Increased Gas Exchange Research Articles

Effects of periodic drought with severe exhaust exposure on particle retention capacity and physiological responses of Photinia × fraseri Dress

Urban plants are regarded as an effective agent to control particulate matter (PM) pollution by absorbing PM. Repeated PM and drought stress in urban areas often cause morphological and physiological damage to plants, resulting in lower ecological benefits. Nevertheless, knowledge in PM retention capability, morphology and physiology of plants under repeated stress and cross stress has been barely available. In order to investigate changes in these aspects under repeated stress, we applied periodic drought with severe exhaust exposure on Photinia × fraseri Dress (a common urban tree species with strong PM retention ability). The study was carried out in a six-period scenario, with a duration of 10 days for each period: initial value (R0), initial stress period (S1), initial recovery period (R1) second stress period (S2), second recovery period (R2) and final stress period (S3). The results are as follows: In terms of periodic factor, PM retention of tail gas stress group (P) and cross stress group (PD) in S2 decreased by 10.00 μg/cm2 and 12.60 μg/cm2 respectively compared with those during S1 (p > 0.05). During S3, the total amount of PM on leaf surface in both P and PD demonstrated a significant decrease (p < 0.05). The retention capacity of P. fraseri may be dramatically limited under multi-period stress. In this experiment, we attribute the decrease of PM retention to the morphological changes (shedding of mature leaves, smaller leaf area and thinner wax layer) and physiological responses (an increase in gas exchange) under multi-period stress. In terms of cross-stress factor, the total retained PM on leaf surface in PD was higher than that in P, especially during S3, and the interaction between drought and PM reached a significant level (p < 0.01, η2 = 0.808), which indicated that drought reduced the loss of dust under PM stress. Changes in morphology and gas exchange indicated that the mechanisms for the high dust retention rate on the leaf surface of PD group varied in the three stress periods. In addition, except the chlorophyll relative value, the alleviated accumulation of MDA and intense production of soluble sugar with PD showed favorable responses to disturbance compared with those in P under the repeated stress. Therefore, we infer that, under multi-period stress of drought and tail gas, P. fraseri may better maintain PM retention ability and resistance than under single stress.

A Parametric Analysis of Capillary Height in Single-Layer, Small-Scale Microfluidic Artificial Lungs.

Microfluidic artificial lungs (μALs) are being investigated for their ability to closely mimic the size scale and cellular environment of natural lungs. Researchers have developed μALs with small artificial capillary diameters (10–50 µm; to increase gas exchange efficiency) and with large capillary diameters (~100 µm; to simplify design and construction). However, no study has directly investigated the impact of capillary height on μAL properties. Here, we use Murray’s law and the Hagen-Poiseuille equation to design single-layer, small-scale μALs with capillary heights between 10 and 100 µm. Each µAL contained two blood channel types: capillaries for gas exchange; and distribution channels for delivering blood to/from capillaries. Three designs with capillary heights of 30, 60, and 100 µm were chosen for further modeling, implementation and testing with blood. Flow simulations were used to validate and ensure equal pressures. Designs were fabricated using soft lithography. Gas exchange and pressure drop were tested using whole bovine blood. All three designs exhibited similar pressure drops and gas exchange; however, the μAL with 60 µm tall capillaries had a significantly higher wall shear rate (although physiologic), smaller priming volume and smaller total blood contacting surface area than the 30 and 100 µm designs. Future μAL designs may need to consider the impact of capillary height when optimizing performance.

Iron oxide nanoparticles and selenium supplementation improve growth and photosynthesis by modulating antioxidant system and gene expression of chlorophyll synthase (CHLG) and protochlorophyllide oxidoreductase (POR) in arsenic-stressed Cucumis melo

Current research reveals the positive role of iron oxide nanoparticles (IONPs) and selenium (Se) in extenuation of arsenic (As) induced toxicity in Cucumis melo. C. melo plants grown in As spiked soil (20 mg kg−1 As) showed reduced growth, chlorophyll (Chl) content, photosynthetic rate, stomatal conductivity and transpiration. On the other hand, the alone applications of IONPs or Se improved growth and physiochemical parameters of C. melo plants. Additionally, exogenous application IONPs and Se synergistically improved the activity of antioxidative enzymes and glyoxalase system in C. melo plants. In addition, the collective treatment of IONPs and Se reduced As uptake, enhanced rate of photosynthesis and increased gas exchange attributes of C. melo plants under As stress. Interactive effect of IONPs and Se regulated reduced glutathione (GSH), oxidized glutathione (GSSG) and ascorbate (AsA) content in C. melo plants exposed to As-contaminated Soil. IONPs and Se treatment also regulated expression of respiratory burst oxidase homologue D (RBOHD) gene, chlorophyll synthase (CHLG) and protochlorophyllide oxidoreductase (POR). Therefore, the combined treatment of IONPs and Se may enhance the growth of crop plants by alleviating As stress.

Effects of shell-integrated Sudan Black dye on the acoustic activity and ultrasound imaging properties of lipid-shelled nanoscale ultrasound contrast agents.

.Significance: An effective contrast agent for concurrent multimodal photoacoustic (PA) and ultrasound (US) imaging must have both high optical absorption and high echogenicity. Integrating a highly absorbing dye into the lipid shell of gas core nanobubbles (NBs) adds PA contrast to existing US contrast agents but may impact agent ultrasonic response.Aim: We report on the development and ultrasonic characterization of lipid-shell stabilized NBs with integrated Sudan Black (SB) B dye in the shell as dual-modal PA-US contrast agents.Approach: Perfluoropropane NBs stabilized with a lipid shell including increasing concentrations of SB B dye were formulated by amalgamation (SBNBs). Physical properties of SBNBs were characterized using resonant mass measurement, transmission electron microscopy and pendant drop tensiometry. Concentrated bubble solutions were imaged for 8 min to assess signal decay. Diluted bubble solutions were stimulated by a focused transducer to determine the response of individual NBs to long cycle (30 cycle) US. For assessment of simultaneous multimodal contrast, bulk populations of SBNBs were imaged using a PA and US imaging platform.Results: We produced high agent yield () with a mean diameter of to 300 nm depending on SB loading. A 40% decrease in bubble yield was measured for solutions with 0.3 and SB. The addition of SB to the shell did not substantially affect NB size despite an increase in surface tension by up to . The bubble decay rate increased after prolonged exposure (8 min) by dyed bubbles in comparison to their undyed counterparts (2.5-fold). SB in bubble shells increased gas exchange across the shell for long cycle US. PA imaging of these agents showed an increase in power (up to 10 dB) with increasing dye.Conclusions: We added PA contrast function to NBs. The addition of SB increased gas exchange across the NB shell. This has important implications in their use as multimodal agents.

A clinical review of using a high-flow nasal cannula for patients with COVID-19 infection

Coronavirus Disease 2019 (COVID-19) is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV 2). The most common manifestations of COVID-19 include fever &gt; 37.5˚C, cough, flu, anosmia, and respiratory distress—the virus cause Acute Respiratory Distress Syndrome (ARDS), which quickly turns into respiratory failure. Therefore COVID-19 patients with ARDS require intensive care in a hospital with oxygen support. One type of oxygen therapy used to treat COVID-19 with ARDS is a High Flow Nasal Cannula (HFNC) administration. This study aimed to determine the effectiveness of HFNC therapy in COVID-19 patients with ARDS. This study used a literature review research design. Sources of literature were carried out on Google Scholar, Science Direct, Pubmed, and Sage Journal, with the final results obtained from eight reviewed articles. The results of the eight articles stated that using HFNC positively impacted the decreased need for mechanical ventilation and increased gas exchange of COVID-19 patients with ARDS.&#x0D; Keywords: COVID-19; oxygen therapy; nursing care; infectious diseases; prevention strategy

Kaolin Film Increases Gas Exchange Parameters of Coffee Seedlings During Transference From Nursery to Full Sunlight.

Increases in water use efficiency (WUE) and the reduction of negative impacts of high temperatures associated with high solar radiation are being achieved with the application of fine particle film of calcined and purified kaolin (KF) on the leaves and fruits of various plant species. KF was applied on young Coffea arabica and Coffea canephora plants before their transition from nursery to full sunlight during autumn and summer. The effects of KF were evaluated through the responses of leaf temperature (Tleaf), net CO2 assimilation rate (A), stomatal conductance (gs), transpiration (E), WUE, crop water stress index (CWSI), index of relative stomatal conductance (Ig), initial fluorescence (F0), and photosynthetic index (PI) in the first 2–3 weeks after the plant transitions to the full sun. All measurements were performed at midday. In Coffea plants, KF decreased the Tleaf up to 6.7°C/5.6°C and reduced the CWSI. The plants that were not protected with KF showed lower A, gs, E, and Ig than those protected with KF. C. canephora plants protected with KF achieved higher WUE compared with those not protected by 11.23% in autumn and 95.58% in summer. In both Coffea sp., KF application reduced F0, indicating reduced physical dissociation of the PSII reaction centers from the light-harvesting system, which was supported with increased PI. The use of KF can be recommended as a management strategy in the transition of Coffea seedlings from the nursery shade to the full sunlight, to protect leaves against the excessive solar radiation and high temperatures, especially in C. canephora during the summer.

Innovation in grapevine water status monitoring and drought adaptation: leaf angle and temperature regulation

Increase of frequency, duration, and intensity of drought and heatwave and related water and heat crops stress are among the principal effects of climate change. This paper reports: (i) the effect of calcite particle film (CaPF) as a mitigation strategy against heat stress in well-watered (WW) or in drought-stress (D) conditions; and (ii) response of leaf angle variation to stomatal conductance changes induced by drought stress of Aleatico grapevine cultivar. Results have showed that CaPF, under WW conditions, reduced leaf temperature, and increased gas exchange, but, under very severe water stress, CaPF treatment was ineffective. Leaf angle ranged from 70° (WW vines) to 100° (drought stressed vines) and showed a good fit (R2=0.81) with stomatal conductance within the range of 0.25 – 0.05 mol m-2s–1proving it might be a reliable proxy of vine water status.

Ácidos orgânicos aliados ao pacobutrazol modificam o florescimento de mangueira ‘Keitt’

Abstract The objective of this study was to evaluate the effectiveness of fulvic acids and free amino acids on paclobutrazol in the flowering of mango ‘Keitt’ cultivated in the semi-arid region. The experiment was performed from 2017 to 2018 simultaneously in two orchards with the same plants and management characteristics, located in Cabrobó, State of Pernambuco, Brazil. The experimental design was randomized blocks with four treatments and five replications of four trees. The treatments were: T1: paclobutrazol + water (control); T2: paclobutrazol + fulvic acids; T3: paclobutrazol + amino acids; T4: paclobutrazol + fulvic acids + amino acids. Applying fulvic acids plus paclobutrazol increased gas exchange efficiency, favoring flowering and fruiting. In contrast, amino acids alone or with fulvic acids decreased the flowering efficiency.

Noninvasive ventilation in children: A review for the pediatric anesthesiologist.

Preserving adequate respiratory function is essential in the perioperative period. Mechanical ventilation with endotracheal intubation is widely used for this purpose. In select patients, noninvasive ventilation (NIV) may be an alternative to invasive ventilation or may complement respiratory management. NIV is used to provide ventilatory support and increase gas exchange at the alveolar level without the use of an invasive artificial airway such as an endotracheal tube or tracheostomy. NIV includes both continuous positive airway pressure (CPAP) and noninvasive positive pressure ventilation. Indications for NIV range from acute hypoxic respiratory failure in the intensive care unit or the emergency department, to chronic respiratory failure in patients with neuromuscular disease with nocturnal hypoventilation. In the perioperative setting, NIV is commonly applied as CPAP, and bilevel positive airway pressure (BPAP). There are limited data on the role of NIV in children in the perioperative setting, and there are no clear guidelines regarding optimal timing of use and pressure settings of perioperative NIV. Contraindications to the use of NIV include reduced level of consciousness, apnea, severe respiratory distress, and inability to maintain upper airway patency or airway protective reflexes. Common problems encountered during NIV involve airway leaks and asynchrony with auto-triggering. High-flow nasal oxygen (HFNO) has emerged as an alternative to NIV when trying to decrease the work of breathing and improve oxygenation in children. HFNO delivers humidified and heated oxygen at rates between 2 and 70L/min using specific nasal cannulas, and flows are determined by the patient's weight and clinical needs. HFNO can be useful as a method for preoxygenation in infants and children by prolonging apnea time before desaturation, yet in children with decreased minute ventilation or apnea HFNO does not improve alveolar gas exchange. Clinicians experienced with these devices, such as pediatric intensivists and pulmonary medicine specialists, can be useful resources for the pediatric anesthesiologist caring for complex patients on NIV.

Stomatal responses in grapevine become increasingly more tolerant to low water potentials throughout the growing season.

The leaf of a deciduous species completes its life cycle in a few months. During leaf maturation, osmolyte accumulation leads to a significant reduction of the turgor loss point (ΨTLP ), a known marker for stomatal closure. Here we exposed two grapevine cultivars to drought at three different times during the growing season to explore if the seasonal decrease in leaf ΨTLP influences the stomatal response to drought. The results showed a significant seasonal shift in the response of stomatal conductance to stem water potential (gs ~Ψstem ), demonstrating that grapevines become increasingly tolerant to low Ψstem as the season progresses in coordination with the decrease in ΨTLP . We also used the SurEau hydraulic model to demonstrate a direct link between osmotic adjustment and the plasticity of gs ~Ψstem . To understand the possible advantages of gs ~Ψstem plasticity, we incorporated a seasonally dynamic leaf osmotic potential into the model that simulated stomatal conductance under several water availabilities and climatic scenarios. The model demonstrated that a seasonally dynamic stomatal closure threshold results in trade-offs: it reduces the time to turgor loss under sustained long-term drought, but increases overall gas exchange particularly under seasonal shifts in temperature and stochastic water availability. A projected hotter future is expected to lower the increase in gas exchange that plants gain from the seasonal shift in gs ~Ψstem . These findings show that accounting for dynamic stomatal regulation is critical for understanding drought tolerance.

Riddled with holes: Understanding air space formation in plant leaves.

Plants use energy from sunlight to transform carbon dioxide from the air into complex organic molecules, ultimately producing much of the food we eat. To make this complex chemistry more efficient, plant leaves are intricately constructed in 3 dimensions: They are flat to maximise light capture and contain extensive internal air spaces to increase gas exchange for photosynthesis. Many years of work has built up an understanding of how leaves form flat blades, but the molecular mechanisms that control air space formation are poorly understood. Here, I review our current understanding of air space formation and outline how recent advances can be harnessed to answer key questions and take the field forward. Increasing our understanding of plant air spaces will not only allow us to understand a fundamental aspect of plant development, but also unlock the potential to engineer the internal structure of crops to make them more efficient at photosynthesis with lower water requirements and more resilient in the face of a changing environment.

The Role of Plant-Associated Bacteria, Fungi, and Viruses in Drought Stress Mitigation.

Drought stress is an alarming constraint to plant growth, development, and productivity worldwide. However, plant-associated bacteria, fungi, and viruses can enhance stress resistance and cope with the negative impacts of drought through the induction of various mechanisms, which involve plant biochemical and physiological changes. These mechanisms include osmotic adjustment, antioxidant enzyme enhancement, modification in phytohormonal levels, biofilm production, increased water and nutrient uptake as well as increased gas exchange and water use efficiency. Production of microbial volatile organic compounds (mVOCs) and induction of stress-responsive genes by microbes also play a crucial role in the acquisition of drought tolerance. This review offers a unique exploration of the role of plant-associated microorganisms—plant growth promoting rhizobacteria and mycorrhizae, viruses, and their interactions—in the plant microbiome (or phytobiome) as a whole and their modes of action that mitigate plant drought stress.

Cluster Thinning Does Not Improve Fruit Composition in Grapevine Red Blotch Virus-infected Vitis vinifera L.

The impact of grapevine red blotch virus (GRBV) on <i>Vitis vinifera</i> L. manifests predominantly as reductions in gas exchange, berry total soluble solids, and anthocyanins. Disease management is currently restricted by incomplete understanding of virus spread and is thus limited to vine removal. The present study investigated the potential of irrigation and cluster thinning to improve fruit quality in GRBV-infected Pinot noir vines. Two irrigation levels—grower standard and supplemental (2x grower standard)—were applied in a factorial combination with two cluster thinning levels—thinned to one cluster/shoot (at peppercorn-sized berries) and nonthinned (control)—on two different rootstocks: Riparia Gloire and 3309C. Vine growth, disease severity, and fruit composition were observed for three years to understand the potential effects of the treatments on GRBV-infected vines. Supplemental irrigation attenuated the proportion of red leaves, but thinning did not have a consistent effect. Supplemental irrigation increased yield by 16 to 23% and berry mass by 9 to 10% between rootstocks. Thinning clearly decreased yield, but it also increased berry mass by 4 to 11% between rootstocks. Supplemental irrigation increased gas exchange in 2020, yet thinning slightly reduced gas exchange. These impacts on gas exchange did not affect total soluble solids in the fruit at harvest. Increases in berry sugar content indicate that sugar import increased commensurately with berry size as a function of both increased irrigation and cluster thinning. Crop load (Ravaz index) exhibited a correlation with berry sugar for the Riparia Gloire rootstock only, suggesting that crop load adjustment has a limited impact on ripening for GRBV-infected vines. Neither irrigation nor thinning significantly impacted anthocyanin concentration, and the impact on other secondary metabolites was inconsistent. The respective increase or decrease in yield may determine whether the limited improvements of supplemental irrigation and thinning on fruit quality in GRBV-infected vines are beneficial.

Nitrogen and Phosphorus Addition to Soil Improves Seed Yield, Foliar Stomatal Conductance, and the Photosynthetic Response of Rapeseed (Brassica napus L.)

The effects of nitrogen and phosphorus levels on the physiological traits, yield, and seed yield of rapeseed (Brassica napus L.), were studied in a farm research project of Zanjan University. Three levels of nitrogen (0, 100, and 200 kg/ha) and three levels of phosphorus (0, 75, and 150 kg/ha) were considered. The results showed that an increase in nitrogen level caused an increase in the leaf chlorophyll content so that the application of 200 kg/ha of nitrogen increased the chlorophyll content of the leaves until the mid-grain filling stage. Nitrogen application lowered leaf stomatal conductance in the early flowering stage whereas the stomatal conductance was increased during the late flowering stage. Nitrogen application (100 and 200 kg/ha) also increased the quantum yield of photosystem II. On the other hand, with the application of 150 kg/ha and 75 kg/ha of phosphorus, the leaf stomatal conductance and the quantum yield of photosystem II in the early flowering stage increased respectively. The results showed that the application of 200 kg/ha of nitrogen and 75 kg/ha of phosphorus significantly increased seed and oil yield compared to the control. In addition, the number of siliques per plant and the weight of 1000 seeds showed an increasing trend that was affected by nitrogen and phosphorus levels. This study demonstrated that nitrogen enhanced the chlorophyll content, leaf area, and consequently, the quantum yield of photosystem II. Nitrogen also augmented the seed filling duration, seed yield, and oil yield by increasing gas exchange. As a result, the application of 100 kg/ha of nitrogen together with 75 kg/ha phosphorus showed the greatest effect on the qualitative and quantitative yield of rapeseed. However, the application of 200 kg/ha of nitrogen alone or in combination with different levels of phosphorus did not significantly increase many of the studied traits.

Innovative Soluble Silicon Leaf Source Increase Gas Exchange, Grain Yield and Economic Viability in Common Bean

New soluble sources of silicon (Si) have arrived in the agribusiness. Some of them are being considered efficient by their used composition, improving absorption of this beneficial element, photosynthetic parameters, and yield. However, the economic feasibility of using this source must be considered. Thus, the present study aimed to evaluate the effect of the foliar application of increasing concentrations of Si on the physiological aspects grain yield in common bean and the economic viability of silicon application. Randomized block design with seven Si concentrations: 0.00, 0.33, 0.66, 1.00, 1.33, 1.66 and 2.00 g L− 1. Solutions were applied via foliar spraying covering the whole treatment area. Solutions were provided in triplicates and three different days after sowing (40, 55, and 70 DAS). Si accumulation, gas exchange (stomatal conductance, transpiration, photosynthesis, and internal CO2 concentration), photochemical efficiency, productivity, and economic viability were evaluated. Foliar applications of Si as sodium and potassium silicate stabilized with sorbitol were found to be efficient in providing Si for bean cultivation. The beneficial effect of Si application in the photosynthetic and yield parameters was observed in this study. However, when Si concentration is higher than 1.16 g L− 1 it is considered not economically viable.

Cannabis sativa L. photoautotrophic micropropagation: a powerful tool for industrial scale in vitro propagation

Global demands for an in vitro culture of cannabis have never been more sought after as countries shift their paradigm towards legalization. Cannabis conventional (photomixotrophic) micropropagation has not been suitable enough for large-scale propagation due to a high degree of plant hyperhydricity, low growth rate, poor rooting, and acclimation efficiency. In the present study, cannabis photoautotrophic micropropagation method is introduced with the purpose of overcoming the difficulties that conventional micropropagation entails when conducted at a large scale. The roles of rockwool medium pH and moisture content, cutting length, basal wounding methods, light intensity, and culture vessel gas exchange capacity were assessed with the intention of increasing productivity of micropropagation method. The results showed 300 mL per vessel of fertilizer solution containing 5-mM MES buffer stabilized medium pH and increased rooting success. Both 5- and 7-cm cutting lengths significantly increased the percent of rooted plants compared to 3-cm cutting length. However, the basal wounding methods did not significantly improve or impede the rooting success. The highest rooting success was also obtained with 150 μmol m−2 s−1 of photosynthetic photon flux density compared to 50 and 100 μmol m−2 s−1. Increasing gas exchange rates either using more permeable vessels or aeration practices significantly improved the rooting success. Overall, more than 90% of cannabis plantlets grown in photoautotrophic micropropagation are rooted in 2 wk of culture followed by 4 d ex vitro acclimation period, which was remarkably shorter than any other available method in cannabis micropropagation. This study not only optimizes a method for cannabis photoautotrophic micropropagation using passive ventilation for the first time but also scales up in vitro clonal propagation for in vitro commercial production.

Novel Therapy: Extra Corporal Hemoperfusion Regenerated Pulmonary Function and Reduce Primary Graft Dysfunction in an ARDS Pig EVLP and Lung Transplantation Model

<h3>Purpose</h3> Despite improvements in lung transplantation (LTx), severe primary graft dysfunction (PGD) remains the leading cause of early mortality. In addition, a major challenge to LTx as a therapy, is the scarcity of donor organ. One major reason for rejecting a lung donor offer is acute lung injury in fear for severe PGD. To increase the number of donor organs, the possibilities of repairing damaged lungs is appealing. Cytokine filtration has shown to have an immunomodulation capacity and might therefore increase the tolerability towards the donor organ. <h3>Methods</h3> In the present study we induce acute respiratory distress syndrome (ARDS) using lipopolysaccharide (LPS) in donor pigs. Lungs where then treated with or without a cytokine filtration system in two steps. The first treatment step occurs during the use of ex vivo lung perfusion (EVLP). The left lung was subsequently transplanted, and treatment step two was initiated using ex vivo hemoperfusion in the recipient. The transplanted lung was thereafter evaluated after a right pneumonectomy to evaluate the impact on PGD at 48 hours. Figure 1) Overview. Figure 2a) Filtration EVLP 2b) Hemoperfusion recipient <h3>Results</h3> All pulmonary grafts had moderate to severe ARDS at the initiation of EVLP. Over the course of EVLP, the treated lungs increased their gas exchange capacity.The treated group required significantly less inotropic support post-transplantation and showed improved hemodynamic stability compared to the control group. During the first day post-transplantation no significant difference could be seen in the gas exchange between the groups. During the second day, however, and especially after the right pneumonectomy, a significant increase in gas exchange could be seen in the treated group compared to the controls. <h3>Conclusion</h3> Hemoperfusion post transplantation using cytokine filtration did regenerate lung function in ARDS injured donor lungs and did significantly reduced PGD.

Ecophysiological Responses of Copaifera langsdorffii Grown in Mining Tailings Under Lower Water Availability

The objective of this work was to test the effect of water limitation on Copaifera langsdorffii Desf. cultivated in mining tailings from the dam rupture in Mariana City, Brazil. Plants were grown in the mining tailing and under two conditions: field capacity (FC) and 50% FC for 60 days. The effects of water restriction on growth, gas exchange, water potential, and leaf anatomy of C. langsdorffii were evaluated. The experimental design was completely randomized with two treatments and 15 replicates, and data was submitted to one-way ANOVA to p < 0.05. Mining tailings showed adequate nutrient levels and the presence of Al, Cd, Pb, and Cr as well as very small particles of 1.19 μm in diameter. The reduction in water availability promoted no changes in the shoot fresh weight, however, increased this parameter for the roots. In addition, water limitation increased plant investment in the root system while reduced biomass allocation to shoots. Lower water levels also increased the root length, number of leaves, and leaf area. However, both water potential and content were not changed by reduced water availability. Lower water levels also increased gas exchange parameters and chlorophyll content. In addition, 50% FC increased the stomatal length/width ratio and their size though no effect in stomatal density was found. Thus, Copaifera langsdorffii grows and thrives in mining tailings even under reduced water availability up to 50% FC showing potential for reforestation systems.

Physiological and Productive Response of Two Varieties of Tomato (&amp;lt;i&amp;gt;Solanum lycopersicon&amp;lt;/i&amp;gt;) to the Application of &amp;lt;i&amp;gt;Glomus iranicum&amp;lt;/i&amp;gt; in the Region of Extremadura

Two varieties of tomato plants, H 1015 (1) and H 3402 (2) from two adjoining commercial farms located in San Benito, Extremadura and cultivated in the same soil and fertirrigation conditions, were inoculated with the arbuscular mycorrhizal fungus Glomus iranicum variety Tenuihypharum, (AMF) from the commercial product Mycogrowth. The applied treatments to the plants were: control 1, AMF 1, control 2 and AMF 2. The physiological indicators and productive responses of the plants from the four treatments were studied. The percentage of mycorrhization, soil moisture, the growth of dry aerial biomass, leaf water potential (Ψ leaf), stomatal conductance (gs), photosynthetic rate (Pn) and performance of its components rate were evaluated 81 days after transplantation. The (Ψ leaf) and (Pn) were measured twice (10.00 and 13.00 h). The results showed that symbiosis between tomato plants and the AMF was successful. Plants of both varieties treated with AMF, had better physiological performance, increased leaf water potential, increased gas exchange (stomatal conductance and photosynthetic rate), and showed improvements in growth, quality and productivity at plot level. The positive effects of this fungus show that it could result of great importance for reducing the use of chemical fertilizers, at least partially, in the future.

Correction to: Effects of chemical sterilization of the culture media, porous membranes and luminosity on in vitro culture of Eucalyptus grandis × Eucalyptus urophylla

Hybrid combinations of Eucalyptus have increased due to expansion of plantations into unconventional areas and to the search for higher quality timber. However, most of these species have difficulties surviving in vitro cultivation. Active chlorine and sealing systems are often used to reduce contamination and increase gas exchange. The aim of the present study is to evaluate the establishment, multiplication, elongation and adventitious rooting of E. grandis × E. urophylla. Two clones (C1 and C2) and four active chlorine concentrations (0.000%, 0.001%, 0.003%, and 0.005%) were tested in the establishment and multiplication phases. Three sealing forms (W/M, 1/M and 3/M) and the same four active chlorine concentrations were applied to the elongation phase. Two luminosities (dark and light) and three sealings (W/M, 1/M and 3/M) were tested during adventitious rooting. Active chlorine concentration of 0.005% led to the lowest fungal contamination rate and to the highest in vitro establishment. Active chlorine concentration of 0.003% resulted in the greatest length and highest number of shoots per explant in the multiplication phase. There were no phytotoxicity problems and the quality of plants grown in an environment with active chlorine was maintained in comparison with those grown in an autoclave. The increase in gas exchange in ventilation systems had a positive impact on the in vitro growth and development of plants.