2025-04-11 2017, Volume 28 Issue 4

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  • Endre Gy. Tóth , Zoltán A. Köbölkuti , Andrzej Pedryc , Mária Höhn

    In this review we summarized recent historical records and molecular studies on evolutionary history and phylogeography of Scots pine with focus on the European highly fragmented distribution area of the species. Fossilized pollen, plant micro- and macrofossil records provided evidences on the large-scale species’ range shifts and demographic changes during the Quaternary. Populations of Scots pine were documented both in the glacial (incl. full glaciation) and interglacial periods. Recolonization of Europe after the glaciation originated from the (Sub) Mediterranean areas like the Balkan Peninsula but also from around the Eastern Alps and the surroundings of the Danube plain. Fennoscandia and northern European Baltic regions were most probably colonized from two main directions, from Western Europe and from the Russian Plain. Modern history of Scots pine was hardly affected by anthropogenic activities that started to strengthen in the Bronze and Iron Age. Along with the fossil records, molecular genetic tools were used to infer the origin and putative history including migration, differentiation and demography of the species. In this paper we compiled the major publications (30) of molecular genetic studies of the past 20 years derived from distinctly inherited organelle genomes (mitochondrial, chloroplast, nuclear) revealed by different marker systems (mtDNA-cox1, -nad1, -nad3, -nad7, ISSR, cpSSR, nSSR, B-SAP, SNP). It is important to consider that different phylogeographic patterns can be drawn by the analysis of different DNA marker types. Accordingly the use of more than one marker simultaneously outlines the most sophisticated phylogeographical pattern on the genetic lineages and can reveal high differentiation of the European distribution. Combined marker systems and markers derived from coding sequences have also been used to detect species’ phylogeographic patterns, but these were rarely applied to Scots pine. Although new molecular techniques can provide higher resolution data for populations, the reviewed results can shape the direction of further studies.

  • Hamed Yousefzadeh , Abbas Saidi , Somayeh Tayebi , Davoud Kartoolinejad , Reza Naghdi

    Castanea sativa is a valuable tree species in Hyrcanian forests, an evolutionary relict ecosystem whose communities suffer from overexploitation and fungal diseases. In the current study, three species delimitation methods were utilized with ITS regions sequencing to determine the taxonomic status of Septoria causing leaf blotch of C. sativa in Hyrcanian forests. The results indicated that the length of ITS region in the genus Septoria (extracted from GenBank) varied from 650 to 680 bp. There were almost three times more variable sites in ITS1 than in ITS2. The ITS2 secondary structure of Hyrcanian Septoria community had the highest similarity with Septoria castaneicola, except for some differences in helix II and III. Also, Hyrcanian samples had minimum genetic distances with S. castaneicola and maximum with Septoria quercicola. The maximum parsimony method divided the studied Septoria genus into three distinct clades, mostly located in clade I. Clade II consisted entirely of Septoria aciculosa, while clade III contained S. castaneicola as well as Hyrcanian samples.

  • Dong Qin , Huanhuan Wang , Chunhao Zhang , Zeyuan Yu , Yu Gary Gao , Fuchun Xie , Ning Hung , Junwei Huo

    The effects of exogenous gibberellic acid (GA3) and abscisic acid (ABA) on the total respiratory rate, percentages of total respiratory rate contributed by respiratory pathways [Embden-Meyerhof- Parnas Pathway (EMP), Pentose Phosphate Pathway (PPP), and Tricarboxylic Acid Cycle (TCA)], and conversion of starch to soluble sugars in the buds of black currants during secondary bud burst were investigated to determine the relationship between respiratory rates and secondary bud burst. ‘Adelinia’, a black currant cultivar that is prone to secondary bud burst after the first harvest, was used in this study. Mature bushes of Adelinia were sprayed with 30 mg/L GA3 and 50 mg/L ABA to manipulate bud burst. The results showed that exogenous applications of GA3 and ABA had opposite effects on bud respiratory rate. Generally, GA3 treatment increased the total respiratory rate and respiratory rate of the TCA and PPP, and the respiratory rates after GA3 treatment were higher than those of control. While ABA treatment mostly decreased the total respiratory rate and the respiratory rate of TCA and PPP in buds in comparison to control. In terms of the percentage of the three respiratory rates in comparison to the total respiratory rate, GA3 treatment significantly increased the percentage of TCA and PPP respiratory rate in comparison to the control (P < 0.01), whereas ABA decreased the rates. GA3 significantly increased the content of soluble sugars and decreased the starch content, while the starch content in buds after ABA treatment was significantly higher than that of the control. All results showed that PPP is a critical process for the second bud burst in black currants. While the EMP–TCA pathway is still dominant in bud respiration, provides a series of basic materials and energy (ATP). The conversion of starch to soluble sugars is essential for bud burst. Thus, we conclude that an energy shortage is a main contributor in ABA inhibition of the secondary bud burst of black currants.

  • Xin Lu , Haiqing Hu , Long Sun

    Active organic carbon in soil has high biological activity and plays an important role in forest soil ecosystem structure and function. Fire is an important disturbance factor in many forest ecosystems and occurs frequently over forested soils. However, little is known about its impact on soil active organic carbon (SAOC), which is important to the global carbon cycle. To investigate this issue, we studied the active organic carbon in soils in the Larix gmelinii forests of the Da Xing’an Mountains (Greater Xing’an Mountains) in Northeastern China, which had been burned by high-intensity wildfire in two different years (2002 and 2008). Soil samples were collected monthly during the 2011 growing season from over 12 sample plots in burned and unburned soils and then analyzed to examine the dynamics of SAOC. Our results showed that active organic carbon content changed greatly after fire disturbance in relation to the amount of time elapsed since the fire. There were significant differences in microbial biomass carbon, dissolved organic carbon, light fraction organic carbon, particulate organic carbon between burned and unburned sample plots in 2002 and 2008 (p < 0.05). The correlations between active organic carbon and environmental factors such as water content, pH value and temperature of soils, and correlations between each carbon component changed after fire disturbance, also in relation to time since the fire. The seasonal dynamics of SAOC in all of the sample plots changed after fire disturbance; peak values appeared during the growing season. In plots burned in 2002 and 2008, the magnitude and occurrence time of peak values differed. Our findings provide basic data regarding the impact of fire disturbance on boreal forest soil-carbon cycling, carbon-balance mechanisms, and carbon contributions of forest ecosystem after wildfire disturbance.

  • Liwen Zhuang , Jan C. Axmacher , Weiguo Sang

    We analyzed the influence of climate change over the past 50 years on the radial growth of two tree species: Korean pine (Pinus koraiensis) and Yezo spruce (Picea jezoensis), located on Changbai Mountain, Northeast China, using a dendrochronology approach to understand factors that limit the altitude for tree species. Elevated temperatures increased the radial growth of Korean pine and decreased that of Yezo spruce. The positive response of tree growth to hydrothermal conditions was the key reason that the upper limit of elevation of Korean pine followed the temperature fluctuation pattern. Increased temperatures and precipitation and longer growing seasons accelerated Korean pine growth. As the temperature increased, correlations between Korean pine ring-width chronology and precipitation changed from negative to positive. In Yezo spruce, increasing monthly temperatures and inadequate precipitation during the middle and late parts of the growing season led to narrow growth rings, whereas decreasing monthly temperatures and sufficient precipitation during the late growing season promoted growth. Rising temperatures and adequate precipitation increases Korean pine growth, possibly elevating the upper range limit in altitude for this species. In contrast, Yezo spruce growth is negatively affected by warming temperatures and limited precipitation. Under future temperature increases and precipitation fluctuations, the upper limit altitude of Korean pine can reasonably be expected to shift upward and Yezo spruce downward.

  • Shaojun Wang , Hong Wang

    Extreme droughts can adversely affect the dynamics of soil respiration in tree plantations. We used a severe drought in southwestern China as a case study to estimate the effects of drought on temporal variations in soil respiration in a plantation of Eucalyptus globulus. We documented a clear seasonal pattern in soil respiration with the highest values (100.9 mg C–CO2 m−2 h−1) recorded in June and the lowest values (28.7 mg C–CO2 m−2 h−1) in January. The variation in soil respiration was closely associated with the dynamics of soil water driven by the drought. Soil respiration was nearly twice as great in the wet seasons as in the dry seasons. Soil water content accounted for 83–91% of variation in soil respiration, while a combined soil water and soil temperature model explained 90–99% of the variation in soil respiration. Soil water had pronounced effects on soil respiration at the moisture threshold of 6–10%. Soil water was strongly related to changes in soil parameters (i.e., bulk density, pH, soil organic carbon, and available nitrogen). These strongly influenced seasonal variation in soil respiration. We found that soil respiration was strongly suppressed by severe drought. Drought resulted in a shortage of soil water which reduced formation of soil organic carbon, impacted soil acid–base properties and soil texture, and affected soil nutrient availability.

  • Yang Yang , Zhenbo Liu , Yixing Liu

    The vibrational performance of wood materials critical affects the acoustic quality of a lute. The purpose of this research was to apply a multiple choice model to predict the quality of musical instruments based on data on lute soundboard vibrational properties of Paulownia wood. In the lute production, lute material selection mainly depends on the subjective evaluation of technicians, which is not only inefficient, but inaccurate. In this study, nine lutes were fabricated. Using the multiple selection model, the lute tone quality was predicted by the soundboard wood vibration data. Compared with the actual value, the dependent value predicted by the count of observations with the maximum probability had 22 erroneous judgments. The model precision is 87.78%. The results confirmed that the prediction model can be used as a guideline for the selection of the soundboard wood in musical instrument plants.