NMR analysis of pine tree oleoresin composition of the Pinus subgenus

Методом ЯМР проведен анализ состава живиц восьми видов сосен подрода Pinus: черной австрийской (P. nigra), аллепской (P. halepensis), горной (P. montana), жесткой (P. rigida), Коха (P. kochiana Klotsch), Муррея (P. murrayana Balf), обыкновенной (P. sylvestris) и Палласа (P. nigra subsp. pallasiana), произрастающих в различных районах. Кроме того, исследовано содержание смоляных кислот, выделенных в 1963 г. из живиц трех видов сосен того же подрода: черной австрийской, крючковатой (P. uncinata) и кулундинской (P. sylvestris ssp. Kulundensis). Установлено, что состав живиц названных видов сосен хорошо описывается наличием восьми смоляных кислот (абиетиновая, дегидроабиетиновая, изопимаровая, левопимаровая, неоабиетиновая, палюстровая, пимаровая и сандаракопимаровая) и девяти монотерпенов (камфен, 3-карен, лимонен, мирцен, α-пинен, β-пинен, терпинолен, βфелландреен, п-цимол). Количественное содержание этих смоляных кислот зависит от многих факторов (вида сосен, времени и места сбора живицы, а также условий сбора и хранения образцов). Кроме того, наблюдаются реакции изомеризации и окисления, приводящие к перераспределению состава. В изученных живицах содержание монотерпенов сильно отличается, являясь наименьшим у сосны аллепской и наибольшим у сосны обыкновенной. The NMR method was used to analyze oleoresin composition of eight species of Pinus subgenus: Austrian black (P. nigra), Alleps (P. halepensis), mountain (P. montana), hard (P. rigida), Koch (P. kochiana Klotsch), Murray (P. murrayana Balf), common (P. sylvestris) and Pallas (P. nigra subsp. pallasiana) growing in different areas. In addition, the content of resin acids isolated in 1963 from the oleoresins of three species of pines belonging to the same subgenus: black Austrian, hooked (P. uncinata) and Kulunda (P. sylvestris ssp. Kulundensis) was studied. It was found that the oleoresin composition of the named pine species is well described by the presence of eight resin acids (abietic, dehydroabietic, isopimaric, levopimaric, neoabietic, palustrine, pimaric and sandaracopymaric) and nine monoterpenes (camphor, 3-caren, limonene, myrcene, α-pinene, β-pinene, terpinolen, β-felandreene, p-cymol). The quantitative content of these resin acids depends on many factors (pine species, time and place of oleoresin collection, and sample collection and storage conditions). In addition, isomerization and oxidation reactions are observed, leading to a redistribution of the composition. In the studied oleoresins, the content of monoterpenes differs greatly, being the lowest in Alleps pine and the highest in Scots pine.

Drought Drives Growth and Mortality Rates in Three Pine Species under Mediterranean Conditions

Drought constrains tree growth in regions with seasonal water deficit where growth decline can lead to tree death. This has been observed in regions such as the western Mediterranean Basin, which is a climate-warming hotspot. However, we lack information on intra- and inter-specific comparisons of growth rates and responses to water shortage in these hotspots, considering tree species with different drought tolerance. We sampled several sites located in north-eastern Spain showing dieback and high mortality rates of three pine species (Pinus sylvestris, Pinus pinaster, Pinus halepensis). We dated death years and reconstructed the basal area increment of coexisting living and recently dead trees using tree ring data. Then, we calculated bootstrapped Pearson correlations between a drought index and growth. Finally, we used linear mixed-effects models to determine differences in growth trends and the response to drought of living and dead trees. Mortality in P. sylvestris and P. pinaster peaked in response to the 2012 and 2017 droughts, respectively, and in sites located near the species’ xeric distribution limits. In P. halepensis, tree deaths occurred most years. Dead trees showed lower growth rates than living trees in five out of six sites. There was a strong growth drop after the 1980s when climate shifted towards warmer and drier conditions. Tree growth responded positively to wet climate conditions, particularly in the case of living trees. Accordingly, growth divergence between living and dead trees during dry periods reflected cumulative drought impacts on trees. If aridification continues, tree drought mortality would increase, particularly in xeric distribution limits of tree species.

Quantitative Disease Resistance to White Pine Blister Rust at Southwestern White Pine’s (Pinus strobiformis) Northern Range

White pine blister rust, caused by the non-native, invasive fungal pathogen Cronartium ribicola, is a significant cause of mortality in white pines (Pinus subgenus Strobus) in North America. Along with climate-driven range contraction, mortality from blister rust can seriously impact the abundance and distribution of the nine white pine species native to the United States and Canada. Very little evaluation of this disease in southwestern white pine (Pinus strobiformis) has been previously undertaken, but genetic resistance to the disease has been documented, including major gene resistance (MGR) conferred by a dominant R gene. Data is emerging suggesting that the species also has quantitative disease resistance (QR). Our results suggest QR occurs at low frequency, with perhaps 10% of trees having a moderate level (> 35% survival). We assessed progeny arrays from 40 P. strobiformis families (1873 seedlings), originating from three populations, inoculated with C. ribicola. Subsequently, the seedlings were assessed for signs, symptoms and resulting impact in a common garden trial over a 7.5-year period to determine the types and frequency of resistance in a portion of this species’ range. There was a high incidence of both stem symptoms and mortality in the P. strobiformis families tested, and families ranged in survival from 0 to 84.6%. Three families had > 70% survival, representing perhaps the highest documented QR to date in a North American white pine species. Approximately 29.1% of the 441 surviving seedlings showed no stem symptoms, and of the approximately 70.8% of seedlings surviving with infections only few (24 of 316) had infections of moderate to high severity. QR traits associated with improved survival were primarily related to lower severity of infection, a reduced number of stem symptoms, and an increased number of bark reactions. Despite the high overall susceptibility, the presence of QR appears to be at a frequency and level useful to forest managers involved in restoration and reforestation efforts.

Dendrometric variables and traumatic resin ducts in pine species associated with wood-stripping: a traditional practice in the conifer forests of Central Mexico

Background: In La Malinche National Park (LMNP), Pinus species are exploited mainly because they are a non-woody source of products such as ocote (resinous wood chips) and wood. Questions/Objective: Which Pinus species are subjected to wood-stripping (WS) in the LMNP? What are their dendrometric characteristics? Do WS trees present traumatic resin ducts associated with the ocoteo practice? Does the number of trees subjected to WS increase with altitude? Study site and dates: La Malinche National Park; Tlaxcala, México, 2017-2018. Methods: Random stratified sampling was done in a total of 33 plots in three different altitudes to quantify the number of damaged and undamaged trees and the total height and diameter per tree in each plot. Increment borers were obtained to estimate tree age, samples were taken for taxonomic determination, and tissue samples to evaluate mechanical damage. Results: Pine species subjected to wood-stripping (ocoteo) were P. leiophylla, P. montezumae, P. pseudostrobus, and P. teocote, with P. montezumae being the most affected in high and mid altitudes. WS trees were those with the greatest diameter and with the largest number of traumatic resin ducts. The species having the highest number of traumatic resin ducts was P. teocote. Conclusions: WS intensity in the LMNP is greater in the mid and low altitudes and in trees of greater diameter, height, and age. The species most affected by WS is P. montezumae and all WS individuals have a significantly higher number of traumatic resin ducts.

Anatomical and blue intensity methods to determine wood density converge in contributing to explain different distributions of three palaeotropical pine species

Wood density constitutes an integrative trait of water relations and growth. We compared the recently developed blue intensity (BI) method, which has only rarely been applied to tropical conifers, for determining wood density with anatomical analyses in studying the three rarely investigated palaeotropical pine species Pinus kesiya, P. dalatensis and P. krempfii, which co-occur in South-Central Vietnam, but differ in their distribution areas. For species comparisons, we also calculated the hydraulic conductivity of the xylem with the Hagen-Poiseuille equation and the water potential causing 50% loss of hydraulic conductivity () based on the anatomical analyses. We hypothesized (i) that the BI values are correlated with the cell wall fractions, the calculated hydraulic conductivity and the values; and (ii) that the wider occurrence of P. kesiya, which also can grow at drier sites, is reflected by higher wood density, lower hydraulic conductivity, lower (more negative) values and a smaller variation in the wood anatomical features across the years compared to the other two species. In agreement to our hypotheses, the results of the BI and the anatomical method were closely correlated, especially for sapwood, and P. kesiya exhibited features that are related to the growth at drier sites and to a higher tolerance towards drought: higher wood density and cell wall:lumen area ratios of its smaller xylem conduits, lower calculated hydraulic conductivity and more negative values. The BI method is well suitable for determining the wood density in tropical conifers. As a fast and inexpensive method, it may be used for initial screening woody species for their water transport capacity and drought resistance.