Foliage Age and Pollution Alter Content of Phenolic Compounds and Chemical Elements in Pinus nigra Needles

Changes of phenolics and chemical elements [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), boron (B), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni) and cobalt (Co)] content in needles of black pine ( Pinus nigra) as dependent on age of needles (5–6 classes) and pollution were examined. The content of ortho-diphenols (o-dPh) and total phenols (TPh) was significantly higher at a polluted site than at a control one. It increased with age of needles at both sites. At the polluted site contents of N, K, Mg in black pine needles were lower and of Fe, Ni and F were higher than at the control site. An increase of content with age of needles at both sites was detected for Ca, Fe, B and F, and a decrease for N, P, K, Cu and Ni. The content of elements in different age classes of needles is connected with their mobility. The content of phenolics is negatively correlated with main nutrients and positively with some toxic elements.     

Impact of Cameraria ohridella on Aesculus hippocastanum growth and long-term effects of trunk injection with pesticides

Defoliation caused annually by Cameraria ohridella has a considerable impact on the general condition of horse chestnut trees. We investigated the consequences of tree endotherapy against this insect. Wood samples, leaves and insect specimens were collected ten years after the treatment (injection) with pesticides. Insect invasion was manifested in all investigated trees by distinct radial growth depression. Treatment resulted in a growth upturn, while non-treated trees maintained decreased growth. The overall foliage infestation level was lower in treated trees, but pupal mass and potential fecundity of insect females were not affected. Our study revealed a long-lasting, positive effect of endotherapy on trees’ appearance and growth.     

Weak competitive ability may explain decline of Taxus baccata

Context

Taxus woodlands suffer from a lack of natural regeneration across its whole distribution range.

Aims

In Knyazhdvir Reserve in Ukraine Taxus baccata primarily competes with Abies alba. It has been assumed that in the conditions of deep shade, yews have a greater competitive advantage than firs.

Methods

To verify this hypothesis, a plot with both species growing under the canopy was established. Wood samples were taken from 20 trees of T. baccata and 20 trees of A. alba.

Results

There were no differences in the mean tree-ring width, height and age between both species. Due to a lack of spatial separation of both species, yews and firs inhabited the same area in the analysed plot. Fir seedlings (up to 0.5?m) were recorded to grow under yew saplings (above 0.5?m), but the inverse situation of yew seedlings growing under fir saplings was not seen.

Conclusion

Seedling distribution, tree-ring growth rate, possibility of growth of fir seedlings under yew saplings and greater potential growth suggested that fir was predisposed to having the competitive edge over yew. Our results may confirm the hypothesis that T. baccata has a restricted distribution because of weak competitive abilities and can exist only in habitats where faster growing species are absent. The results call into question the prevailing opinion that human influences are the principal cause for the decline of T. baccata.     

Differential reaction of Pinus sylvestris, quercus robur and Q. petraea trees to nitrogen and sulfur pollution

Establishment of the Nitrogen Fertilizer Factory in Pulawy, Poland (NFFP) in 1966 resulted in contamination of the environment with nitrogen and sulfur compounds. As a result, radial stem growth declined in Pinus sylvestris and increased in Quercus robur. In this study we explored possible causal agents responsible for differences in pollution response among P. sylvestris, Q. robur and Q. petraea species, including differential uptake of nitrogen oxide pollutants by foliage and nutrient imbalances. We compared trees growing in the vicinity of the NFFP and a control area and found that Q. robur leaves were characterized by a relatively smaller N increase than those of P. sylvestris. It is possible that relatively high accumulation of N by pine could cause metabolic dysfunction in that species. However, differences in the concentration of nitrogen or activity of nitrate reductase did not sufficiently explain observed growth differences among the studied species. It is likely that among the factors contributing to the increased growth of oaks after the establishment of NFFP there is the rapid decline and mortality of pollution-sensitive Scots pine trees, easing competition for light and nutrients in the remaining Quercus trees.     

Consequences of cutting off distal ends of cotyledons of Quercus robur acorns before sowing

• Background   

Production of seedlings, especially in containers, requires simultaneous germination and emergence. Mechanical scarification often speeds up the growth of embryo axes, increases the percentage of germinating seeds and seedling emergence. Cutting off the distal ends of cotyledons is a mechanical scarification technique sometimes used in the container production of oak seedlings. However the consequences of this procedure for seedling development are little known. We wanted to determine these effects on development and metabolic changes of pedunculate oak (Quercus robur L.) seedlings.     

Distribution of elements along the length of Scots pine needles in a heavily polluted and a control environment

Pollution often causes visible symptoms of foliar injury. The injury is sometimes associated with an increase in the accessibility of toxic elements to plants as a result of acidification of the soil. We investigated the distribution of elements (N, P, K, Ca, Mg, Mn, S, Fe, B, Cu, Zn, Al, F, Pb, Cd, Cr, Ni and Co) in healthy current-year needles of Scots pine (Pinus sylvestris L.) growing at an unpolluted control site and at a site polluted mainly by SO(2), HF and Al(3+) from a fertilizer factory established in 1917. Needles from both sites were sampled before the appearance of visible injury and cut into five sections of equal length (tip, base and three middle parts). The mean concentrations of major nutrients were 20-30% lower in needles at the polluted site than in needles at the control site, whereas the concentrations of aluminum and fluorine were higher in needles at the polluted site. An increase in concentration from needle base to tip was detected for N, Fe, B, and Al at both sites and for Mn only at the polluted site. Fluoride accumulated in the tips of needles only at the polluted site, which could explain the necroses of needle tips at this site. The distribution of elements along the length of the needles was influenced by pollution, element mobility and the distal accumulation of toxic elements.