Effects of irrigation strategies and soils on field-grown potatoes: Gas exchange and xylem [ABA]

Gas exchange was measured in potatoes (cv. Folva) grown in lysimeters (4.32 m²) in coarse sand, loamy sand, and sandy loam and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. PRD and DI as water-saving irrigation treatments received 65% of FI and started after tuber bulking and lasted for six weeks until final harvest. Midday photosynthesis rate (A_n) and stomatal conductance (g_s) of fully irrigated (FI) plants were lowest in coarse sand and mean A_n of diurnal measurements in FI, PRD and DI tended to be lower in this soil as compared with the loamy sand and sandy loam. The results revealed that diurnal values of A_n and g_s in PRD and DI were consistently lower than FI without reaching significant differences in accordance with findings that xylem [ABA] in PRD was significantly higher than FI, and tended to be higher than in DI. Diurnal measurements showed that A_n reached peak values during mid-morning and midday, while g_s were highest during the morning. Intrinsic water use efficiency (A_n/g_s) correlated linearly well with the leaf to air vapor pressure deficit (VPD) and the slope of the line revealed the rate of A_n/g_s increase per each kPa increase in VPD, i.e. approximately 10 μmol mol⁻¹. Transpiration efficiency (A_n/T) of PRD was higher than DI, which shows slightly better efficient water use than DI. The slope of the linear relationship between transpiration efficiency and VPD decreased from −2.03 to −1.04 during the time course of the growing season, indicating the negative effect of leaf ageing on photosynthesis and thus on plant water use efficiency. This fact shows the possibility to save water during last growth stages through applying water-saving irrigations without much effect on transpiration efficiency.     

Effects of dietary turmeric administration on stress,immune, antioxidant and inflammatory responses of common carp (Cyprinus carpio) during copper exposure

The present study assessed the effects of dietary turmeric on Cyprinus carpio resistance and responses to copper exposure. First, the fish were assigned to four treatments received diets supplemented with 0 (control), 5, 10 and 20 g/kg turmeric for 3 weeks. Thereafter, the fish were exposed to lethal concentration (3.5 mg/L) of ambient copper for 24 hr and mortality was 65.3%, 41.8%, 22.7% and 20.6%, respectively. In the second experiment, the fish were fed with the aforementioned diets and simultaneously exposed to sub‐lethal concentration (0.25 mg/L) of ambient copper for 3 weeks. Copper exposure led to increases in plasma cortisol, glucose, malondialdehyde (MDA), alanine transaminase (ALT) and aspartate transaminase (AST), and decrease in plasma T₄, T₃, lysozyme, alternative complement haemolytic (ACH50), bactericidal activities, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and blood red blood cell count (RBC) and haemoglobin. Moreover, copper exposure led to significant upregulation of tumour necrosis factor‐alpha (TNF‐a) and interleukin 1‐beta (IL1‐b), and significant downregulation of interleukin 10 (IL10) gene expressions in the fish liver. Turmeric administration at 10 g/kg significantly mitigated/inhibited the copper‐induced negative effects, which seems to be due to the augmenting of the antioxidant defence.     

Evaluation of yield and some physiological changes in corn and sorghum under irrigation regimes and application of barley residue,zeolite and superabsorbent polymer

In order to investigate the changes in chlorophyll fluorescence, chlorophyll, relative water content (RWC) and forage yield of corn and sorghum under various irrigation regimes and combination treatments of barley residue, zeolite and superabsorbent polymer, an experiment was conducted over 2 years in Kerman, Iran. A randomized complete block design arranged in a factorial split was used with three replications. Two irrigation regimes of normal and drought stress based on 70 and 140 mm cumulative pan evaporation, respectively, and two plant species (corn and sorghum) as factorial combinations were compared in the main plots. Five treatments, (1) 10 t ha^?1 zeolite + 4.5 t ha^?1 residue, (2) 60 kg ha^?1 superabsorbent + 4.5 t ha^?1 residue, (3) 5 t ha^?1 zeolite + 30 kg ha^?1 superabsorbent + 4.5 t ha^?1 residue, (4) 4.5 t ha^?1 residue and (5) – control, were compared in subplots. In both plants, forage yield, potential quantum yield (Fv/Fm), chlorophyll a, total chlorophyll and carotenoid contents decreased significantly under drought stress. Chlorophyll a content, SPAD index and Fv/Fm were higher in corn than in sorghum, but RWC was higher in sorghum. Corn produced higher forage yield (62.8 t ha^?1) than sorghum (49.3 t ha^?1). The application of 10 t ha^?1 zeolite with 4.5 t ha^?1 residue increased most traits more than any of the other treatments, but the superabsorbent had no significant effect on the studied traits.     

土地利用变化对塔里木河中游胡杨林的影响研究

本研究区位于塔里木河中游地区,本研究选取耕地变化、输水堤防的建设以及油气田开发三种土地利用方式,在大量野外调查的基础上,在3S技术和历史数据的支持下,分析了这些土地利用方式变化对胡杨林生态系统的影响。研究结果表明:研究区1992年之后内耕地大量增加,输水堤防对堤防内外侧胡杨生态系统具有不同影响,油气田开发会造成生态破坏和环境污染等问题。     

Pan‐continental invasion of Pseudorasbora parva: towards a better understanding of freshwater fish invasions

In recent years, policy‐makers have sought the development of appropriate tools to prevent and manage introductions of invasive species. However, these tools are not well suited for introductions of non‐target species that are unknowingly released alongside intentionally‐introduced species. The most compelling example of such invasion is arguably the topmouth gudgeon Pseudorasbora parva, a small cyprinid species originating from East Asia. A combination of sociological, economical and biological factors has fuelled their rapid invasion since the 1960s; 32 countries (from Central Asia to North Africa) have been invaded in less than 50 years. Based on a combination of monitoring surveys (2535 populations sampled) and literature reviews, this paper aims to quantify and characterise important invasion parameters, such as pathways of introduction, time between introduction and detection, lag phase and plasticity of life history traits. Every decade, five new countries have reported P. parva introduction, mainly resulting from the movement of Chinese carps for fish farming. The mean detection period after first introduction was 4 years, a duration insufficient to prevent their pan‐continental invasion. High phenotypic plasticity in fitness related traits such as growth, early maturity, fecundity, reproductive behaviour and the ability to cope with novel pathogens has predisposed P. parva to being a strong invader. The Pseudorasbora parva invasion has provided quantitative data for the development of 1) early warning systems across different spatial scales; 2) rapid eradication programmes prior to natural spread in open systems and 3) sound risk assessments with emphasis on plasticity of life history traits.     

Responses of cucumber plant to NH4 and NO3 nutrition: The relative addition rate technique vs. cultivation at constant nitrogen concentration

Different N sources (NO₃⁻, NH₄⁺, or NH₄NO₃) at different relative addition rates (RAR) were supplied to cucumber (Cucumis sativus L.), a species sensitive to NH₄⁺ toxicity. For comparison, cucumber plants were also grown at constant concentrations of 1 and 5 mM NH₄⁺ or 5 mM NO₃⁻. The fresh weight of NH₄⁺-fed plants at RAR 0.15 and RAR 0.25 day⁻¹ was similar to that of NO₃⁻-fed plants, while at RAR 0.35 or RAR 0.45 day⁻¹ growth reduction occurred. When available as a constant concentration, NH₄⁺ decreased plant growth at 5 mM. It is concluded that at low rates of N supply the relative addition rate technique can be used for growing cucumber plants with NH₄⁺ as sole N source without deleterious effects.     

Sediment source fingerprinting: benchmarking recent outputs,remaining challenges and emerging themes

Journal of Soils and Sediments - This review of sediment source fingerprinting assesses the current state-of-the-art, remaining challenges and emerging themes. It combines inputs from international...     

Effects of sodium diformate on growth performance,gut microflora,digestive enzymes and innate immunological parameters of Asian sea bass (Lates calcarifer) juveniles

This study was conducted to evaluate the effects of dietary sodium diformate (NaDF) on growth performance, gut microflora, digestive enzyme activities and immune response parameters of Asian sea bass (Lates calcarifer) juveniles. Fish with initial weight of 12.5 ± 0.4 g were fed with five experimental diets contained 0.0 (control), 5, 10.0, 15.0 and 20 g NaDF kg^?1 in triplicate for 6 weeks. Fish fed diet containing 5 g NaDF kg^?1 had significantly the highest final body weight and feed intake among different treatments. The gut total viable bacterial counts gradually decreased with increasing dietary NaDF level. Specific activity of chymotrypsin improved in fish fed diets administered with NaDF compared to the control group. Fish fed 5 g NaDF kg^?1 diet showed the highest serum lysozyme level among different treatments. The serum classical pathway activity of complement showed higher level in fish fed diets contained 5 and 10 g NaDF kg^?1 than other groups. According to break‐point regression method analysis, the optimum inclusion of dietary NaDF in L. calcarifer juveniles was estimated between 4.6 and 5.1 g/kg, when specific growth rate and feed conversion ratio were plotted against dietary NaDF levels.     

Composition of ovarian fluid in endangered Caspian brown trout, <Emphasis Type="Italic">Salmo trutta caspius</Emphasis>, and its effects on spermatozoa motility and fertilizing ability compared to freshwater and a saline medium

In this study, ovarian fluid composition and its effects on the motility and fertilizing ability of sperm were studied in endangered Caspian brown trout, Salmo trutta caspius, and were compared with a saline activation medium (125 mM NaCl, 30 mM Glycine, 20 mM Tris–HCl, pH = 9.0) and freshwater as the control. The ovarian fluid was composed of sodium 164.4 ± 4.4 mM l⁻¹, potassium 1.8 ± 0.1 mM l⁻¹, calcium 0.6 ± 0.1 mM l⁻¹, magnesium 0.4 ± 0.02 mM l⁻¹, chloride 127.4 ± 5.9 mM l⁻¹, total protein 389.5 ± 89.6 mg 100 ml⁻¹, cholesterol 9.3 ± 1.2 mg dl⁻¹, and glucose 3.3 ± 0.2 mM l⁻¹. The percentage of motile spermatozoa and the duration of sperm motility were significantly higher in ovarian fluid (62 ± 3%, 74.6 ± 0.8 s) than freshwater (35 ± 4%, 44 ± 1 s), but they did not differ significantly from saline medium (56 ± 3%, 74.3 ± 0.7 s) (P > 0.05). Higher eyeing rates were observed after the activation of sperm in ovarian fluid and saline solution than freshwater when 35,000 or 350,000 spermatozoa per egg were added into the activation media. However, no significant differences were observed at higher concentrations of spermatozoa per egg (730,000) (P > 0.05). Also, this study showed that the ovarian fluid composition can be considered as a species-specific character among salmonid fishes. As a conclusion, the results of this study recommend the use of ovarian fluid or the saline solution as an activation medium in the artificial reproduction of Caspian brown trout.