Evergreen Tree Species Research Articles

The Playground Shade Index: A New Design Metric for Measuring Shade and Seasonal Ultraviolet Protection Characteristics of Parks and Playgrounds.

Current shading strategies used to protect outdoor playgrounds from harmful solar radiation include the placement of artificial cloth weaves or permanent roofing over a playground site, planting trees in proximity to playground equipment, and using vegetation or surface texture variations to cool playground surfaces. How and where an artificial shade structure is placed or a tree is planted to maximize the shade protection over specific playground areas, requires careful assessment of local seasonal sun exposure patterns. The Playground Shade Index (PSI) is introduced here as a design metric to enable shade and solar ultraviolet exposure patterns to be derived in an outdoor space using conventional aerial views of suburban park maps. The implementation of the PSI is demonstrated by incorporating a machine learning design tool to classify the position of trees from an aerial image, thus enabling the mapping of seasonal shade and ultraviolet exposure patterns within an existing 7180 m2 parkland. This is achieved by modeling the relative position of the sun with respect to nearby buildings, shade structures, and the identified evergreen and deciduous tree species surrounding an outdoor playground.

Augmented anticancer effect and antibacterial activity of silver nanoparticles synthesized by using Taxus wallichiana leaf extract.

Taxus wallichiana is an evergreen tree species found in the Himalayan region of Pakistan. The tree possesses important secondary metabolites such as Taxol that has been implicated in treating breast, ovarian and colon cancer. Therefore keeping in view the importance of this plant species, silver nanoparticles were synthesized using Taxus wallichiana aqueous leaf extract and evaluated for their anti-bacterial and anti-cancer properties. Silver (Ag) nanoparticles (NPs) were characterized for their optical, morphological and structural features using techniques such as UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) and were evaluated for their antibacterial activity and anti-cancer activity using U251 cell line. The study showed that the UV-absorbance peak of Ag2O NPs at 450 nm shifted to 410 nm, affirming the formation of leaf extract Ag NPs. Similarly structural studies revealed the crystalline nature of the cubic structure of the Ag crystal with an average crystallite size of 29 nm. FTIR analysis exhibited the existence of different functional elements including O-H and N-H and phenolic groups. Non-spherical glomerular shaped Taxus wallichiana Ag NPs were observed from SEM studies and EDX profile showed Ag as the main element along with constituent of biological origin. The synthesized Ag NPs showed significant antibacterial activity against Salmonella typhi, and Staphylococcus aureus. The cytotoxic activity of Ag NPs on U251 brain cancer cells showed a synergistic effect with 10 ug/mL concentration after 48 and 72 h incubation based on cell viability assay indicating promising glioblastoma drug potential.

A Review on Michelia Champaca and Flowers

Michelia champaca Linn. Known as Champaca is Belonging to family of Magnoliaceae. It Consists of 12 genera and 220 species of evergreen trees and shrubs. In recent times there are several reports of medical specialty roles and activities of Michelia champaca and its active principles on the circulatory system, antipyretic, diuretic1.The Phytochemical analysis of the leaves and flowers of the plant showed the presence of alkaloids, tannins, glycosides, carbohydrates, amino acids, flavonoids and sterol in different solvent system. The petroleum ether extract of the dried flower contained n-alkane hydrocarbons, unsaturated aliphatic ketones, beta sistosterol and quercetin. The quercetin forms the first report of its occurrence in the genus Michelia(Shalini and Jaggi 2004) Lago et al (2009) reported that volatile oils contained six sesquiterpene hydrocarbons, four oxygenated sesquiterpenes and two aliphatic alcohols from water using dichloromethane solvent in leaves of M. champaca L. This article provides the collective information about the phytochemical constituents isolated from various parts of this plant used in a modern scenario for the treatment of various ailments like β-sitosterol, sesquiterpenes, parthenolide, dihydro parthenolide, gallic acid, quercetin, liriodenine, essential oils, starch, etc. Traditional uses of the plant in the treatment of various disease like rheumatism, gout, diuretic, febrifuge, etc..

Rainfall Partitioning by Evergreen and Deciduous Broad-Leaved Xerophytic Tree Species: Influence of Rainfall, Canopy Characteristics, and Meteorology

Understanding how rainfall is partitioned into throughfall, stemflow, and interception losses by xerophytic trees is important for evaluating afforestation projects and modeling hydrological budgets in semi-arid regions. However, information regarding rainfall partitioning by xerophytic trees and the controlling factors in semi-arid regions remains underrepresented in the literature. We examined whether plant functional groups have a significant impact on rainfall partitioning in two xerophytic trees (evergreen species: Pinus tabuliformis (Pinales:Pinaceae) hereafter called P. tabuliformis, deciduous species: Robinia pseudoacacia L. (Fabales:Fabaceae) hereafter called R. pseudoacacia) commonly used for afforestation on the semi-arid Loess Plateau of China, and evaluated the effects of rainfall, canopy characteristics and meteorological variables on rainfall partitioning. The event-based gross rainfall, throughfall and stemflow were measured during both growing (May–October) and dormant (January–April and November–December) seasons in 2015 and 2016 within an afforested watershed in semi-arid Loess Plateau of China. During our study period, the average rainfall depth for growing season and dormant season was 8.4 mm (varied from 0.2 to 57.6 mm) and 5.6 mm (varied from 0.2 to 41.6 mm), respectively. On average, the measured throughfall, stemflow and interception loss for R. pseudoacacia accounted for 81.8%, 1.4% and 16.8% of gross rainfall, respectively. Corresponding values for P. tabuliformis were 75.1%, 0.7% and 24.1%, respectively. Significant differences (p < 0.05) in stemflow were detected between R. pseudoacacia and P. tabuliformis during both the growing and dormant seasons. The rainfall partitioning components were significantly positively correlated with individual rainfall amounts. The minimum rainfall required to generate stemflow was 5.2 mm for R. pseudoacacia and 5.9 mm for P. tabuliformis during the growing season, and 3.1 mm for R. pseudoacacia and 6.0 mm for P. tabuliformis during the dormant season. Smaller rainfall events contributed to a lower percentage of rainfall amount, throughfall and stemflow but higher percentage of canopy interception loss. The percentage of throughfall and stemflow showed an increased tendency with increasing rain-fall characteristics, while the increasing rainfall characteristics resulted in a decrease in relative interception loss. During the growing season, leaf area index is significantly correlated with throughfall and interception loss of R. pseudoacacia, while there were no significant correlation between meteorological variables and rainfall partitioning. In general, the depth of rainfall partitioning can be predicted reasonably well by using the developed multiple regression models, but the proportions of rainfall partitioning had a relative lower accuracy using the developed models, especially for relative interception loss. To better predict canopy interception loss, other plant morphological and meteorological variables should be considered.

Variation in Community Structure of the Root-Associated Fungi of Cinnamomum camphora Forest.

Plant-associated microbial communities play essential roles in the vegetative cycle, growth, and development of plants. Cinnamomum camphora is an evergreen tree species of the Lauraceae family with high ornamental, medicinal, and economic values. The present study analyzed the composition, diversity, and functions of the fungal communities in the bulk soil, rhizosphere, and root endosphere of C. camphora at different slope positions by high-throughput sequencing. The results showed that the alpha diversity of the fungal communities in the bulk soil and rhizosphere of the downhill plots was relatively higher than those uphill. A further analysis revealed that Mucoromycota, the dominant fungus at the phylum level, was positively correlated with soil bulk density, total soil porosity, mass water content, alkaline-hydrolyzable nitrogen, maximum field capacity, and least field capacity. Meanwhile, the prevalent fungus at the class level, Mortierellomycetes, was positively correlated with total phosphorus and available and total potassium, but negatively with alkaline-hydrolyzable nitrogen. Finally, the assignment of the functional guilds to the fungal operational taxonomic units (OTUs) revealed that the OTUs highly enriched in the downhill samples compared with the uphill samples, which were saprotrophs. Thus, this study is the first to report differences in the fungal community among the different soil/root samples and between C. camphora forests grown at different slope positions. We also identified the factors favoring the root-associated beneficial fungi in these forests, providing theoretical guidance for managing C. camphora forests.

The complete chloroplast genome sequence of Michelia macclurei (Dandy, 1928) (Magnoliaceae), an important fire-resistant tree species

Michelia macclurei (Dandy, 1928) is an evergreen broad-leaved tree species native to South China. This species has great ecological and economic importance. However, the genomic study of M. macclurei has lagged far behind. Here, we reported the complete chloroplast genome sequence of M. macclurei. The chloroplast genome size of M. macclurei was 160,139 bp, consisting of a pair of inverted repeat (IR) regions (26,575 bp), which was separated by a large single copy (LSC) region (88,167 bp) and a small single copy (SSC) region (18,822 bp). A total of 113 unique genes were annotated, including 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. The overall GC content was 39.2%. Phylogenetic analysis based on 16 whole chloroplast genome sequences of Michelia species suggested that M. macclurei and M. maudiae are sister to each other, and jointly sister to M. chapensis.

Review on Artocarpus nobilis Thw. (Moraceae): An Endemic Plant of Sri Lanka

The genus Artocarpus consists of about 50 species of large evergreen trees with various medicinal and economical uses. Artocarpus nobilis (Family: Moraceae) is commonly referred to as Ceylon breadfruit and it is endemic to Sri Lanka. Synonyms of A. nobilis are Artocarpus imperialis André, Artocarpus pubescens Moon and Saccus nobilis (Thwaites) Kuntze. Extracts from leaves, bark, fruits and latex are rich in phytochemical compounds such as flavanones, flavonoids, triterpenoids, xanthones, stilbenes and chalcones. These bioactive compounds contribute to various pharmacological properties of Ceylon breadfruit (Artocarpus nobilis). It is used in Ayurvedic and folk medicine to treat asthma, diarrhea, worm infestations and wound healing. It also used in traditional ayurvedic formulations like Chandana guli wattoruwa. Several research that has been carried out on this plant include the evaluation of antibacterial activity, anti-inflammatory activity, antioxidant, antifungal, biosorption and Glutathione-S transferase inhibitory activities. Apart from these it is a productive source of edible fruit and yield good timber. A combination of traditional and new technologies will be important in the future to develop therapeutic products from Artocarpus nobilis. In this present review, attempts on providing comprehensive information on research conducted on A. nobilis.

Evergreen and deciduous tree species show distinct strategies to synchronize with seasonality in mid-elevational forests of central Himalaya

Synchronisation of the leaf phenological patterns with favourable environmental conditions and the variations in the leaf traits allow tree species to coexist, support biodiversity and maintain forest productivity with a larger implication on the global carbon cycle. However, within a forest whether plants with contrasting phenological attributes follow similar or distinct adaptive strategies for resource gain in response to seasonality and how they avoid niche-overlap to coexist is less clear. Further, whether the trade-offs between faster leaf growth within a shorter duration and vice-versa as proposed in the worldwide leaf economic spectrum (WLES) holds at the local scale remain inconclusive. Here, we aim to (1) describe patterns of temporal variation in leaf exposure (i.e. initiation, the peak of exposure, longevity, and expansion period) and leaf structural properties (i.e. area, dry mass, specific leaf area, dry-mass lost, construction cost, and mass acquired before the rainy season) among 12 coexisting evergreen and deciduous trees; and (2) explore whether the predictions of the WLES framework hold for evergreen and deciduous mid-elevation trees of the central Himalaya range. Results suggest that with an earlier leaf flush/leaf initiation and faster leaf recruitment in deciduous tree species, these plant species may maximize resource gains while investing less in structural parts of the leaves. In contrast, evergreens exhibit a higher investment in structural traits and retain leaves for a longer period and thereby maximizing resource gains from the growing season. The principal component analysis showed that PC-1 and PC-2 cumulatively explained 68.4% of the total variation in leaf traits. There was a distinct grouping of evergreen and deciduous species along the principal axis-1 for trait variation, suggesting a niche separation, which may allow species to coexist. When tested for the significance of differences in the average values of leaf traits, we found that deciduous trees had higher average values for mass before the rainy season (MRS), dry mass-loss (DML), specific leaf area (SLA), and leaf area (LA) than evergreens. The leaf life span of evergreens was significantly higher compared to the deciduous form which may allow evergreens to pay back the leaf construction cost which on average is higher than deciduous tree species. In a way, deciduous may adopt the resource acquisition strategy while evergreen exhibits a resource conservation strategy. The proposed generalized conservative-acquisitive traits axis of the world leaf economic spectrum thereby holds true for mid-elevational tree species in the central Himalaya.

Leaf phenotypic variation in natural populations of <i>Quillaja saponaria</i> and its relationship with climatic variation

Quillaja saponaria is a sclerophyllus evergreen tree species distributed from 30° to 38° S in Central Chile. In this wide distribution it is expected that the species exhibits phenotypic plasticity in the morphology of leaves associated to climate variation; however, the information on this topic is still scarce. We studied leaf phenotypic variation and its relationship with temperature, precipitation, and aridity in 85 stands of Q. saponaria throughout the natural distribution of the species. The results show that the basal diameter of petiole, the number of secondary veins, and the basal diameter of the principal vein increased with precipitation and decreased with aridity, while the length, basal diameter and the relative length of the petiole decreased with temperature. This confirms that phenotypic variation for foliar characters in Q. saponaria is related to climatic variables indicating an adapting capability of the species to the wide range of environmental conditions in which grows.

Diminishing returns: A comparison between fresh mass vs. area and dry mass vs. area in deciduous species.

“Diminishing returns” in leaf economics occurs when increases in lamina mass (M), which can either be represented by lamina dry mass (DM) or fresh mass (FM), fail to produce proportional increases in leaf surface area (A), such that the scaling exponent (α) for the M vs. A scaling relationship exceeds unity (i.e., α > 1.0). Prior studies have shown that FM vs. A is better than DM vs A in assessing diminishing returns in evergreen species. However, the superiority of FM vs. A over DM vs. A has been less well examined for deciduous species. Here, we applied reduced major axis protocols to test whether FM vs. A is better than DM vs. A to describe the M vs. A scaling relationship, using a total of 4271 leaves from ten deciduous and two evergreen tree species in the Fagaceae and Ulmaceae for comparison. The significance of the difference between the scaling exponents of FM vs. A and DM vs. A was tested using the bootstrap percentile method. Further, we tested the non-linearity of the FM (DM) vs. A data on a log-log scale using ordinary least squares. We found that (i) the majority of scaling exponents of FM vs. A and DM vs. A were >1 thereby confirming diminishing returns for all 12 species, (ii) FM vs. A was more robust than DM vs. A to identify the M vs. A scaling relationship, (iii) the non-linearity of the allometric model was significant for both DM vs. A and FM vs. A., and (iv) the evergreen species of Fagaceae had significantly higher DM and FM per unit area than other deciduous species. In summary, FM vs. A is a more reliable measure than DM vs. A when dealing with diminishing returns, and deciduous species tend to invest less biomass in unit leaf light harvesting area than evergreen species.

Understanding vegetation structures in green spaces to regulate atmospheric particulate matter and negative air ions

Green spaces can effectively reduce atmospheric particulate matter (PM) pollution and regulate negative air ions (NAI), this ecological function of green spaces is directly determined by their types and structures. However, the mechanism of the interactions among the types and structures of green spaces, PM, and NAI are still unclear. In the present study, we selected Dongling Park in Shenyang, China as an example of a typical green space. We ran field experiments to analyze the influences of various green space types and structures on PM10, PM2.5, and NAI. The results showed that green spaces had significantly lower PM10 and PM2.5 and higher NAI concentrations than non-green spaces. Among the four vegetation types (tree-shrub-herb, tree-herb, shrub-herb, and tree-shrub), the tree-shrub-herb type most effectively decreased atmospheric PM10 and PM2.5 concentrations (32.54 ± 8.14% and 21.26 ± 4.07%, respectively) and increased NAI concentrations (115.43 ± 10.00%) to a significantly greater extent than the other vegetation types (p < 0.05). Canopy density was strongly and significantly positively correlated with PM2.5 and PM10 concentrations (r = 0.84* and r = 0.86**, respectively). By contrast, shrub layer richness was significantly negatively correlated with PM2.5 and PM10 concentrations (r = −0.68* and r = −0.74*, respectively). Furthermore, significant positive correlations with NAI concentrations were detected in the canopy density and proportion of evergreen tree species significantly (r = 0.40* and r = 0.46*, respectively). The results illustrate that the green space vegetation types and structures, especially the density of tree canopy, the richness of shrub layer, and the proportion of evergreen tree species, can influence the airborne PM10, PM2.5 and NAI concentrations. Therefore, vegetation types and structures should be considered in the process of planning urban green spaces that perform the ecological function of improving air quality.

First report of Colletotrichum fioriniae causing leaf spot on Schima superba in the world.

Schima superba Gardn. et Champ. is a subtropical evergreen tree species naturally distributed mainly in China, Japan, and Vietnam. It is primarily planted for its timber and urban landscaping in China (Ni, 1996). In September 2018, leaves necrotic spots were observed on S. superba in Jiangxi Forest Breeding Center (28°57'19.52" N, 115°39'21.32" E), Jiangxi Province, China. The disease incidence was about 30%. Initially, spots were circular to semicircular, grayish-brown in the center with dark brown margin, then expanded and eventually collapsed into sunken necrotic lesions. To identify the agent, diseased leaves were collected randomly. Pieces (5 × 5 mm) from the lesion borders were surfaced sterilized in 70% ethanol (30 s), 3% NaOCl (60 s), and rinsed 3 times in sterile water. These pieces were put on potato dextrose agar (PDA) and cultured at 25 °C. Pure cultures were obtained by monosporic isolation, and 3 isolates (MH-1, MH-2, MH-3) were used for morphological studies and phylogenetic analyses. On PDA, colonies were initially white, cottony, then became pinkish to deep-pink at the center and pink on the reverse. Conidia were fusiform with acute ends, smooth-walled, hyaline, 13.7-18.5 × 4.6-6.1 µm (16.4 ± 1.3× 5.3 ± 0.6 µm, n = 100). Conidiophores were colorless to pale brown, smooth, septate. Conidiogenous cells were colorless to pale brown, smooth, cylindrical to ampulliform. The morphological characteristics fit the descriptions of Colletotrichum acutatum J. H. Simmonds sensu lato (Damm et al., 2012). For accurate identification, genomic DNA of 3 isolates was extracted, and the internal transcribed spacer (ITS), actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), beta-tubulin 2 (TUB2), and chitin synthase (CHS-1) were amplified and sequenced using the corresponding primers (Weir et al., 2012). The sequences were deposited in GenBank (ITS: MZ325946, MZ325947, MW584318; ACT: MZ399375, MZ419566, MW661171; CHS-1: MZ399376, MZ419567, MW661172; MZ399377, GAPDH: MZ419568, MW661173; TUB2: MZ399378, MZ419569, MW661174). Five loci were concatenated, and the aligned sequences (1528bp) were 99.89% homologous to ex-type C. fioriniae (Marcelino & Gouli) R. G. Shivas & Y. P. Tan CBS128517. Phylogenetic analysis using the maximum likelihood showed that 3 isolates were clustered in C. fioriniae clade with 100% bootstrap support. Based on the multi-locus phylogeny and morphology, 3 isolates were identified as C. fioriniae. Pathogenicity tests were performed on 36 seedlings of S. superba (2-year-old). The leaves were wounded slightly and inoculated with a drop of spore suspension (106 conidia/mL). The sterile water was used as controls. All the tested leaves were covered with black plastic bags to keep them moist for 2 days. All seedlings were placed in the greenhouse (25 °C, 12 h light/dark) for 10 days, and all inoculated leaves had typical symptoms. The controls were asymptomatic. The same fungus was reisolated from the lesions, fulfilling Koch's postulates. Colletotrichum fioriniae was described as a new species from the C. acutatum s. l. (Shivas et al., 2009), and it was an important plant pathogen, such as Pyrus spp. (Pavlović et al., 2019), Morus alba L. (Xue et al., 2019), and so on. This is the first report of the newly emerging disease of S. superba caused by C. fioriniae in the world, and its potential threat should be evaluated in the future. This study provided crucial information for epidemiologic studies and appropriate control strategies.

Implications of Foliar Particulate Matter Deposition on the Physiology and Nutrient Allocation of Dominant Perennial Species of the Indo-Gangetic Plains.

The ramifications of different concentrations of foliar particulate matter on the physiology, nutrient stoichiometry, allocation pattern, and their corresponding re-translocation rates were investigated for evergreen (Mangifera indica and Psidium guajava), semi-evergreen (Ficus religiosa and Azadirachta indica), and deciduous (Dalbergia sissoo) tree species in a simulation experiment over an exposure period of 2 years. Physiological parameters (Pn, gs, Ci, E, and WUE), nutrient stoichiometry (C: N) in different plant parts, and their allocation pattern for five macro- (C, N, K, Mg, Ca) and five (Zn, Ni, Mn, Cu, Fe) micro-elements at two different concentrations of particulate matter (ambient and elevated) with respect to control (no particulate load) were assessed. Significant differences in nutrient concentrations and their re-translocation rates were observed between the treatments in evergreen species compared to deciduous species. The photosynthetic rate significantly declined with an increase in foliar deposition of particulate matter. Higher variations in C, N, K, Mg, and Zn levels were found compared to other elements under particulate matter stress and the ratio of C/N showed a slight decline in mature leaves except in deciduous tree species. The nutrient stoichiometry revealed that the deciduous species were more tolerant whereas the re-translocation efficiency was maximum for the semi-evergreen tree species. The nutrient allocation was found greater in foliage compared to branch in evergreen and was opposite in semi-evergreen and deciduous tree species. The element re-translocation rate indicated an inconsistent behavior in nutrient recycling under the particulate matter load depending upon the tree species. The study entrenched a critical change in nutrient re-translocation and allocation pattern under the particulate stress in different parts of the tree, suggesting a novel approach for screening the tree species for sustainable plantation and planning of urban areas.

Rhizosphere soil bacterial communities and nitrogen cycling affected by deciduous and evergreen tree species.

Deciduous and evergreen trees differ in their responses to drought and nitrogen (N) demand. Whether or not these functional types affect the role of the bacterial community in the N cycle during drought remains uncertain. Two deciduous tree species (Alnus cremastogyne, an N2‐fixing species, and Liquidambar formosana) and two evergreen trees (Cunninghamia lanceolata and Pinus massoniana) were used to assess factors in controlling rhizosphere soil bacterial community and N cycling functions. Photosynthetic rates and biomass production of plants, 16S rRNA sequencing and N‐cycling‐related genes of rhizosphere soil were measured. The relative abundance of the phyla Actinobacteria and Firmicutes was higher, and that of Proteobacteria, Acidobacteria, and Gemmatimondaetes was lower in rhizosphere soil of deciduous trees than that of evergreen. Beta‐diversity of bacterial community also significantly differed between the two types of trees. Deciduous trees showed significantly higher net photosynthetic rates and biomass production than evergreen species both at well water condition and short‐term drought. Root biomass was the most important factor in driving soil bacterial community and N‐cycling functions than total biomass and aboveground biomass. Furthermore, 44 bacteria genera with a decreasing response and 46 taxa showed an increased response along the root biomass gradient. Regarding N‐cycle‐related functional genes, copy numbers of ammonia‐oxidizing bacteria (AOB) and autotrophic ammonia‐oxidizing archaea (AOA), N2 fixation gene (nifH), and denitrification genes (nirK, nirS) were significantly higher in the soil of deciduous trees than in that of the evergreen. Structural equation models explained 50.2%, 47.6%, 48.6%, 49.4%, and 37.3% of the variability in copy numbers of nifH, AOB, AOA, nirK, and nirS, respectively, and revealed that root biomass had significant positive effects on copy numbers of all N‐cycle functional genes. In conclusion, root biomass played key roles in affecting bacterial community structure and soil N cycling. Our findings have important implications for our understanding of plants control over bacterial community and N‐cycling function in artificial forest ecosystems.

Transcriptome Profiling of a Common Mistletoe Species Parasitizing Four Typical Host Species in Urban Southwest China.

Comparing gene expressions among parasitic plants infecting different host species can have significant implications for understanding host–parasite interactions. Taxillus nigrans is a common hemiparasitic species in Southwest China that parasitizes a variety of host species. However, a lack of nucleotide sequence data to date has hindered transcriptome-level research on T. nigrans. In this study, the transcriptomes of T. nigrans individuals parasitizing four typical host species (Broussonetia papyrifera (Bpap), a broad-leaved tree species; Cryptomeria fortunei (Cfor), a coniferous tree species; Cinnamomum septentrionale (Csep), an evergreen tree species; and Ginkgo biloba (Gbil), a deciduous-coniferous tree species) were sequenced, and the expression profiles and metabolic pathways were compared among hosts. A total of greater than 400 million reads were generated in nine cDNA libraries. These were de novo assembled into 293823 transcripts with an N50 value of 1790 bp. A large number of differentially expressed genes (DEGs) were identified when comparing T. nigrans individuals on different host species: Bpap vs. Cfor (1253 DEGs), Bpap vs. Csep (864), Bpap vs. Gbil (517), Cfor vs. Csep (259), Cfor vs. Gbil (95), and Csep vs. Gbil (40). Four hundred and fifteen unigenes were common to all six pairwise comparisons; these were primarily associated with Cytochrome P450 and environmental adaptation, as determined in a KEGG enrichment analysis. Unique unigenes were also identified, specific to Bpap vs. Cfor (808 unigenes), Bpap vs. Csep (329 unigenes), Bpap vs. Gbil (87 unigenes), Cfor vs. Csep (108 unigenes), Cfor vs. Gbil (32 unigenes), and Csep vs. Gbil comparisons (23 unigenes); partial unigenes were associated with the metabolism of terpenoids and polyketides regarding plant hormone signal transduction. Weighted gene co-expression network analysis (WGCNA) revealed four modules that were associated with the hosts. These results provide a foundation for further exploration of the detailed molecular mechanisms involved in plant parasitism.

Plant photosynthetic overcompensation under nocturnal warming: lack of evidence in subtropical evergreen trees.

Increased plant photosynthesis under nocturnal warming is a negative feedback mechanism to overcompensate for night-time carbon loss to mitigate climate warming. This photosynthetic overcompensation effect has been observed in dry deciduous ecosystems but whether it exists in subtropical wet forest trees is unclear. Two subtropical evergreen tree species (Schima superba and Castanopsis sclerophylla) were grown in a greenhouse and exposed to ambient and elevated night-time temperature. The occurrence of the photosynthetic overcompensation effect was determined by measuring daytime and night-time leaf gas exchange and non-structural carbohydrate (NSC) concentration. A reduction in leaf photosynthesis for both species and an absence of persistent photosynthetic overcompensation were observed. The photosynthetic overcompensation effect was transient in S. superba due to respiratory acclimation and stomatal limitation. For S. superba, nocturnal warming resulted in insufficient changes in night-time respiration and NSC concentration to stimulate overcompensation and inhibited leaf stomatal conductance by increasing the leaf-to-air vapour pressure deficit. The results indicate that leaf stomatal conductance is important for the photosynthetic overcompensation effect in different tree species. The photosynthetic overcompensation effect under nocturnal warming may be a transient occurrence rather than a persistent mechanism in subtropical forest ecosystems.

Seasonal variations in the amount of black carbon particles deposited on the leaf surfaces of nine Japanese urban greening tree species and their related factors

As black carbon (BC) particles can be deposited on the leaf surfaces, urban greening is considered to be effective in purifying urban air. However, little information on the seasonal variations in the amount of BC particles deposited on the leaf surfaces (BC amount on the leaves) is available in Japanese urban greening tree species. Therefore, we investigated seasonal variations in the BC amount on the leaves of evergreen (Quercus glauca, Quercus myrsinaefolia, Osmanthus fragrans and Ilex rotunda) and deciduous (Zelkova serrata, Styrax japonica, Magnolia kobus, Cornus kousa and Cornus florida) broad-leaved tree species. The BC amount on the leaves tended to increase from April for different periods, and then reached a saturated state in the tree species, excluding M. kobus. In the 4 evergreen broad-leaved trees, the seasonal variation was positively correlated with the atmospheric concentration of BC particle. In the 5 deciduous broad-leaved trees, the seasonal variation was negatively and positively correlated with the water-repellence (water droplet contact angle) and the amount of epicuticular wax on the leaf surface, respectively. Therefore, the BC amounts on the leaves of evergreen and deciduous broad-leaved urban tree species are considered to be mainly regulated by environmental factors and leaf surface characteristics, respectively.

Dynamics of Soil CO2 Efflux and Vertical CO2 Production in a European Beech and a Scots Pine Forest

The conversion of coniferous forest to deciduous forest is accompanied by changes in the vertical distribution of fine roots and soil organic carbon (SOC) content. It is unclear how these changes affect soil CO2 efflux and vertical soil CO2 production, considering changing climate. Here, we present the results of a 6-year study on CO2 efflux, covering relatively warm-dry and cool-wet years. A combination of the flux-gradient method and closed chamber measurements was used to study the CO2 efflux and the vertical distribution of soil CO2 production in a beech (Fagus sylvatica L.) and a pine (Pinus sylvestris L.) forest in northeast Germany. We observed, on average, similar CO2 efflux with 517 (±126) and 559 (±78) g C m–2 a–1 for the beech site and the pine site, respectively. CO2 efflux at the beech site exceeded that at the pine site during the wet year 2017, whereas in dry years, the opposite was the case. Water availability as indicated by precipitation was the primary determining long-term factor of CO2 efflux, whereas seasonal variation was mainly affected by soil temperature, and—in the case of beech—additionally by soil water content. CO2 efflux decreased more dramatically (-43%) at the beech site than at the pine site (-22%) during the warm-dry year 2018 compared to the cool-wet year 2017. We assumed that drought reduces heterotrophic respiration (Rh) at both sites, but additionally decreases autotrophic respiration (Ra) at the beech stand. Soil CO2 production at the beech site ranged over a greater soil depth than at the pine site, attributed to different fine root distribution. The organic layer and the A horizon contributed 47 and 68% of total CO2 efflux at the beech site and the pine site, respectively. The seasonal patterns of different CO2 efflux between both sites were assumed to relate to different phases of tree physiological activity of deciduous compared to evergreen tree species.

Cell-level anatomy explains leaf age-dependent declines in mesophyll conductance and photosynthetic capacity in the evergreen Mediterranean oak Quercus ilex subsp. rotundifolia.

Leaves of Mediterranean evergreen tree species experience a reduction in net CO2 assimilation (AN) and mesophyll conductance to CO2 (gm) during aging and senescence, which would be influenced by changes in leaf anatomical traits at cell level. Anatomical modifications can be accompanied by the dismantling of photosynthetic apparatus associated to leaf senescence, manifested through changes at the biochemical level (i.e., lower nitrogen investment in photosynthetic machinery). However, the role of changes in leaf anatomy at cell level and nitrogen content in gm and AN decline experienced by old non-senescent leaves of evergreen trees with long leaf lifespan is far from being elucidated. We evaluated age-dependent changes in morphological, anatomical, chemical and photosynthetic traits in Quercus ilex subsp. rotundifolia Lam., an evergreen oak with high leaf longevity. All photosynthetic traits decreased with increasing leaf age. The relative change in cell wall thickness (Tcw) was less than in chloroplast surface area exposed to intercellular air space (Sc/S), and Sc/S was a key anatomical trait explaining variations in gm and AN among different age classes. The reduction of Sc/S was related to ultrastructural changes in chloroplasts associated to leaf aging, with a concomitant reduction in cytoplasmic nitrogen. Changes in leaf anatomy and biochemistry were responsible for the age-dependent modifications in gm and AN. These findings revealed a gradual physiological deterioration related to the dismantling of the photosynthetic apparatus in older leaves of Q. ilex subsp. rotundifolia.

Phytochemical Characterization and in vitro Antioxidant, in vitro Antidiabetic Activity of Manilkara hexandra Seed Extract

Manilkara hexandra (Roxb.) Dubard is a large evergreen tree species widely distributed throughout India and other countries and belongs to family Sapotaceae. Conventionally, the entire plant has been used for the treatment of various diseases. The present study has been carried out for identification of its bioactive constituents by high resolution-liquid chromatography-quadrupole-time-of-flight-mass spectrometry (HR-LC-QTOF-MS) and evaluation of in vitro antioxidant and in vitro antidiabetic activity of the methanolic extract of the seeds of the plant. Twenty-eight bioactive compounds from the methanolic extract of Manilkara hexandra seeds (MEMH) were identified using HR-LC-QTOF-MS. In vitro antioxidant activity of MEMH was evaluated using 1,1-diphenyl-2-picryl-hydrazyl, nitric oxide, superoxide, and hydroxyl radical scavenging assays and the IC50 values for MEMH were found to be similar to standard drug. In vitro antidiabetic activity was also evaluated using anti α-amylase and anti-α-glucosidase assays and the IC50 values for MEMH were found to be good as compare to standard drugs. The compounds identified by HR-LC-MS partly explain the various therapeutic effects of the seeds of the plant. Thus, it can be concluded that MEMH is rich in bioactive phytochemicals and possesses potential antidiabetic and antioxidant activity.