Effects of the interaction between drought and shade on water relations, gas exchange and morphological traits in cork oak (Quercus suber L.) seedlings     

I. Aranda  L. Castro  M. Pardos  L. Gil  J.A. Pardos 《Forest Ecology and Management》2005,210(1-3):117-129

The combined effect of drought and light on different physiological and biochemical traits was assessed in cork oak (Quercus suber L.) seedlings grown under two levels of light availability and submitted to a long-standing drought. Watering was withdrawn after germination and seedlings were allowed to dry to a water content of ca. 50% of field capacity. At this point, water-stressed seedlings were grown under moderate drought and two light regimes: high light (HL—50%) and low light (LL—2%). Soil water in control plants was kept close to field capacity (90–100%) for both light environments. Water-relations parameters derived from P–V curves, gas exchange and water status at predawn (Ψ_pd) were evaluated at twice during the experiment. Nitrogen and chlorophyll contents were determined in the same leaves used for the gas exchange measurements. In addition, maximum rate of carboxylation (V_cmax) and electronic transport (J_max) were derived from A–C_i curves in well-watered seedlings.

The variation on moisture availability during the experiment was the same under both light environments. In control plants, Ψ_pd was over −0.3 MPa at the two harvests, while stressed seedlings decreased to −0.9 MPa, with no differences between light treatments. Water stress decreased osmotic potentials at full (Ψπ₁₀₀) and zero turgor (Ψπ₀). The regressions between both potentials and Ψ_pd showed a higher intercept in shade grown seedlings. This fact will point out the higher osmoregulation capacity in sun seedlings whatever water availability.

Nitrogen investment on a per leaf mass (N_mass), chlorophyll content (Chl_mass) and SLA tended to show a typical pattern of sun-shade acclimation. Thus, the three parameters increased with shade. Only for N_mass there was a significant effect of watering, since water stress increased N_mass.

LL plants showed a lower photosynthetic capacity in terms of maximum net photosynthesis at saturating light (A_max), which was related to a decrease in V_cmax and J_max. Both parameters varied with specific leaf area (SLA) in a similar way. The low-light environment brought about a higher nitrogen investment in chlorophyll, while under high-light environment the investment was higher in carboxylation (V_cmax) and electronic transport (F_max).

Stomatal conductance to water vapour (g_wv) and A_max were lower in low-light seedlings independently of watering. In addition, there was a trend to keep higher intrinsic water use efficiency (IWUE) under high light environment. The increase of IWUE under water stress was higher in HL seedlings. This was as consequence of the steeper decline in g_wv as Ψ_pd decreased. The decrease of A_max with Ψ_pd occurred in a similar way in LL and HL seedlings. Thus, the HL seedlings tended to sustain a higher ability to increase IWUE than LL seedlings when they were submitted to the same water stress.  相似文献   

Alopecia areata universalis in a dog          下载免费PDF全文

Pedro J. Ginel  Beatriz Blanco  María Pérez‐Aranda  Rafael Zafra  Elena Mozos 《Veterinary dermatology》2015,26(5):379-e87

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Inheritance of Aluminum Tolerance and its Effects on Grain Yield and Grain Quality in Oats (Avena Sativa L.)     

Itamar Cristiano Nava  Carla Andréa Delatorre  Ismael T. de Lima Duarte  Marcelo Teixeira Pacheco  Luiz Carlos Federizzi 《Euphytica》2006,148(3):353-358

Summary Aluminum toxicity due to the cation Al⁺³ is a major factor limiting yields in acid soils. Wide genetic variability to aluminum tolerance is found in oat genotypes. The objectives of this study were to determine the number of genes controlling aluminum tolerance in oats and to verify if any detrimental effects were present of the aluminum tolerance genes on grain yield and grain quality in Al⁺³free soils. Aluminum tolerance was estimated as the average regrowth of the main root after exposure to toxic levels of Al⁺³ in a hydroponic solution under controlled conditions. The number of genes controlling that trait was estimated from the distribution of the average root regrowth frequencies in a population of 333 recombinant inbred lines (RIL's) in generations F_5:6 and F_5:7. The effects on grain yield and grain quality were assessed in a subpopulation of 162 RIL's chosen based on their aluminum tolerance response. Aluminum tolerance in the evaluated population was controlled by one dominant major gene with the tolerant genotypes carying Al _a Al _a and the sensitive ones al _a al _a alleles. No detrimental effects of the Al _a allele on grain yield or grain quality were detected.Part of the Master of Science dissertation of the first author  相似文献   

大豆根构型在玉米/大豆间作系统中的营养作用   总被引：23，自引：0，他引：23  

唐劲驰  佘丽娜  廖红  陈怀珠  孙祖东  严小龙 《中国农业科学》2005,38(6):1196-1203

 运用根构型不同的大豆品种与玉米进行间作，比较大豆根构型在玉米/大豆间作系统中的营养作用。结果表明，玉米与大豆间作具有明显的间作优势，间作作物的生物量、氮磷含量都显著好于单作。玉米与浅根型大豆品种巴西10号间作，间作优势大于与深根型大豆品种本地2号。说明大豆根构型在玉米/大豆间作系统中具有十分重要的作用。间作系统的氮磷养分竞争比率表明，玉米/大豆这类豆科/禾本科间作组合的优势主要来自对氮的优势性吸收，而玉米与不同基因型大豆间作的优势差异则主要来源于对土壤磷吸收的差异。浅根型大豆品种不仅有利于两种间作作物对土壤磷的吸收，同时还有利于对氮的吸收。  相似文献   

Effect of a new thermal treatment in combination with saprobic fungal incubation on the phytotoxicity level of alperujo     

Sampedro I  Aranda E  Rodríguez-Gutiérrez G  Lama-Muñoz A  Ocampo JA  Fernández-Bolaños J  García-Romera I 《Journal of agricultural and food chemistry》2011,59(7):3239-3245

Byproducts generated from food industries, such as olive oil mills, have been studied to decrease harmful pollution and their environmental consequences. In this work, a new thermal pretreatment and saprobic fungal incubation to detoxify alperujo (two-phase olive mill waste) have been evaluated in view of its use as fertilizer in agriculture. The sequential use of both methods simplifies the thermal conditions and incubation times of the fungal treatment. Optimization of the thermal treatment from 150 to 170 °C for 45 and 15 min, respectively, reduced the incubation time with Coriolpsis rigida from 20 to 10 weeks needed to reduce phytotoxic effects on tomato plants. Therefore, the combination of thermal and biological treatments will allow the development of the potential benefits of alperujo to improve nutrients in agricultural soil.  相似文献   

Time-resolved spectral studies of blue-green fluorescence of artichoke (Cynara cardunculus L. Var. Scolymus) leaves: identification of chlorogenic acid as one of the major fluorophores and age-mediated changes     

Morales F  Cartelat A  Alvarez-Fernández A  Moya I  Cerovic ZG 《Journal of agricultural and food chemistry》2005,53(25):9668-9678

Synchrotron radiation and the time-correlated single-photon counting technique were used to investigate the spectral and time-resolved characteristics of blue-green fluorescence (BGF) of artichoke leaves. Leaves emitted BGF under ultraviolet (UV) excitation; the abaxial side was much more fluorescent than the adaxial side, and in both cases, the youngest leaves were much more fluorescent than the oldest ones. The BGF of artichoke leaves was dominated by the presence of hydroxycinnamic acids. A decrease in the percentage of BGF attributable to the very short kinetic component (from 42 to 20%), in the shape of the BGF excitation spectra, and chlorogenic acid concentrations indicate that there is a loss of hydroxycinnamic acid with leaf age. Studies on excitation, emission, and synchronized fluorescence spectra of leaves and trichomes and chlorogenic acid contents indicate that chlorogenic acid is one of the main blue-green fluorophores in artichoke leaves. Results of the present study indicate that 20-42% (i.e., the very short kinetic component) of the overall BGF is emitted by chlorogenic acid. Time-resolved BGF measurements could be a means to extract information on chlorogenic acid fluorescence from the overall leaf BGF.  相似文献   

Nutritional evaluation of pea (Pisum sativum L.) protein diets after mild hydrothermal treatment and with and without added phytase     

Urbano G  Aranda P  Gómez-Villalva E  Frejnagel S  Porres JM  Frías J  Vidal-Valverde C  López-Jurado M 《Journal of agricultural and food chemistry》2003,51(8):2415-2420

The effect of mild hydrothermal treatment and the addition of phytase under optimal conditions (pH 5.5, 37 degrees C) on the nutritive utilization of the protein of pea (Pisum sativum L.) flour was studied in growing rats by examining the chemical and biological balance. Mild hydrothermal treatment produced reductions of 83, 78, and 72%, respectively, in the levels of alpha-galactosides, phytic acid, and trypsin inhibitors and also produced a significant increase in the digestive utilization of protein. The additional fall in the levels of phytic acid caused by the addition of phytase did not lead to a subsequent improvement in the digestive utilization of protein. The mild hydrothermal treatment of pea flour produced a significant increase in the metabolic utilization of protein and carbohydrates, which was reflected in the protein efficiency ratio and food transformation growth indices. These effects were not observed in the phytase-supplemented pea diet.  相似文献   

Inactivation of the gene encoding zinc-binding lipoprotein 103 impairs the infectivity of Streptococcus suis     

Aranda J  Teixidó L  Fittipaldi N  Cortés P  Llagostera M  Gottschalk M  Barbé J 《Canadian journal of veterinary research》2012,76(1):72-76

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Autologous Platelet Concentrates as an Adjunctive Treatment for Chronic Laminitis in a Mare with Pituitary Pars Intermedia Dysfunction     

Jorge U. Carmona  Catalina López  Ismael J. Samudio 《Journal of Equine Veterinary Science》2013

The aim of this article was to describe a case of a 7-year-old mare with chronic laminitis secondary to pituitary pars intermedia dysfunction that was successfully treated with autologous platelet concentrates (APC) obtained by the tube method, 4 months before being treated with oral pergolide. After the diagnosis of pituitary pars intermedia dysfunction, the patient was treated with three intralesional injections of APC at 10-day intervals. APC presented a mean concentration of 430 ± 22 × 10⁶ platelets and 8.6 ± 1.3 leukocytes/mL. The treatment with APC produced growth of the hooves at a rate of 5 mm/wk and substantially reduced the foot pain (lameness) after two APC applications. The mare could be ridden 2 weeks after the third APC treatment. The treatment with oral pergolide 4 months later improved the clinical picture of the patient, albeit hirsutism remained. APC could be useful as adjunctive treatment of chronic laminitis in horses. However, additional clinical studies are necessary to determine the safety and effectiveness of APC in chronic laminitis.  相似文献   

西班牙FERTIUM MAXIMA:致力打造全球种肥领导企业     

Ismael Panart 《中国农资》2019,(28)

<正>Fertium总部位于西班牙萨拉戈萨市,隶属于Tervalis集团,是一家专业化肥生产商和服务分公司,为种植者提供作物营养方面最先进的技术产品,注重农业的可持续发展、尊重环境,提倡合理使用农业营养产品,责任是既满足当下农业需求,而不损害未来的可能性。  相似文献