scholarly journals Foliar-Applied Surfactants and Urea Temporarily Reduce Carbon Assimilation of Grapefruit Leaves

2001 ◽  
Vol 126 (4) ◽  
pp. 486-490 ◽  
Author(s):  
Vladimir Orbovic ◽  
John L. Jifon ◽  
James P. Syvertsen
Keyword(s):  
Penetration Rate ◽  
Carbon Assimilation ◽  
Contact Angles ◽  
Poncirus Trifoliata ◽  
Citrus Paradisi ◽  
Inhibitory Effects ◽  
Surfactant Solutions ◽  
Leaf Surfaces ◽  
Net Assimilation ◽  
Underlying Mechanisms

Although urea can be an effective adjuvant to foliar sprays, we examined effects of additional surfactants on urea penetration through leaf cuticles along with the effect of urea with and without surfactants on net gas exchange of leaves of `Marsh' grapefruit (Citrus paradisi Macf.) trees budded to Carrizo citrange (C. sinensis L. Osbeck × Poncirus trifoliata L. Raf.) rootstock. Various combinations of urea, a nonionic surfactant (X-77), and an organosilicone surfactant (L-77), were applied to grapefruit leaves and also to isolated adaxial cuticles. When compared to X-77, L-77 exhibited superior surfactant features with smaller contact angles of droplets deposited on a teflon slide. Both L-77 and X-77 initially increased penetration rate of urea through cuticles, but the effect of X-77 was sustained for a longer period of time. The total amount of urea which penetrated within a 4-day period, however, was similar after addition of either surfactant. Solutions of either urea, urea + L-77, urea + X-77, or L-77 alone decreased net assimilation of CO2 (ACO2) for 4 to 24 hours after spraying onto grapefruit leaves. A solution of X-77 alone had no effect on ACO2 over the 4-day period. Although reductions in ACO2 were similar following sprays of urea formulated with two different surfactants, the underlying mechanisms may not have been the same. For the urea + X-77 treatment, X-77 increased the inhibitory effects of urea on ACO2 indirectly by increasing penetration of urea into leaves. For the urea + L-77 formulation, effects of L-77 on ACO2 were 2-fold, direct by inhibiting ACO2 and indirect by increasing urea penetration. One hour after application, scanning electron microscopy (SEM) of leaf surfaces treated with X-77 revealed that they were heavily coated with the residue of the surfactant, whereas leaves treated with L-77 looked similar to nontreated leaves with no apparent residues on their surfaces. The amount of X-77 residue on the leaves was lower 24 hours after application than after 1 hour as observed by SEM.

scholarly journals Interaction of surfactants with barley leaf surfaces: time-dependent recovery of contact angles is due to foliar uptake of surfactants

Planta ◽  
2021 ◽  
Vol 255 (1) ◽  
Author(s):  
Johanna Baales ◽  
Viktoria V. Zeisler-Diehl ◽  
Yaron Malkowsky ◽  
Lukas Schreiber
Keyword(s):  
Leaf Surface ◽  
Pure Water ◽  
Contact Angles ◽  
Time Dependent ◽  
Alcohol Ethoxylate ◽  
Leaf Physiology ◽  
Surfactant Solutions ◽  
Surface Wax ◽  
Leaf Surfaces ◽  
Barley Leaf

Abstract Main conclusion Time-dependent contact angle measurements of pure water on barley leaf surfaces allow quantifying the kinetics of surfactant diffusion into the leaf. Abstract Barley leaf surfaces were sprayed with three different aqueous concentrations (0.1, 1.0 and 10%) of a monodisperse (tetraethylene glycol monododecyl ether) and a polydisperse alcohol ethoxylate (BrijL4). After 10 min, the surfactant solutions on the leaf surfaces were dry leading to surfactant coverages of 1, 10 and 63 µg cm−2, respectively. The highest surfactant coverage (63 µg cm−2) affected leaf physiology (photosynthesis and water loss) rapidly and irreversibly and leaves were dying within 2–6 h. These effects on leaf physiology did not occur with the lower surfactant coverages (1 and 10 µg cm−2). Directly after spraying of 0.1 and 1.0% surfactant solution and complete drying (10 min), leaf surfaces were fully wettable for pure water and contact angles were 0°. Within 60 min (0.1% surfactant) and 6 h (1.0% surfactant), leaf surfaces were non-wettable again and contact angles of pure water were identical to control leaves. Scanning electron microscopy investigations directly performed after surfactant spraying and drying indicated that leaf surface wax crystallites were partially or fully covered by surfactants. Wax platelets with unaltered microstructure were fully visible again within 2 to 6 h after treatment with 0.1% surfactant solutions. Gas chromatographic analysis showed that surfactant amounts on leaf surfaces continuously disappeared over time. Our results indicate that surfactants, applied at realistic coverages between 1 and 10 µg cm−2 to barley leaf surfaces, leading to total wetting (contact angles of 0°) of leaf surfaces, are rapidly taken up by the leaves. As a consequence, leaf surface non-wettability is fully reappearing. An irreversible damage of the leaf surface fine structure leading to enhanced wetting and increased foliar transpiration seems highly unlikely at low surfactant coverages of 1 µg cm−2.

scholarly journals 187 Foliar Application of Urea to Citrus: Effects of Non-ionic and Organosilicone Adjuvants

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 422F-423
Author(s):  
Vladimir Orbovic ◽  
John L. Jifon ◽  
James P. Syvertsen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Foliar Application ◽  
Penetration Rate ◽  
Contact Angles ◽  
Urea Uptake ◽  
Leaf Surfaces ◽  
Negative Effect ◽  
Adjuvant Effects ◽  
Scanning Electron

Urea solutions, with or without non-ionic (X-77) and organosilicone (L-77) surfactant, were applied to Citrus leaves and isolated cuticles to examine adjuvant effects on urea uptake and leaf net gas exchange. When compared to X-77, L-77 exhibited superior features as a surfactant, resulting in smaller contact angles of droplets deposited on teflon slide. Both L-77 and X-77 had a strong effect on penetration rate of urea within first 20 min of experiment. Effect of L-77 on urea penetration rate decreased quickly within next 20 min, whereas the effect of X-77 was sustained over a 24-h period following application. When compared to solution of urea alone, addition of X-77 to urea resulted in significant increase of the total amount of urea that penetrated the cuticles. The effect of L-77 was smaller, although the total amount of urea that penetrated the cuticles within a 4-day period was similar for both surfactants. Solutions of either urea alone, urea+L-77 and urea+X-77, or L-77 alone, induced a negative effect on net CO2 assimilation (ACO2) for 4 to 24 h after they were sprayed onto leaves. X-77, when applied alone, had no effect on ACO2. Scanning electron microscopy revealed that 1 h after application, leaf surfaces treated with X-77 appeared to be heavily coated, as opposed to those treated with L-77, which appeared similar to untreated control leaves.

Protocatechuic Acid Protects Platelets from Apoptosis via Inhibiting Oxidative Stress-Mediated PI3K/Akt/GSK3β Signaling

2021 ◽  
Author(s):  
Fuli Ya ◽  
Kongyao Li ◽  
Hong Chen ◽  
Zezhong Tian ◽  
Die Fan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Caspase 3 ◽  
Protocatechuic Acid ◽  
Human Platelets ◽  
Ros Generation ◽  
Inhibitory Effects ◽  
Platelet Apoptosis ◽  
Phosphatidylserine Exposure ◽  
Underlying Mechanisms

AbstractOxidative stress plays crucial roles in initiating platelet apoptosis that facilitates the progression of cardiovascular diseases (CVDs). Protocatechuic acid (PCA), a major metabolite of anthocyanin cyanidin-3-O-β-glucoside (Cy-3-g), exerts cardioprotective effects. However, underlying mechanisms responsible for such effects remain unclear. Here, we investigate the effect of PCA on platelet apoptosis and the underlying mechanisms in vitro. Isolated human platelets were treated with hydrogen peroxide (H2O2) to induce apoptosis with or without pretreatment with PCA. We found that PCA dose-dependently inhibited H2O2-induced platelet apoptosis by decreasing the dissipation of mitochondrial membrane potential, activation of caspase-9 and caspase-3, and decreasing phosphatidylserine exposure. Additionally, the distributions of Bax, Bcl-xL, and cytochrome c mediated by H2O2 in the mitochondria and the cytosol were also modulated by PCA treatment. Moreover, the inhibitory effects of PCA on platelet caspase-3 cleavage and phosphatidylserine exposure were mainly mediated by downregulating PI3K/Akt/GSK3β signaling. Furthermore, PCA dose-dependently decreased reactive oxygen species (ROS) generation and the intracellular Ca2+ concentration in platelets in response to H2O2. N-Acetyl cysteine (NAC), a ROS scavenger, markedly abolished H2O2-stimulated PI3K/Akt/GSK3β signaling, caspase-3 activation, and phosphatidylserine exposure. The combination of NAC and PCA did not show significant additive inhibitory effects on PI3K/Akt/GSK3β signaling and platelet apoptosis. Thus, our results suggest that PCA protects platelets from oxidative stress-induced apoptosis through downregulating ROS-mediated PI3K/Akt/GSK3β signaling, which may be responsible for cardioprotective roles of PCA in CVDs.

scholarly journals Desenvolvimento vegetativo e custo de produção de porta-enxertos de citros em recipientes para fins de subenxertia

2007 ◽  
Vol 42 (5) ◽  
pp. 679-687 ◽  
Author(s):  
Eduardo Augusto Girardi ◽  
Francisco de Assis Alves Mourão Filho ◽  
Sônia Maria de Stefano Piedade
Keyword(s):  
Citrus Sinensis ◽  
Poncirus Trifoliata ◽  
Citrus Paradisi ◽  
Citrus Jambhiri ◽  
Citrus Volkameriana

O objetivo deste trabalho foi avaliar o desenvolvimento vegetativo e estimar o custo de produção de 11 porta-enxertos de citros para fins de subenxertia, em diferentes recipientes. Avaliaram-se limão 'Cravo' clone Limeira (Citrus limonia Osbeck); citrumelo 'Swingle' (Poncirus trifoliata (L.) Raf. x Citrus paradisi Macf.); tangerina 'Cleópatra' (Citrus reshni Hort. ex Tanaka); tangerina 'Sunki' (Citrus sunki Hort. ex Tanaka); limão 'Volkameriano' clone Catânia 2 (Citrus volkameriana Pasquale); laranja 'Caipira' clone DAC (Citrus sinensis L. Osbeck); limão 'Rugoso da África' clone Mazoe (Citrus jambhiri Lush.); Poncirus trifoliata 'Davis A'; tangerina 'Sun Shu Sha Kat' (Citrus sunki Hort. ex Tanaka); tangerina 'Sunki' clone 2506 ou Fruto Grande (Citrus sunki Hort. ex Tanaka) e Poncirus trifoliata 'Barnes'. Foram utilizados tubetes de 290 mL, sacolas de 1,7 L, e porta-enxertos transplantados de tubetes de 75 mL para sacolas de polietileno de 1,7 e 4,5 L. Porta-enxertos produzidos diretamente em sacolas de 1,7 L atingem ponto ideal de subenxertia em menor tempo, de 100 a 150 dias após a semeadura, e permitem a obtenção de plantas maiores e com sistema radicular adequado, porém com custo de produção superior ao sistema de produção em tubetes de 290 mL.

scholarly journals Mudas de laranjeira 'valência' sobre dois porta-enxertos e sob diferentes manejos de adubação

2010 ◽  
Vol 32 (3) ◽  
pp. 855-864 ◽  
Author(s):  
Eduardo Augusto Girardi ◽  
Francisco de Assis Alves Mourão Filho ◽  
André Siqueira Rodrigues Alves
Keyword(s):  
Citrus Sinensis ◽  
Poncirus Trifoliata ◽  
Citrus Paradisi

O manejo da adubação é uma das principais práticas culturais para a produção de mudas cítricas em cultivo protegido. Avaliou-se o efeito de seis tipos de manejo das adubações comercialmente recomendadas na produção de mudas de laranjeira 'Valência' [Citrus sinensis (L.) Osbeck] enxertada sobre os porta-enxertos limoeiro 'Cravo' (Citrus limonia Osbeck) e citrumeleiro 'Swingle' [Citrus paradisi Macf. x Poncirus trifoliata (L.) Raf.]. As avaliações foram conduzidas a partir da transplantação dos porta-enxertos até 180 dias após a enxertia, em viveiro empresarial, em Conchal-SP. Os manejos corresponderam a duas soluções de fertilizantes solúveis aplicadas isoladamente, soluções de fertilizante solúveis associadas a fertilizante de liberação controlada e aplicação exclusiva de fertilizante de liberação controlada. O delineamento experimental adotado foi o fatorial 2 x 6 (porta-enxerto x manejo da adubação), em blocos casualizados, com três repetições e 12 mudas na parcela. O limoeiro 'Cravo' induziu maior crescimento ao enxerto. O crescimento vegetativo das mudas foi similar após o uso de fertilizantes solúveis ou de liberação controlada, apesar da grande variação de quantidades totais de nutrientes fornecidas às plantas. Desta forma, o viveirista poderá optar pelo manejo mais econômico ou prático, conforme as condições locais.

scholarly journals Performance of Minneola tangelo trees grafted over six rootstocks in Colombia Tropical Lowland (1997-2010)

2017 ◽  
Vol 66 (3) ◽  
pp. 397-402
Author(s):  
Hans Chaparro ◽  
David Ricardo Hernández ◽  
Diana Mayerly Mateus ◽  
Javier Orlando Orduz Rodriguez
Keyword(s):  
Fruit Quality ◽  
Citrus Sinensis ◽  
Productive Efficiency ◽  
Poncirus Trifoliata ◽  
Tree Size ◽  
The Other ◽  
Citrus Paradisi ◽  
Tropical Lowland ◽  
Citrus Orchards

‘Cleopatra’ tangerine (Citrus reshni hort. ex Tanaka) is a commonly used rootstock in the piedmont of Meta department, Colombia for establishing of commercial citrus orchards. Have allowed a late production entrance rootstock and produced big plants when grafted with tangelo ‘Minneola’ (C. reticulata Blanco x C. paradise Macf), decreasing the productive efficiency in plants and hard crop practices. The evaluated performance were as follows:  tree size, productive efficiency and fruit quality of tangelo ‘Minneola’ grafted in six rootstocks. It found that the cumulated production of 11 years was better with Citrumelo ‘Swingle’ (Citrus paradisi Macf. × Poncirus trifoliata (L.) Raf) with 1388.3 kg tree-1, followed by ‘Cleopatra’ (Citrus reshni hort. ex Tanaka) with 893.2 kg.tree-1, in last place was ‘Carrizo’ (Citrus sinensis Osb. × Poncirustrifoliata (L.) Raf) with 182.9 kg tree-1. The other rootstocks, had a medium production. The greatest height and canopy value, was found with ‘Cleopatra’ without significant differences with Citrumelo ‘Swingle’. In fruit quality no significant differences occurred.

scholarly journals Biochemical and mesophyll diffusional limits to photosynthesis are determined by prey and root nutrient uptake in the carnivorous pitcher plant Nepenthes × ventrata

2020 ◽  
Vol 126 (1) ◽  
pp. 25-37
Author(s):  
Sebastià Capó-Bauçà ◽  
Marcel Font-Carrascosa ◽  
Miquel Ribas-Carbó ◽  
Andrej Pavlovič ◽  
Jeroni Galmés
Keyword(s):  
Nutrient Uptake ◽  
Protein Complexes ◽  
Photosynthetic Apparatus ◽  
Carbon Assimilation ◽  
Nutrient Status ◽  
Carnivorous Plants ◽  
Pitcher Plant ◽  
Carbon Isotopic ◽  
Underlying Mechanisms ◽  
Photosynthetic Assimilation

Abstract Background and Aims Carnivorous plants can enhance photosynthetic efficiency in response to prey nutrient uptake, but the underlying mechanisms of increased photosynthesis are largely unknown. Here we investigated photosynthesis in the pitcher plant Nepenthes × ventrata in response to different prey-derived and root mineral nutrition to reveal photosynthetic constrains. Methods Nutrient-stressed plants were irrigated with full inorganic solution or fed with four different insects: wasps, ants, beetles or flies. Full dissection of photosynthetic traits was achieved by means of gas exchange, chlorophyll fluorescence and immunodetection of photosynthesis-related proteins. Leaf biochemical and anatomical parameters together with mineral composition, nitrogen and carbon isotopic discrimination of leaves and insects were also analysed. Key Results Mesophyll diffusion was the major photosynthetic limitation for nutrient-stressed Nepenthes × ventrata, while biochemistry was the major photosynthetic limitation after nutrient application. The better nutrient status of insect-fed and root-fertilized treatments increased chlorophyll, pigment–protein complexes and Rubisco content. As a result, both photochemical and carboxylation potential were enhanced, increasing carbon assimilation. Different nutrient application affected growth, and root-fertilized treatment led to the investment of more biomass in leaves instead of pitchers. Conclusions The study resolved a 35-year-old hypothesis that carnivorous plants increase photosynthetic assimilation via the investment of prey-derived nitrogen in the photosynthetic apparatus. The equilibrium between biochemical and mesophyll limitations of photosynthesis is strongly affected by the nutrient treatment.

scholarly journals Mycorrhizas enhance drought tolerance of citrus by altering root fatty acid compositions and their saturation levels

2019 ◽  
Vol 39 (7) ◽  
pp. 1149-1158 ◽  
Author(s):  
Qiang-Sheng Wu ◽  
Jia-Dong He ◽  
A K Srivastava ◽  
Ying-Ning Zou ◽  
Kamil Kuča
Keyword(s):  
Fatty Acid ◽  
Drought Tolerance ◽  
Strong Association ◽  
Regulation Of Gene Expression ◽  
Am Fungi ◽  
Unsaturation Index ◽  
Arbuscular Mycorrhizas ◽  
Poncirus Trifoliata ◽  
Underlying Mechanisms ◽  
Fatty Acid Compositions

Abstract Arbuscular mycorrhizas (AMs) have the ability to enhance drought tolerance of citrus, but the underlying mechanisms have not been clearly elucidated. Considering the strong association of cell membrane fatty acid (FA) unsaturation with plant drought tolerance, the present study hypothesized that AM fungi (AMF) modulated the composition and unsaturation of FAs to enhance drought tolerance of host plants. Drought-sensitive citrus rootstocks, trifoliate orange (Poncirus trifoliata) seedlings, were inoculated with AMF (Funneliformis mosseae) for 3 months and were subsequently exposed to drought stress (DS) for 8 weeks. Mycorrhizal seedlings exhibited better plant growth performance, higher leaf water potential and lower root abscisic acid concentrations under both well-watered (WW) and DS conditions. Arbuscular mycorrhiza fungus inoculation considerably increased root methyl oleate (C18:1), methyl linoleate (C18:2) and methyl linolenate (C18:3N3) concentrations under both WW and DS conditions, and root methyl palmitoleate (C16:1) concentrations under WW, while it decreased root methyl stearate (C18:0) levels under both WW and DS. These changes in the composition of FAs of mycorrhized roots resulted in higher unsaturation index of root FAs, which later aided in reducing the oxidative damage on account of lower concentration of malondialdehyde and superoxide radicals. The changes of these FAs were a result of AMF-up-regulating root FA desaturase 2 (PtFAD2), FA desaturase 6 (PtFAD6) and Δ9 FA desaturase (PtΔ9) genes under WW and PtFAD2, PtFAD6 and Δ15 FA desaturase (PtΔ15) genes under DS conditions. Our results confirmed that mycorrhization brought significant changes in root FA compositions, in addition to regulation of gene expression responsible for increasing the unsaturation level of FAs, a predisposing physiological event for better drought tolerance of citrus.

Investigation of the life history and infestation of Phyllocnistis citrella (Lepidoptera: Gracillariidae) on four different hosts

2019 ◽  
Vol 151 (3) ◽  
pp. 329-339
Author(s):  
Maryam Atapour ◽  
Shiva Osouli
Keyword(s):  
Life History ◽  
Mass Rearing ◽  
Immature Stage ◽  
Poncirus Trifoliata ◽  
Citrus Paradisi ◽  
Phyllocnistis Citrella ◽  
Citrus Leafminer ◽  
Valencia Orange ◽  
Control Programmes ◽  
History Of

AbstractPhyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), also known as the citrus leafminer, is a serious pest in Citrus Linnaeus (Rutaceae) nurseries in Iran. Few studies have been performed on the life history of this pest on different citrus hosts. In this work, the infestation rate and biological aspects of P. citrella were investigated using four citrus hosts: Valencia orange (Citrus sinensis (Linnaeus) Osbeck), trifoliate orange (Poncirus trifoliata (Linnaeus) Rafinesque), grapefruit (Citrus paradisi Macfadyen), and sweet lemon (Citrus aurantifolia Swingle). Moths preferred laying eggs on leaves with a width ranging from 1–2 cm, and the highest oviposition was observed on the Valencia orange (51.2 eggs/female). The numbers of pupae and infested leaves were significantly higher on C. sinensis and C. aurantifolia. The entire developmental period of the immature stages was 13.8 and 15.4 days in C. aurantifolia and C. sinensis, respectively, while it increased to 21.8 and 24.7 days in C. paradisi and P. trifoliata. The rate of mortality of the immature stage was the highest in these two latter hosts as well (29–31%). Moths showed the highest emergence and longevity on C. sinensis and C. aurantifolia. The results indicate that C. sinensis and C. aurantifolia are susceptible hosts that can be recommended for the mass-rearing of this species in non-chemical pest control programmes.

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