Chronic cork oak decline and water status: new insights     

Constança S. P. Camilo-Alves  Margarida Vaz  M. Ivone Esteves Da Clara  Nuno Manuel De Almeida Ribeiro 《New Forests》2017,48(6):753-772

Chronic decline and Sudden death are two syndromes of cork oak (Quercus suber) dieback. Mortality is associated with water stress, but underlying physiological mechanisms are poorly understood. Here, we investigated the physiological performance of declining trees during the summer drought. Leaf water potential, gas-exchange, fluorescence of photosystem II and leaf and root starch concentration were compared in healthy (asymptomatic) and declining trees. Low annual cork increment in declining trees indicated tree decline for several years. All trees showed similar water status in spring. In summer, declining trees showed lower predawn leaf water potential (?2.0 vs. ?0.8 MPa), but unexpectedly higher midday leaf water potential than healthy trees (?2.8 vs. ?3.3 MPa). The higher midday water potential was linked to by means of strongly reduced stomatal conductance and, consequently, transpiration. This study is pioneer showing that declining trees had high midday water potential. A tendency for lower sap flow driving force (the difference between predawn and midday water potential) in declining trees was also associated with reduced photosynthesis, suggesting that chronic dieback may be associated with low carbon uptake. However, starch in roots and leaves was very low and not correlated to the health status of trees. Declining trees showed lower water-use efficiency and non-photochemical quenching in summer, indicating less resistance to drought. Contrarily to chronic decline, one tree that underwent sudden death presented predawn leaf water potential below the cavitation threshold.  相似文献   

Foraging wireworms are attracted to root-produced volatile aldehydes     

Fanny Barsics  Benjamin M. Delory  Pierre Delaplace  Frédéric Francis  Marie-Laure Fauconnier  Éric Haubruge  François J. Verheggen 《Journal of pest science》2017,90(1):69-76

Soil-dwelling insects are known to react to chemical cues they encounter in the rhizosphere. Whether wireworms (Coleoptera, Elateridae) use root-emitted volatile organic chemicals to localize their host plant remains, however, poorly understood. Here, we aimed at identifying chemical cues released by barley roots that attract Agriotes sordidus. In a first behavioral experiment, we assessed the ability of wireworms to orient towards live barley roots, using dual-choice olfactometers suitable for belowground insects. Then, we collected the volatile organic compounds (VOC) produced by barley roots using a dynamic head-space sampling approach. VOC were quantified and identified using gas chromatography—mass spectrometry (GC–MS). The odorant blend is composed of four aldehydes, namely hexanal, (E)-hex-2-enal, (E)-non-2-enal, and (E,Z)-nona-2,6-dienal. In a second set of dual-choice bioassays, wireworms were attracted towards a synthetic blend of these four major compounds. However, the synthetic blend was not as attractive as live roots, which is partially explained by the absence of CO₂, commonly known as a strong attractant for soil-dwelling insects. While CO₂ indicates the presence of living material in the vicinity, we hypothesize that additional VOC inform about the plant suitability. A better understanding of these belowground signals would contribute to the development of new integrated control strategies against wireworms.  相似文献   

Xylem traits in European beech (Fagus sylvatica L.) display a large plasticity in response to canopy release     

Estelle Noyer  Barbara Lachenbruch  Jana Dlouhá  Catherine Collet  Julien Ruelle  François Ningre  Meriem Fournier 《Annals of Forest Science》2017,74(2):46

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Unraveling the tripartite interactions among the woolly poplar aphid,its host tree,and their environment: a lead to improve the management of a major tree plantation pest?     

Aurélien Sallé  Sophie Pointeau  Stéphanie Bankhead-Dronnet  Catherine Bastien  François Lieutier 《Annals of Forest Science》2017,74(4):79

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Polycyclic Aromatic Hydrocarbon Oxidation from Concentrates Issued from an Attrition Process of Polluted Soil Using the Fenton Reagent and Permanganate     

Malika Bendouz  Justine Dionne  Lan Huong Tran  Lucie Coudert  Guy Mercier  Jean-François Blais 《Water, air, and soil pollution》2017,228(3):115

This study was conducted to determine the optimal conditions for PAH degradation from highly contaminated attrition sludge (PAC) using a Fenton process or successive permanganate (KMnO₄) oxidation and Fenton processes. The following parameters were studied to optimize the Fenton oxidation process: the amounts of reactants based on the stoichiometric oxidant demand (SOD), the reactant addition protocol and number of doses, and the solid/liquid ratio (S/L). The results showed that the following conditions were optimum: TS?=?30%, 7.5 times SOD, H₂O₂/Fe²⁺ ratio?=?10, and added five times during 60 min, which allowed the degradation of 43% of total 27 PAHs from the PAC. Successive Fenton and KMnO₄ oxidation processes were also tested. PAH degradation using a sequential Fenton process followed by KMnO₄ oxidation (or KMnO₄ followed by Fenton) was higher than for the use of Fenton or KMnO₄ treatment alone. Up to 71% of the total 27 PAHs were degraded when using a combination of both processes. It appeared that the sequential treatment is a viable method for the significant degradation of 27 PAHs from PAC (t value?>?2.77).  相似文献   

Lime and Nutrients Effects on Jatropha curcas Cultivated on an Amazonian Soil     

José Zilton Lopes Santos  Bruno Fernando Faria Pereira  José Augusto Figueira da Silva  Carlos Alberto Franco Tucci  Sílvio Vieira da Silva  Tainah Manuela Benlolo Barbosa 《Communications in Soil Science and Plant Analysis》2017,48(11):1280-1290

We evaluated the effects of macronutrient and micronutrient omission, and of liming, on Jatropha curcas (JC) in greenhouse study. The experimental design was a factorial combination of 2 liming treatments (nil or 4.5 t. ha^?1 of dolomitic lime) x 7 combinations of fertility status, with five replications. The concentrations and uptake of nutrients by JC plants follow the order: nitrogen > potassium > calcium ≥ Magnesium > sulfur > phosphorus > iron > boron > manganese > zinc > copper (N > K > Ca ≥ Mg > S > P > Fe > B > Mn > Zn > Cu), but the growth of JC plants was negatively affected mainly by omission of macronutrients, in the following order: P > N = K = S, on limed soil. Phosphorus is the most critical element for development. JC is responsive to micronutrients only when applied together with macronutrients. Potassium chloride is not recommended as K⁺ source for JC crop. Lime is recommended to improve growth and nutritional status of JC plants.  相似文献   

Liming as an ameliorator of copper toxicity in black oat (Avena strigosa Schreb.)     

Vítor Gabriel Ambrosini  Daniel José Rosa  Alex Basso  Marcelo Borghezan  Rosete Pescador  Alcione Miotto 《Journal of plant nutrition》2017,40(3):404-416

This study aimed to assess the effect of liming as an ameliorator of copper (Cu) toxicity in black oats (Avena strigosa Schreb.) grown in soil with a sandy texture. The treatments were soil supplementation with increasing doses of lime (0.0, 0.5 and 1.0 g kg^?1) and two of Cu (0 and 50 mg kg^?1). Pre-germinated black oat seeds were sown for 30 days in the soil, subsequently, the plant height, root and shoot dry mass and concentration of total chlorophyll, chlorophylls a and b, carotenoids and total soluble carbohydrates and starch were analyzed. The dose of 50 mg kg^?1 soil Cu caused a toxic effect on black oat plant growth and development, affected the internal distribution of nutrients, decreased the leaf chlorophyll concentration and increased the leaf concentration of total soluble carbohydrates and starch. Increasing lime doses ameliorated the toxic effects of Cu.  相似文献   

Digestion and metabolism of low and high residual feed intake Nellore bulls     

Sarah Figueiredo Martins Bonilha  Renata Helena Branco  Maria Eugênia Zerlotti Mercadante  Joslaine Noely dos Santos Gonçalves Cyrillo  Fábio Morato Monteiro  Enilson Geraldo Ribeiro 《Tropical animal health and production》2017,49(3):529-535

Understanding the reasons why animals of similar performances have different feed requirements is important to increase profits for cattle producers and to decrease the environmental footprint of beef cattle production. This study was carried out aiming to identify the associations between residual feed intake (RFI) and animal performance, nutrient digestibility, and blood metabolites related to energy balance of young Nellore bulls during the finishing period. Animals previously classified as low (n?=?13) and high RFI (n?=?12), with average initial body weight of 398 kg and age of 503 days were used. Cattle were fed a high energy diet and were slaughtered when rib fat thickness measured by ultrasound between the 12th and 13th ribs reached the minimum of 4 mm. A completely randomized design was adopted, being data analyzed with a mixed model that included the random effect of slaughter group, the fixed effect of RFI class, and linear effect of the covariate feedlot time. No differences were found (p?>?0.10) between RFI classes for performance, dry matter, and nutrients intake. However, dry (p?=?0.0911) and organic matter (p?=?0.0876) digestibility tended to be lower, and digestibility of neutral detergent fiber corrected for ash and protein (p?=?0.0017), and total digestible nutrients (p?=?0.0657) were lower for high RFI animals, indicating lesser capacity of food utilization. Difference between low and high RFI animals was also found for blood cortisol at the end of the trial (p?=?0.0044), having low RFI animals lower cortisol concentrations. Differences in the ability to digest food can affect the efficiency of transforming feed into meat by Nellore cattle.  相似文献   

Nutraceutic effect of free condensed tannins of <Emphasis Type="Italic">Lysiloma acapulcensis</Emphasis> (Kunth) benth on parasite infection and performance of Pelibuey sheep     

Cesar García-Hernández  Javier Arece-García  Rolando Rojo-Rubio  German David Mendoza-Martínez  Benito Albarrán-Portillo  José Fernando Vázquez-Armijo  Leonel Avendaño-Reyes  Agustín Olmedo-Juárez  Carine Marie-Magdeleine  Yoel López-Leyva 《Tropical animal health and production》2017,49(1):55-61

Forty-five Pelibuey sheep were experimentally infested with nematodes to evaluate the effect of three free condensed tannin (FCT) levels of Lysiloma acapulcensis on fecal egg counts (FECs), packed cell volumes (PCV), ocular mucosa colors (OMC), average daily gain (ADG), and adult nematode count. Five treatments were used: 12.5, 25.0, and 37.5 mg of FCT kg^?1 of body weight (BW); sterile water (control); and ivermectine (0.22 mg kg^?1 of BW) as chemical group. The data were processed through repeated measurement analysis. Even though the three FCT doses decreased (P?<?0.05) the FEC, the highest reduction was obtained with 37.5 mg kg^?1 of BW. No differences were observed in PCV and OMC. Higher ADG (P?<?0.05) was observed with 37.5 mg kg^?1 of BW of FCT. The count of adult nematodes (females and males) in the higher dose of FCT was similar to chemical treatment. Dose of 37.5 mg kg^?1 of BW decreased the parasite infection and improved the lamb performance. Therefore, this dose could be used as a nutraceutic product in sheep production.  相似文献   

Long-term effects of good handling practices during the pre-weaning period of crossbred dairy heifer calves     

Luciana Pontes Silva  Aline Cristina Sant’Anna  Lívia Carolina Magalhães Silva  Mateus José Rodrigues Paranhos da Costa 《Tropical animal health and production》2017,49(1):153-162

The aim of this study was to determine whether applying good practices of handling during the pre-weaning period have long-term effects on behavioral and physiological indicators, health status, and average daily gain (ADG) of crossbred Bos taurus × Bos indicus heifer calves. During the pre-weaning period, 98 crossbred of Holstein × Gir heifer calves were allotted into three treatments: (1) good practices of handling + brushing (GPB; n?=?25), (2) good practices of handling (GP; n?=?25), and (3) control (n?=?48). Every 2 months, four evaluation periods (EV₁ to EV₄) were conducted to record data. Behavioral indicators comprised time to drive (TD), flight speed (FS), flight distance (FD), and composite reactivity score (CRS). Physiological indicators of acute stress during handling comprised respiratory and heart rates. Health status comprised data regarding occurrence of most common diseases (i.e., pneumonia and anaplasmosis). Collected data were analyzed by using a linear mixed model for repeated measures, Tukey’s test, and chi-squared procedures. Treatment influenced (P?<?0.05) TD, FS, and FD but not CRS (P?=?0.78). From EV₁ to EV₃, the control calves had the lowest TD. The GPB group had lower FS than the control but did not differ from GP. The GPB group had lower FD means than the other two groups in EV₂, EV₃, and EV₄. No differences (P?>?0.05) due to treatment were observed on heart and respiratory rates, ADG, or occurrence of pneumonia and anaplasmosis. It was concluded that adoption of good practices of handling during pre-weaning period may lead to long-term positive effects.  相似文献