Vitex Negundo Var Research Articles

Mating strategies of Vitex negundo L. var. heterophylla (Franch.) Rehder (Lamiaceae): A mixed mating system with inbreeding depression.

Plant reproductive ecology is one of the research hotspots in ecology. With the increasing attention paid to the conservation of plant diversity, the research on reproductive characteristics and flowering biological characteristics of more species has attracted more attention. However, plant reproduction is affected by multiple interacting factors such as pollen limitation and resource availability. Vitex negundo var. heterophylla (Franch.) Rehder (Lamiaceae) is a significant species for water and soil conservation. Previous studies have revealed its mating system by the biological characteristics of flowering and SSR markers, but its reproductive strategies remain to be further studied. We evaluated reproductive success through artificial pollination to explore the reproductive characteristics of V. negundo var. heterophylla for the first time. From the results of fruit set, there is a mixed mating system dominated by outcrossing in V. negundo var. heterophylla accompanied by self-compatibility, and it cannot carry out autonomous selfing. Our data show the pollinator-mediated interaction in the success of reproduction, whereas the effect of anemophily is very weak. And the seed germination rate of inbred line progenies was lower than that of hybrid progenies, which is suspected to be caused by inbreeding depression. The research will provide scientific information for the protection and conservation of V. negundo var. heterophylla from the point of view of reproduction. In sum, the results are necessary to protect animal vectors in the background of insect decline.

Secondary shrubs promoted the priming effect by increasing soil particle organic carbon mineralization

IntroductionInputs of additional organic matter to the soil will accelerate or inhibit the decomposition of soil organic carbon (SOC), resulting in a priming effect (PE), which is a key mechanism affecting soil carbon (C) cycling. The impact mechanism of changes in soil properties on the PE is still unclear after vegetation restoration; in particular, the contribution of C pools with different turnover rates to the PE has not been distinguished and quantified.MethodsIn this study, the secondary shrub (SB) (Vitex negundo var. heterophylla) formed by the enclosure of barren grassland was selected as the research object, and the barren grassland (GL) was taken as the control. Equal amounts of 13C-labeled glucose were added to the topsoil for a 45-day incubation experiment to measure the PE. Moreover, soil samples were destructively sampled to explore the fate of new C and changes in POC and MAOC fractions during incubation.ResultsAfter 45 days of incubation, most of the new C formed by glucose flowed to MAOC, with 95.45% in SB soil and 92.29% in GL soil. In the experiment, all soils showed a positive PE. The PE, POC mineralization and MAOC accumulation were higher in SB soil than in GL soil. During incubation, the mineralization of POC was positively correlated with the PE and made a major contribution to the PE. Partial correlation analysis showed that after vegetation restoration, SB further promoted the mineralization of POC by increasing the soil moisture, fungal diversity and necromass C of bacteria, which led to an increase in PE.ConclusionThe SB mainly enhanced PE by increasing soil fungal diversity and mineralization of POC. And increasing PE due to the SB may lead to an increase in soil C emissions. Therefore, we need to adopt forest management and other measures to address the potential risks of increased soil C emissions in the vegetation restoration process.

Chemical constituents from Vitex negundo var. cannabifolia (Sieb. et Zucc.) Hand.-Mazz. (Lamiaceae) and their chemotaxonomic significance

Vitex negundo var. Cannabifolia (Sieb. et Zucc.) Hand.-Mazz. leaves and twigs were used to isolate a new phenyldihydronaphthalene-type lignan (1) along with twenty known compounds. Comprehensive spectroscopic techniques such as UV, IR, NMR, HR-ESI-MS, ORD and ECD were used to identify their structures. Quantum chemical computations were used to assign the absolute configurations (AC) of (1). Using DP4+ analysis, the computed chemical shifts were used to pinpoint relative configuration. Compounds (1–6) were tested for biological activities. Compound (5) significantly decreased the release of lactate dehydrogenase (LDH) by 38% at a concentration of 10 μM, demonstrating that compound (5) had significant anti-inflammatory effects on the activation of the NLRP3 inflammasome, while no compound was found potent at a concentration of 200 μM against tyrosinase. Additionally, the chemotaxonomic significance of the isolated compounds was studied.

Secondary succession of shrub-herb communities in the hilly area of Taihang Mountain.

To document the successional processes of shrub-herb communities after large-scale human disturbance, and understand how changing environmental conditions affect species replacement in semi-humid hilly areas. Utilizing the established permanent plots in the hilly area of Taihang Mountain, we evaluated temporal patterns of vegetation and soil following grass-to-shrub succession. Along secondary succession, Vitex negundo var. heterophylla gradually dominated in dry sunny slope and shared the dominance with Leptodermis oblonga in shaded slope. Herbaceous dominant species in shrub-herb communities switched from Themeda japonica, Bothriochloa ischaemum, Artemisia sacrorum, and Cleistogenes chinensis in 1986 census to B. ischaemum and A. sacrorum in 2008 census, but herb was no longer dominant in 2020 census. As succession progresses, species dominance increased while richness decreased generally, and herb cover and aboveground biomass decreased, whereas shrub height, cover, and aboveground biomass increased significantly. Soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), and total potassium (TK) in topsoil increased significantly while pH declined by 1.04 units over the past three decades. Plant communities transitioned from perennial herbs to shrub-herb and then shrub communities, and V. negundo var. heterophylla dominated in the succession of shrub-herb communities. Climate and soil properties, combined with plant attributes, together drive post-disturbance secondary succession. From a management perspective, the tight coupling between vegetation and soil under local climatic conditions should be considered to improve the fragile ecosystem in the hilly area of Taihang Mountain.

Arbuscular mycorrhizal fungi inoculation exerts weak effects on species- and community-level growth traits for invading or native plants under nitrogen deposition

Nitrogen deposition and biological invasion are two major components of global environmental change. Nitrogen deposition has been considered to enhance the resource availability of recipient habitats, which influences the invasiveness of plant invader and the invasibility of recipient native communities. Nitrogen deposition has been shown to reduce the relative abundances of arbuscular mycorrhizal fungi (AMF) globally. AMF have been found to mutualistically symbiose with approximately 75% of plant species and act as a nutrient supplier. AMF may modify the structure of native plant communities, collaborate with alien plant invaders and thus promote their invasion. The alien woody invader, Rhus typhina L. has been introduced into North China as a horticultural species, invaded the native plant community and outperformed the native competitors in growth and in photosynthetic efficiency. Nevertheless, little is known about if nitrogen deposition and AMF inoculation synergistically alter the invasibility of native plant community. In this study, R. typhina was subjected to the artificial plant community assembled by four co-existing native species – Chenopodium album L., Vitex negundo var. heterophylla (Franch.) Rehd., Rhus chinensis Mill. and Acer truncatum Bunge in a mesocosm experiment. Nitrogen deposition and AMF inoculation were simulated as environmental and biotic filters respectively. Aboveground biomass and biomass proportion, reflecting plant growth and performance, and specific leaf area and chlorophyll concentration correlated with carbon use and photosynthetic capacity of both the alien invader and the native plants were measured and calculated after harvest. We found that AMF inoculation did not alter the trait variation of alien and native species to increasing nitrogen deposition level in general, although AMF inoculation impeded the increase of aboveground biomass for C. album, V. negundo and native community with increasing nitrogen deposition level. In the scenario of nitrogen deposition and AMF inoculation, a stable status of invasion dynamic may be maintained and needs to be checked with integration of traits at extended temporal scale.

Effects of Precipitation Variation on Annual and Winter Soil Respiration in a Semiarid Mountain Shrubland in Northern China

In response to global climate change, future precipitation changes are expected to profoundly influence soil respiration in arid and semiarid areas. However, few studies focus on CO2 emissions from soils undergoing precipitation changes in semiarid mountain shrublands in winter. A precipitation-manipulation experiment with three levels of precipitation (30% decreased precipitation (DP), ambient precipitation (AP), and 30% increased precipitation (IP)) was performed to examine the effects of variable precipitation on soil respiration (SR) and wintertime contributions to annual SR emissions in Vitex negundo var. heterophylla shrub ecosystems located on the Middle Taihang Mountain in Hebei Province, northern China. The results showed that the average annual SR rates and winter SR rates ranged from 1.37 to 1.67 μmol m−2 s−1 and 0.42 to 0.59 μmol m−2 s−1 among the different precipitation treatments. The model based on soil moisture better represented the soil-respiration rates, suggesting that the variable precipitation extended the water’s limitation of the soil’s CO2 emissions. The cumulative annual soil CO2 emissions were 523, 578, and 634 g C m−2 in response to the DP, AP, and IP treatments, respectively. The ratio of the soil CO2 emissions in winter to the annual CO2 emissions varied from 7.6 to 8.8% in response to the different precipitation treatments. Therefore, ignoring the soil CO2 emissions in winter leads to the underestimation of the carbon losses in semiarid shrublands. Our results highlight that variable precipitation significantly influences soil-respiration rates, and soil CO2 emissions in winter must not be ignored when predicting the future feedback between SR and climate change in semiarid regions.

Microbial gradual shifts during the process of species replacement in Taihang Mountain.

Understanding microbial gradual shifts along species replacement can help elucidate the mechanisms driving secondary succession, and predict microbial responses to changing environments. However, how climate-induced species replacement alters microbial processes, and whether microbial shifts follow predictable assembly trajectories remain unclear. Using space-for-time substitution approach, we studied shifts in bacterial and fungal communities in the succession from Leptodermis oblonga to Vitex negundo var. heterophylla shrubland in Taihang Mountain. Species replacement, induced by climate related environmental change, significantly increased the above-ground biomass of shrublands, and TP and TK contents in topsoil. The succession from L. oblonga to V. negundo var. heterophylla communities resulted in the gradually replacement of cold-tolerant microbes with warm-affinity ones, and alterations of microbial communities involved in soil biogeochemical processes. Soil and plant variables, such as above-ground biomass, soil pH, total phosphorus, and total potassium, well explained the variations in microbial communities, indicating that the coordinated changes in plant communities and soil properties during secondary succession caused accompanied shifts in microbial diversity and composition.

Establishment of Fitted Models for Topographical Factors and Coexisting Plants Influencing Distribution of Natural Wild Jujube

Fitting mathematical models to describe the influence of topographic factors and coexisting plants on wild jujube distribution was performed to provide a scientific basis for wild jujube forestation. Investigation quadrats, with straight-line distances between adjacent quadrats of longer than 100 m, were set up in areas of wilderness or low human disturbance, which were rich in wild plant species. Data concerning altitude, slope aspect, slope position and slope degree of each investigation quadrat, as well as the type and number of coexisting wild plants, were collected. Based on this, correlations with the average number, occurrence probability and density of wild jujube and these variables were analyzed, and data models were established. Results of analyses show that topographic factors such as altitude, aspect, gradient, slope and position, play an important role in the distribution of wild jujube; and that Vitex negundo var. heterophylla (Franch.) Rehd. coexistence is related to wild jujube distribution. Both average number and occurrence probability of wild jujube conform to a GaussAmp model with altitude. The highest average number was recorded at 581.24 ± 13.78 m above sea level, and the highest occurrence probability at 462.53 ± 36.67 m above sea level. Average number and occurrence probability of wild jujube were fit to a linear model with slope aspect—with mathematical slope 0.49 ± 0.16—indicating that wild jujube is a light-loving and drought-tolerant plant. Average number and density of wild jujubes were fit to GaussAmp models with slope position. The highest average number and the highest density of wild jujube appears on the upper part of the middle slope. Wild jujube occurrence probability was correlated to slope degree in a quadratic equation model. With an increase in slope degree, the distribution number of wild jujube increased sharply. The survey data of slope position and slope degree further reinforced the observed drought-resistance qualities of wild jujube. Average number and density of wild jujubes were correlated to the number of Vitex negundo var. heterophylla by quadratic equation models. No other plants investigated conformed to a statistically significant relationship with wild jujube distribution. Our results suggest altitude, slope aspect, slope position and slope degree play an important role in wild jujube distribution, and that Vitex negundo var. heterophylla is an important coexistent plant species for wild jujube.

Phenolic Glucosides from the Leaves of Vitex negundo var. cannabifolia.

Four new phenolic glucosides, cannabifolins G-J (1-4), together with four known ones (5-8), were isolated from the leaves of Vitex negundo var. cannabifolia. Their structures were established by comprehensive analysis of 1D and 2D NMR data and comparison of their spectroscopic and physical data with the literature values. Compound 7 exhibited weak inhibition of nitric oxide production stimulated by lipopolysaccharide in BV-2 microglial cells with IC50 value of 132.8 μM.

CHROMATOGRAPHIC ANALYSIS OF CARBOXYLIC ACIDS IN THE FLOWERING SHOOTS OF SOME Vitex L. SPECIES

Introduction. The genus Vitex L. counts more than 200 species of shrubs and trees common to subtropical areas of the Earth. Only fruits of Vitex agnus-castus L. are used in official medicine.
 The aim of our study was to perform the chromatographic analysis of carboxylic acids in the flowering shoots of three Vitex representatives under their cultivation in Ukraine.
 Materials and Methods. Gas chromatography with mass spectrometry (GC/MS) was applied for the analysis of composition and contents of carboxylic acids in the Vitex agnus-castus L., Vitex negundo L. and Vitex negundo var. cannabifolia (Siebold & Zucc.) Hand.-Mazz. flowering shoots.
 Results and Discussion. The Vitex agnus-castus raw material contained the most significant amount of short-chained aliphatic acids (2454 mg/kg). Malonic, oxalic, citric, and malic acids noticeably prevailed in all the raw materials. The largest amount of aromatic acids was found in the Vitex negundo var. cannabifolia (3926 mg/kg) flowering shoots. p-Hydroxybenzoic acid dominated among the aromatic acids in the plant raw materials of all species. The most noticeable total content of unsaturated fatty acids was in the Vitex negundo var. cannabifolia (4793 mg/kg).
 Conclusions. To summarize the contents of valuable carboxylic acids, the obtained results provide the evidence for the development and further pharmacological study of herbal preparations from the flowering shoots of three Vitex species.

GC-MS Analysis of Constituents of Volatile Oil in Different Parts of Vitex negundo var. heterophylla

GC-MS Analysis of Constituents of Volatile Oil in Different Parts of Vitex negundo var. heterophylla

Iridoid glucosides from the leaves of Vitex negundo var. cannabifolia

• Five new and nine known iridoid glucosides were obtained from the leaves of Vitex negundo var. cannabifolia . • The absolute configurations of sugar moieties were determined using a HPLC-UV-based method. • Six isolates increased the cell viability of GES-1 cell insulted by TCA. Five new iridoid glucosides, cannabifolisides A–E ( 1 – 5 ), together with nine analogues ( 6 – 14 ), were isolated from the leaves of Vitex negundo var. cannabifolia. Their structures were elucidated by spectroscopic data (NMR, UV, IR, and MS) analyses and comparison of their spectroscopic and physical data with the literature values. The protective effect of isolated compounds on human gastric epithelial cells were evaluated by measuring the enhanced cell viability of GES-1 cell insulted by TCA. Among these, compounds 4 , 6 , 8 , 10 , 12 , and 14 remarkably increased the cell viability in a concentration-depend manner.

The chloroplast genome sequence and characteristic analysis of Vitex negundo var. heterophylla (Franch.) Rehder

Vitex negundo var. heterophylla (Franch.) Rehder is a common small shrub in northern China. In order to study the fine nectar characteristics and water and soil conservation characteristics of V. negundo, the analysis of chloroplast genome would provide theoretical basis for economic development and germplasm utilization of V. negundo. The chloroplast genome sequence (accession number MW366787) of V. negundo was accepted by high-throughput sequencing technology using a plant from Jiulongshan, Mentougou District, Beijing, China. The total length of the chloroplast genome is 154,438 bp, and the A, T, C and G content of the whole genome is 30.48, 31.26, 19.42, and 18.84%, respectively. The phylogenetic analysis of 16 Verbenaceae plants (including V. negundo) with Arabidopsis thaliana as the outgroup was carried out by the maximum likelihood method; and the result shows that V. negundo is relatively closed to Vitex rotundifolia.

Response of Soil Respiration and Its Components to Precipitation Exclusion in Vitex negundo Var. Heterophylla Shrubland of the Middle Taihang Mountain in North China

Assessing the response of soil heterotrophic and autotrophic respiration to climate change is critical for forecasting terrestrial carbon cycle behavior in the future. In the present study, we conducted a drought experiment in Vitexnegundo var. heterophylla shrub ecosystem of the Middle Taihang Mountain. Three precipitation manipulation treatments (natural conditions/ambient precipitation (CK), reduced precipitation by 30% (PE30), and reduced precipitation by 60% (PE60)) were used to study the impact of different levels of precipitation exclusion on total soil respiration (Rs) and its heterotrophic (Rh) and autotrophic (Ra) components. Our results showed that the rates of Rs and its components were significantly decreased under the precipitation exclusion treatments. The proportion of Rh in Rs reduced from 72.6% for CK to 71.9% under PE60. The annual cumulative C fluxes of Rs decreased by 47.8 g C m−2 in PE30 and 106.0 g C m−2 in PE60, respectively. An exponential relationship was observed between the rate of each soil respiration component and soil temperature in all treatments ( p < 0.01). Moreover, each soil respiration component rate was better represented by a quadratic model which included soil moisture ( p < 0.01). However, including both of soil temperature and soil moisture did not explain more variation in soil respiration components compared than the regression model with soil moisture only. In addition, excluding precipitation increased the temperature sensitivity (Q10 values) of Rs and its Ra and Rh components compared to the control. Collectively, our findings suggest that increased drought will inhibit the release of carbon from the soil to the atmosphere, and will likely decrease the contribution of Rh to Rs in this semiarid shrubland ecosystem.

Effects of thinning on the functional traits of understory Vitex negundo var. heterophylla in Quercus variabilis plantation

Objective The objective of this study is to explore the effect of thinning on the functional traits of roots, stems and leaves of Vitex negundo var. heterophylla under Quercus variabilis plantation in order to provide theoretical basis for the optimization of plantation structure and the regeneration and protection of understory seedlings. Method The V. negundo var. heterophylla in the shrub layer of Q. variabilis plantation 3 years after thinning was taken as the research object, and the differences of leaf area, specific leaf area, leaf dry matter content, stem dry matter content, total root length, specific root length and other structural traits, as well as total nitrogen, total phosphorus, total potassium and total organic carbon content in various plant organs were compared. The relationship between plant functional traits and the understory light environment and soil physical and chemical characteristics was studied. Result After thinning, the aboveground functional traits of plants of V. negundo var. heterophylla such as total leaf organic carbon, leaf area, specific leaf area, leaf organic nitrogen, stem total organic carbon, and the underground functional traits of plants such as root length, root volume, root biomass, the total organic carbon content of roots were significantly higher than those of the control plot (P＜0.05). Correlation and stepwise regression analysis results showed that scattered radiation was the main factor affecting the structural properties of V. negundo var. heterophylla leaves. Direct radiation flux, photosynthetically active radiation and total solar radiation time were the key factors affecting leaf chemical properties, while stem functional properties were mainly affected by the direct radiation and scattered radiation under the forest. Total root length, specific root length and root organic carbon content were significantly correlated with soil non-capillary porosity, soil total porosity, soil organic carbon and soil total nitrogen (P＜0.05), among which soil organic matter content was the key factor affecting functional traits. Conclusion Thinning can significantly promote the development of the functional traits of leaves and roots of Q. variabilis plantation, and has a weak effect on stem functional traits. [Ch, 1 fig. 6 tab. 31 ref.]

Cytotoxic, clonal fidelity, and antioxidant evaluation of in vitro propagated Vitex negundo var. cannabifolia

Vitex negundo L. var. cannabifolia (Sieb. et Zucc.) Hand.-Mazz. is an important medicinal plant rich in bioactive compounds. In vitro tissue culture can be used to produce high-quality starting materials for commercial cultivation. However, the micropropagation technique, especially the comprehensive evaluation of regenerants at the metabolite level, is not well known in this plant species. Employing dormant buds as explants, we developed direct and callus mediated indirect propagation protocols for this species and then evaluated the antioxidant and cytotoxic activities of regenerants. The highest multiple shoot induction frequency of 100%, with a proliferation coefficient of 20.3, was achieved using Murashige and Skoog basal medium with 4.4 µM 6-benzylaminopurine and 1.1 µM 1-naphthylacetic acid. The same medium supplemented with 31.5 µM copper sulfate was optimal for callus differentiation, with a shoot regeneration rate of 81.10%. Inter-simple sequence repeat analysis showed a high genomic fidelity of in vitro regenerants. Chemical, physiological, and cytotoxic analyses indicated that in vitro propagated plants at the adult stage are indistinguishable from wild-grown plants. In particular, the cytotoxicity of V. negundo var. cannabifolia to breast cancer cell line SUM159 reveals the potential of this species for use in treating human breast cancer, with cytotoxic compounds beyond vitexin also apparently observed. Our results indicate that V. negundo var. cannabifolia can be reliably micropropagated in vitro. Moreover, the regenerants have high cytotoxic activity against highly metastatic human breast cancer. We developed efficient micropropagation protocols for Vitex negundo var. cannabifolia, and found the regenerants were consistent with wild-grown plants according to the assessments at the genomic, metabolic, physiological, and cytotoxic levels. We also found the high anticancer activity of V. negundo var. cannabifolia, and confirmed that there are other cytotoxic compounds other than vitexin.

In Vitro Screening of East Asian Plant Extracts for Potential Use in Reducing Ruminal Methane Production.

Simple SummaryMethane from ruminants is a major contributor to total greenhouse gases. Therefore, ruminant nutritionists have proposed strategies to mitigate methane emissions, such as chemical inhibitors and ionophores. However, dietary manipulation including natural feed additives is more practical, considering consumer preferences. Therefore, the current experiment screened 137 plant species, indigenous to East Asian countries, to select novel anti-methanogenic candidates as natural feed additives. Among these species, an extract from the seeds of Pharbitis nil exhibited a maximum 37% reduction of methane in a conformation assay. Identification of active compounds present in the seeds of Pharbitis nil revealed enrichment of polyunsaturated fatty acids, which were dominated by linoleic acid (18:2). The extract had negative effects on the populations of ciliated protozoa and H2-producing Ruminococcus flavefaciens, thereby increasing the proportion of propionate, similar to the effect of monensin. This is the first report to suggest that the seeds of P. nil could be a promising anti-methanogenic alternative to ionophores or oil seeds.Indiscriminate use of antibiotics can result in antibiotic residues in animal products; thus, plant compounds may be better alternative sources for mitigating methane (CH4) production. An in vitro screening experiment was conducted to evaluate the potential application of 152 dry methanolic or ethanolic extracts from 137 plant species distributed in East Asian countries as anti-methanogenic additives in ruminant feed. The experimental material consisted of 200 mg total mixed ration, 20 mg plant extract, and 30 mL diluted ruminal fluid-buffer mixture in 60 mL serum bottles that were sealed with rubber stoppers and incubated at 39 °C for 24 h. Among the tested extracts, eight extracts decreased CH4 production by >20%, compared to the corresponding controls: stems of Vitex negundo var. incisa, stems of Amelanchier asiatica, fruit of Reynoutria sachalinensis, seeds of Tribulus terrestris, seeds of Pharbitis nil, leaves of Alnus japonica, stem and bark of Carpinus tschonoskii, and stems of Acer truncatum. A confirmation assay of the eight plant extracts at a dosage of 10 mg with four replications repeated on 3 different days revealed that the extracts decreased CH4 concentration in the total gas (7–15%) and total CH4 production (17–37%), compared to the control. This is the first report to identify the anti-methanogenic activities of eight potential plant extracts. All extracts decreased ammonia (NH3-N) concentrations. Negative effects on total gas and volatile fatty acid (VFA) production were also noted for all extracts that were rich in hydrolysable tannins and total saponins or fatty acids. The underlying modes of action differed among plants: extracts from P. nil, V. negundo var. incisa, A. asiatica, and R. sachalinensis resulted in a decrease in total methanogen or the protozoan population (p < 0.05) but extracts from other plants did not. Furthermore, extracts from P. nil decreased the population of total protozoa and increased the proportion of propionate among VFAs (p < 0.05). Identifying bioactive compounds in seeds of P. nil by gas chromatography-mass spectrometry analysis revealed enrichment of linoleic acid (18:2). Overall, seeds of P. nil could be a possible alternative to ionophores or oil seeds to mitigate ruminal CH4 production.

Weak Tradeoff and Strong Segmentation Among Plant Hydraulic Traits During Seasonal Variation in Four Woody Species.

Plants may maintain long-term xylem function via efficiency-safety tradeoff and segmentation. Most studies focus on the growing season and community level. We studied species with different efficiency-safety tradeoff strategies, Quercus acutissima, Robinia pseudoacacia, Vitex negundo var. heterophylla, and Rhus typhina, to determine the seasonality of this mechanism. We separated their branches into perennial shoots and terminal twigs and monitored their midday water potential (Ψmd), relative water content (RWC), stem-specific hydraulic conductivity (Ks), loss of 12, 50, and 88% of maximum efficiency (i.e., P12, P50, P88) for 2 years. There were no correlations between water relations (Ψmd, RWC, Ks) and embolism resistance traits (P12, P50, P88) but they significantly differed between the perennial shoots and terminal twigs. All species had weak annual hydraulic efficiency-safety tradeoff but strong segmentation between the perennial shoots and the terminal twigs. R. pseudoacacia used a high-efficiency, low-safety strategy, whereas R. typhina used a high-safety, low-efficiency strategy. Q. acutissima and V. negundo var. heterophylla alternated these strategies. This mechanism provides a potential basis for habitat partitioning and niche divergence in the changing warm temperate zone environment.

Iridoids from Vitex negundo var. heterophylla and their antioxidant activities

Two new iridoids (1-2) together with eight known iridoid glycosides (3-10) were isolated from the 70% EtOH extract of the dried leaves of Vitex negundo var. heterophylla. Their structures were elucidated by extensive spectroscopic analyses. Iridoid aglycones were found for the first time from this plant. All of these compounds were tested for their antioxidant activities. Among them, compound 9 showed moderate radical-scavenging effect on the stable free radical, 1,1-diphenyl-2-picrylhydrazyl, with IC50 values of 26.95 μM.

Vitexnegheteroin M, a new phenolic glycoside from Vitex negundo var. heterophylla

The investigation of chemical constituents from the leaves and seeds of Vitex negundo var. heterophylla resulted in the isolation of one new phenolic glycoside, vitexnegheteroin M (1), together with eleven known compounds (2-12). Their structures were elucidated through extensive spectroscopic analyses including 1D, 2D NMR, HR-ESI-MS, and by comparison with the literature. Among them, compound 3 was obtained from the Vitex genus for the first time, and compounds 4-8, and 10-12 were isolated from this plant for the first time. Their anti-inflammatory activities were investigated by measuring nitric oxide (NO) production in lipopolysaccharide (LPS)-induced murine microglial BV-2 cells. As the obtained results, compound 9 showed the strongest inhibitory activity against LPS-stimulated NO production in BV-2 cells with IC50 value ranging from 8.65 ± 0.67 μM.