Influence of Temperature on Development of Pine Wilt in Scots Pine

The effect of temperature on pine wilt development in Scots pine (Pinus sylvestris) was examined in three experiments. Container-grown pines (4-6 years old) inoculated with 1,500 Bursaphelenchus xylophilus were incubated at constant temperatures in growth chamber for 8 weeks, then at a temperature range of 15-30 C in a greenhouse for 10-12 weeks. Nematode infection was greater, tree mortality was higher, and disease incubation was shorter at 32 and 30 C than at 25, 23, 18, and 11 C. Foliar symptoms developed more rapidly and uniformly at higher temperatures. Ninety-five percent of tree deaths at 32 and 30 C and 88% at 25 and 23 C occurred within the 8-week exposure to constant temperatures. Mortality at 18, 16, and 11 C occurred only after transfer to the greenhouse. Results indicate that pine wilt incidence is directly related and disease incubation period is inversely related to temperature and that high-temperature stress predisposes Scots pine to lethal infection by B. xylophilus.     

Colonization of Fungi and Bacteria in Stumps and Roots of Scots Pine after Thinning and Treatment with Rotstop

The research areas were located in the Pisz Forest District, northeast Poland, in 10‐year‐old Scots pine (Pinus sylvestris L.) plantations, established in 2004 on a clear‐cut area. Reforestation was performed without a biological treatment against root pathogens, despite the presence of Heterobasidion annosum and Armillaria ostoyae in roots and stumps of trees growing previously. The aim of this research was to evaluate how thinning and treatment with the biological control agent Rotstop influences bacterial and fungal communities within roots and stumps. Twelve months after thinning, samples were collected from five stumps in each of two seasons, autumn and spring, from stands on two types of site, one previously forested and one agricultural (20 stumps in total). Wood samples were cultured on agar media, and (i) fungi in the upper part of the stump and (ii) in roots and (iii) bacteria in roots were genetically identified. Sequences were genetically identified by comparing sequences with records held in the GenBank database. We found great differences in the frequency of both fungi and bacteria in roots: they were more frequent (i) in healthy stumps compared to stumps infected with pathogens (H. annosum and A. ostoyae), (ii) in postagricultural soil than in forest soil and (iii) after spring rather than autumn biological treatment. The introduced species Phlebiopsis gigantea was only identified in the parts of the stumps which were above ground level. The bacterium Paenibacillus pini was associated with the presence of H. annosum infecting the stumps from the roots side. In areas seriously threatened by root pathogens, biological treatment can play only a limited role. It can spread to the upper part and impede the production of fruitbodies; however, it has no impact on the development of pathogens in deeper root areas.     

Evolutionary Aspects of Functional and Pseudogene Members of the Phytochrome Gene Family in Scots Pine

According to the neutral theory of evolution, mutation and genetic drift are the only forces that shape unconstrained, neutral, gene evolution. Thus, pseudogenes (which often evolve neutrally) provide opportunities to obtain direct estimates of mutation rates that are not biased by selection, and gene families comprising functional and pseudogene members provide useful material for both estimating neutral mutation rates and identifying sites that appear to be under positive or negative selection pressures. Conifers could be very useful for such analyses since they have large and complex genomes. There is evidence that pseudogenes make significant contributions to the size and complexity of gene families in pines, although few studies have examined the composition and evolution of gene families in conifers. In this work, I examine the complexity and rates of mutation of the phytochrome gene family in Pinus sylvestris and show that it includes not only functional genes but also pseudogenes. As expected, the functional PHYO does not appear to have evolved neutrally, while phytochrome pseudogenes show signs of unconstrained evolution.     

Seasonality of Glutathione Dynamics in Scots Pine and Bilberry

Abstract: Seasonal changes in the glutathione status of Scots pine ( Pinus sylvestris L .) needles and bilberry ( Vaccinium myrtillus L.) stems and leaves were investigated during 1995 and 1997–1998, respectively. The glutathione concentration, the proportion of reduced glutathione (GSH%) and glutathione reductase (GR) activity were measured at monthly intervals throughout one year. The glutathione concentration and GSH% in current year's Scots pine needles were highest during late summer, but decreased during autumn. It is suggested that exchange reactions between free and protein-bound glutathione may be involved in this reduction. Both metabolites decreased towards summer in the previous year's needles. GR activity exhibited the lowest values in summer and the highest values in winter in both needle generations. In bilberry stems, glutathione peaked during midwinter, while GSH% remained high and relatively constant throughout the year. GR activity was highest in August, after which it gradually declined. In bilberry leaves, the total glutathione concentration was high in early summer. This peak was followed by a sharp decrease during midsummer. GR activity in the leaves was very low, but showed a clear increase towards autumn. Obviously, glutathione metabolism showed considerable seasonal variation in Scots pine needles and in bilberry leaves and stems, but the pattern of variation differed between the studied species and organs.     

Rosellinia aquila Among Fungi on Branches of Sessile Oak with Symptoms of Decline

Rosellinia aquila was found for the first time in crowns of sessile oaks, Quercus robur (Mattuschka) Liebl., with symptoms of decline. The fungus occurred mostly on diseased branches but also colonized twigs with healthy appearance. Its anamorph and teleomorph stages were produced abundantly on dead branches after long incubation in moist conditions. Colonization of oak trees by R. aquila was likely to have been facilitated by higher humidity and temperature in the oak stands.     

Study on Rosellinia necatrix Isolates Causing White Root Rot Disease in Taiwan

White root rot is a serious soil‐borne disease of several woods and crops. Recently, white root rot of tea shrubs and ornamental trees has increasingly been observed in Taiwan. Thirty‐six isolates of white root rot pathogen, showing pear‐shape swellings adjacent to the hyphal septa, had been isolated from samples of white root rot collected from Taiwan for about 4 years. The pathogen isolates produced Dematophora anamorph. Conidia of the pathogen were one‐celled, hyaline, subglobal, with truncate base, 2.9–5.8 × 1.9–3.5 μm . Ascospore dimensions were in the range of 37.0–55.0 × 5.4–7.9 μm with a short, longitudinal and straight germ slit, which complied with Rosellinia necatrix. Based on molecular studies, the pathogen isolates collected from Taiwan except R701 were identified as R. nectarix. Isolate R701, which was relatively polymorphic in internal transcribed spacer DNA sequence than other isolates, was temporarily considered as R. necatrix‐related pathogenic Rosellinia spp. All the tea cuttings (Camellia sinensis) inoculated with isolates developed typical white root rot symptoms. Pathogenicity tests demonstrated the presence of variation in virulence among the Rosellina isolates. Most of the R. necatrix isolates originating from Acer morrisonense were less virulent than those that originated from other hosts. The pathogenic Rosellinia spp., isolate R701, was also highly virulent to both cultivars of tea cuttings.     

Increase of biodiversity in homogeneous Scots pine stands by an ecologically diversified management

Three important parameters of biodiversity in first generation Scots pine (Pinus sylvestris) forests on sandy soils have been evaluated: herbal layer diversity, natural regeneration and stand structure. The study took place in the Belgian Campine region, where the original oak–birch forest, degraded to heathlands in the course of time, were finally replaced by monocultures of Scots pine. These first generation pine forests are characterized by a low biodiversity. In maturing stands of this type, however, a spontaneous increase of biodiversity is noticed. Herbal species richness is very limited in all age classes. Different natural regeneration patterns are found. Referring to stand structure, the lengthening of the rotation favours the ingrowth of several hardwood species. As a consequence, the homogenous Scots pine stands are gradually and spontaneously transformed into heterogeneous mixed stands, featuring a noticeable increase in biodiversity. Selected human interventions may further increase biodiversity. The fundamental management principles are discussed: avoidance of major disturbances, lengthening of the rotation period, use of native tree species and natural regeneration, protection of microbiotopes and permanent monitoring.     

Fractionation of the proteinases present in the endosperm of germinating seed of Scots pine, Pinus sylvestris

When fresh extracts of endosperms separated from germinating seeds of Scots pine were dialysed at 5°C, proteinase activity on haemoglobin at pH 3.7 showed only a small initial increase, proteinase activities on casein at pH 5.4 and at pH 7.0 increased several-fold, and all the corresponding inhibitor activities disappeared (Salmia and Mikola 1980, Physiol. Plant. 48: 126–130). To find out what happens during dialysis, both fresh and dialysed extracts were fractionated by gel chromatography on Sephacryl S-200. – The fresh extracts had a major proteinase peak (mol. wt. 42,000) with high activity at pH 3.7 and moderate activities at pH 5.4 and 7.0 (pine proteinase I) and a smaller peak (mol. wt. 30,000) with high activity at pH 5.4 and 7.0 and smaller activity at pH 3.7 (pine proteinase II). In dialysed extracts the situation was reversed: the peak of proteinase I was very small while the peak of proteinase II was very high. Apparently, proteinase I is largely inactivated during dialysis while the activity of proteinase II increases, at least partly due to destruction of inhibitors. – The two enzymes were -SH proteinases, as they were completely inhibited by p -hydroxymercuribenzoate; both of them were also inhibited by the endogenous proteinase inhibitors of resting pine seeds. Besides these enzymes, the endosperm extracts contained pepsin-like acid proteinase activity, which is not affected by the endogenous inhibitors. This enzyme activity was largely inactivated during dialysis.     

Drivers of stem radial variation and its pattern in peatland Scots pines: A pilot study

Dendrometers are useful tools to analyze intra-annual variation of radial growth in trees, but have rarely been applied in marginal environments. Our aim in this study was to explore stem radial variation (SRV) of Scots pines (Pinus sylvestris L.) growing in a marginal environment on top of a peatland and compare it with stem radial variation of Scots pines growing in a nearby forest. We compared high-resolution (30 min) tree-growth of the peatland and forest pines in two consecutive years in two ways. First, we modeled raw SRV using site and weather parameters as predictors, to determine if and in what way stem radial variation depends on the site type. Second, we split the SRV signal into sub-series of varying length to test for differences between the time-series pattern of peatland and forest SRV with clustering methods and classifier models. We found indications that site type is influencing raw stem radial variation as: 1) an intercept, i.e. forest trees tended to grow more than peatland trees (as expected); 2) an interaction factor with structural and weather parameters, i.e. response of the forest trees to changing environmental parameters was different than the response of the peatland trees. Conversely, with regard to the temporal pattern of the stem radial variation, we found that the conditions within one year, e.g. weather patterns, were more important than site conditions, especially at short time scales. However, with increasing length of the sub-series the relative accuracy of the classifier models increased. Our results indicate that the site type was important for the raw SRV (amplitude) but not for the SRV pattern, which might be important to consider when comparing intra-annual signals from multiple sites.     

Total, organic and extractable-P in humus and soil beneath Sitka spruce planted in pure stands and in mixture with Scots pine

Total, organic and extractable P were measured in the humus and underlying soil to 10 cm depth beneath Sitka spruce (SS) and mixed Sitka spruce and Scots pine (SS+SP) stands planted on upland heath. The humus beneath SS+SP contained significantly (p<0.01) greater amounts of total and organic-P than that in SS and the mixed stands had more effectively retained approximately 87 per cent of previously applied fertilizer-P, totalling 100 kg P ha^–1, compared with 70 per cent in SS. Despite the larger amounts of total-P in the mixed plots 0.01 M CaCl₂ extractable molybdate reactive phosphorus (MRP) was significantly (p<0.05) greater in SS+SP humus only during March and April. Greater concentrations of MRP were released from the humus and soil during July and August at a mean rate of 58 g P ha^–1 day^–1. This coincided with drying of the soil during the summer and the rate of release, attributed to death of fine roots and microorganisms, was 4 to 30 times greater than reported values for rates of net mineralization of P from forest soils.     

Inhibitors of endogenous proteinases in Scots pine seeds: Fractionation and activity changes during germination

Resting seeds of Scots pine (Pinus sylvestris L.) contain inhibitors which inhibit the proteinase activity present in germinating seeds but have no effect on trypsin or chymotrypsin. When a crude inhibitor preparation was chromatographed on Sephadex G-75, the inhibitor activity separated into four peaks with elution volumes corresponding to the molecular weights 24,000, 14,600, 14,000, and 9000. Each of the inhibitors affected both the hydrolysis of haemoglobin at pH 3.7 and the hydrolysis of casein at pH 5.4 and 7.0 by proteinase extracts prepared from “germinating” endosperms. These results suggest that one major proteinase was possibly acting in all the assays. In resting seeds inhibitor activity was present in both the embryo and the endosperm, the activity (per mg dry weight) in the embryo being about 2-fold that in the endosperm. In the endosperms of germinating seeds the inhibitor activity per seed decreased at about the same rate as total N and dry weight. In the seedlings the activity per seedling remained approximately constant. The patterns of the activity changes suggest that the inhibitors do not control the breakdown of storage proteins; a more probable function is the protection of other cellular components from the high proteinase activities required for the rapid proteolysis during germination.     

Fluctuation in free and conjugated polyamines in Scots pine seedlings after changes in temperature and daylength

Free, soluble and insoluble conjugated polyamines from the needles, roots and stem of five month old Scots pine (Pinus sylvestris L.) seedlings inoculated with Suillus variegatus (Fr.) O. Kuntze and seedlings without inoculation were analysed during decrease in daylength and temperature. Temporary changes in free, soluble and insoluble conjugated polyamine pools caused by a decrease in daylength or temperature were observed. Inoculation of pine seedlings affected significantly the polyamine levels of five month old pine seedlings. The roots of inoculated seedlings contained significantly higher levels of free and soluble conjugated purtrescine and free, soluble conjugated and insoluble conjugated spermidine than the roots of noninoculated seedlings. The needles of inoculated seedlings contained significatly higher concentrations of free putrescine and soluble conjugated spermidine but lower amount of free spermine than the needles of noninoculated seedlings. The stems of inoculated seedlings contained higher concentrations of free putrescine but lower amounts of insoluble conjugated spermine. Changes in polyamine levels in noninoculated seedlings were observed after shortening of the daylength, whereas in inoculated ones changes were induced mainly by the decrease in temperature. The possible role of polyamines in the initial stage of cold hardening process is discussed.     

Differences in nitrate and ammonium uptake between Scots pine and European larch

In forest soils, ammonium is usually the predominant form of inorganic nitrogen. However, the capacity of trees to utilize both NO₃ ^- and NH₃ ⁺ may provide greater flexibility in responding to changes of nitrogen supply from the environment. Such capacity has been studied in seedlings of Scots pine (Pinus sylvestris L.) and European larch (Larix decidua Mill.) grown in the presence or absence of either nitrate or ammonium. Nitrate-induced plants showed a higher nitrate uptake rate than non-induced plants; this difference was almost negligible after 24 h of exposure to NO₃ ^-. Ammonium uptake in both species was consistently higher than that of nitrate, regardless of prior nitrogen provision. In both nutrient conditions, larch showed a more efficient transport system in comparison with Scots pine, with higher ammonium and nitrate uptake rates in both induced and non-induced plants. This was consistent also with the activity of nitrate reductase, measured in vivo in roots and leaves. This revised version was published online in June 2006 with corrections to the Cover Date.     

An estimation of Scots pine (Pinus sylvestris L.) ecosystem productivity on reclaimed post-mining sites in Poland (central Europe) using of allometric equations

The work presents determination of the productivity of post-mining ecosystems (PME) derived from the aboveground biomass and annual biomass increment of Scots pine (Pinus sylvestris L.) stands. Single tree biomass assessment data from 42 cut trees were used in developing local allometric equations which may be used as an index during post-mining reforestation projects. The total biomass of pine ecosystems was determined from dendrometric measurements of sample plots with the use of elaborated equations. Forest floor vegetation was determined using the harvest method. Control plots were set up in the vicinity of the mining-sites at a managed forest on natural pine sites (NPS). Results confirm wide ecological amplitude of pine and indicate a high PME productivity on all substrates (2.79-4.34 Mg ha⁻¹ yr⁻¹).     

Observations on the teleomorph of the white root rot fungus,Rosellinia necatrix, and a related fungus,Rosellinia aquila

The process of teleomorph development in the white root rot fungusRosellinia necatrix is described on diseased roots of Japanese pear. Stromata were also found on dead plants in nonagricultural lands such as yards and forests. The stroma ofR. aquila is also described. Research based on the program for Promotion of Basic Research Activities for Innovative Biosciences.     

Effects of age and site quality on the distribution of biomass in Scots pine (Pinus sylvestris L.)

The distribution of the above-ground and below-ground biomass of Scots pine in southern Finland were investigated in trees of different ages (18–212 years) from two types of growth site. Secondly, some structural regularities were tested for their independence of age and growth site. Trees were sampled from dominant trees which could be expected to have a comparable position in stands of all ages. All stands were on sorted sediments. The biomass of the sample trees (18 trees) was divided into needles, branch sapwood and heartwood, stem sapwood and heartwood, stem bark, stump, large roots (diameter >20 cm), coarse roots (five classes) and fine roots. The amount of sapwood and heartwood was also estimated from the below-ground compartments. Trees on both types of growth site followed the same pattern of development of the relative shares of biomass compartments, although the growth rates were faster on the more fertile site. The relative amount of sapwood peaked after canopy closure, coinciding with the start of considerable heartwood accumulation. The relative amount of needles and fine roots decreased with age. The same was true of branches but to a lesser degree. The relative share of the below-ground section was independent of tree age. Foliage biomass and sapwood cross-sectional area were linearly correlated, but there were differences between the growth sites. Needle biomass was linearly correlated with crown surface area. The fine root to foliage biomass ratio showed an increasing trend with tree age.     

Porphyrin metabolism in chill-stressed seedlings of Scots pine (Pinus sylvestris)

Scots pine ( Pinus sylvestris L.) is generally resistant to chilling temperatures. Porphyrin metabolism under low temperature stress was studied in etiolated seedlings of Scots pine. Low temperatures affect porphyrin accumulation in at least 3 different temperature sensitive sites: 1) the light activated accumulation of 5-aminolevulinic acid, a porphyrin precursor, 2) the metabolism of 5-aminolevulinic acid to form porphyrins and 3) a preferential accumulation of chlorophyll a over chlorophyll b . The temperature sensitivity of pine is compared to maize ( Zea mays L.), a chilling sensitive plant.     

The role of low-level ozone exposure and mycorrhizas in chemical quality and insect herbivore performance on Scots pine seedlings

The effects of low‐level ozone exposure and suppression of natural mycorrhizas on the above‐ground chemical quality of Scots pine (Pinus sylvestris L.) needles and insect herbivore performance were studied in a two‐year field experiment. Seedlings were fumigated with the ozone doses 1.5–1.7 times the ambient, and natural mycorrhizal infection level was about 35% reduced in roots with fungicide propiconazole. On ozone‐exposed seedlings the mean relative growth rate (MRGR) of Lygus rugulipennis Popp. nymphs was lower than on ambient ozone seedlings, but Gilpinia pallida Klug sawfly larvae grew better on elevated ozone seedlings than on ambient ozone seedlings. MRGR of Schizolachnus pineti Fabr. and Cinara pinea L. aphid nymphs or Neodiprion sertifer Geoffr. sawfly larvae or the oviposition of L. rugulipennis and N. sertifer were not affected by ozone exposure. Although ozone exposure did not affect total phenolics, total terpene, total or individual resin acid, total free amino acid, nutrient or sugar concentrations in needles, MRGR of L. rugulipennis positively correlated with total terpenes and MRGR of G. pallida positively with total amino acids. In addition, ozone exposure increased serine and proline concentration and marginally also starch concentration in needles. When mycorrhizas were reduced with fungicide, only MRGR of L. rugulipennis nymphs increased, but performance of other insect herbivores studied was not changed. However, number of L. rugulipennis eggs correlated positively with mycorrhizal infection level and also with total sugars. Reduction of mycorrhizas did not strongly affect the concentrations of analysed compounds in needles, because only phosphorus and potassium and some individual resin acids were reduced by fungicide treatment. These results suggest that low‐level ozone exposure and moderately declined mycorrhizal infection do not drastically affect either the above‐ground chemical quality of Scots pine seedlings or performance of studied insect herbivores.     

Fractionated extraction and speciation of macronutrients from Scots pine and Norway spruce needles of different ages

Summary The relationship between proteins and the macroelements potassium, magnesium, calcium, sulphur and phosphorus was studied in homogenates of needles of different ages from Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L.) Karst.]. Complete extractions by acid digestion, protein extractions by a buffer-detergent and non-protein extractions by a buffer alone showed that most of the potassium and magnesium of the needles was soluble independent of the proteins. Only a minor part (50–60 ppm, dry weight) of the magnesium could be referred to the chlorophyll content of the needles. Both potassium and magnesium appeared independent of the protein gel filtration. This was also valid for the minor fraction of the total calcium content, which was extractable in a buffer. Heterogeneous calcium deposits are also suggested by extraction using a chelator (EGTA). Part of the buffer-soluble sulphur and phosphorus compounds occurred independently of solubilized proteins, and had complex distribution patterns after gel filtration, even outside the high molecular separation range. It is suggested that further analyses along the present lines, compared with conventional analyses on total extracts, may extend the usefulness of mineral nutrient analyses in plants.     

Influence of climatypes of Scots pine on certain chemical and microbiological characteristics of soils

By using multivariate statistical analysis, the influence of Scots pine climatypes on a set of chemical and microbiological properties of soil, i.e., soil C/N, C_mic/C_org, and C_mic/N_mic, was revealed in a series of long-term (ca. 30 years) field experiments, which were carried out according to the same scheme under contrasting environmental and soil conditions of Siberian forestries.