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ABSTRACT:In this paper, the effect of the Bio-Algeen ® product (bio-alginate from the seaweed Ascophyllum nodosum (Linnaeus) Le Jolis) was evaluated in relation to basic mycorrhizal and growth characteristics of Norway spruce (Picea abies (Linnaeus) H. Karsten) seedlings. The seedlings were planted in a forest nursery in 5 different treatments: 4 treatments with the Bio-Algeen ® product in different regimes (soaking, granulate, soaking + granulate, irrigation) and control. Compared to the control, mycorrhizal characteristics of the treated seedlings differed significantly for soaking treatment only, but they were less favourable for all treatments with this product. Among the growth characteristics, the height of aboveground parts was significantly taller compared to the control for soaking and granulate treatments, while the shoot dry weight was significantly higher for granulate treatment only. Both of these characteristics showed higher values across all treatments compared to the control. Although treated seedlings showed worse mycorrhizal characteristics, their growth was not affected by these characteristics. Thus, Bio-Algeen ® can be used for an improvement of seedling growth in forest nurseries.Keywords: Ascophyllum nodosum; ectomycorrhiza; nurseries; Picea abies; seaweed Pre-planting application of plant growth regulators and other preparations supporting the growth of plant roots appears to be an affordable way to increase the growth of roots and to improve the tree survival (Scagel, Linderman 2001). Seaweeds and derived products are widely utilized as important sources of organic and inorganic compounds, organic fertilizers, and stimulants to increase plant growth and yield (Khan et al. 2009). Ascophyllum nodosum (Linnaeus) Le Jolis is the most frequently used seaweed belonging to the order Fucales Kylin. It occurs close to sheltered rocky shores in the North Atlantic (Olsen et al. 2010). From the seaweeds are extracted hydrolysates known as bioalginates. These are concentrated solutions of selected seaweed gels and natural polysaccharides composed of polyuronic acids. Bio-alginates contain also a wide range of biologically active agents, including amino acids, oligopeptides, organic acids, minerals, trace elements, and phytohormones (auxins). In contact with metals that are present in water, bio-alginates form a gel-flake system that is insoluble in water (Vostroupal 2007).Growth-promoting effects of bio-alginates on plants have been assessed on important agronomic and horticultural plants, namely flax, potatoes, hops, rapeseed, white mustard, lettuce, bluegrass, maize, barley (Vlk 1990), wheat (Vašáková et al. 1995), clover

This study evaluates the influence of repeated artificial drought stress on the fine root characteristics -including ectomycorrhizae -of Norway spruce [Picea abies (L.) Karst]. The experimental site consisted of two plots in a mature spruce monoculture stand. The water regime at parts of both plots was regulated by shelters and an isolation trench during vegetation season (spring to autumn) since 2010. Root samples were collected during autumn in 2010, 2012, and 2013. Root analyses revealed the effect of drought stress on mycorrhizal root tips changed over time. While a density of active mycorrhizae was about 34% lower in drought-stressed areas compared to nonstressed (control) areas in 2010, it increased by 15% in 2012 and by 22% in 2013 over both plots. We observed the less pronounced effect of drought on a proportion of active mycorrhizae, but it generally followed the pattern of active mycorrhizae density. The density of nonactive mycorrhizae was not influenced by drought but significantly fluctuated during the course of the experiment. Other root characteristics such as the dry mass of fine roots (< 1 mm), the specific length of fine roots (< 1 mm) and the composition of the ectomycorrhizal community (primarily dominated by Amphinema byssoides, Tylospora fibrillosa, Tylopilus felleus, and Cenococcum geophilum) were also not significantly influenced by drought. Our results indicate the ability of Norway spruce fine roots to compensate for repeated drought stress of the intermediate intensity.

Since 2008, spruce bud blight (Gemmamyces piceae (Borthw.) Casagr.) has been spreading epidemically in forest stands of the Czech Republic’s Ore Mountains. This fungus, with a disjunct Holarctic range, injures buds, especially of Colorado blue spruce (Picea pungens Engelm.). Damaged buds do not sprout, and, in case of a stronger attack, the tree does not recover its assimilation apparatus and may die. Within the past few years, there has been a huge spread of this fungus throughout the mountain range. This paper summarizes the biology of G. piceae, its host plants, and presents the first findings from the massive outbreak of G. piceae. In 2015, an increase in damage was detected on Norway spruce (Picea abies (L.) Karst). The course of the G. piceae epidemic had been monitored in 25 permanent research plots over the course of 11 years. In the case of Colorado blue spruce, stands aged 10–60 years were attacked, with 60% of buds damaged on average. The intensity of damage to Norway spruce buds was around 25%. Norway spruce infestation varied significantly depending upon the age of the stand (GLMM: p < 0.01). In the age class of 31–60 years, on average 80% of individuals were infested. In older stands, only 42% of trees were infested, and no infestation was found in individuals younger than 15 years. In Colorado blue spruce, the distribution of the pathogen was continuous, whereby all individuals in the research plots were affected, and, with the exception of a few trees, the infestation was lethal or resulted in a significant reduction of the assimilation apparatus. The development of damage on Colorado blue spruce can be characterized as continuous growth.