Effects of Alkalization of the Environment on the Anatomy of Scots Pine (Pinus sylvestris) Needles

The effects of alkaline dust emitted from a cement plant for over 40 years on the anatomy of needles of Scots pine and lignin accumulation were analysed. Comparative analytical studies were conducted in stands similar as to their silvicultural indicators, climate and age in alkalised and in a relatively unpolluted area. Cross-section of needles were stained, photographed under microscope and measured. It was found that, due to the alkalisation of the environment, the total area of the needle cross-section, needle width and thickness and the area of mesophyll had decreased. At the same time, the vascular bundles and epidermis had increased. The greatest anatomical and biochemical differences between the needles from trees growing under optimum conditions and in the alkalised area were observed in the oldest needles. Visual analysis of cross-sections and biochemical analysis showed accumulation of lignin in older needles but more intensively in alkalised areas than in control.     

Relationships between Lignin and Nutrients in Picea Abies L. under Alkaline Air Pollution

The influence of alkaline dust pollution (pH of water solution12.3–12.6) from a cement plant (Kunda, Estonia) and alkalizedgrowth substrate on lignin and mineral composition of the needles of 75–90-yr-old Norway spruce was studied on sample plots established at different distances from the emission source. Disbalanced content of nutrients and an increase in thelignin content were found under the high level of air pollution.The contents of K, Ca, S and B in needles were higher, while those of Mn and N were lower in heavily polluted plots. A strongcorrelation was found between lignin and K, N and B concentrations as well as Ca/K in needles and shoots. Stimulation of lignification of needles correlated with the pollution load. Reduction of needle growth was observed and a negative correlation was established between the lignin concentration in tissues and the length of needles under the impact of dust pollution.     

Responses of wheat yield,quality and bread-making properties on the sulphur fertilization

This study presents a versatile influence of sulphur (S) application on winter wheat – beginning with the influence on the grain yield and primary quality indices, followed by the one on the bread-making properties of flour and dough, and ending with the one on the quality indices of baked products. Field experiments were conducted at two locations on haplic Luvisol and calcaric Cambisol during five years. S was given as NS-fertilizers on the background of N100 during wheat tillering. Flour and dough properties for bread-making were determined by using a farinograph Brabender. The baking tests were carried out in laboratory conditions. The influence of S on the grain yield and quality, and bread-making properties of wheat depended on the year and location. As the average of field experiments conducted at two locations, the application of S significantly increased the grain yield (r?=?0.960). The increasing yields were accompanied by decreasing contents of wet gluten (r?=?0.825). However, the significant positive (r?=?0.938) effect of the S application on the Gluten index was revealed, which is a good predictor of the baking quality of wheat flour. The S addition by nitrogen fertilization resulted also in a positive shift of the N:S ratio in grains, which is better for the bread-making quality. The significant positive effects of the S application on the dough stability time (r?=?0.898) and on the farinograph quality number (r?=?0.917) were demonstrated. The loaf volume was significantly (r?=?0.842) increasing under the influence of S. Thus, the application of S in parallel with increasing yields improved several bread-making parameters of wheat.     

Functional conversion between A-type and delayed rectifier K+ channels by membrane lipids

Voltage-gated potassium (Kv) channels control action potential repolarization, interspike membrane potential, and action potential frequency in excitable cells. It is thought that the combinatorial association between distinct alpha and beta subunits determines whether Kv channels function as non-inactivating delayed rectifiers or as rapidly inactivating A-type channels. We show that membrane lipids can convert A-type channels into delayed rectifiers and vice versa. Phosphoinositides remove N-type inactivation from A-type channels by immobilizing the inactivation domains. Conversely, arachidonic acid and its amide anandamide endow delayed rectifiers with rapid voltage-dependent inactivation. The bidirectional control of Kv channel gating by lipids may provide a mechanism for the dynamic regulation of electrical signaling in the nervous system.     

Changes in the canopies of Pinus sylvestris and Picea abies under alkaline dust impact in the industrial region of Northeast Estonia

Studies were carried out in 1999, 2005 and 2007 in the area of Kunda cement plant in Northeast Estonia on sample plots 3 km W and 2.5 and 5 km E of Kunda. As control stands, two plots for pine and spruce were established in Lahemaa National Park (34-38 km W of Kunda). The selected pine and spruce stands were 75-85-year-old Myrtillus site type, of 0.7-0.8 density and II quality class, with moderately dense or sparse understorey. The values concerning needle density and number of needle scars were higher for shoots formed in the period of higher pollution than for the shoots grown under a considerably lower pollution load. Although the cement dust pollution has notably decreased from year to year, the number of needle pairs per 1 cm of the shoot was 1.8-2.1 times greater in the shoots formed in 1998 than in those formed in 2003, whereas the changes were statistically reliable. Possibly the low temperatures at the time of shoot and needle formation affected the density of needles on all sample plots, and thus the number of needles on shoots formed in 2003 was many times smaller. After the significant fall in the pollution load since 1996 the length growth of needles intensified around Kunda cement plant, at the same time no changes occurred in the length growth of needles in the control area. As compared to the data from 1998, the length growth of pine needles had improved, especially 2.5 and 5 km E from the cement plant, needles being respectively 1.5 and 1.1 cm longer than 6 years ago. The stimulation of the growth of pine and spruce needles 2.5 and 5 km E of the cement plant may be a sign of a positive effect of reduced doses of cement dust in soil. The greater length of pine and spruce needles is the reason for the larger biomass of the needles.     

The Quality of Stemwood of Pinus sylvestris in an Alkalised Environment

The impact of long-term dust pollution emitted from a cement plant on soil chemistry, and the concentrations of plant nutrients, lignin, cellulose and hemicellulose in the stemwood of 80–85-year-old Pinus sylvestris was investigated at different distances from the emission source. It was found that alkaline cement dust (pH 12.3–12.6) emissions for over 40 years resulted in an alkalisation (pH 6.7–7.9) of the polluted soil compared to a pH value of 3.8 in unpolluted soil. There were also nutrient imbalances in the soil, as well as certain disturbances in mineral nutrition processes and accumulation of nutrients in the tree stems. The average concentrations of K, Ca and Mg in stems were higher and those of N and P lower than in the unpolluted area. The lignin (L) content in stemwood increased, hemicellulose (Hc) decreased, while cellulose (Ce) did not change. A variation in the partitioning of L, Ce, Hc and nutrients between different sections of stems and between trees from different sample plots was found. L, Ce and Hc were not related to the internal K, Ca and Mg concentrations. Correlations were established between L, Ce, or Hc content and C content, and between L and Hc content in stem tissues. The contents of wood components were not related to N or P in the alkalised areas, but seemed to be more associated with P than with N. Alterations in the arbitrarily chosen ratio L/(Ce + Hc) indicated changes in wood quality, and a negative correlation with N/P was found in stem tissue in the polluted area, while positive correlations with N/Mg and Ca/Mg were found in the control area.     

Assessment of plant nutrients’ dynamics in organically and conventionally managed soils by means of different extraction methods

The aim of this study was to investigate what kind changes in the soil fertility parameters occur depending on different farming methods. The field experiment was performed on sandy loam Luvisol during 2008–2014. The following treatments were carried out: organic (ORG), organic with farmyard cattle manure (ORGFYM) and conventional with farmyard cattle manure and mineral fertilizers (CONFYM). Soil samples were collected yearly in September and analyzed for P, K, Mg and Ca by the Mehlich III method. In parallel, ammonium lactate extractable P and K (AL method), and ammonium acetate extractable Mg and Ca (NH₄OAc-method) were determined. The Pearson correlation coefficients between the analysis results achieved by the Mehlich III method and alternative methods were calculated. In all the treatments, no significant changes in soil Corg content were established over seven years. A significant (p?AL in the soil but considerable decrease in the soil K_AL content was revealed. The application of cattle manure (60?t?ha^?1 for the 5-year crop rotation) in both organic and conventional treatments sustained the status of available nutrients in the soil. The Pearson correlation coefficients between Mehlich III and AL methods for P (r?=?0.770, p?r?=?0.922, p?4OAc-methods was found in the case of Mg (r?=?0.951, p?r?=?0.841, p?Mehlich III/P_AL quotient was inversely proportional with the Ca_{Mehlich III} values.     

Growth and Biomass Partitioning of 6-Year-Old Spruces under Alkaline Dust Impact

Two-year-old seedlings of Picea abies L., P. glauca L. and P. mariana L. were planted in a sample plot subjected to high concentrations of cement dust and in an unpolluted (control) area in 1990. In 1994, the six-year-old trees were dug up in the pre-bud-break period for morphological assessment. Comparison of biomass formation and the lengths of different organs of the trees showed that alkalization of the growth substrate (pH 8.1) and the high level of dust pollution load (600–2400 g m^-2yr^-1) are serious factors inhibiting height growth by 61%, the length of shoots and needles by 75 and 28%, respectively, and the dry weights of roots by 88%, stems by 90%, shoots by 91% and needles by 55%. The ratio of roots to shoots dry weights increased in all species of spruces under stress. P. mariana was the most sensitive to dust pollution impact and alkalization of the environment.     

Ground vegetation under natural stress conditions in Scots pine forests on fixed sand dunes in southwest Estonia

Ecosystems on dunes are influenced by critical environmental factors (mineral nutrients, water deficiency, etc.) considered decisive for their existence. The present paper is based on studies carried out on dunes on the coastal area of the Baltic Sea, southwest Estonia. The nature of forest ecosystems on dunes was studied from the aspects of chemical characteristics of soil, vascular plant species richness and diversity. Sampling sites on the dunes with different heights were selected in Cladina and in Vaccinium vitis-idaea site-type Scots pine forests. Vascular plant species richness and diversity were related to edaphic gradients. On the dune with a height of 32.1 m a.s.l., significant relationships were revealed between the number of species of ground vegetation, pH, volumetric water content in soil and the position of the sample plots. No relationships were revealed between the number of vascular plant species, soil pH, volumetric water content and mineral nutrients on the dune with a height of 9 m a.s.l. The most frequent and abundant plant species on the higher dune were Deschampsia flexuosa, Vaccinium vitis-idaea and V. myrtillus; the highest number of species were found at the bottom of the dune, while on the top only some xeromorphic species such as Festuca ovina, Sedum acre and Crepis tectorum occurred. On the lower dune, the most frequent were Vaccinium vitis-idaea, V. myrtillus and Melampyrum pratense, while V. uliginosum was found only on the bottom and slope and Empetrum nigrum on the top of the dune.