In Vitro Studies of Antifungal Activity of Colloidal Silver against Important Plants Pathogens

Colloids and especially silver are increasingly used in a variety of worldwide applications because of their potential antimicrobial activity and their plasmotic and conductivity properties. This research reports the fungitoxic properties of colloidal silver on mycelial growth of important plant pathogens: Alternaria brassicicola, Botrytis cinerea, Aspergillus flavus, Aspergillus niger, Fusarium culmorum, Fusarium oxysporum, Penicillium digitatum and Sclerotinia sclerotiorum. Although variable responses towards each compound were observed within the species the results revealed a clear reaction to limiting mycelium growth relative to various concentration of Colloidal silver (CS). Results were expressed as effective concentrations which inhibit mycelial growth by 50% and 90% respectively (EC50 and EC90). Efficiency of colloidal silver on mycelial growth inhibition of different isolates based on EC50 have the following values: 3.69 ppm for Alternaria brassicicola, 7.32 ppm for Botrytis cinerea, 18.21 ppm for Aspergillus flavus, 10.43 ppm for Aspergillus niger, 11.99 ppm for Fusarium culmorum, 12.27 ppm for Fusarium oxysporum, 10.82 ppm for Penicillium digitatum and 6.34 ppm for Sclerotinia. According to the obtained results the antifungal activity of colloidal silver particles as biocide has potential for using it as a non-aggressive treatment in horticulture and sustainable horticulture

The Influence of Rootstock on the Growth and Fructification of Cherry Cultivars in a High Density Cultivation System

The influence of rootstock on the growth and fruiting of three sweet cherry cultivars (‘Bigarreau Burlat’, ‘Kordia’, ‘Regina’) was studied under the pedoclimatic conditions of Cluj-Napoca, Romania, in 2014-2016. The trees were grafted on Gisela 5 rootstock, trained as Zahn Spindle and the orchard had a density of 1666 trees/ha. Roots were cut twice, at 50 cm distance from the trunk, in an angle of 45° and 30 cm depth, as followed: first time, to the autumn, in fall leaves time, on one side of the row and the second time, in spring, at blooming time, at the other side of the row. The rootstocks influenced height of the trees, the shoot growth, the number of long and fruiting branches, trunk cross sectional area yield and precocity, with differences statistically assured. The longest shoots, in mean values, gave the variant with cultivars grafted on Mahaleb rootstock (111.7 cm). ‘Gisela 5’ rootstock decreases the average length of annual growth (93.3 cm). Trees grafted on Mahaleb formed more long fruiting branches and fewer short fruiting branches than those grafted on ‘Gisela 5’. The biggest average trunks cross sectional area were obtained for the cultivars grafted on Mahaleb (62.1 cm2). Also, rootstocks influenced the height of the trees. The cumulative yield was almost double in variants where the trees were grafted on ‘Gisela 5’ (23.2 kg/tree), compared to the variants where the trees were grafted on Mahaleb (13.1 kg/tree)

<i>Epipactis bucegensis</i>—A Separate Autogamous Species within the <i>E. helleborine</i> Alliance

A new species of Epipactis from Bucegi Natural Park ROSCI0013, Southern Carpathians, Central Romania is described. Three medium-sized populations of Epipactis bucegensis (65–70 individuals in total) were discovered in the south-eastern, subalpine area of the park. To properly describe and distinguish the newly found taxon from other Romanian Epipactis, 37 morphological characters were measured directly from living plants and flowers. Moreover, a detailed taxonomic treatment and description with corresponding colour photos and line drawings illustrations of the holotype are also included. Epipactis bucegensis is an obligate autogamous species that partially resembles Epipactis muelleri, from which it differs in the basal distribution of leaves on the stem (vs. median distribution); near-erect leaf posture (vs. horizontally spread, arched downwards); lanceolate–acuminate, yellowish-green leaves (vs. oval–elongate, vivid-green leaves); bipartite labellum lacking the mesochile (vs. tripartite labellum); crimson-red, wide, ovoid–elongated, flattened hypochile (vs. dark-brown to black roundish hypochile); triangular, white epichile with a sharply tapering apex (vs. heart-shaped, greenish-yellow epichile with obtuse, roundish apex); and two wide-apart, purple, pyramidal calli (vs. two closely placed, attenuated, mildly wrinkled, greenish-yellow calli). Epipactis bucegensis is easily distinguished from all other European Epipactis taxa by the bipartite, wide labellum that lacks the mesochile. In addition, information regarding its distribution (maps), habitat, ecology, phenology and IUCN conservation assessments are provided