Changes In Leaf Anatomy Research Articles

Leaf transcriptomes from C3, C3-C4 intermediate, and C4 Neurachne species give insights into C4 photosynthesis evolution.

The C4 photosynthetic pathway is hypothesized to have evolved from the ancestral C3 pathway through progressive changes in leaf anatomy and biochemistry with extant C3-C4 photosynthetic intermediate species representing phenotypes between species demonstrating full C3 and full C4 states. The Australian endemic genus Neurachne is the only known grass group that contains distinct, closely related species that carry out C3, C3-C4 intermediate, or C4 photosynthesis. To explore and understand the molecular mechanisms underlying C4 photosynthesis evolution in this genus, leaf transcriptomes were generated from two C3, three photosynthetic intermediate (proto-Kranz, C2-like, and C2), and two C4 Neurachne species. The data were used to reconstruct phylogenetic relationships in Neurachne, which confirmed two independent C4 origins in the genus. Relative transcript abundances substantiated the photosynthetic phenotypes of individual species and highlighted transcriptional investment differences between species, including between the two C4 species. The data also revealed proteins potentially involved in C4 cycle intermediate transport and identified molecular mechanisms responsible for the evolution of C4-associated proteins in the genus.

Effect of light-induced changes in leaf anatomy on intercellular and cellular components of mesophyll resistance for CO2 in Fagus sylvatica.

Mesophyll resistance for CO2 diffusion (rm) is one of the main limitations for photosynthesis and plant growth. Breeding new varieties with lower rm requires knowledge of its distinct components. We tested new method for estimating the relative drawdowns of CO2 concentration (c) across hypostomatous leaves of Fagus sylvatica. This technique yields values of the ratio of the internal CO2 concentrations at the adaxial and abaxial leaf side, cd/cb, the drawdown in the intercellular air space (IAS), and intracellular drawdown between IAS and chloroplast stroma, cc/cbd. The method is based on carbon isotope composition of leaf dry matter and epicuticular wax isolated from upper and lower leaf sides. We investigated leaves from tree-canopy profile to analyse the effects of light and leaf anatomy on the drawdowns and partitioning of rm into its inter- (rIAS) and intracellular (rliq) components. Validity of the new method was tested by independent measurements of rm using conventional isotopic and gas exchange techniques. 73% of investigated leaves had adaxial epicuticular wax enriched in 13C compared to abaxial wax (by 0.50‰ on average), yielding 0.98 and 0.70 for average of cd/cb and cc/cbd, respectively. The rIAS to rliq proportion were 5.5:94.5% in sun-exposed and 14.8:85.2% in shaded leaves. cc dropped to less than half of the atmospheric value in the sunlit and to about two-thirds of it in shaded leaves. This method shows that rIAS is minor but not negligible part of rm and reflects leaf anatomy traits, i.e. leaf mass per area and thickness.

Growth, gas exchange, and leaf anatomy of Echinodorus grandiflorus (Cham. & Schltr.) Micheli under Pb contamination.

Lead (Pb) can be deposited in aquatic environments that are especially subject to pollution due to wastewater and sewage disposal. This study aimed to evaluate the tolerance of Echinodorus grandiflorus (Cham. & Schltr.) Micheli to Pb and changes in growth, gas exchange, and leaf anatomy. Experiments were conducted with E. grandiflorus plants exposed to the following Pb concentrations in nutrient solution: [0; 0.75; 1.5; 3.0 and 9.0μM Pb (NO 3)2] in a greenhouse for 60days. At the end of the experiment, the lead concentration, growth, leaf gas exchange, and changes in leaf anatomy were evaluated. There was no mortality of E. grandiflorus plants, and they accumulated higher concentrations of Pb proportional to the concentration of the pollutant in the solution. Pb did not cause significant changes in growth, stomatal conductance, transpiration, and Ci/Ca rate but reduced the photosynthesis in E. grandiflorus. The leaf anatomy showed significant changes in the presence of Pb, reducing the epidermis and chlorophyll parenchyma. E. grandiflorus demonstrated tolerance to Pb, surviving and growing under contamination; however, it negatively modified its leaf anatomy and photosynthesis in the presence of the metal.

Interannual Variation in Gas Exchange and Leaf Anatomy in Cenostigma pyramidale Is Exacerbated through El Niño and La Niña Climate Events

This study sheds light on the remarkable physiological adaptations that the Cenostigma pyramidale makes, particularly during periods of extreme water scarcity, and their remarkable ability to rebound when a new rainy season arrives. C. pyramidale employs a survival strategy to mitigate the adverse effects of water shortage and then endures challenging environmental conditions and sustaining vital functions. Previously, this species was classified as deciduous since it retained at least 40% of its leaves to sustain basal gas exchange rates. The discrepancy in classification arises from differences in study methodologies, with this research being conducted in the field under natural conditions. This study demonstrates a negative correlation between rainfall and specific leaf area (SLA), highlighting that plants with smaller SLA are more drought-tolerant. Changes in leaf anatomy, including an increase in palisade parenchyma and reduction in spongy tissue, serve as adaptive strategies to enhance photosynthesis under water stress conditions. Hydraulic conductance plays a crucial role in plant adaptation to water scarcity. An intricate interplay between leaf anatomy and hydraulic conductance is observed, with adjustments in xylem characteristics influencing leaf gas exchange. The phenotypic plasticity is high in C. pyramidale, demonstrating the species’ ability to adapt to changing environmental conditions. In summary, this study illuminates the multifaceted strategies employed by plants to cope with water scarcity, from leaf shedding to anatomical and physiological adaptations, highlighting the resilience of native species in arid environments. These findings offer valuable insights into plant responses to environmental stress and their ability to thrive in challenging conditions.

Leaf hydraulic properties of Antarctic plants: effects of growth temperature and its coordination with photosynthesis.

One of the well-documented effects of regional warming in Antarctica is the impact on flora. Warmer conditions modify several leaf anatomical traits of Antarctic vascular plants, increasing photosynthesis and growth. Given that CO2 and water vapor partially share their diffusion pathways through the leaf, changes in leaf anatomy could also affect the hydraulic traits of Antarctic plants. We evaluated the effects of growth temperature on several anatomical and hydraulic parameters of Antarctic plants and assessed the trait co-variation between these parameters and photosynthetic performance. Warmer conditions promoted an increase in leaf and whole plant hydraulic conductivity, correlating with adjustments in carbon assimilation. These adjustments were consistent with changes in leaf vasculature, where Antarctic species displayed different strategies. At higher temperature, Colobanthus quitensis decreased the number of leaf xylem vessels, but increased their diameter. In contrast, in Deschampsia antarctica the diameter did not change, but the number of vessels increased. Despite this contrasting behavior, some traits such as a small leaf diameter of vessels and a high cell wall rigidity were maintained in both species, suggesting a water-conservation response associated with the ability of Antarctic plants to cope with harsh environments.

Tratamento foliar com metil jasmonato na restrição do crescimento e na anatomia de foliar de Begônia ‘Dragon Wing’

Abstract The application of plant growth regulators, primarily gibberellin inhibitors, is the main approach used for controlling the growth of ornamental plants. However, there is a growing interest in alternative products due to the risk of environmental toxicity associated with traditional methods. Methyl jasmonate (MeJa) is a natural substance found in plants and is considered to have low toxicity when used appropriately. Its use as a growth regulator has shown promise for controlling plant growth, but its effects have not been extensively explored in ornamental growth restriction. This study investigated the effects of foliar application of different concentrations of MeJa (0, 50, 100, and 150 µM) on the growth and leaf anatomy of Begonia ‘Dragon Wing’ Pink and Red. Plant growth parameters were evaluated, and qualitative-quantitative histological analyses of Begonia leaves were conducted. MeJa was efficient in compacting the plants, reducing height in 17.57% and diameter in 8.98% without compromising biomass, root growth, and flowering aspects. The average concentration studied also caused changes in leaf anatomy, increasing the thickness of the abaxial epidermis, reducing mesophyll thickness, the number of calcium oxalate crystals, and the size and number of stomata. The results demonstrated the promising effect of MeJa on controlling the growth of potted ornamental plants.

Biochemical and Structural Diversification of C4 Photosynthesis in Tribe Zoysieae (Poaceae).

C4 photosynthesis has evolved independently multiple times in grass lineages with nine anatomical and three biochemical subtypes. Chloridoideae represents one of the separate events and contains species of two biochemical subtypes, NAD-ME and PEP-CK. Assessment of C4 photosynthesis diversification is limited by species sampling. In this study, the biochemical subtypes together with anatomical leaf traits were analyzed in 19 species to reveal the evolutionary scenario for diversification of C4 photosynthesis in tribe Zoysieae (Chloridoideae). The effect of habitat on anatomical and biochemical diversification was also evaluated. The results for the 19 species studied indicate that 11 species have only NAD-ME as a decarboxylating enzyme, while eight species belong to the PEP-CK subtype. Leaf anatomy corresponds to the biochemical subtype. Analysis of Zoysieae phylogeny indicates multiple switches between PEP-CK and NAD-ME photosynthetic subtypes, with PEP-CK most likely as the ancestral subtype, and with multiple independent PEP-CK decarboxylase losses and its secondary acquisition. A strong correlation was detected between C4 biochemical subtypes studied and habitat annual precipitation wherein NAD-ME species are confined to drier habitats, while PEP-CK species prefer humid areas. Structural adaptations to arid climate include increases in leaf thickness and interveinal distance. Our analysis suggests that multiple loss of PEP-CK decarboxylase could have been driven by climate aridization followed by continued adaptive changes in leaf anatomy.

Co-application of copper oxide nanoparticles and Trichoderma harzianum with physiological, enzymatic and ultrastructural responses for the mitigation of salt stress

Chemical contamination or nutrient pollution is concerning for health, environmental, and economic reasons. Ecofriendly surface modification of nanoparticles is a consistent challenge for agricultural purposes. In response to this environmental concern, CuO-NPs synthesized through biological method using green source and characterized for morphological and structural features through SEM (scanning electron microscope) and TEM (transmission electron microscope) spectroscopy. Our research findings illustrate that the presence of salt stress induces a notable decline in both physiological and biochemical parameters within plants. Nevertheless, the utilization of T. harzianum and CuO-NPs exhibited a mitigating effect on the detrimental consequences induced by salt stress in plants. The application of T. harzianum and the simultaneous co-inoculation with CuO-NPs notably enhanced fresh biomass and facilitated vegetative growth in comparison to the control group. Furthermore, the exposure of both T. harzianum inoculum and Copper oxide nanoparticles resulted in a significant reduction of oxidative stresses, including reactive oxygen species (ROS) levels, H2O2, and lipid peroxidation (MDA) levels in the above-ground parts of the plant, while also minimizing electrolyte leakage (EL) by reducing root growth. Additionally, the co-inoculation of the endophyte and CuO-NPs led to a significant enhancement in antioxidant enzymatic activities, such as superoxide dismutase (SOD) and chitinase (CAT) activity in the above-ground parts, under salt stress conditions. The inoculum, along with its combination with CuO-NPs, decreased electrolyte conductivity and improved total chlorophyll contents as compared to the control. The combined application of T. harzianum and CuO-NPs improved salt tolerance in A. thaliana plants by triggering salt-associated gene expression. These findings suggest that the application of T. harzianum and CuO-NPs can considerably promote leaf anatomical changes in A. thaliana and have ability to enhance salt tolerance, particularly in saline areas.

Variations in leaf anatomical characteristics drive the decrease of mesophyll conductance in poplar under elevated ozone.

Decline in mesophyll conductance (gm ) plays a key role in limiting photosynthesis in plants exposed to elevated ozone (O3 ). Leaf anatomical traits are known to influence gm , but the potential effects of O3 -induced changes in leaf anatomy on gm have not yet been clarified. Here, two poplar clones were exposed to elevated O3 . The effects of O3 on the photosynthetic capacity and anatomical characteristics were assessed to investigate the leaf anatomical properties that potentially affect gm . We also conducted global meta-analysis to explore the general response patterns of gm and leaf anatomy to O3 exposure. We found that the O3 -induced reduction in gm was critical in limiting leaf photosynthesis. Changes in liquid-phase conductance rather than gas-phase conductance drive the decline in gm under elevated O3, and this effect was associated with thicker cell walls and smaller chloroplast sizes. The effects of O3 on palisade and spongy mesophyll cell traits and their contributions to gm were highly genotype-dependent. Our results suggest that, while anatomical adjustments under elevated O3 may contribute to defense against O3 stress, they also cause declines in gm and photosynthesis. These results provide the first evidence of anatomical constraints on gm under elevated O3 .

The CO2 fertilization effect on leaf photosynthesis of maize (Zea mays L.) depends on growth temperatures with changes in leaf anatomy and soluble sugars

Understanding the potential mechanisms and processes of leaf photosynthesis in response to elevated CO2 concentration ([CO2]) and temperature is critical for estimating the impacts of climatic change on the growth and yield in crops such as maize (Zea mays L.), which is a widely cultivated C4 crop all over the world. We examined the combined effect of elevated [CO2] and temperature on plant growth, leaf photosynthesis, stomatal traits, and biochemical compositions of maize with six environmental growth chambers controlling two CO2 levels (400 and 800 μmol mol−1) and three temperature regimes (25/19°C, 31/25°C, and 37/31°C). We found that leaf photosynthesis was significantly enhanced by increasing growth temperature from 25/19°C to 31/25°C independent of [CO2]. However, leaf photosynthesis drastically declined when the growth temperature was continually increased to 37/31°C at both ambient CO2 concentration (400 μmol mol−1, a[CO2]) and elevated CO2 concentration (800 μmol mol−1, e[CO2]). Meanwhile, we also found strong CO2 fertilization effect on maize plants grown at the highest temperature (37/31°C), as evidenced by the higher leaf photosynthesis at e[CO2] than that at a[CO2], although leaf photosynthesis was similar between a[CO2] and e[CO2] under the other two temperature regimes of 25/19°C and 31/25°C. Furthermore, we also found that e[CO2] resulted in an increase in leaf soluble sugar, which was positively related with leaf photosynthesis under the high temperature regime of 37/31°C (R2 = 0.77). In addition, our results showed that e[CO2] substantially decreased leaf transpiration rates of maize plants, which might be partially attributed to the reduced stomatal openness as demonstrated by the declined stomatal width and stomatal area. These results suggest that the CO2 fertilization effect on plant growth and leaf photosynthesis of maize depends on growth temperatures through changing stomatal traits, leaf anatomy, and soluble sugar contents.

Review Aktivitas Fotosintesis pada Tanaman Sorgum (Sorghum bicolor) dalam Kondisi Cekaman Kekeringan

Sorghum (Sorghum bicolor L. Moench) is a cereal crop that has the potential to be developed in Indonesia as a food, feed and industrial crop. Sorghum is a C4 plant that has the advantage of efficiency in hot and dry environments. Drought stress is one of the most limiting environmental factors for crop productivity worldwide, and can be caused by water deficits in the soil and in the atmosphere. On the decreasing leaf water status, the rate of CO2 assimilation and the conductance of stomata decreased rapidly. The CO2 concentration mechanism is able to saturate C4 photosynthesis under the relatively low intercellular CO2 concentration. In addition, CO2 photorespiration is likely to be repaired before it exits the bundle sheat cells. The effects of non-stomatal factors include reduced activity of photosynthetic enzymes, inhibition of nitrate assimilation, induction of premature aging, and changes in leaf anatomy. Photosynthesis in C4 plants, including sorghum, involves, others, the PEPC and Rubisco enzymes. Drought can also trigger oxidative stress, which is an environmental condition that has increased Reactive Oxygen Species (ROS) due to an over reduction of the photosynthesis process.

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

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

Changes of stomatal distribution and leaf thickness in response to transpiration rate in six dicot plant species

Changes in leaf anatomy can be influenced by the surrounding environment and several other factors. Shade plants or ornamental plants themselves also have their characteristics in responding to surrounding conditions through transpiration. This study aimed to measure the rate of transpiration related to changes in the distribution of stomata and leaf thickness of six types of dicot ornamental plants and to describe the leaf anatomy of each type. The experiment used Completely Randomized Design (CRD) with six types of plants as treatment with three replications. Transpiration rate was measured by modified lysimeter method, stomatal distribution was calculated from the ratio of the number of stomata to epidermal cells and leaf anatomy was observed using preserved slide made from paraffin method. Data were analyzed by SAS with CRD model and correlation was performed between transpiration rate and leaf thickness. The results showed that the transpiration rate, leaf thickness, and stomatal distribution were significantly different at α = 0.05 amongst plants. The transpiration rate was inversely proportional to leaf thickness with various correlation coefficients. The leaf anatomy of six plant species showed various thicknesses between tissues. Further research needs to be done to explain the rate of transpiration with changes in leaf anatomy.

Yield photosynthesis and leaf anatomy of maize in inter- and mono-cropping systems at varying plant densities

Increasing plant density can increase cereal crop yields. However, the physiological and anatomical mechanisms of grain yield increase at high plant densities in maize-based intercropping systems are not well understood. A two-year field experiment was conducted in 2018 and 2019 to investigate grain yield, photosynthetic characteristics, stomatal traits, and leaf anatomy of maize plants in an intercropping system with high plant densities. Two cropping patterns (monocropping and intercropping) and three plant densities (D1, 78,000 plants ha−1; D2, 103,500 plants ha−1; D3, 129,000 plants ha−1) were arranged in a randomized block design. Increasing maize plant density significantly increased maize yield, and intercropping gave a significant yield advantage over monocropping under the same plant density. Intercropping combined with high plant density increased the leaf area and SPAD value of maize, increasing the photosynthesis rates after the harvest of pea. At the twelfth leaf stage, the stomatal density and stomatal area of intercrops combined with medium plant density increased by respectively 10.5% and 18.4% relative to their values for the corresponding density of monocrops. Although leaf thickness of maize was reduced by increasing plant density, the chloroplast number and grana lamella number were higher in intercropping than in monocropping under different plant densities. These positive changes in leaf anatomy resulted in increased photosynthesis, suggesting a physiological basis for the increase in grain yield.

Mixed red and blue light promotes tomato seedlings growth by influencing leaf anatomy, photosynthesis, CO2 assimilation and endogenous hormones

The light frequency of red (R) and blue (B) plays a crucial role within plant growth cycle. Whereas, the relationship between the metabolic pathways involved in photosynthesis and carbohydrate accumulation in tomato seedling and hormone regulation still needs further investigation. This research comprehensively analyzed changes in leaf anatomy, stomatal traits, pigment content, gas exchange parameters, chlorophyll fluorescence, Rubisco and Calvin cycle-related enzyme expression and activities, as well as endogenous hormones biosynthesis in tomato (Solanum lycopersicum L.) seedlings, which radiated by four light qualities, including monochromatic white light (W), B, R and mixed light of R and B (RB). The findings showed the biomass accumulation as well as CO2 assimilation were greatly increased in seedlings under B and especially under RB light. Their leaves were also thicker, and stomatal conductance, levels of pigment, photosynthetic electron transport capacity, and the photosynthetic rate were enhanced. In addition, enzyme expression level and activity related to the Calvin cycle were up-regulated. Moreover, RB-induced growth was accompanied by a significant inhibition in gibberellin (GA) concentration as well as an increment in auxin (indole-3-acetic acid (IAA)) in stem and root. Overall, photosynthesis of RB-treated seedlings was positively regulated by leaf anatomy and photosynthetic electron transportation as well as maintaining the activation states of the Calvin cycle, and then inducing changes in carbohydrate accumulation. In addition, both GA and IAA were found to be involved causally in the increased shoot and root biomass of tomato seedlings under RB treatment.

Leaf anatomical characteristics are less important than leaf biochemical properties in determining photosynthesis responses to nitrogen top-dressing.

The photosynthetic capacity of leaves is dramatically influenced by nitrogen (N) availability in the soil, as CO2 concentration in chloroplasts and photosynthetic biochemical capacity are related to leaf N content. The relationship between mesophyll conductance (gm) and leaf N content was expected to be shaped by leaf anatomical traits. However, the increased gm in mature leaves achieved by N top-dressing is unlikely to be caused by changes in leaf anatomy. Here, we assessed the impacts of N supply on leaf anatomical, biochemical, and photosynthetic features, specifically, the dynamic responses of leaf anatomy, biochemistry, and photosynthesis to N top-dressing in tobacco. Plant performance was substantially affected by soil N status. In comparison with the leaves of plants subjected to low N treatment, leaves of plants with high N treatment photosynthesized significantly more, due to higher CO2 diffusion conductance and photosynthetic biochemical capacity. The high gm in high N-treated leaves apparently related to modifications in the leaf anatomy; however, the rapid response of gm to N top-dressing cannot be fully explained by leaf anatomical modifications.

Systemic effects of rising atmospheric vapor pressure deficit on plant physiology and productivity.

Earth is currently undergoing a global increase in atmospheric vapor pressure deficit (VPD), a trend which is expected to continue as climate warms. This phenomenon has been associated with productivity decreases in ecosystems and yield penalties in crops, with these losses attributed to photosynthetic limitations arising from decreased stomatal conductance. Such VPD increases, however, have occurred over decades, which raises the possibility that stomatal acclimation to VPD plays an important role in determining plant productivity under high VPD. Furthermore, evidence points to more far‐ranging and complex effects of elevated VPD on plant physiology, extending to the anatomical, biochemical, and developmental levels, which could vary substantially across species. Because these complex effects are typically not considered in modeling frameworks, we conducted a quantitative literature review documenting temperature‐independent VPD effects on 112 species and 59 traits and physiological variables, in order to develop an integrated and mechanistic physiological framework. We found that VPD increase reduced yield and primary productivity, an effect that was partially mediated by stomatal acclimation, and also linked with changes in leaf anatomy, nutrient, and hormonal status. The productivity decrease was also associated with negative effects on reproductive development, and changes in architecture and growth rates that could decrease the evaporative surface or minimize embolism risk. Cross‐species quantitative relationships were found between levels of VPD increase and trait responses, and we found differences across plant groups, indicating that future VPD impacts will depend on community assembly and crop functional diversity. Our analysis confirms predictions arising from the hydraulic corollary to Darcy's law, outlines a systemic physiological framework of plant responses to rising VPD, and provides recommendations for future research to better understand and mitigate VPD‐mediated climate change effects on ecosystems and agro‐systems.

Stress Response of Miscanthus Plants and Soil Microbial Communities: A Case Study in Metals and Hydrocarbons Contaminated Soils

Second-generation biofuel crop miscanthus is one of the most promising plants tested for phytomanagement of contaminated sites. In this preliminary pot case study, the most used hybrid Miscanthus x giganteus was cultivated in three different real contaminated soils: agricultural soil contaminated with Cd; post-military soil slightly contaminated with Zn, Pb and Cd; and soil contaminated by petroleum industry with metals and hydrocarbons. The stress response of plants and soil microbial communities was monitored to receive data that are important for successful phytomanagement application. With metals only, the plant grew well, and chlorophyll fluorescence measurement proved their good vitality. Changes in leaf anatomy (leaf thickness and sclerenchyma cells area) were additionally determined in post-military soil compared to agricultural. On the contrary, in petroleum-contaminated soil, the biomass yield was too reduced and also physiological parameters were significantly decreased. The response of microbial communities also differed. In agricultural soil, no microbial stress was determined. In post-military soil, it became reduced during the experiment, and in petroleum contamination, it increased year-on-year. It could be concluded that miscanthus is suitable for cultivation in metals contaminated soils with potential for microbial communities support, but in soil contaminated by the petroleum industry, its application did not seem meaningful.

Leaf anatomical aspects of CABMV infection in Passiflora spp. by light and fluorescence microscopy

Cowpea aphid-borne mosaic virus (CABMV) is the main pathogen that affects passion fruit, causing woodiness disease in Brazil. The identification of sources of resistance in Passiflora is necessary for the development of resistant cultivars. The objective of this work was to evaluate the reaction of eight species of Passiflora to CABMV and to verify leaf anatomical changes caused by CABMV. Inoculations were performed and symptoms were evaluated until 55 days after inoculation using a scale ranging from 1 (without symptoms) to 4 (highly susceptible). Simultaneously, leaves from infected and control plants for anatomical analysis were collected. The severity of the disease was calculated using the disease index (DI%) and the means were grouped using the Scott-Knott test. The wild species Passiflora malacophylla, P. setacea and P. suberosa were classified as resistant to CABMV. In contrast, P. alata and P. edulis were susceptible to the virus, with DI values of 58.2 and 51.9%, respectively. Leaf anatomical changes were more drastic in P. edulis and P. alata. In P. edulis, the infection resulted in changes in the organization of the vascular bundles. Resistant wild species showed few anatomical changes. The resistance found in wild species opens the prospect of performing interspecific crosses.

Foliar elemental microprobe data and leaf anatomical traits consistent with drought tolerance in

In food-productive river basins, ecosystems reliant on natural flows are affected by climate change and water removal. One such example is Australia’s Murray–Darling Basin (MDB), to which the ecologically important black box tree Eucalyptus largiflorens (Myrtaceae) is unique. Little is known about its mineral nutrition and response to flooding. A field study conducted at Hattah Kulkyne National Park on the MDB examined nutrient and Al distribution in mature and young foliage of trees whose status varied with respect to the presence of surface floodwaters. Black box is also of interest due to emerging evidence of its capacity to accumulate high foliar salt concentrations. Here, cryo scanning electron microscopy alone (SEM), combined with energy dispersive spectroscopy (SEM-EDS) and X-ray fluorescence (XRF) spectroscopy were applied to evaluate leaf anatomy and elemental patterns at the cellular and whole-leaf levels. Variation in whole-leaf elemental levels across flooded and dry trees aligned with known nutritional fluctuations in this drought-tolerant species reliant on occasional infrequent flooding. The microprobe data provide evidence of drought tolerance by demonstrating that extended conditions of lack of water to trees do not elicit leaf anatomical changes nor changes to leaf cellular storage of these elements. Foliar Na concentrations of ~2000–6000 mg kg–1 DW were found co-localised with Cl in mesophyll and dermal cells of young and mature leaves, suggesting vacuolar salt disposal as a detoxification strategy.