Influence of biological products on the growth and development of large-fruited cranberry under greenhouse conditions

The aim of this study was to determine the influence of various biological fertilizers on the growth and development of plants of the large-fruited cranberry and the degree of mycorrhizal association in their roots under controlled conditions. Plants of the ‘Pilgrim’, ‘Stevens’ and ‘Ben Lear’ cranberry cultivars were planted in rhizoboxes filled with soils collected from the areas of Krojczyn and Motoga. The following experimental treatments with fertilizers were applied: control plants, plants fertilized with NPK, a bacterial-mycorrhizal consortium, Vinassa, lignite + Vinassa, Florovit Natura and the fertilizer Crop-UP. The study has shown that there was a tendency to stimulate the vegetative growth and development of cranberry plants through the use of bio-fertilizers and beneficial fungi obtained from the rhizosphere of these plants. There was a tendency for the fresh and dry weight of cranberry shoots to increase, especially in ‘Ben Lear’, under the influence of the bio-fertilizer Florovit Natura when compared with the control plants fertilized with NPK. Compared with the NPK control, all of the bio-fertilizers significantly increased mycorrhizal frequency in the roots of the tested plants of the large-fruited cranberry, with the exception of Crop-UP and lignite compost used in conjunction with Vinassa in ‘Stevens’. No statistically significant differences were obtained for plant size and root colonisation by ericoid fungi in the plants grown in the soil from the areas of Motoga and Krojczyn.

Screening Commercial Peat and Peat-based Products for the Presence of Ericoid Mycorrhizae

Pieris floribunda (Pursh) Benth. & Hook., a known host of ericoid fungi, was used as a model plant to investigate the presence of ericoid mycorrhizal fungi in select peat and peat-based products. After growing in each medium for 75 days, roots of seedlings were examined and average percent colonization was determined for each sample. Results indicate that these fungi are present in the majority of peat and peat-based media tested. Seedlings grown in some of the selected media had a greater percentage of root cells colonized by ericoid mycorrhizae than others in the study.

564 Screening Commercial Peat and Peat-based Products for the Presence of Ericoid Mycorrhizae

A study was conducted to investigate the presence of ericoid mycorrhizal fungi in select peat and peat-based products. Vaccinium corymbosum, a known host of ericoid fungi, was used as a model plant. Peat and peat-based products were obtained from all major sources that supply the northeastern United States. Seedling roots were examined and average percent colonization was determined for each sample. Results indicate that these fungi are present in the majority of peat and peat-based media tested. Seedlings grown in some of the selected media exhibited an increased percentage of colonized root cells. Mycorrhizal fungi colonizing roots of test plants were isolated. These fungi exhibited typical ericoid fungal growth characteristics.

Ericoid mycorrhizal fungi: cellular and molecular bases of their interactions with the host plant

A number of soil-borne fungi are able to form typical ericoid mycorrhizae with plants belonging to Ericales. Together with Hymenoscyphus ericae, the first isolate from roots of ericaceous plants, other fungal species belonging to the genus Oidiodendron and many sterile mycelia have been recognized as mycorrhizal by several authors. A high genetic diversity was even found when a population of ericoid mycorrhizal fungi isolated from a single plant of Calluna vulgaris was analysed with morphological and molecular techniques. Ericoid fungi have a relevant saprotrophic potential, as they can degrade several organic polymers present in the soil matrices. Different cell wall degrading enzymes, which are part of this arsenal and are produced in vitro by several ericoid fungi, have been investigated biochemically. Immunocytochemical studies on the production of pectin degrading enzymes during the infection process of host and non-host plants suggest that regulation mechanisms for the production of cell wall degrading enzymes in vivo may be a crucial step for the establishment of successful mycorrhiza with host plants. Key words: ericoid mycorrhizae, cell wall degrading enzymes, polygalacturonase, DNA-RAPD techniques.