To meet the urgent needs for variety breeding and variety-right protection in the genus Gynostemma,this study developed the guidelines for the testing of distinctness,uniformity,and stability(DUS)for new varieties of this genus in accordance with GB/T 19557.1 and relevant international standards.A total of 58 Gynostemma germplasm resources were collected from nine provinces,covering two major applied species(G.longipes and G.pentaphyllum)and 10 other species,including G.burmanicum and G.yixingense.Field trials were conducted in Zhenping county,Shaanxi province,where all germplasms were uniformly planted using asexual propagation.Through observations across the entire growth cycle,trait expression at each developmental stage were systematically recorded,and 42 traits were screened,encompassing rhizomes,stems,leaves,flowers,fruits,seeds,and other organs.These traits included 5 qualitative traits,31 quantitative traits,and 6 pseudo-qualitative traits,as well as 29 visual traits,11 measurable traits,and 2 traits evaluated using both methods.Variation analysis of 12 measurable traits showed coefficients of variation ranging from 8.42%to 53.83%,with the highest value observed for rhizome dry weight(53.83%).Most traits exhibited significant differences among varieties.Correlation analysis indicated that only 31 of the 66 trait pairs exhibited significant or highly significant correlations,and correlations among most traits were weak,thus avoiding redundancy in discriminatory power.Measurable traits were graded using the median-average standard deviation method combined with the least significant difference(LSD)method.The contents of gypenoside A,gypenoside XLIX,and total gypenosides were incorporated into the testing system,and nine standard varieties were initially selected to correct for environmental effects.This study established a systematic trait evaluation system for the genus Gynostemma,helping to address challenges arising from interspecific morphological similarity and difficulties in identification.It provides scientific and technological support for the identification,breeding,and protection of new Gynostemma varieties,and also serves as a reference for the development of DUS testing guidelines for medicinal plants.

Supported by the "Policy Research Project on Understory TCM Cultivation" of the National Administration of Traditional Chinese Medicine, the project team conducted field investigations across 72 understory TCM bases in 46 counties and districts spanning 15 provinces(municipalities, autonomous regions), covering 40 TCM species, and carried out policy interviews and surveys with relevant provincial-level administrative departments. The paper analyzed the regional development experience regarding(understory) TCM in Yunnan, Guizhou, and Jilin. These regions, through high-level policy promotion, scientific planning, and systematic support, developed replicable practical experience in industrial layout, financial support, technical services, and market system construction. The paper summarized the strong adaptability demonstrated by TCM with long cultivation histories or strong growth momentum, such as Ginseng Radix et Rhizoma, Epimedii Folium, Gastrodiae Rhizoma, and Polygonati Rhizoma, in understory cultivation, and also pointed out challenges they face in technology, market, and quality control. The study identified eight profit models of five types, including resource-driven, natural ecology adaptation, industrial chain improvement, project-driven, and order-oriented models, providing diverse development path references for different regions and entities. Based on these findings, this study recommended that future efforts should strengthen targeted policy guidance, technological innovation, and industrial chain collaboration to promote the high-quality development of the understory TCM industry, ultimately achieving the dual goals of ecological protection and industrial revitalization.

Understory ecological cultivation of Chinese medicinal herbs is a crucial component of China's national strategy for developing forest-based economies, yet it frequently faces challenges such as low yields and high production costs. This review synthesizes comparative studies on the active constituent content of nine medicinal herbs-Panax ginseng, P. quinquefolius, P. notoginseng, Polygonatum, Dendrobium, Paris polyphylla, Coptis chinensis, Bletilla striata, and Epimedium-between understory cultivation and field cultivation. The findings indicate that Dendrobium in understory cultivation systems generally exhibit higher levels of polysaccharides than greenhouse-grown counterparts. For C. chinensis, alkaloid content shows no significant difference between understory cultivation and shaded field cultivation. Extended growth periods enable P. ginseng and P. quinquefolius to achieve total and rare ginsenoside concentrations surpassing those of short-cycle cultivated counterparts. The quality of Polygonatum, P. notoginseng, P. polyphylla, and B. striata is influenced by forest stand type and shade intensity, with no clear patterns yet established. Flavonoid accumulation in Epimedium is sensitive to canopy closure, exhibiting an optimal light-intensity range. Moreover, understory cultivation enhances soil microbial diversity and reduces the abundance of certain phytopathogens, suggesting potential ecological pest/disease-suppression effects, although direct evidence regarding pest/disease incidence rates and agrochemical residues remains lacking. Overall, the impact of understory cultivation on medicinal herb quality is species-specific and environmentally contingent, with quality advantages likely arising from moderate abiotic stress, extended growth duration, and enhanced biodiversity. Future research should standardize experimental designs, quantify key ecological factors, and deepen mechanism understanding of forest-medicinal herb interactions to support high-quality industry development.

Epimedium pubescens, a shade-tolerant medicinal plant, currently faces supply shortages. To investigate the regulatory mechanisms of shading intensity on its growth and quality, this study established four treatments under a Phoebe zhennan plantation: inter-row artificial shading (0% shading, S-0; 50% shading, S-50; 75% shading, S-75) and natural canopy shading (S-93). When monitoring environmental factors, photosynthetic parameters, biomass, and total flavonol glycoside content, significant differences among treatments were only observed regarding solar radiation. Compared with inter-row treatments, S-93 reduced the maximum net photosynthetic rate and per-plant biomass by 33%-86% and 35%-71%, respectively. Structural equation modeling revealed that understory radiation indirectly influenced yield by regulating the vapor pressure deficit and net photosynthetic rate (R2 = 0.95). Economic assessments, based on hectare-scaled yield (converted from plot units) and input costs (seedlings, land rental, labor), indicated that the 75% inter-row shading treatment applied from July to October (S-75) was optimal, generating a net annual income of 56,924.5 USD & centerdot;ha-1. This study provides a theoretical basis for the understory cultivation of E. pubescens.

Based on extensive research into the current status of understory medicinal herb cultivation and an in-depth analysis of existing problems, this study proposes policy and technical recommendations to promote sustainable and high-quality development. The research team conducted field investigations in advantageous cultivation regions across seven provinces(autonomous regions), including Guangxi, Yunnan, Fujian, and Jilin, supplemented by policy reviews and literature analysis. The findings reveal that although understory medicinal herb cultivation benefits from ecological advantages and policy support, it still faces a series of problems, such as an underdeveloped service system, insufficient regulatory capacity, low market alignment, and immature technical systems. It should be particularly noted that understory cultivation commonly encounters specific challenges, including the economic dilemma of high input and low output, mismatches between forest canopy density and the light requirements of medicinal plants, ambiguous boundaries between ecological protection and utilization in policy implementation, and weak research support, leading to high trial-and-error costs in technology adoption. The following development recommendations are proposed:(1) establish a coordination mechanism between forestry and traditional Chinese medicine authorities to integrate planning and policy synergy;(2) enhance the alignment of understory medicinal herb cultivation with market demand;(3) develop an independent technical system and standards for understory medicinal herb cultivation, such as establishing a variety suitability framework based on canopy density classification and ecological cultivation protocols;(4) strengthen research focused on industrial development, with priority given to large-scale plantations(e.g., pine and fir forests), dual-purpose food-medicine species(Polygonatum, Gastrodia elata), vine species, and intercropping effects;(5) establish a quality certification system and corresponding regulatory framework for understory-cultivated medicinal materials to promote premium pricing;(6) improve land-use policies and supporting infrastructure, clarifying utilization rights for different forest types and simplifying approval procedures for temporary facilities.

IntroductionThe sustainable utilization of traditional Chinese medicine resources highlights the dual ecological and economic value of cultivating Epimedium pubescens in forest understories. Nevertheless, the spatiotemporal dynamics of its photosynthetic physiology and the primary regulatory factors under varying tree canopy conditions remain insufficiently characterized.MethodsThis study examined the physiological responses of E. pubescens story by monitoring its photosynthetic traits and key environmental factors across three artificial forest types (Phellodendron amurense, Phoebe zhennan, and Camptotheca acuminata) during the growing season (April–December), with plants assessed at different planting positions (inter-row vs. under-canopy). analyze.ResultsThe results showed that spatiotemporal differences in the understory microenvironment were regulated by canopy characteristics and stand density, with solar radiation being the key factor driving spatial variation. Diurnal dynamics of net photosynthetic rate (Pn) and stomatal conductance (gs) showed significant spatial differences across the three forest stands. At the monthly scale, photosynthetic characteristics varied by tree species: in P. zhennan forests, Pn of inter-row plants was significantly higher than that of under-canopy plants throughout the growing season; in P. amurense and C. acuminata forests, significant positional differences in gs occurred in autumn and summer. Variance decomposition and structural equation modeling further revealed that Pn was primarily driven by solar radiation at both diurnal (R² = 0.524) and seasonal scales (independent explanatory rate 34.3%), while gs was mainly regulated by vapor pressure deficit at the diurnal scale and by air humidity at the seasonal scale (β = 0.49.DiscussionThis study provides a physiological and ecological basis for canopy light transmittance regulation and precision cultivation of E. pubescens and similar crops under artificial forests.

Clarifying the two-dimensional spatial distribution and the seasonal yield dynamics of Epimedium pubescens roots in agroforestry systems can provide an ecological theoretical basis and technical support for optimizing the understory cultivation patterns of E. pubescens. E. pubescens plants cultivated in Ginkgo biloba forests(YX), Phellodendron amurense forests(HB), and monocropping fields(CK) were taken as research subjects. Stratified sampling was conducted during the summer and winter harvest seasons to analyze root spatial distribution, morphological characteristics, and biomass allocation. Additionally, high-performance liquid chromatography(HPLC) was employed to determine the total flavonol glycoside content. The results demonstrated that the spatial distribution of E. pubescens roots exhibited significant differences among planting patterns. Specifically, the HB group showed a significantly higher proportion of fine roots in the surface soil layer(0-10 cm) than the YX and CK groups, whereas the YX group displayed more extensive root distribution in deeper soil layers(30-50 cm) than the HB and CK groups. The root morphology of E. pubescens was significantly influenced by planting patterns and seasonal variations. In summer, the root length density of E. pubescens in the YX group decreased by 56%-75%(P<0.05) in the 0-20 cm soil layer compared with that in the CK group, whereas in winter, both agroforestry systems showed significantly higher root length density than the CK group. No significant difference was observed in aboveground or belowground biomass of E. pubescens among different planting patterns. However, the YX group exhibited significantly higher root biomass allocation ratio and significantly lower rhizome biomass allocation ratio than the CK and HB groups. These findings indicate that E. pubescens roots exhibit remarkable phenotypic plasticity, enabling adaptive adjustment strategies to enhance resource acquisition efficiency in agroforestry systems.

Understory planting of medicinal plants is a new planting mode that connects Chinese herbal medicine(CHM)with forest resources.The complex and variable understory environmental factors will inevitably affect the yield and quality of understory CHM.This research summarized the research progress on understory planting of medicinal plants based on forest types and environmental factors within the forest from the perspectives of understory light,air temperature and humidity,soil characteristics,and the interaction between crops within the forest.The results showed that the complex and variable light,temperature and humidity,and soil factors(such as fertility,acidity and alkalinity,and microorganisms)under the forest could affect the yield and quality of medicinal plants to varying degrees through physiological activities such as photosynthesis and respiration,resulting in a significant increase or decrease in yield and quality compared to open field cultivation.In addition,the competition or mutual benefit between different crops within the forest could lead to differences in the yield and quality of understory medicinal plants compared to open field cultivation.A reasonable combination of planting could achieve resource sharing and complementary advantages.Therefore,conducting systematic research on the effects of understory environmental factors on the yield and content of medicinal plants with different growth and development characteristics can provide theoretical guidance and technical references for formulating comprehensive strategies for understory planting of medicinal plants,such as selecting suitable medicinal plant varieties,optimizing planting density,and conducting reasonable forest management,thus contributing to the sustainable development and ecological protection of CHM.

Short rotation plantation forestry (SRF) is being widely adopted to increase wood production, in order to meet global demand for wood products. However, to ensure maximum gains from SRF, optimised management regimes need to be established by integrating robust predictions and an understanding of mechanisms underlying tree growth. Hybrid ecophysiological models, such as potentially useable light sum equation (PULSE) models, are useful tools requiring minimal input data that meet the requirements of SRF. PULSE models have been tested and calibrated for different evergreen conifers and broadleaves at both juvenile and mature stages of tree growth with coarse soil and climate data. Therefore, it is prudent to question: can adding detailed soil and climatic data reduce errors in this type of model? In addition, PULSE techniques have not been used to model deciduous species, which are a challenge for ecophysiological models due to their phenology. This study developed a PULSE model for a clonal Populus tomentosa plantation in northern China using detailed edaphic and climatic data. The results showed high precision and low bias in height (m) and basal area (m2 center dot ha-1) predictions. While detailed edaphoclimatic data produce highly precise predictions and a good mechanistic understanding, the study suggested that local climatic data could also be employed. The study showed that PULSE modelling in combination with coarse level of edaphic and local climate data resulted in reasonably precise tree growth prediction and minimal bias.

Elucidating the effects of understory environmental factors on the yield and active constituent content of medicinal plants is essential for standardizing understory cultivation techniques in medicinal plant production. This study focused on Epimedium pubescens cultivated under forest canopies. By dynamically monitoring understory environmental factors across three plantations(Phellodendron amurense, Camptotheca acuminata, and Phoebe zhennan) and open-field cultivation(CK), this study assessed variations on different spatial scales(varying forest stands and understory positions) and temporal scales. Dynamic sampling and analysis of E. pubescens yields and flavonol glycoside content were conducted, elucidating the dynamic variation characteristics and influencing factors of both the yield and active constituent content of E. pubescens in understory cultivation. The results demonstrated that:(1)The spatial variations in understory environmental factors depended on tree species characteristics and stand density, while maintaining consistent patterns across temporal scales.(2)The yields of E. pubescens and the total flavonol glycoside content in the inter-row space of the three plantations were comparable to those of CK, while the yield of E. pubescens in the inter-row space increased by 90%(P. amurense), 101%(C. acuminata), and 107%(P. zhennan), respectively, compared with that under the canopy.(3)Understory air humidity was the environmental factor contributing most significantly to the yield formation of E. pubescens. The harvest yield could be quantitatively expressed by an exponential function of air humidity(y=0.167 7e~(0.072 4x), P<0.05, R~2=0.45). These findings provide theoretical guidance and technical support for the understory cultivation of E. pubescens and similar medicinal plants.

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Severe soil desiccation in mature forests has been discovered in many water-stressed regions around the world, threatening sustainable forest development. Only by understanding fine root distributions and root water uptake patterns of different forest stands can we timely deal with the severe water stress in tree growth. During the 2019 growing season, we repeated isotopic and soil water content sampling for four Populus tomentosa stands in the North China Plain (two young stands with lower-or higher-competition structure, and two mature stands with lower-or higher-competition structure), and fine root sampling was performed at the end of the growing season. The hydrogen-oxygen stable isotope method and the Bayesian mixture model were used to determine root water uptake patterns. The findings revealed that stand age had no effect on fine root distributions in the 0-2 m profile. However, P. tomentosa became more reliant on the deeper soil water with stand development. The stand structure did not affect fine root distributions of young stands but significantly affected that of mature stands. Regardless of developmental stage, the higher-competition structure would increase trees' relative water uptake from the middle layers. However, this increase was at the expense of a decrease in the relative water uptake from shallow layers during the young stage and from deep layers during the mature stage. Furthermore, we discovered that the groundwater level in this area may have dropped to an extent that groundwater cannot provide sufficient water supply for P. tomentosa. This study clearly shows that fine root distribution patterns cannot be used to replace root water uptake patterns. In addition, the findings of this article will serve as a theoretical foundation for sustainable forest management in fast-growing plantations in other water-stressed areas around the world.

Gynostemma is an important medicinal and food plant of the Cucurbitaceae family. The phylogenetic position of the genus Gynostemma in the Cucurbitaceae family has been determined by morphology and phylogenetics, but the evolutionary relationships within the genus Gynostemma remain to be explored. The chloroplast genomes of seven species of the genus Gynostemma were sequenced and annotated, of which the genomes of Gynostemma simplicifolium, Gynostemma guangxiense and Gynostemma laxum were sequenced and annotated for the first time. The chloroplast genomes ranged from 157,419 bp (Gynostemma compressum) to 157,840 bp (G. simplicifolium) in length, including 133 identical genes: 87 protein-coding genes, 37 tRNA genes, eight rRNA genes and one pseudogene. Phylogenetic analysis showed that the genus Gynostemma is divided into three primary taxonomic clusters, which differs from the traditional morphological classification of the genus Gynostemma into the subgenus Gynostemma and Trirostellum. The highly variable regions of atpH-atpL, rpl32-trnL, and ccsA-ndhD, the repeat unilts of AAG/CTT and ATC/ATG in simple sequence repeats (SSRs) and the length of overlapping regions between rps19 and inverted repeats(IRb) and between ycf1 and small single-copy (SSC) were found to be consistent with the phylogeny. Observations of fruit morphology of the genus Gynostemma revealed that transitional state species have independent morphological characteristics, such as oblate fruit and inferior ovaries. In conclusion, both molecular and morphological results showed consistency with those of phylogenetic analysis.

Exploring the relationships between water uptake, fine root, and soil water is essential for many fields, such as plant physiology, ecological hydrology, and water conservancy. In four Populus tomentosa stands with different ages (young and mature) and stand structures (low and high stand density), we matched root water uptake patterns obtained from stable isotope techniques with fine root and soil water distributions, respectively. The effects of soil water content and meteorological factors on these matching degrees were further explored. Increased competition intensity within a stand would suppress the matching degree between fine root distribution and water uptake pattern (MFR), but have little effect on the matching degree between soil water distribution and water uptake pattern (MSR). Additionally, water uptake pattern was closer to soil water distribution (average MSR were 0.89) than to fine root distribution in mature stands (average MFR were 0.68), while water uptake pattern matched both fine root and soil water distribution closely in young stands (average MFR and MSR were 0.89 and 0.83). There is a relatively high positive or negative correlation between MFR and MSR in all four stands. Compared with the direct effect of soil water content, the influence of meteorological factors on matching degrees was weak. The results indicate that the expression of water uptake function of the young stand depends on a combination of root structure and available water resources, while the water uptake function of mature stands is driven more by available water resources rather than root structure.

以陕西安康平利县"八道"种源长梗绞股蓝为试验材料,采用珍珠岩、泥炭、园土、河沙、蛭石基质为原料按一定配比设置8种基质处理.通过定期或连续测定不同处理基质特性(总孔隙度、持水孔隙度、通气孔隙度)、扦插苗生根(起始萌根时间、生根率)及萌芽生长(萌芽长度、展叶数、生物量)特性、根系形态特征(根平均直径、根总表面积、根总长、根总体积)与叶片生理生态特征(比叶质量、Pn、Gs、Tr、Ci),以明确不同基质处理下长梗绞股蓝扦插过程生根萌芽动态变化的特征,探究基质物理性质对其影响机制,并初步筛选出适宜扦插基质及最佳移栽时间范围.结果表明:在扦插第24天T2(泥炭)处理萌芽长度显著高于其他处理(P＜0.05),根总长、根总表面积、根总体积等值最高,且根总长、根总表面积显著高于不含泥炭的试验处理(P＜0.05).在此基础上,又发现扦插苗比根长、根组织密度和萌芽长度均与基质总孔隙度显著相关(P＜0.05,R2＞0.95),且萌芽长度与比根长和根组织密度也显著相关(P＜0.05,R2=0.99).综上所述,长梗绞股蓝扦插生根萌芽相互影响,而基质总孔隙度是显著影响根和叶生长的主要因素,较高总孔隙度的基质应用有助于缩短扦插繁殖时间,而该研究中泥炭可作为长梗绞股蓝扦插最佳基质,且扦插第12～24天适宜移栽.

Understanding the relationship between trunk sap flow and tree diameter is crucial for tree-stand transpiration upscaling and sap flow measurement strategy design, because of well-known tree-to-tree variations in sap flow metrics. However, whether and how this relationship will vary intra-and inter-annually, and the underlying mechanisms, are still poorly understood. We measured the sap flow of 126 trees throughout a six-year experi-ment (2016-2021) in a temperate poplar (Populus tomentosa) forest with five irrigation management regimes. Simultaneously, we also monitored meteorological factors, leaf area indices, and soil water contents. There was a great variability of both sap flux (SF) and sap flux density (SFD) across trees, and this variability tended to be larger in older stands. Patterns of the relationships between SF, SFD, and diameter at breast height (DBH) changed markedly from year to year. A nonlinear positive correlation (P < 0.001) between SF and DBH was found, except in 2016 when canopy closure did not occur. In contrast, no correlations between SFD and DBH were observed in most years, but their correlations became positive and linear in two wet years (2018, 2021) (P < 0.05). The power (Q) of DBH to explain tree-to-tree sap flow variations exhibited enormous change on both intra-and inter-annual scales, underpinned by different mechanisms. The potential transpiration demand of trees mainly determined the intra-annual variation of Q, but its effect depended on stand development, whereas the environmental water supply mostly controlled the inter-annual variation of Q. Based on these results, we provide some recommendations on sap flow measurement and stand transpiration estimation for pure tree plantations in water-limited regions. Our findings should assist the accurate prediction of stand water use in plantation forests of both poplar and other tree species.

Introduction:Fine roots are the critical functional organs of plants to absorb water and nutrients from the soil environment, while the relation between fine root morphological characteristics and yield & quality has received less attention for medicinal plants. Methods:Therefore, we investigated the relationship between fine root morphological characteristics and biomass & gypenosides content. We explored the primary environmental drivers of fine root indicators for Gynostemma longipes from three provenances cultivated at two altitude habitats. Results:At the end of the growing season, compared with the low-altitude habitat, the underground biomass of G. longipes in the high-altitude habitat increased significantly by 200%~290% for all three provenances. The response of gypenosides content to different altitude habitats varied with provenance and plant organs. The biomass of G. longipes strongly depended on the fine root characteristic indicators (P < 0.001), fine root length density, and fine root surface area. Our results also showed that the harvest yield of G. longipes could be effectively increased by promoting the growth of fine roots per unit leaf weight (P < 0.001, R2 = 0.63). Both fine root length density and fine root surface area had strong positive correlations with soil nutrient factors (R2 > 0.55) and a strong negative correlation with soil pH (R2 > 0.48). In a word, the growth of G. longipes is strongly controlled by the fine root morphological characteristics through the response of fine roots to soil nutrient factors and pH. Discussion:Our findings will help to deepen the understanding of the root ecophysiological basis driven by soil factors for the growth and secondary metabolites formation of G. longipes and other medicinal plants under changing habitat conditions. In future research, we should investigate how environmental factors drive plant morphological characteristics (e.g., fine roots) to affect the growth & quality of medicinal plants over a longer time scale.

Understanding the long-term variations of stand water balance and carbon stocks under different water inputs is crucial for sustainable forest management under climate change. However, due to the lack of in-situ data, how forest plantations respond to variation in water inputs during stand development remains poorly understood. We varied water inputs with distinct irrigation amounts and measured the water-balance components, carbon stock growth, and water productivity during a whole rotation (2015-2019) in poplar plantations. Furthermore, in 2020, soil water contents in our stand and an adjacent 37-year-old poplar plantation were measured. Under rainfed conditions, soil water storage of different layers decreased greatly year by year, especially at the 2-3 m depth, such that transpiration was curtailed in 2019, a dry year. By 2019, the 0-2 m depth layer became periodically dried, and the 2-3 m was persistently dried, which was further confirmed by observations in 2020. Additionally, serious soil desiccation occurred throughout the 0-6 m soil depth in the 37-year-old poplar stand. Increasing the water inputs avoided stand water stress and decreased the drying rate of the deep soil. Furthermore, the highest water inputs treatment brought great increases in groundwater recharge, carbon stock growth, and water productivity. This treatment also led to 67% higher soil water storage in the 0-1 m soil layer and 23% higher soil water storage in the 1-6 m layer by the end of 2019, as compared to the rainfed treatment. However, these advantages were small or disappeared if the water inputs were insufficient. Our findings will be helpful to predict water relations and facilitate sustainable forest management under climate change in water-limited regions.

Prenylated flavonol glycosides in Epimedium plants, as key medicinal components, are known to have great pharmaceutical activities for human health. Among the main prenylated flavonol glycosides, the modification mechanism of different sugar moieties is still not well understood. In the current study, a novel prenylated flavonol rhamnoside xylosyltransferase gene (EpF3R2″XylT) was cloned from E. pubescens, and the enzymatic activity of its decoding proteins was examined in vitro with different prenylated flavonol rhamnoside substrates and different 3-O-monosaccharide moieties. Furthermore, the functional and structural domains of EpF3R2″XylT were analyzed by bioinformatic approaches and 3-D protein structure remodeling. In summary, EpF3R2″XylT was shown to cluster with GGT (glycosyltransferase that glycosylates sugar moieties of glycosides) through phylogenetic analysis. In enzymatic analysis, EpF3R2″XylT was proven to transfer xylose moiety from UDP-xylose to prenylated flavonol rhamnoside at the 2″-OH position of rhamnose. The analysis of enzymatic kinetics showed that EpF3R2″XylT had the highest substrate affinity toward icariin with the lowest Km value of 75.96 ± 11.91 mM. Transient expression of EpF3R2″XylT in tobacco leaf showed functional production of EpF3R2″XylT proteins in planta. EpF3R2″XylT was preferably expressed in the leaves of E. pubescens, which is consistent with the accumulation levels of major prenylflavonol 3-O-triglycoside. The discovery of EpF3R2″XylT will provide an economical and efficient alternative way to produce prenylated flavonol trisaccharides through the biosynthetic approach.

Stomatal conductance (g(s)) is the main limiting factor for photosynthesis and is sensitive to plant water status. Accurately assessing the behavior of g(s) under water deficit stress is essential to model plants carbon and water flux, which govern vegetation biomass production and dynamics. However, direct measurement of g(s) with gas exchange analyzer can be time-consuming and laborious, especially under field conditions, thus constraining the data availability for validating the modeling outcome. This difficulty can be solved if measurement of g(s) is automated. Here, we report on dynamics of g(s) and the maximum (g(smax)) of Populus tomentosa, derived from automatically recorded meteorological variables and sap flux density (J(s)) and turgor pressure sensors outputs (Z) measured in three P. tomentosa trees from a short-rotation plantation subjected to different water stress levels along a whole growing season. The simulated g(smax) was related to aboveground (ABM) and underground biomass (UBM) increase by leaf area. J(s) and Z were continuously measured using sap flow and ZIM sensors. Our results showed that the sensitivity of J(s) to air vapor deficit (D) (i.e. J(s)/D) correlated well with g(s), and the sensitivity of Z to D (i.e. dZ/dD) was well coupled with g(smax). In addition, the ABM increase was linearly aligned with simulated g(smax) multiplied by leaf area (LA) (R-2 > 0.7). Also, increment in UBM was significantly correlated with simulated g(smax) * LA across all observed trees, being the best described by a logistic function (R-2 > 0.7). We conclude that g(s) can be well simulated through automatic monitoring of J(s) and Z for different meteorological and soil water content conditions. Moreover, the simulated g(smax) was also closely related to biomass production both above and underground, which opens the possibility for using it to manage irrigation in smart agriculture and forestry in the future.