Cornus Controversa Research Articles

Photosystems functioning, the content of chemical elements, flavonoids and brassinosteroids in leaves of chimera Cornus controversa

he formation of chimera is a well-known phenomenon in variegated ornamental and wild plants, but the biochemical peculiarities of this phenomenon are not well studied. The purpose of this work was to conduct a comparative study of the photosynthetic apparatus functioning, the content of macro-, microelements, flavonoids and brassinosteroids in the variegated and green leaves of the periclinal chimera Cornus controversa plant grown in the collection of M. M. Gryshko National Botanical Garden of the NAS of Ukraine. Sampling was made during the period from June to October 2022. The content of photosynthetic pigments and brassinosteroids was measured spectrophotometrically, autofluorescence of leaf tissues was studied using an inverted microscope with a multi-channel fluorescence imaging system, Normalized difference vegetation index (NDVI) – using GreenSeeker devices and fluorimeter, the level of macro- and microelements – using plasma emission spectrometer. Phenolic secondary metabolites were separated by HPTLC. To assess the protective capacity of flavonoids, a bioassay on the germination of radish seeds Raphanus in the presence of AlCl3 was used. It was shown that green leaves of C. controversa chimera, compared to variegated ones, had a twice as high NDVI index, maintained photosynthetic function longer in autumn, and had higher content of macronutrients (Mg, Ca and S) but lower concentration of toxic metals (Al, Cu, Fe, Zn, Ti). Instead, variegated leaves accumulated more brassinosteroids and phenolic metabolites, which were found not only to reduce the toxic effect of aluminum but also to have a growth-stimulating effect on the roots of radish seedlings. Such specialization of green and variegated leaves may contribute to better plant chimeras adaptation to environmental pollution. Keywords: brassinosteroids, Cornus controversa, macroelements, microelements, NDVI index, periclinal chimera, phenolic metabolites, photosynthetic pigments, tissue autofluorescence

Using UAV RGB Images for Assessing Tree Species Diversity in Elevation Gradient of Zao Mountains

Vegetation biodiversity in mountainous regions is controlled by altitudinal gradients and their corresponding microclimate. Higher temperatures, shorter snow cover periods, and high variability in the precipitation regime might lead to changes in vegetation distribution in mountains all over the world. In this study, we evaluate vegetation distribution along an altitudinal gradient (1334–1667 m.a.s.l.) in the Zao Mountains, northeastern Japan, by means of alpha diversity indices, including species richness, the Shannon index, and the Simpson index. In order to assess vegetation species and their characteristics along the mountain slope selected, fourteen 50 m × 50 m plots were selected at different altitudes and scanned with RGB cameras attached to Unmanned Aerial Vehicles (UAVs). Image analysis revealed the presence of 12 dominant tree and shrub species of which the number of individuals and heights were validated with fieldwork ground truth data. The results showed a significant variability in species richness along the altitudinal gradient. Species richness ranged from 7 to 11 out of a total of 12 species. Notably, species such as Fagus crenata, despite their low individual numbers, dominated the canopy area. In contrast, shrub species like Quercus crispula and Acer tschonoskii had high individual numbers but covered smaller canopy areas. Tree height correlated well with canopy areas, both representing tree size, which has a strong relationship with species diversity indices. Species such as F. crenata, Q. crispula, Cornus controversa, and others have an established range of altitudinal distribution. At high altitudes (1524–1653 m), the average shrubs’ height is less than 4 m, and the presence of Abies mariesii is negligible because of high mortality rates caused by a severe bark beetle attack. These results highlight the complex interactions between species abundance, canopy area, and altitude, providing valuable insights into vegetation distribution in mountainous regions. However, species diversity indices vary slightly and show some unusually low values without a clear pattern. Overall, these indices are higher at lower altitudes, peak at mid-elevations, and decrease at higher elevations in the study area. Vegetation diversity indices did not show a clear downward trend with altitude but depicted a vegetation composition at different altitudes as controlled by their surrounding environment. Finally, UAVs showed their significant potential for conducting large-scale vegetation surveys reliably and in a short time, with low costs and low manpower.

Effects of water extract from Cornus controversa on the expression levels of DiSOC1-b and DiCCoAOMT1 genes related with the growth of dove tree seedlings

Abstract Although characterization of plant interactions has become a research hotspot to assess the adaptability of endangered plants, the underlying molecular basis remains elusive. Dove tree (Davidia involucrata) seedlings were watered with distilled water (CK), leaf water extract (0.025 g mL−1) and branch water extract (0.1 g mL−1) from Cornus controversa, respectively. Subsequently, the morphology, biomass and gene expression levels of DiSOC1-b and DiCCoAOMT1 were analyzed. The results showed that morphological traits and biomass accumulation of D. involucrata seedlings were decreased by the addition of leaf water extracts, and increased by branch water extracts. Moreover, the gene expression level of DiSOC1-b was significantly down-regulated, while the gene expression level of DiCCoAOMT1 was significantly up-regulated in the stems and roots of D. involucrata upon treatment with leaf water extracts of C. controversa. In contrast, the gene expression level of DiSOC1-b was significantly up-regulated in the leaves and stems, while the gene expression level of DiCCoAOMT1 was significantly down-regulated in the roots of D. involucrata upon treatment with branch water extracts of C. controversa. In addition, the expression level of DiSOC1-b was positively correlated with most of morphological traits and total biomass (P < 0.05), while DiCCoAOMT1 was negatively correlated with the majority of morphological traits in D. involucrata seedlings (P < 0.05). Taken together, these results suggest that water extracts from the leaves and branches of the C. controversa exhibit opposite allelopathic effects and affect the expression levels of genes related to growth (DiSOC1-b) and environmental adaptability (DiCCoAOMT1) in D. involucrata seedlings.

Karyotype evolution of the Asterids insights from the first genome sequences of the family Cornaceae.

Cornaceae is a core representative family in Cornales, the earliest branching lineage in the Asterids on the life tree of angiosperms. This family includes the only genus Cornus, a group of ~55 species. These species occur widely in Northern Hemisphere and have been used as resources for horticultural ornaments, medicinal and industrial manufacturing. However, no any genome sequences are available for this family. Here, we reported a chromosome-level genome for Cornus controversa. This was generated using high-fidelity plus Hi-C sequencing, and totally ~771.80 Mb assembled sequences and 39,886 protein-coding genes were obtained. We provided evidence for a whole-genome duplication event (WGD) unique to C. controversa. The evolutionary features of this genome indicated that the expanded and unique genes might have contributed to response to stress, stimulus and defense. By using chromosome-level syntenic blocks shared between eight living genomes, we found high degrees of genomic diversification from the ancestral core-eudicot genome to the present-day genomes, suggesting an important role of WGD in genomic plasticity that leads to speciation and diversification. These results provide foundational insights on the evolutionary history of Cornaceae, as well as on the Asterids diversification.

A Deep Learning-Based Model for Tree Species Identification Using Pollen Grain Images

The objective of this study was to develop a deep learning-based tree species identification model using pollen grain images taken with a camera mounted on an optical microscope. From five focal points, we took photographs of pollen collected from tree species widely distributed in the Japanese archipelago, and we used these to produce pollen images. We used Caffe as the deep learning framework and AlexNet and GoogLeNet as the deep learning algorithms. We constructed four learning models that combined two learning patterns, one for focal point images with data augmentation, for which the training and test data were the same, and the other without data augmentation, for which they were not the same. The performance of the proposed model was evaluated according to the MCC and F score. The most accurate classification model was based on the GoogLeNet algorithm, with data augmentation after 200 epochs. Tree species identification accuracy varied depending on the focal point, even for the same pollen grain, and images focusing on the pollen surface tended to be more accurately classified than those focusing on the pollen outline and membrane structure. Castanea crenata, Fraxinus sieboldiana, and Quercus crispula pollen grains were classified with the highest accuracy, whereas Gamblea innovans, Carpinus tschonoskii, Cornus controversa, Fagus japonica, Quercus serrata, and Quercus sessilifolia showed the lowest classification accuracy. Future studies should consider application to fossil pollen in sediments and state-of-the-art deep learning algorithms.

THE RELATIONSHIP BETWEEN BULK DENSITY AND THERMAL CONDUCTIVITY IN VARIOUS KOREAN WOODS

The article deals with the effects of bulk density on thermal conductivity in specimens of 15Korean woods (Zelkova serrata, Pinus densiflora, Cornus controversa, Betula schmidtii, Betula platyphylla var. japonica, Ginkgo biloba L.,Cedrela sinensis A. Juss., Fraxinus mandshurica, Ulmus davidiana var. japonica, Prunus sargentii Rehder, Paulownia tomentosa (Thunb.) Steud., Larix kaempferi (Lamb.) Carrière, Robinia pseudoacacia, Kalopanax septemlobus and Tilia amurensis).The results of this study were compared with previous studies performed on wood specimens fromChina, India, and Turkey. Consistent with these previous studies, bulk density and thermal conductivity were positively correlated in Korean woods, and a simple regression model with a very high correlation of R2(94%) was obtained. Interestingly, we observed some variation between our simple regression models and those generated by previous researchers who had examined non-Korean woods.

Comparative Study on Flora Characteristics and Species Diversity on Dam Slopes for Sustainable Ecological Management: Cases of Eight Dams in Korea

Dams are gray infrastructure, providing various benefits such as flood control, water supply, and power generation. In order to create the next generation of infrastructure that explores how nature can act as infrastructure to meet development and ecological sustainability, artificial plantings have been attempted on dam slopes in Korea since 2000. As the planted trees are now stabilized to form a forest, it is time to study the floral characteristics and functions for effective ecological management and the safety of the dams. In this study, we investigated and analyzed flora in the slopes of eight dams in Korea. The comparative study of the whole flora in both the planted zones of the slopes of dams and left and right forests of dams revealed that the number of plant species was higher in the planted zones than in the left and right forests of the same size area. The plant family containing the greatest number of species in the slopes was Asteraceae, followed by Poaceae, Fabaceae, and Rosaceae. Currently, the community structures and families in the slopes of dams exhibit the characteristics of habitats in the initial stage of vegetation succession. Our investigation of planted species and immigration species in the slopes revealed that the latter comprised 89.9%. An average of 34.4% of species were interacting with the dam slope and the left and right forests. The species diversity index on dam slopes showed a tendency to be higher as the number of planted species increased and the period time increased. Average growth heights of planted trees were identified as 0.5–1.6 m for the shrubs layer, 3.5–4.5 m for the small trees layer, and 6.0–7.2 m for the trees layer. The heights of major trees, including Pinus densiflora, Quercus spp., Prunus sargentii, Styrax japonicus, and Cornus controversa, were similar to or higher than those of their counterparts in natural forests. As a result, dam slopes were similar to natural forests, having potential as habitats for various flora. To harmoniously maintain the ecological health and safety of water resource facilities of the slopes of dams, however, it is necessary to conduct periodic and various investigations on changes of the flora and growth of trees, and actively manage them.

Relationship between diet and occurrence around human settlements in Asiatic black bears

Increased occurrences of bears in human settlements in search of food have led to a high incidence of human–bear interactions in Japan; therefore, a better understanding of bear occurrence in relation to bears' diet is required to establish effective management practices. In this study, we investigated the composition of the diet of Asiatic black bears (Ursus thibetanus) and the number of bear sightings in Shirakawa Village, Gifu Prefecture, Japan, during pre- and hyperphagic periods (Aug–Dec) from 2008 to 2016. In years with low numbers of sightings, bears consumed natural foods in natural areas, such as fruits of Japanese bird cherry (Prunus grayana), dogwood (Swida controversa), oak (Quercus spp.), and beech (Fagus crenata), which constituted the main part of the bears' diet in our study area. In years with a medium number of sightings, bears consumed both natural and anthropogenic foods in or near human habitations, such as Japanese chestnut (Castanea crenata) and kaki (Diospyros kaki). In the high-sighting year of 2014, bears exhibited a particularly strong preference for Japanese walnut (Juglans mandshurica) and kaki. The number of bear sightings was negatively related to the consumption rates of Japanese bird cherry, dogwood, oak, and beech, and positively related to the consumption rates of Japanese walnut, Japanese chestnut, and kaki. These findings suggest that consumption of fleshy fruits in late summer or hard mast in autumn in or near human settlements has a large effect on the risk of bear–human interactions.

Variation and Correlation between the Physical Properties of Dogwood Seeds

Information about the physical properties of berries of selected dogwood species is available in the literature, but the basic physical traits of berry seeds have not been investigated to date. In this study, the terminal velocity, thickness, width, length, angle of external friction and mass of seeds of 11 dogwood species were measured. The measured parameters were used to calculate the geometric mean diameter, aspect ratio and sphericity index of each seed. The average values of the evaluated parameters were determined in the following range: terminal velocity - from 9.95 to 13.15 m s-1, thickness - from 3.31 to 5.02 mm, width - from 4.14 to 5.38 mm, length - from 4.33 to 11.55 mm, angle of external friction - from 9.97 to 29.85 ºC, mass - from 33.06 to 175.51 mg. The analyzed dogwood species were arranged in the following ascending order based on the geometric mean diameter of their seeds: Cornus macrophylla, Cornus alba, Cornus amonum, Cornus kousa, Cornus obliqua, Cornus controversa, Cornus walteri, Cornus sanguinea, Cornus florida, Cornus officinalis and Cornus mas. The seeds of Cornus alba, Cornus controversa, Cornus florida, Cornus kousa, Cornus macrophylla, Cornus mas and Cornus officinalis could be sorted with the use of mesh sieves with longitudinal openings, the seeds of Cornus macrophylla, Cornus sanguinea and Cornus walteri - with the use of mesh sieves with round openings, and the seeds of Cornus alba, Cornus macrophylla and Cornus obliqua - with the use of cylindrical graders.

Successful seedling establishment of arbuscular mycorrhizal-compared to ectomycorrhizal-associated hardwoods in arbuscular cedar plantations

Thinning is an effective method to create mixed hardwood-conifer forests, as it results in successful hardwood recruitment. However, it remains unclear to what extent mycorrhizal association (AM, or arbuscular mycorrhizae vs. ECM, ectomycorrhizae) affects hardwood recruitment. In this study, we explored which hardwood mycorrhizal type was more advantageous to recruit into a Cryptomeria japonica (AM conifer) plantation. We compared seedling recruitment success (i.e. seedling emergence, survival, and growth) between AM and ECM hardwoods during five years after thinning at various levels: 67% thinned (intensive), 33% thinned (weak) and un-thinned treatments (control). We also investigated the percent colonization of mycorrhizal fungi for the seedlings of the most dominant AM (Cornus controversa) and ECM (Quercus serrata) hardwoods in both the C. japonica plantation and an adjacent forest dominated by ECM tree species (e.g. Q. serrata, Alnus hirsuta var. sibirica, Castanea crenata). During the five years, seedling emergence and survival were greater in AM than ECM for most of the different emergence cohorts, resulting in a greater number of individuals for AM rather than ECM hardwoods for all thinning intensities. Vertical growth of the seedlings was also greater for AM than ECM species, particularly for early emerging cohorts in both the weak and intensive treatments. Percent colonization of AM fungi to AM seedlings was greater in the AM conifer plantation than in the adjacent ECM-dominant forest. In contrast, percent colonization of ECM fungi to ECM-type seedlings was lower in the plantation compared to the adjacent forest. These results suggest that AM hardwoods could easily be recruited to AM conifer plantations, probably due to the fact that AM-type seedlings could easily become associated with AM fungi in the same mycorrhizal-type plantation. Growth of the AM seedlings was enhanced, which was likely to be due to the sharing of AM fungi, which translocate nutrients via hyphal networks. In contrast, recruitment of ECM-type seedlings was strongly inhibited, probably due to the lack of colonization of the ECM fungi in the AM-type plantation. This study demonstrates that mycorrhizal associations play an important role in recruitment success of hardwoods into AM conifer plantations. Thus, when forest managers intend to convert conifer plantations to mixed hardwood and conifer forests, they should consider the role of mycorrhizal fungal type in future species composition.

Horizontal and elevational patterns of masting across multiple species in a steep montane landscape from the perspective of forest mammal management

ABSTRACTMasting of trees affects the activity of large mammals that feed on their fruits, but the spatial patterns of masting at the scale of mammal home ranges across multiple tree species have rarely been investigated. Furthermore, the effects of elevation, which may affect site productivity and thereby alter temporal patterns of masting, have often been ignored. We investigated fruit production by 403 trees of six species that are preferred by Asian black bears over 10 years within a 30 × 30-km2 landscape at 700–1600 m elevations, as well as the horizontal and elevational structures of intraspecies and interspecies synchrony. Higher elevation was related to greater temporal variation in fruiting for Quercus crispula. Among heterospecific relationships, two Quercus species and Swida controversa showed fruiting synchrony, whereas Prunus grayana produced more fruit when Quercus and Swida produced less. Fagus crenata and Castanea crenata did not exhibit masting synchrony, neither positive nor negative, with other species. Spatially, most tested species showed positive autocorrelations with horizontal distance, particularly between close trees (4–10 km), whereas autocorrelations with elevational difference showed negligible spatial structure across elevational distance. Positive spatial correlations between different species were found only for the two Quercus species. These findings imply that variation in movement patterns among individual Asian black bears should be greater in Quercus mast years and that most bears will range more widely than average in non-mast years for Quercus.

What nature separated, and human joined together: About a spontaneous hybridization between two allopatric dogwood species (Cornus controversa and C. alternifolia).

In this study, possible hybridization between two allopatric species, Cornus controversa and Cornus alternifolia, was explored using molecular and morphological approaches. Scanning electron microscope analyses of the adaxial and the abaxial leaf surfaces yielded a few new not yet described characters typical for the particular species and intermediate for hybrids. With the use of 14 Random Amplified Polymorphic DNA and 5 Amplified Fragment Length Polymorphism primer combinations, 44 fragments species specific to C. controversa and 51 species specific to C. alternifolia were obtained. Most of these bands were also found in putative hybrids. All clustering analyses based on binary data combined from both methods confirmed a separate and intermediate status of the hybrids. Hybrid index estimates for hybrids C1-C5 indicated that all were the first generation of offspring (F1). Chloroplast intergenic spacers (trnF-trnL and psbC-trnS) were used to infer the hybridization direction. Based on the assumption of maternal inheritance of chloroplast DNA, C. controversa seems to be the maternal parent of the hybrid. Internal transcribed spacer sequences of the five hybrids analyzed here indicated higher similarity with the sequences of C. controversa (all shared the majority of its single nucleotide polymorphisms). Sequence analysis of PI-like genes fully confirmed the hybrid origin of C1-C5 hybrids. Our results also showed that two specimens in the C. alternifolia group, A1 and A3, are not free of introgression. They are probably repeated backcrosses toward C. alternifolia. Furthermore, molecular data seem to point not only to unidirectional introgression toward C. controversa (the presence of hybrids) but to bidirectional introgression as well, since the presence of markers specific for C. controversa in the profiles of C. alternifolia specimen A3 was observed.

The medicinal active ingredients and their associated key enzyme genes are differentially regulated at different growth stages in Cornus officinalis and Cornus controversa

Revealing the dynamic accumulation and synthesizing mechanism of medicinal active ingredients will be of great significance for the evaluation and utilization of crops in medicinal industry. Dogwood (Cornus officinalis Sizb. et Zucc.), a perennial deciduous tree in the Cornaceae family, possesses important medicinal values in protecting nerves, treating diabetes and kidney diseases, and preventing inflammation and apoptosis. Dengtaishu (Cornus controversa Hemsl.) is another perennial tree in the Cornaceae family. As a Cornus plant that is phylogenetically close to C. officinalis, it is widely used as horticultural landscape plants. Revealing the difference of active ingredients between the two plants within the same genus as well as its molecular mechanism will help improve resource utilization of medicinal crops. In this study, a systematic analysis on the fruit characters, content of active ingredients and expression of key enzyme genes of C. officinalis and C. controversa was conducted. First, the main fruit characters and active ingredients in fruits and leaves of C. officinalis and C. controversa during different growth stages were determined and analyzed. The key enzyme genes geraniol 10-dehydrogenase (G10H) and secologanin synthase (SLS) in the loganin synthesis pathway of C. officinalis and C. controversa were cloned, and the expression level of G10H and SLS was determined by quantitative real-time PCR (qRT-PCR) in leaves and fruits of the two species at different growth stages. Finally, correlation analysis between the content of loganin and the expression of G10H and SLS was conducted to reveal the possible molecular mechanism of loganin synthesis. The results showed that: (1) The fruit length, seed length, and 100-fruit weight of C. officinalis were significantly higher than those of C. controversa (P < 0.01). (2) The content of total sugar and cornel iridoid glycosides (CIGs) in fruits were significantly higher than those in leaves in both the two species, and they increased significantly with the duration of growth period. (3) The content of six active ingredients in leaves was significantly lower than that in fruits of the two species. Except for 5-hydroxymethylfurfural, the content of other five active ingredients in fruits of C. officinalis was significantly higher than that of C. controversa. (4) The content of loganin, cornuside, and protocatechuate in leaves of C. controversa were significantly higher than that of fruits of C. officinalis. (5) G10H was mainly expressed in the fruits of two species, and the expression in fruits of C. officinalis was significantly higher than that of C. controversa. The expression of SLS in fruits and leaves of C. controversa was significantly higher than that of C. officinalis at late growth stage. (6) Correlation analysis between loganin content and gene expression indicated that there was a positive correlation between the expression of G10H and the content of loganin, while the expression of SLS was negatively correlated with the content of loganin. These results first raise the possibility that C. controversa can be used as an alternative to C. officinalis in resource utilization. Meanwhile, the best harvest time with best quality and high yield for C. officinalis and C. controversa was determined. Furthermore, it was speculated that the significant differences of the expression of G10H and SLS in loganin synthesis pathway might be the main reason for the differences of active ingredients between the two species within the same genus. Taken together, these results will further provide insights into the improvement of both the quality and the yield of medicinal crops using approaches of germplasm breeding and genetic engineering.

Different contributions of birds and mammals to seed dispersal of a fleshy-fruited tree

Birds and mammals are important seed dispersers of fleshy-fruited plants. Although their behaviors are different, they frequently consume the same species. Thus to understand the dispersal of fleshy-fruited plants, the contribution of birds and mammals to seed dispersal has to be evaluated. Besides, within birds or mammals, some species may functionally different from others. In this study, we examined seed dispersal of the fleshy-fruited tree Swida controversa focusing on the difference between two frugivore groups (birds and mammals), and differences between species within groups. Collected seeds and S. controversa trees were identified using simple sequence repeat (SSR) genotyping, thus enabling to determine the distance between mother tree and dispersed seeds. The avian species were identified by DNA barcoding of feces, whereas the mammalian species were identified by the shape and smell of feces. Most seeds that fell near or under the maternal trees were dispersed by birds, resulting in short seed dispersal distances (average, 13m). DNA barcoding detected five taxa of avian dispersers. No differences were detected in seed dispersal distance by different avian taxa (i.e., the distance between dispersed seeds and their maternal trees within the research plot); however the rate of seed immigration from outside the research plot by some avian taxa varied significantly. The seed dispersal distance by mammals was significantly further (127m; min > 50m) than that by birds. Additionally, immigrated seeds accounted for approximately two-thirds of mammal-dispersed seeds, indicating that these seeds were from outside the research plot, and that mammals significantly contributed to the long-distance seed dispersal of S. controversa. No differences in seed dispersal distance were detected between different mammalian taxa. Overall, this study revealed that birds and mammals show clearly different seed dispersal patterns, and thus, they play different roles in the regeneration of S. controversa.

Size-dependent variation in leaf functional traits and nitrogen allocation trade-offs in Robinia pseudoacacia and Cornus controversa.

Tree species vary in how they invest resources to different functions throughout their life histories, and investigating the detailed patterns of ontogenetic changes in key functional traits will aid in predicting forest dynamics and ecosystem processes. In this context, we investigated size-dependent changes in key leaf functional traits and nitrogen (N) allocation trade-offs in black locust (Robinia pseudoacacia L., an N-fixing pioneer species) and giant dogwood (Cornus controversa Hemsl., a mid-successional species), which have different life-history strategies, especially in their light use. We found that the leaf mass per area and leaf carbon concentrations increased linearly with tree size (diameter at breast height, DBH), whereas leaf N concentrations decreased nonlinearly, with U- and hump-shaped patterns in black locust and giant dogwood, respectively. We also discovered large differences in N allocation between the two species. The fraction of leaf N invested in cell walls was much higher in black locust than in giant dogwood, while the opposite was true for the light harvesting N fraction. Furthermore, these fractions were related to DBH to varying degrees: the cell wall N fraction increased with DBH for both species, whereas the light harvesting N fraction of giant dogwood decreased nonlinearly and that of black locust remained constant. Instead, black locust reduced the fraction of leaf N invested in other N pools, resulting in a smaller fraction compared to that of giant dogwood. On the other hand, both species had similar fraction of leaf N invested in ribulose-1,5-bisphosphate carboxylase/oxygenase across tree size. This study indicated that both species increased leaf mechanical toughness through characteristic changes in N allocation trade-offs over the lifetimes of the trees.

Long‐term ecological research on Korean forest ecosystems: the current status and challenges

AbstractThe present study aims to monitor the long‐term changes in forest structure, productivity, nutrient cycling, and to accumulate ecological information on forest ecosystem in Korea. There are six long‐term ecological research sites and seven flux measurement sites in Korea. The Gwangneung experimental forest (GEF) located in the central cool‐temperate forest sub zone is known as a model site where many interdisciplinary researches have been ongoing actively since mid‐1990s over all other Korea long‐term ecological research sites (KLTER). Collected data and information through monitoring and investigation of changes in forest ecosystem have been stored in a database for analyses. The relative importance of tree species (%) of GEF was in the order Quercus serrata (20) = Euonymus oxyphyllus (20) &gt; Carpinus laxiflora (12). The total biomass and basal area were 249.53 t ha−1 and 26.66 m2 ha−1, respectively. There were 136 taxa with 49 families, with 97 genera, 11 varieties, 3 forma, and 1 subspecies in 1 ha permanent plot. The increase in temperature has been estimated to have negative effects on tree growth. The litter decomposition rate was in the order Cornus controversa &lt; C. cordata &lt; C. laxiflora &lt; Q. serrata. The average litterfall and soil respiration were 5803 kg ha−1 and 8600 kg C ha−1, respectively. Further, the GEF, a KLTER site tended to be almost carbon neutral with an annual growth average of 51,000 ± 78,000 kg ha−1. The data from six LTER sites are digitalized and classified to build data catalogs on the ecological information system. The information on stand dynamics and materials and energy budget in the forest ecosystem is utilized for impact assessment and the study of adaptation strategy for forest ecosystem to climate change.

Photosynthetic performance and anti-oxidative response of Cornus controversa seedlings under cadmium and lead stress

The photosynthetic efficiency of Cornus controversa leaves was decreased significantly under Cd treatment while it was not affected by Pb exposure. Cd decreased while Pb treatment increased the chlorophyll contents of Cornus controversa leaves. Furthermore, the peroxidase (GPX) activities were decreased after Cd treatment while elevated by Pb exposure in Cornus controvera seedlings. In addition, both Cd and Pb exposures increased the malondialdehyde (MDA) and proline contents and elevated the superoxide dismutase (SOD) activities of Cornus controvera seedlings. Collectively, these results indicated that Cornus controversa may be more tolerant to Pb than Cd toxicity. This finding will contribute to the evaluation of planting Cornus controversa in heavy metal polluted soil conditions.

The Dispersal Effectiveness of Avian Species in Japanese Temperate Forest

Seed dispersal effectiveness (SDE) is one of the best parameters for estimating the benefit that a plant obtains from a dispersal agent. SDE includes quantitative and qualitative components. Previous avian studies of SDE estimation have been conducted mainly in temperate shrub lands or in tropical forests; data are limited for temperate forests, especially, the quality of seed-deposition sites. In this study, we estimated the SDE of birds for Wild Cherry Cerasus jamasakura and Giant Dogwood Cornus controversa fruits in a temperate Japanese forest. These trees prefer sunny sites so we focused on the light conditions at seed-deposition sites and categorized three microhabitat types: forest-gap, forest-edge, and forest-interior. We observed avian seed removal at fruiting trees, conducted a bird census to estimate microhabitat selectivity and collected bird-dispersed seeds. We then counted seedling emergence. Finally, we constructed generalized linear mixed models that combined bird census and dispersed seed data to identify influential seed disperser(s) for each tree species. Frugivorous behavior was recorded for eight avian species for C. jamasakura and 12 for C. controversa. Of these birds, one for the former, and two for the latter preferentially selected forest-gap or forest-edge trees during each fruiting period. The density of dispersed seeds and seedlings was higher in the forest-gap or forest-edge. Additionally, the frequency with which Japanese White-eye Zosterops japonicus visited was a significant variable for seed density in each microhabitat. The results suggested that microhabitat selectivity may affect the density of dispersed seeds in each microhabitat. Furthermore, a bird with a high quantitative SDE may not necessarily also have a high qualitative SDE. Thus, it is important to estimate qualitative and quantitative SDE by focusing especially on the seed-deposition site for each bird in order to evaluate the actual SDE in temperate forests.

Anti-quorum sensing and anti-biofilm formation activities of plant extracts from South Korea

Objective: To investigate anti-quorum sensing (anti-QS) and anti-biofilm formation (anti- BF) activities of the ethanol extracts of 388 plants. Methods: The anti-QS activity of the plant extracts was evaluated by disc-diffusion assays using the bio-reporter strain, Chromobacterium violaceum CV017. Pseudomonas aeruginosa PAO1, Yersinia enterocolitica ATCC 9610, and Agrobacterium tumefaciens C58, which possess QS systems, were used to evaluate the anti- BF activity of the plant extracts. Results: Among 388 plant extracts, the Cornus controversa (C. controversa) and Cynanchum wilfordii extracts exhibited the strongest anti-QS activity. The C. controversa extract exhibited anti-BF activity against Pseudomonas aeruginosa, Yersinia enterocolitica and Agrobacterium tumefaciens, whereas the Cynanchum wilfordii extract exhibited no anti-BF activity against Pseudomonas aeruginosa. In addition, the C. controversa extract suppressed soft rot of cabbage. Conclusions: The C. controversa extract inhibits bacterial QS and BF, and is capable of controlling soft rot. Therefore, this extract has potential for the prevention and treatment of bacterial infections and for the development of alternatives to antibiotics.

Host and geographic range extensions of Melanconiella, with a new species M. cornuta in China

Members of Melanconiella are opportunistic pathogens and endophytic fungi, and have been found to confined so far, on the collection of host family Betulaceae. Moreover, two fresh specimens associated with canker and dieback of Cornus controversa and Juglans regia collected in Shaanxi, China were found as distinct and new species of Melanconiella, based on morphological and multi-gene, combined, phylogenetic analyses (ITS, LSU, rpb2 and tef1-α). Results also revealed the host and geographic range extensions of this genus. Melanconiella cornuta sp. nov. is introduced with an illustrated account and differs from similar species in its host association and multigene phylogeny.