Marian J. Giertych

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.

Altered root growth and plant chemistry of Pinus sylvestris seedlings subjected to aluminum in nutrient solution

One-year-old Scots pine (Pinus sylvestris L.) seedlings were grown for 9 weeks in nutrient solutions containing 0, 0.5, 1, 2 and 4 mM aluminum nitrate (Al(NO3)3) at pH 4.2. Nine weeks exposure to Al significantly reduced total plant, shoot and root mass and caused a linear decline in proportional allocation of biomass to roots. Relative growth rate of roots declined to as low as zero. Aluminum treatment decreased calcium and magnesium uptake and increased Al content in roots and needles. After 3 weeks of exposure a 10–60% increase in total phenols in roots and a 20–40% increase in o-diphenols in roots and needles were noted. Roots affected by Al showed degeneration of meristematic cells, fewer cell divisions, deformation in cell walls and higher lignification and suberization. The majority of root apices were structurally similar to dormant roots, and a premature senescence of the entire root system was observed. Net photosynthetic rate after 6 weeks of treatment was negatively correlated with needle Al content and Al/Ca ratio (r < -0.9, P < 0.1). The results suggest that Scots pine may be more susceptible to Al than was expected based on previous experiments.

Do secondary sexual dimorphism and female intolerance to drought influence the sex ratio and extinction risk of Taxus baccata

Sex ratio and sexual dimorphism were studied in the dioecious tree Taxus baccata. We examined five populations of T. baccata in Poland and Ukraine to identify the differences between male and female individuals. The sex of all individuals, height and diameter, needle length and area, specific leaf area (SLA), the number of stomata rows, stomatal density, and content of carbon and nitrogen were measured to identify the differences between male and female individuals. The relationship between sex ratio and climatic conditions, age and population size were analysed using data collected from the field and the literature. Female trees were shorter than males, but needles of females were longer and had larger area. Although there were no differences among sexes in SLA, nitrogen and carbon concentration, we found a positive correlation between nitrogen concentration and SLA among females. The sex ratio changed with tree height within populations, and taller height classes were biased in favour of males. Regardless of population age, the percentage of females within populations was positively correlated with precipitation. Probably high reproductive effort caused female trees to lose in competition with males, and this loss may also be enhanced by lower drought tolerance in females and could contribute to risk of extinction for T. baccata. The continental geographic range of T. baccata may be restricted by limited occurrence of females, which demand higher water resources than males.

Influence of mineral fertilization on food quality of oak leaves and utilization efficiency of food components by the gypsy moth

Host plant quality is a key determinant of the performance of larvae of herbivorous insects. The effects of nitrogen and dolomite fertilization on the quality of pedunculate oak, Quercus robur L. (Fagaceae) foliage, as a food for gypsy moth, Lymantria dispar L. (Lepidoptera: Lymantriidae) larvae were evaluated. The seedlings were divided into five fertilization treatments (nonfertilized control, commercial nutrient solution, commercial nutrient solution + (NH4)2SO4, commercial nutrient solution + KNO3, and commercial nutrient solution + dolomite). The experiment was performed in Petri dishes, in each of which a fresh leaf from one treatment and one larva were placed. Insect performance assays, survival, development, growth, and food utilization were evaluated for each fertilization treatment. Leaf samples were assayed for nitrogen and other main nutrients, soluble carbohydrates, and phenolic compounds. The fertilizer treatment with added ammonium improved gypsy moth performance, and the amount of food eaten was the lowest in this treatment. Utilization of elements from the food depended on the element and on the fertilization treatment. The insect bodies retained 50–64% of the nitrogen and 55–79% of the phosphorus. The results show that the efficiency of conversion of ingested food (ECI) and the efficiency of conversion of digested food (ECD) differ among the fertilization treatments, but it is not possible to define a general trend. Our results suggest that fertilization (especially ammonium) of host plants can increase herbivore performance, decrease the amount of food needed, and increase its utilization efficiency.

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

Abstract• BackgroundProduction 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.• ResultsThe majority of seedlings from acorns with cut cotyledons emerged two weeks earlier, more simultaneously and their total emergence (due to rejecting spoiled acorns) was ca. 20% higher. The main result is that the strong damage to cotyledons (more than one fifth of acorn mass) caused a decrease of seedling height and mass even after the second growing season. Negative consequences on seedling root/shoot ratio or on their metabolism were not observed.• Conclusion We conclude that this method is useful for seedling production in containers when acorn mass is reduced by one fifth.

Influence of native and alien Prunus species and light conditions on performance of the leaf beetle Gonioctena quinquepunctata

The polyphagous beetle Gonioctena quinquepunctata Fabricius (Coleoptera: Chrysomelidae) is a serious leaf pest of the native European bird cherry, Prunus padus L., and the invasive alien black cherry, Prunus serotina Ehrh. (Rosaceae). In the shade, leaf damage is extensive in both species, whereas in full light, it is extensive in P. padus, but very low in P. serotina. We determined the influence of Prunus species and light conditions on differences in performance of both sexes of this folivore. In a laboratory experiment in which larvae were fed with leaves of a single species grown under particular light conditions, we measured larval, pupal, and adult mass, efficiency of conversion of ingested food (ECI), duration of development, total food eaten, and relative growth rate. In the field, we observed differences in beetle mass on shrubs of the two species growing under various light conditions. From the field observations, we hypothesised that leaves of the invasive P. serotina are not an equally good food source as leaves of P. padus for G. quinquepunctata, and the preference of these beetles for shaded shrubs is most favourable for their growth and development. Under laboratory conditions, we found that the beetle growth rate was not affected significantly by Prunus species or light conditions, despite the significant effect of light condition on the structure and chemical composition of Prunus seedlings. The lower ECI value for larvae feeding on sunlit leaves was compensated for by their higher level of consumption. In the field, adult insect mass was higher on P. padus than on P. serotina, and higher on sunlit shrubs of both species than on shaded ones. Under natural conditions, the mass of adult insects is probably also affected by other factors, such as predators and competition among folivores.

Carbon allocation in seedlings of deciduous tree species depends on their shade tolerance

Carbon assimilated during photosynthesis is allocated to basic needs, such as growth, defense, and storage of nutrients. The aim of this study was to explore potential relationships between carbon allocation and light conditions during growth, including shade tolerance of species. We studied species that represent light-demanding (Sorbus aucuparia, Betula pendula), intermediate (Carpinus betulus, Quercus robur), and shade-tolerant (Acer platanoides, Fagus sylvatica) trees. We exposed seedlings to two light treatments (full sunlight and shade), and explored how these conditions affect plant growth and biomass allocation, as well as the levels of phenolic compounds, nonstructural carbohydrates, carbon, and nitrogen. We hypothesized that light-demanding species invest less carbon in chemical defenses against pathogens and/or herbivores compared to shade-tolerant species. On the other hand, light-demanding species showed the greater part of assimilated carbon allocate to growth processes. As a result, the stem diameter above the root collar, the mass of leaves, stems, coarse, and fine roots were larger under full-sunlight conditions in all species, except for greater height of A. platanoides and Q. robur under shade conditions. Leaves from full light were characterized by lower nitrogen content, higher carbon and phenolic contents, and a higher carbon/nitrogen ratio compared with leaves from seedlings grown in shade. In the case of shade-tolerant species, a trade-off mechanism can be proposed that such species restrict their usual allocation of carbon to defense and radial growth, while instead of investing it in increasing their heights and storage capacities. According to the light-demanding species, it was not possible to identify a trade-off mechanism and how carbon allocation is restricted upon exposure to shade conditions, except for the reduced allocation to the root mass.

Light conditions affect the performance of Yponomeuta evonymellus on its native host Prunus padus and the alien Prunus serotina

The bird cherry ermine moth, Yponomeuta evonymellus L., is considered an obligatory monophagous insect pest that feeds only on native European Prunus padus L. In recent years, however, increased larval feeding on alien P. serotina Ehrh. has been observed. In both species, general defoliation is extensive for shade grown trees, whereas it is high in P. padus, but very low in P. serotina, when trees are grown in full light conditions. The aim of the present study was to identify how the plant host species and light conditions affect the performance of Y. evonymellus. The influence of host species and light condition on their growth and development, characterized by the parameters of pupation, adult eclosion, body mass, potential fecundity, and wing size, was measured in a 2 × 2 experimental design (two light treatments, two hosts). In comparison with high light (HL) conditions, a greater percentage of pupation and a longer period and less dynamic adult emerge was observed under low light (LL) conditions. The effect of host species on these parameters was not significant. In contrast, mass, fecundity and all of the studied wing parameters were higher in larvae that grazed on P. padus than on P. serotina. Similarly the same parameters were also higher on shrubs in HL as compared with those grown under LL conditions. In general, light conditions, rather than plant species, were more often and to a greater extent, responsible for differences in the observed parameters of insect development and potential fecundity.

Preferential feeding and occupation of sunlit leaves favors defense response and development in the flea beetle, Altica brevicollis coryletorum--a pest of Corylus avellana.

The monophagous beetle, Altica brevicollis coryletorum, is a major leaf pest of Corylus avellana (common hazel). In contrast to majority of the other studied species of shrubs, sunlit leaves are grazed to a much greater extent than shaded leaves. Since the observation of a link between leaf irradiance level and A. brevicollis feeding is unique, we hypothesized that feeding preference of this beetle species is related to the speed needed to escape threats i.e. faster jumping. We also hypothesized that sunlit leaves are more nutritious and easier to consume than the leaves of shaded shrubs. Results indicated that beetle mass was greater in beetles occupying sunlit leaves, which is consistent with our second hypothesis. The study also confirmed under laboratory conditions, that larvae, pupae and beetles that were fed full-light (100% of full light) leaves were significantly heavier than those fed with shaded leaves (15% of full light). In the high irradiance conditions (higher temperature) duration of larval development is also reduced. Further results indicated that neither the concentration of soluble phenols, leaf toughness, or the number of trichomes could explain the insect’s preference for sunlit leaves. Notably, measurements of jump length of beetles of this species, both in the field and under laboratory conditions, indicated that the defense pattern related to jumping was associated with light conditions. The jump length of beetles in the sun was significantly higher than in the shade. Additionally, in laboratory tests, beetle defense (jumping) was more strongly affected by temperature (15, 25, or 35°C for 24h) than by leaf type. The effect of sunlit, higher nutrient leaves (greater level of non-structural carbohydrates) on defense (jumping) appears to be indirect, having a positive effect on insect mass in all developmental stages.

Larval food affects oviposition preference, female fecundity and offspring survival in Yponomeuta evonymellus

1. Yponomeuta evonymellus is a monophagous moth that feeds on Prunus padus which is native to Europe. In recent years, larval feeding and egg clusters have also been observed on non‐native Prunus serotina plants; however, survival of larvae on this new host is very low.