Combined effect of virus infection and water stress on water flow and water economy in grapevines

Water limitation is one of the major threats affecting grapevine production. Thus, improving water‐use efficiency (WUE) is crucial for a sustainable viticulture industry in Mediterranean regions. Under field conditions, water stress (WS) is often combined with viral infections as those are present in major grape‐growing areas worldwide. Grapevine leafroll‐associated virus 3 (GLRaV‐3) is one of the most important viruses affecting grapevines. Indeed, the optimization of water use in a real context of virus infection is an important topic that needs to be understood. In this work, we have focused our attention on determining the interaction of biotic and abiotic stresses on WUE and hydraulic conductance (K_h) parameters in two white grapevine cultivars (Malvasia de Banyalbufar and Giró Ros). Under well‐watered (WW) conditions, virus infection provokes a strong reduction (P < 0.001) in K_petiole in both cultivars; however, K_leaf was only reduced in Malvasia de Banyalbufar. Moreover, the presence of virus also reduced whole‐plant hydraulic conductance (K_hplant) in 2013 and 2014 for Malvasia de Banyalbufar and in 2014 for Giró Ros. Thus, the effect of virus infection on water flow might explain the imposed stomatal limitation. Under WS conditions, the virus effect on K_plant was negligible, because of the bigger effect of WS than virus infection. Whole‐plant WUE (WUE_WP) was not affected by the presence of virus neither under WW nor under WS conditions, indicating that plants may adjust their physiology to counteract the virus infection by maintaining a tight stomatal control and by sustaining a balanced carbon change.     

Sedimentation of Bacillus sphaericus in tap water and sewage water

Formulations of Bacillus sphaericus products were applied in 1-m columns of clean water and sewage water in tubes. Samples taken through valves attached to the walls of the tubes showed that spores settled as a function of application method, droplet size, particle size, and water characteristics. In a mixture of deionized and tap water, the slowest sedimentation rate was obtained with a primary powder sonicated in water with 0.1% detergent. This product and a commercial fluid product settled faster in sewage water than in clean water and after 4 weeks, most spores were found in the sediment. In clean water, most spores remained suspended during the 4 weeks but the density was highest at the bottom. Calculation of total spore numbers in the columns after 4 weeks indicated that about 90% of spores disappeared in clean water, and 95-97% disappeared in sewage water. Bioassays showed that toxicity declined in parallel with the sedimentation, but at a higher rate, indicating a loss of toxicity from the residual spores.     

北京市水足迹及农业用水结构变化特征

运用水足迹的理论和方法计算评价了1990—2005年北京市水足迹及水资源利用的可持续性,在此基础上进一步分析了北京市农业用水结构的变化特征。结果表明:(1)北京市水足迹从1990年的81.5亿m3上升至2005年的168.6亿m3,人均水足迹由750.1m3上升为1096.0m3;(2)北京市水资源匮乏度不断升高,1995年以来水资源自给率呈下降趋势,与之相对应的水资源依赖度越来越高;(3)农业部门用水量在本地用水量中的比例平均每年为55.1%,虚拟水净输入量在虚拟水净输入总量中的比例平均每年达到89.1%;(4)高耗水型作物产品生产用水比例升高加大了农业用水压力,动物产品生产用水量呈增加趋势,2001—2005年动物产品生产引入的虚拟水占到其虚拟水总量的81.3%。北京市水资源利用呈不可持续状态,通过农业系统内部结构的优化调整,实现农业部门水资源的高效利用是缓解北京市水资源紧缺问题的关键。     

Self quenching of chlorosome chlorophylls in water and hexanol-saturated water

The optical properties of a methyl ester homolog of bacteriochlorophylld (BChld _M ) and bacteriochlorophyllc (BChlc) in H₂O, hexanol-saturated H₂O and methanol were studied by absorption, fluorescence emission, and circular dichroism (CD). In H₂O, BChld _M spontaneously forms an aggregate similar to that formed in hexane, with absorption maximum at 730 nm and fluorescence emission at 748 nm. For the pigment sample in hexanol-saturated H₂O, while the absorption peaks at 661 nm, only slightly red-shifted compared to the monomer, the fluorescence emission is highly quenched. When diluted 2–3 fold with H₂O, the absorption returns to around 720 nm, characteristic of an aggregate. The CD spectrum of the H₂O aggregate exhibits a derivative-shaped feature with positive and negative peaks, while the amplitude is lower than that of chlorosomes. The Fourier transform infrared spectra of BChld _M aggregates in H₂O and hexane were measured. A 1644 cm^–1 band, indicative of a bonded 13¹-keto group, is detected for both samples. A marker band for 5-coordinated Mg was observed at 1611 cm^–1 for the two samples as well. To study the kinetic behavior of the samples, both single-photon counting (SPC) fluorescence and transient absorption difference spectroscopic measurements were performed. For BChld _M in hexanol-saturated H₂O, a fast decay component with a lifetime of 10 to 14 ps was detected using the two different techniques. The fast decay could be explained by the concentration quenching phenomenon due to a high local pigment concentration. For the pigment sample in H₂O, SPC gave a 16 ps component, whereas global analysis of transient absorption data generated two fast components: 3.5 and 26 ps. The difference may arise from the different excitation intensities. With a much higher excitation in the latter measurements, other quenching processes, e.g. annihilation, might be introduced, giving the 3.5 ps component. Finally, atomic force microscopy was used to examine the ultrastructure of BChld _M in H₂O and hexanol-saturated H₂O. Pigment clusters with diameters ranging from 15 to 45 nm were observed in both samples.     

Root growth and water uptake during water deficit and recovering in wheat

Root growth and soil water content were measured in a field experiment with wheat subjected to two periods of water deficit. The first period was induced early in the season between the early vegetative stage (22 DAS) and late terminal spikelet (50 DAS), the second period at mid-season between terminal spikelet (42 DAS) and anthesis (74 DAS). Total root growth was reduced under water deficit by a reduction in the top 30 cm, while the root system continued to grow in the deeper soil profile between 30 and 60 cm. Shortly after rewatering, the growth pattern reverted to fastest root growth rates in the shallow soil layers. In relative terms, the total root system increased in relation to the above ground dry matter under water shortage. The early-, the mid-season water deficit treatments, and the control treatment had total root length of 27.4, 19.4 and 30.6 km m^-2, respectively, about 2 wk before maturity. Evapotranspiration declined under water deficit, but water uptake in deeper layers increased. Water uptake per unit root length was reduced with water deficit and was still low shortly after rewatering. Remarkable was the increase in water uptake at 2–3 weeks after rewatering, both deficit treatments exceeded the control by almost 100%. This increase in water uptake followed the burst of new root growth in the upper regions of the soil. However, water uptake rates subsequently declined towards maturity, being between 0.15 L km^-1 d^-1 and 0.17 L km^-1 d^-1 for the early and mid-season water deficit treatments, slightly higher than the control, 0.12 L km^-1 d^-1. The results showed that the crop subjected to early water deficit could compensate for some of the reductions in root growth during subsequent rewatering, but the impact of the mid-season water deficit treatment was more severe and permanent.     

Renal water and solute excretion in the Atlantic stingray in fresh water

Freshwater, male Atlantic stingrays Dasyatis sabina , from Lake Jesup, Florida, U·S·A·, excreted a dilute urine similar in composition to freshwater teleosts and lampreys with the exception that urea was the primary osmolyte. Urine flow rate was 2·5 to 10 fold higher than that reported for freshwater teleosts resulting in high free-water clearance. Mass-specific free-water clearance values from euryhaline elasmobranchs inhabiting freshwater environments greatly exceed those for freshwater teleosts and are nearly equivalent to those of freshwater lampreys.     

Occurrence of mycobacteria in water treatment lines and in water distribution systems

The frequency of recovery of atypical mycobacteria was estimated in two treatment plants providing drinking water to Paris, France, at some intermediate stages of treatment. The two plants use two different filtration processes, rapid and slow sand filtration. Our results suggest that slow sand filtration is more efficient for removing mycobacteria than rapid sand filtration. In addition, our results show that mycobacteria can colonize and grow on granular activated carbon and are able to enter distribution systems. We also investigated the frequency of recovery of mycobacteria in the water distribution system of Paris (outside buildings). The mycobacterial species isolated from the Paris drinking water distribution system are different from those isolated from the water leaving the treatment plants. Saprophytic mycobacteria (present in 41.3% of positive samples), potentially pathogenic mycobacteria (16.3%), and unidentifiable mycobacteria (54.8%) were isolated from 12 sites within the Paris water distribution system. Mycobacterium gordonae was preferentially recovered from treated surface water, whereas Mycobacterium nonchromogenicum was preferentially recovered from groundwater. No significant correlations were found among the presence of mycobacteria, the origin of water, and water temperature.     

人工林地浑水入渗性能与通用入渗模型

采用双环法 ,通过 130场田间的浑水与清水入渗对比试验 ,对两种土壤质地的刺槐、侧柏人工林地的浑水入渗性能进行了研究。结果表明 ,含沙径流——浑水可显著削弱人工林地土壤的入渗性能 ,降低天然降水与土壤水的转换能力及人工林涵养水源的作用 ,其削减能力随着入渗水流含沙量、泥沙中小于 0 .0 1mm物理性粘粒含量的增加或入渗历时的延长而增大 ,并受到土壤质地的强烈影响。在土壤质地相同条件下 ,人工林地浑水的入渗能力随人工林树种的不同而异。刺槐林地土壤入渗能力大于侧柏林地 ;与相同立地退耕还林后仅 1a的新造林地相比较 ,退耕还林后 13a生的侧柏林地 ,土壤浑水入渗和清水入渗能力均减小 ;但退耕还林后 13a生的刺槐林地 ,清水入渗能力明显增强 ,浑水入渗能力因入渗水流特性不同而异。通过 L evenberg-Marquardt非线性参数拟合 ,求得了两种土壤质地条件下 ,3种林分积水型浑水与清水入渗的通用模型。该模型既可用于清水入渗预报 ,又可用于不同含沙量和泥沙粒度组成浑水入渗能力的预测     

Diet of Rana cancrivora in fresh water and brackish water environments

Rana cancrivora Gravenhorst inhabits both fresh water and brackish water swamps and ditches in Singapore. Food items in the gut of frogs from both habitats have been examined. The diet of frogs collected near brackish water was predominantly crustacean and included crabs ( Sesarma spp.), while the diet of those collected near fresh water comprised mainly insects. Gut contents of frogs included all the small animal species found in the respective environments, the choice of prey appearing to be limited only by size.     

不同土壤水分条件下丹参耗水特征与水分利用率的研究

~~不同土壤水分条件下丹参耗水特征与水分利用率的研究@高扬$中国科学院、水利部水土保持研究所!陕西杨陵712100 @梁宗锁$中国科学院、水利部水土保持研究所!陕西杨陵712100;西北农林科技大学生命科学学院,陕西杨陵712100 @刘燕$陕西省药品监督管理局!西安710061~~~~[1] LIN J (林佳),XU L ZH(徐丽珍),LI Y(李琰), YANG SH L(杨世林). Comparison of tanshinone Ⅱ A content in the radix of Salvia miltiorrhiza Bge. from different producing area[J]. China Journal of Chinese Materia Medica(中国中药杂志), 2002.…     

Oxygen consumption rates of tilapia in fresh water, sea water, and hypersaline sea water

Whole animal oxygen consumption rates and plasma constituents were determined in the tilapia O. mossambicus , acclimated for 1 month in fresh water, sea water, and 1·6 × sea water. Oxygen consumption rates for the three water salinities were: 177·2 ± 16·86, 78·6 ± 2·32, and 195·4 ± 15·39 mg O₂ kg⁻¹ h⁻¹ (means ± 1 s.e.), respectively. Plasma prolactin (tPRL₁₈₈) concentration was significantly lower in 1·6 × sea water compared to fresh and sea water. There were no significant differences among mean plasma cortisol concentration and lysozyme activity. Ventilation was significantly higher in fish in sea water compared to the fish in fresh and 1·6 × sea water. The lowest oxygen consumption rates were found in fish acclimated to sea water. That salinity is probably closest to the brackish waters from which they were captured in the wild, and this agreement likely reflects the selection for optimal morphological and physiological characteristics to live in that environment.     

Mycobacteria in water and loose deposits of drinking water distribution systems in Finland

Drinking water distribution systems were analyzed for viable counts of mycobacteria by sampling water from waterworks and in different parts of the systems. In addition, loose deposits collected during mechanical cleaning of the main pipelines were similarly analyzed. The study covered 16 systems at eight localities in Finland. In an experimental study, mycobacterial colonization of biofilms on polyvinyl chloride tubes in a system was studied. The isolation frequency of mycobacteria increased from 35% at the waterworks to 80% in the system, and the number of mycobacteria in the positive samples increased from 15 to 140 CFU/liter, respectively. Mycobacteria were isolated from all 11 deposits with an accumulation time of tens of years and from all 4 deposits which had accumulated during a 1-year follow-up time. The numbers of mycobacteria were high in both old and young deposits (medians, 1.8 x 10(5) and 3.9 x 10(5) CFU/g [dry weight], respectively). Both water and deposit samples yielded the highest numbers of mycobacteria in the systems using surface water and applying ozonation as an intermediate treatment or posttreatment. The number and growth of mycobacteria in system waters correlated strongly with the concentration of assimilable organic carbon in the water leaving the waterworks. The densities of mycobacteria in the developing biofilms were highest at the distal sites of the systems. Over 90% of the mycobacteria isolated from water and deposits belonged to Mycobacterium lentiflavum, M. tusciae, M. gordonae, and a previously unclassified group of mycobacteria. Our results indicate that drinking water systems may be a source for recently discovered new mycobacterial species.