridine orange, 0.01% malachite green, and 0.01% carbol fuchsin. A comparative microscopic assessment was made of the effects of staining with the four types of dyes the structures of mycorrhizal fungi formed in strawberry roots. Mycorrhizal frequency (F%) in the stained root samples was also compared. Next, the usefulness of these dyes for staining the roots of other fruit plant species, such as apple, sweet cherry, blackcurrant and sour cherry, was evaluated. It was concluded that the staining of roots at a temperature of up to 65&#176C did not cause tissue breakdown, and that the clearing time used—20 to 30 minutes, and the use of carbol fuchsin were found to be the most effective combinations in achieving good quality microscopic images. During microscopic examinations, a satisfactory contrast was noted between root tissues and the structures of mycorrhizal fungi. The use of carbol fuchsin for staining roots also helped to expose a greater number of fungal structures and obtain higher values of mycorrhizal frequency in the roots of strawberries, blackcurrants, sour cherries, sweet cherries and apples, in comparison with other dyes tested. The newly developed method of staining roots with carbol fuchsin, compared with the method used previously (Phillips and Hayman, 1970), is both less time consuming and less labour intensive.