Vein Density Research Articles

Preserving the cerebellar hemispheric tentorial bridging veins through a novel tentorial cut technique for supracerebellar approaches.

The objective of this study was to describe the distribution pattern of cerebellar hemispheric tentorial bridging (CHTB) veins on the tentorial surface in a case series of perimedian or paramedian supracerebellar approaches and to describe a novel technique to preserve these veins. A series of 141 patients with various pathological processes in different locations was operated on via perimedian or paramedian supracerebellar approaches by the senior author from July 2006 through October 2022 and was retrospectively evaluated. During surgery, the number and locations of all CHTB veins were recorded to establish a distribution map on the tentorial surface, divided into nine zones. Patients were classified into four groups according to the surgical technique used to manage CHTB veins: 1) group 1 consisted of CHTB veins preserved without intervention during surgery or no CHTB veins found in the surgical route; 2) group 2 included CHTB veins coagulated during surgery; 3) group 3 included CHTB veins preserved with arachnoid and/or tentorial dissection from the cerebellar or tentorial surface, respectively; and 4) group 4 comprised CHTB veins preserved using a novel tentorial cut technique. Overall, 141 patients were included in the study. Of these 141 patients, 38 were in group 1 (27%), 32 in group 2 (22.7%), 47 in group 3 (33.3%), and 24 in group 4 (17%). The total number of CHTB veins encountered was 207 during surgeries on one side. According to the distribution zones of the tentorium, zone 5 had the highest density of CHTB veins, while zone 7 had the lowest. Of the patients in group 4, 6 underwent the perimedian supracerebellar approach and 18 had the paramedian supracerebellar approach. There were 39 CHTB veins on the surface of the 24 cerebellar hemispheres in group 4. The tentorial cut technique was performed for 27 of 39 CHTB veins. Twelve veins were not addressed because they did not present any obstacles during approaches. During surgery, no complications were observed due to the tentorial cut technique. Because there is no way to determine whether a CHTB vein can be sacrificed without complications, it is important to protect these veins in supracerebellar approaches. This new tentorial cut technique in perimedian or paramedian supracerebellar approaches makes it possible to preserve CHTB veins encountered during supracerebellar surgeries.

Anatomical and physiological consequences of beech leaf disease in Fagus grandifolia L.

AbstractBeech leaf disease (BLD) is a foliar disease of American Beech (Fagus grandifolia L.) causally linked to the nematode Litylenchus crenatae mccannii and has rapidly spread throughout central and northeastern North America. This study aimed to characterize the anatomical and physiological differences between asymptomatic and symptomatic leaves to provide evidence for a mechanistic link between abnormal leaf development associated with BLD and the long‐term decline of affected trees. We found that leaf mass per area (LMA) and leaf thickness were 45% and 249% higher in symptomatic regions, respectively. The difference in leaf thickness was largely attributable to the spongy mesophyll being 410% thicker in symptomatic as compared with asymptomatic regions of the leaves, but palisade mesophyll and abaxial epidermal tissues were also thicker in symptomatic regions. While major vein density was not significantly different, minor vein density was significantly lower in symptomatic regions, suggesting that the effects on leaf development occur after the formation and initial development of first‐ and second‐order veins. Stomatal density was also lower in symptomatic leaves. Maximum photosynthetic rates were approximately 61% lower in symptomatic leaves and respiration rate increased as the percentage of affected leaf tissue increased. Collectively, our data show reduced photosynthetic capacity, increased respiration rates, and higher leaf construction costs, which will likely have a negative, long‐term impact on the carbon balance of trees affected by BLD.

Correlation of Vein-Rich Tumor Microenvironment of Intrahepatic Cholangiocarcinoma With Tertiary Lymphoid Structures and Patient Outcome

Intrahepatic cholangiocarcinoma (iCCA) is an aggressive cancer composed of large-duct and small-duct types. Understanding the tumor immune microenvironment and its related vascular system is important for developing novel and efficient therapies. We focused on tertiary lymphoid structure (TLS) as a hallmark of antitumor immunity and investigated the clinicopathologic significance of TLSs and the influence of vascular microenvironment on TLS formation in iCCAs. We examined 261 iCCA cases clinicopathologically and analyzed the vascular system using immunohistochemistry. Single-cell (102,685 cells) and bulk RNA (33 iCCA cases) sequencing analyses were performed using data sets downloaded from public databases, and endothelial cell characteristics in iCCA tissues and functional networks related to the tumor microenvironment were bioinformatically examined. High densities of both intratumoral and peritumoral TLSs were significantly associated with prolonged survival only in large-duct-type iCCA. Multivariate analyses showed that peritumoral TLS was a prognostic factor for the large-duct type. TLS-rich iCCA had a significantly higher vein density and tumor-infiltrating T-cell count than TLS-poor iCCA. Both the presence of TLSs and high vein endothelial cells in iCCA tissues were significantly associated with molecular networks representing active immune responses in transcriptomic analysis. Vein density was a prognostic factor in patients with large-duct and small-duct types. This suggests that TLS formation is involved in a microenvironment with high vein density, which represents an antitumor-directed immune microenvironment.

Altitudinal variation pattern in Daphniphyllum macropodum leaf traits and influencing environmental factors in Mao'er Mountain, China

Analyzing the pattern of altitudinal variation in the leaf traits and their networks of a particular tree species of similar age and its influencing factors could contribute to understanding the impacts of environmental factors on leaf traits and excluding the interference of genetic factors. We investigated the stomatal, structural, chemical, and vein traits of Daphniphyllum macropodum leaves in middle-aged forests, following the altitudinal gradient (1100, 1500, and 1900 m) on Mao'er Mountain. The objectives of this study were to reveal patterns in leaf trait and leaf trait networks variation, the life strategy of the tree species, and the major environmental factors affecting the altitudinal variations. The results showed that leaf area, specific leaf area, leaf thickness, leaf dry matter content, chlorophyll content, nitrogen content, phosphorus content, C:N, C:P, vein density, and vein diameter varied significantly across altitudes. Mean annual temperature and total radiation explained 42.1% and 16.2% of leaf-trait variation, respectively. They served as key environmental factors driving the altitudinal variation in leaf traits. Mean annual temperature exhibited the greatest influence on leaf area (R2=0.73), and total radiation exerted the most prominent effect on leaf thickness (R2=0.72). Both relationships were significantly positive. D. macropodum exhibited low leaf nitrogen and phosphorus at the low altitude of 1100 m, and the overall and local trait networks were loose, adopting a conservative resource strategy. At the medium altitude of 1500 m, leaf nutrient contents were relatively high. The overall network of leaf traits was tightly connected and local network was loose. By enhancing the dependency among leaf traits, and improving phosphorus utilization efficiency, D. macropodum could cope with competition in deciduous forests and adopt resource acquisition strategies. Further, at the highest altitude of 1900 m, D. macropodum had relatively large leaf thickness, chlorophyll content, and leaf dry matter content, but relatively small leaf area. The local network connections were tight while the overall network looseness, indicating a resource conserving strategy. The trade-off relationship between C:P and leaf phosphorus content was closely related to phosphorus use efficiency, and its variation was an important indicator for identifying life strategies of D. macropodum in different altitudes.

Leaf Traits of Parashorea malaanonan Along Elevational Gradient in Mount Makiling Forest Reserve, Philippines

Studying leaf trait variation and relationships along elevational gradients will enhance our understanding of how plants respond to changing environmental conditions. Thus, we analyzed the leaf traits variation in ecologically and economically important Parashorea malaanonan and the potential influence of environmental covariables (rainfall, relative humidity, and air temperature) on leaf traits along an elevational gradient in Mount Makiling Forest Reserve (MMFR). Three sampling sites were selected based on elevation, i.e., low (400–500 masl), mid (500–600 masl), and high (> 600 masl). The leaf samples were collected from seedlings, saplings, and adult trees of P. malaanonan. There was no significant variation in most of the measured leaf traits, leaf area (LA), specific leaf area (SLA), leaf thickness (LT), leaf length-to-width ratio (L:W) across sampling sites, except vein density (VD). The SLA and LT at high elevations are significantly and negatively correlated (r2 = 0.7396). The environmental covariables had a significant (p < 0.05) impact on the leaf traits of P. malaanonan. The observed variation in some leaf traits may have been influenced by the elevation gradient and its associated environmental conditions. Thus, P. malaanonan may have developed adaptive mechanisms to cope with the changing environment. Keywords: conservation, elevational gradients, environmental variables, leaf traits, Parashorea malaanonan

Coordination of hydraulic and functional traits in ten species of trees of the Sonoran Desert

Leave’s vein xylem and stomata hydraulic traits should be critically linked to modulating plant responses to drought in leaves of desert species, influencing traits at the whole-plant level and promoting adaptation. We tested for coordination among leaf vein xylem anatomical traits across different hierarchical orders (hydraulic vessel diameter, vein area, free veins per area, areolas per area, total free veins number, total areola number) and stomatal traits (stomatal size, stomatal density, stomatal index, leaf total stomatal area, leaf total stomatal number) as well as their relationship with the leaf area in ten tree species from the Sonoran Desert scrub, Mexico. Moreover, these traits were correlated with other hydraulic and functional traits associated with resource use strategies (hydroscape area, stem-specific density, leaf mass per area, and leaf phenology). Leaf total stomatal area and number were positively associated with vessel diameters at the midrib and with leaf total free terminal veins and areola number, indicating coordination between water transpiration and transport. Also, interspecific differences fit species along a physiological resource use spectrum, following an exploitative vs. conservative physiological axis. Accordingly, species with lower leaf longevity (LL) and foliage duration at the canopy (FD) displayed higher values of stomatal indices and free vein densities, higher stomata density; and anatomical traits related to higher hydraulic conductance and gas exchange in comparison to species with higher LL and FD. Therefore, in this community, species have been selected to take advantage of different temporal hydrological niches to enhance survival under unpredictable and highly seasonal water availability.

How dense can you be? New automatic measures of vein density in angiosperm leaves.

Because of the trade-off between water loss and carbon dioxide assimilation, the conductivity of the transpiration path in a leaf is an important limit on photosynthesis. Closely packed veins correspond to short paths and high assimilation rates while widely spaced veins are associated with higher resistance to flow and lower maximum photosynthetic rates. Vein length per area (VLA) has become the standard metric for comparing leaves with different vein densities; its measurement typically utilizes digital image processing with varying amounts of human input. Here, we propose three new ways of measuring vein density using image analysis that improve on currently available procedures: (1) areole area distributions, (2) a sizing transform, and (3) a distance map. Each alternative has distinct practical, statistical, and biological limitations and advantages. In particular, we advocate the log-transformed modal distance map of a vein mask as an estimator to replace VLA as a standard metric for vein density. These methods, for which open-source code appropriate for high-throughput automation is provided, improve on VLA by producing determinate measures of vein density as distributions rather than point estimates. Combined with advances in image quality and computational efficiency, these methods should help clarify the physiological and evolutionary significance of vein density.

Teasing out elevational trends in infraspecific Prunus taxa: A vein analysis approach.

Using 33 specimens collected from across their range in Turkey, we demonstrate that the subspecies of Prunus microcarpa C.A.Mey react very differently to altitude. We first outline a simplified, flexible protocol for sectioning and removing the epidermis of small, difficult-to-image leaves for leaf vein studies. We then used venation analysis software to evaluate the two subspecies of this wild cherry in relation to altitude. We also found key differences in venation features between short-shoot and long-shoot leaves for each taxon. Differences include statistically significant negative correlation between vein density, and positive correlation between areole area and altitude in long-shoot leaves of Prunus microcarpa subsp. microcarpa, while its short-shoot leaves had a positive relationship between maximum areole area, and negative relationship between vein density, numbers of veins and endpoints. Meanwhile, P. microcarpa subsp. tortuosa (Boiss. & Hausskn.) Browicz recorded trends that were largely opposite of this, but beside vein thickness and areole area, were not statistically significant. This difference may be part of each taxon's overarching syndrome of anatomical and morphological adaptations to its external environment. RESEARCH HIGHLIGHTS: Features of vein density and thickness fell, while areole area and vein length rose with altitude in P. microcarpa. P. microcarpa subsp. tortuosa showed opposite trends, but reacted less strongly to altitude. Short-shoot and long-shoot have significantly different venation parameters. Using sections proportionate to leaf size is useful to compare venation of leaves that vary due to dimorphism. We discuss protocol strategies for imaging of difficult leaves for venation analyses.

Effect of leaf phenology and morphology on the coordination between stomatal and minor vein densities.

Leaf phenology (evergreen vs. deciduous) and morphology (simple vs. compound) are known to be related to water use strategies in tree species and critical adaptation to certain climatic conditions. However, the effect of these two traits and their interactions on the coordination between minor vein density (MVD) and stomatal density (SD) remains unclear. In this study, we examined the leaves of 108 tree species from plots in a primary subtropical forest in southern China, including tree species with different leaf morphologies and phenologies. We assessed nine leaf water-related functional traits for all species, including MVD, SD, leaf area (LA), minor vein thickness (MVT), and stomatal length (SL). The results showed no significant differences in mean LA and SD between either functional group (simple vs. compound and evergreen vs. deciduous). However, deciduous trees displayed a significantly higher mean MVD compared to evergreen trees. Similarly, compound-leaved trees have a higher (marginally significant) MVD than simple-leaved trees. Furthermore, we found that leaf morphology and phenology have significantly interactive effects on SL, and the compound-leafed deciduous trees exhibited the largest average SL among the four groups. There were significant correlations between the MVD and SD in all different tree groups; however, the slopes and interceptions differed within both morphology and phenology. Our results indicate that MVD, rather than SD, may be the more flexible structure for supporting the coordination between leaf water supply and demand in different leaf morphologies and phenologies. The results of the present study provide mechanistic understandings of the functional advantages of different leaf types, which may involve species fitness in community assembly and divergent responses to climate changes.

Nutrient resorption responses of female and male Populus cathayana to drought and shade stress.

Nutrient resorption can increase nutrient use and play important roles in terrestrial plant nutrient cycles. Although several studies have reported individual responses of plant nutrient resorption to drought or shade stress, the interaction of drought and shade remains unclear, especially for dioecious plants. This study explored whether nutrient resorption is correlated to growth characteristics (such as biomass and root/shoot ratio [R/S ratio]) and leaf economics (such as leaf thickness, leaf mass per area [LMA] and leaf vein density [LVD]) in female and male Populus cathayana across different conditions. We found that drought stress significantly increased nitrogen (N) resorption efficiency (NRE) in both sexes, but shade and interactive stress decreased NRE in P. cathayana females. Under drought stress, nutrient resorption was sexually dimorphic such that P. cathayana males have higher NRE than females. Furthermore, NRE and phosphorous (P) resorption efficiency (PRE) were positively related to R/S ratio, leaf thickness, LMA, and LVD in both sexes across different treatments. Our study is the first to present how nutrient resorption is related to biomass accumulation and allocation, and leaf economics, suggesting that nutrient uptake may be modulated by R/S ratio and leaf economics, which is important for understanding the conservation mechanism of plant nutrients.

A rapid method to quantify vein density in C4 plants using starch staining.

C4 photosynthesis has evolved multiple times in the angiosperms and typically involves alterations to the biochemistry, cell biology and development of leaves. One common modification found in C4 plants compared with the ancestral C3 state is an increase in vein density such that the leaf contains a larger proportion of bundle sheath cells. Recent findings indicate that there may be significant intraspecific variation in traits such as vein density in C4 plants but to use such natural variation for trait-mapping, rapid phenotyping would be required. Here we report a high-throughput method to quantify vein density that leverages the bundle sheath-specific accumulation of starch found in C4 species. Starch staining allowed high-contrast images to be acquired permitting image analysis with MATLAB- and Python-based programmes. The method works for dicotyledons and monocotolydons. We applied this method to Gynandropsis gynandra where significant variation in vein density was detected between natural accessions, and Zea mays where no variation was apparent in the genotypically diverse lines assessed. We anticipate this approach will be useful to map genes controlling vein density in C4 species demonstrating natural variation for this trait.

Integrated global analysis in spider flowers illuminates features underlying the evolution and maintenance of C4 photosynthesis.

The carbon concentrating mechanism-C4 photosynthesis-represents a classic example of convergent evolution, but how this important trait originated and evolved remains largely enigmatic. The spider flower Gynandropsis gynandra is a valuable leafy vegetable crop and medicinal plant that has also been recognized as a C4 model species. Here we present a high-quality chromosome-scale annotated genome assembly of G. gynandra through a combination of Oxford Nanopore Technology (ONT), HiFi and Hi-C technology. The 17 super-scaffolds cover 98.66% of the estimated genome (997.61Mb), with a contig N50 of 11.43Mb and a scaffold N50 of 51.02Mb. Repetitive elements occupy up to 71.91% of its genome, and over half are long terminal repeat retrotransposons (LTR-RTs) derived from recent bursts, contributing to genome size expansion. Strikingly, LTR-RT explosion also played a critical role in C4 evolution by altering expression features of photosynthesis-associated genes via preferential insertion in promoters. Integrated multiomics analyses of G. gynandra and the ornamental horticulture C3 relative Tarenaya hassleriana reveal that species-specific whole-genome duplication, gene family expansion, recent LTR-RT amplification, and more recent tandem duplication events have all facilitated the evolution of C4 photosynthesis, revealing uniqueness of C4 evolution in the Cleome genus. Moreover, high leaf vein density and heat stress resilience are associated with shifted gene expression patterns. The mode of C3-to-C4 transition found here yields new insights into evolutionary convergence of a complex plant trait. The availability of this reference-grade genomic resource makes G. gynandra an ideal model system facilitating efforts toward C4-aimed crop engineering.

Diurnal Regulation of Leaf Photosynthesis Is Related to Leaf-Age-Dependent Changes in Assimilate Accumulation in Camellia oleifera.

In order to clarify the mechanism of diurnal changes in photosynthesis of leaves of different leaf ages in Camellia oleifera, current-year leaves (CLs) and annual leaves (ALs) were used as the test materials to analyze the diurnal changes in photosynthetic parameters, assimilate contents and enzyme activities, as well as structural differences and expression levels of sugar transport regulating genes. The rate of net photosynthesis in CLs and ALs was highest in the morning. During the day, there was a decrease in the CO2 assimilation rate, and this decrease was greater in ALs than in CLs at midday. The maximal efficiency of photosystem II (PSII) photochemistry (Fv/Fm) showed a decreasing trend as the sunlight intensity increased, but no significant difference between CLs and ALs was found. Compared with CLs, ALs showed a greater decrease in the carbon export rate at midday and the levels of sugars and starch increased significantly in ALs, accompanied by higher enzyme activity of sucrose synthetase and ADP-glucose pyrophosphorylase. In addition, compared with CLs, ALs had a larger leaf vein area and higher leaf vein density, as well as higher expression levels of sugar transport regulating genes during the day. It is concluded that the excessive accumulation of assimilate is an important factor contributing to the midday depression of photosynthesis in Camellia oleifera annual leaves on a sunny day. Sugar transporters may play an important regulatory role in excessive accumulation of assimilate in leaves.

Adaptation strategies of leaf traits and leaf economic spectrum of two urban garden plants in China

BackgroundPrevious studies of the relationships between traits have focused on the natural growth conditions of wild plants. Urban garden plants exhibit some differences in plant traits due to environmental interference. It is unknown whether the relationships between the leaf traits of urban garden plants differ under distinct climates. In this study, we revealed the variation characteristics of the leaf functional traits of trees, shrubs, and vines in two urban locations. Two-way ANOVA was used to reveal the response of plant leaf traits to climate and life forms. Pearson correlation analysis and principal component analysis were used to calculate the correlation coefficient between the leaf functional traits of plants at the two locations.ResultsLeaf dry matter content (LDMC) and vein density (VD) of different life forms in Mudanjiang were higher than those in Bozhou (P < 0.05), and the relative water content (RWC) in Bozhou was higher, whereas vein density (VD) of trees and shrubs in the two urban locations was significant (P < 0.05), but the vines were not significant. The photosynthetic pigments of tree and shrub species were larger in Mudanjiang, but the opposite was true for the vines. Both leaf vein density (VD) and stomatal density (SD) showed a very significant positive correlation in the two urban locations (P < 0.01), and both were significantly positively correlated with specific leaf area (SLA) (P < 0.05); and negatively correlated with leaf thickness (LT), and the relationship between pigment content were closer.ConclusionThe response to climate showed obvious differences in leaf traits of different life forms species in urban area, but the correlations between the traits showed convergence, which reflects that the adaptation strategies of garden plant leaves to different habitats are both coordinated and relatively independent.

Foliar Phenotypic Plasticity Reflects Adaptation to Environmental Variability.

Arabidopsis thaliana ecotypes adapted to native habitats with different daylengths, temperatures, and precipitation were grown experimentally under seven combinations of light intensity and leaf temperature to assess their acclimatory phenotypic plasticity in foliar structure and function. There were no differences among ecotypes when plants developed under moderate conditions of 400 µmol photons m-2 s-1 and 25 °C. However, in response to more extreme light or temperature regimes, ecotypes that evolved in habitats with pronounced differences in either the magnitude of changes in daylength or temperature or in precipitation level exhibited pronounced adjustments in photosynthesis and transpiration, as well as anatomical traits supporting these functions. Specifically, when grown under extremes of light intensity (100 versus 1000 µmol photons m-2 s-1) or temperature (8 °C versus 35 °C), ecotypes from sites with the greatest range of daylengths and temperature over the growing season exhibited the greatest differences in functional and structural features related to photosynthesis (light- and CO2-saturated capacity of oxygen evolution, leaf dry mass per area or thickness, phloem cells per minor vein, and water-use efficiency of CO2 uptake). On the other hand, the ecotype from the habitat with the lowest precipitation showed the greatest plasticity in features related to water transport and loss (vein density, ratio of water to sugar conduits in foliar minor veins, and transpiration rate). Despite these differences, common structure-function relationships existed across all ecotypes and growth conditions, with significant positive, linear correlations (i) between photosynthetic capacity (ranging from 10 to 110 µmol O2 m-2 s-1) and leaf dry mass per area (from 10 to 75 g m-2), leaf thickness (from 170 to 500 µm), and carbohydrate-export infrastructure (from 6 to 14 sieve elements per minor vein, from 2.5 to 8 µm2 cross-sectional area per sieve element, and from 16 to 82 µm2 cross-sectional area of sieve elements per minor vein); (ii) between transpiration rate (from 1 to 17 mmol H2O m-2 s-1) and water-transport infrastructure (from 3.5 to 8 tracheary elements per minor vein, from 13.5 to 28 µm2 cross-sectional area per tracheary element, and from 55 to 200 µm2 cross-sectional area of tracheary elements per minor vein); (iii) between the ratio of transpirational water loss to CO2 fixation (from 0.2 to 0.7 mol H2O to mmol-1 CO2) and the ratio of water to sugar conduits in minor veins (from 0.4 to 1.1 tracheary to sieve elements, from 4 to 6 µm2 cross-sectional area of tracheary to sieve elements, and from 2 to 6 µm2 cross-sectional area of tracheary elements to sieve elements per minor vein); (iv) between sugar conduits and sugar-loading cells; and (v) between water conducting and sugar conducting cells. Additionally, the proportion of water conduits to sugar conduits was greater for all ecotypes grown experimentally under warm-to-hot versus cold temperature. Thus, developmental acclimation to the growth environment included ecotype-dependent foliar structural and functional adjustments resulting in multiple common structural and functional relationships.

Adaptive diversity in structure and function of C4 photosynthetic components.

Many tropical and subtropical plant lineages have independently evolved C4 photosynthesis. The convergent evolution of this complex functional trait from different ancestors is reflected in variations in the structural and biochemical characteristics of C4 components such as enzymes and cellular specializations. The mechanism of C4 carbon concentration mostly involves coordinated function of mesophyll and bundle sheath cells. Important adaptations of the C4 syndrome include increased vein density and the development of photosynthetic bundle sheath cells with low gas conductance. In addition, the enzymes and transporters of the C4 pathway evolved via the co-option of multiple genes, each derived from a specific lineage of isoforms present in nonC4-ancestors. In particular, the adaptation of C4 enzymes resulted in a variety of structural and biochemical modifications, generally leading to increased catalytic efficiency and regulation by metabolites and post-translational modifications. Differences in these adaptations are particularly evident in the C4-acid decarboxylation step, which can be catalyzed by three decarboxylases that define the C4 subtypes. Associated with the biochemical subtypes, there are also differences in the extend of grana staking and localization of bundle sheath cells chloroplasts. The presence of a suberin layer and symplastic connections also likely vary among the different C4-subtypes. This review examines the current understanding of the diversity of structural and functional changes in key components of the C4 carbon concentration mechanism. This knowledge is necessary not only to identify divergent solutions for convergent optimization of C4 components in different C4 lineages, but also to guide their creation for rational synthetic biology approaches.

Vein density in C4 and C3 leaves: One step closer to understanding the molecular genetic basis.

Vein density in C4 and C3 leaves: One step closer to understanding the molecular genetic basis.

Petal Morphology Is Correlated with Floral Longevity in Paeonia suffruticosa

Floral longevity (FL) is an important floral functional trait which is critical for flowering plants. FL shows great diversity among angiosperms; however, there is limited information on the mechanisms that influence differences in floral longevity, especially the relationship between petal anatomical traits and floral longevity. We aimed to examine (1) the relationships between petal anatomical traits and FL in tree peony cultivars and (2) the petal anatomical characteristics of longer FL cultivars. Eleven traits of six tree peony cultivars with different FL were investigated, including six water conservation traits (petal thickness, cuticle thickness, number of cell layers, mesophyll thickness, adaxial epidermis thickness and abaxial epidermis thickness), three water supply traits (vein density, number of xlylem vessels and xylem vessel diameter), petal fresh mass and petal dry mass across cultivars. There are significant differences in traits related to water conservation and water supply ability of tree peonies with different FL. Tree peony cultivars with long FL were characterized by the thicker Mesophyll, cuticles, adaxial and abaxial epidermis of the petals. There was a positive correlation between FL and vessel number and vessel diameter. These results suggest that the ability to retain water in flowers is associated with floral longevity. Petal traits related to water conservation and supply, including vein densities, mesophyll thickness, and epidermis thickness, are beneficial for prolonging the flower longevity in tree peonies.

Functional consequences of light intensity on soybean leaf hydraulic conductance: Coordinated variations in leaf venation architecture and mesophyll structure

Leaf hydraulic conductance (Kleaf) is a critical determinant of photosynthesis. Prior research has assessed the influence of light intensity on Kleaf by affecting leaf veins. However, whether the mesophyll structure is associated with leaf hydraulic acclimation to different light intensities remains unclear. We investigated the responses of leaf gas exchange and Kleaf to different growth light intensities and checked for the correlation of Kleaf with leaf structural traits in soybean. Low light significantly reduced Kleaf, but Kleaf and stomatal conductance remain coordinated. Low light decreased the stomatal density to match the balance between in water supply and carbon gain capacity. The decline in Kleaf under low growth light condition was partly due to for the reduction of the water movement through leaf veins because of reduced leaf vein thickness and density and xylem conduit size. In addition, low light reduces the mesophyll cell‐to‐cell connectivity and increased the volume fraction of intercellular air space. As a result, the area available for liquid‐phase flow decreases, and subsequently decreased Kleaf. The present study highlights the coordination role between leaf venation architecture and mesophyll structure influencing Kleaf in response to light intensity.

Exploration Targeting in the Shadan Porphyry Gold–Copper Deposit, Lut Block, Iran: Analysis of Spatial Distribution of Sheeted Veins and Lithogeochemical Data

The Lut Block is a potential porphyry-style mineralized region in Iran including the well-explored Shadan porphyry gold-copper deposit, which has an extensive zone of gold- and copper-bearing stockwork-like sheeted veins. The structural setting of this deposit is a key to understanding the genesis of the mineralization. Our field studies show that the mineralization occurs as steeply dipping ore bodies along NW–SE transpressional faults. The zones with a high frequency of veins and volume of veins have a NW–SE trend, which is closely related to transpressional faults. We propose that such a compressional regime inhibits focused ore-forming fluid flow to higher levels in the crust. After a local change in stress field, fluid depressurization and channeling along transpressional faults generated the sheeted veins. This indicates an important role of these transpressional faults in focusing and controlling mineralization within this porphyry deposit, which has important implications for the exploration of porphyry deposits on a regional scale. The spatial distribution of sheeted veins is used to examine gold anomalies from lithogeochemical data extracted by fractal models. The results show that a combination of high vein density and high vein volume areas with gold anomalies could result in identifying areas with greater potential at the deposit to regional scale.