开花前后变水条件对春小麦的补偿效应

在防雨棚内的盆栽实验条件下 ,研究了 4种梯度的 10种水分组合对红芒麦和宁春 10号产量及耗水量等的影响 .结果表明 ,试验期间充分灌水、轻度、中度、重度干旱处理 ,随着干旱程度的加剧 ,株高、干物质积累、产量、耗水量都逐渐减少 ;红芒麦灌浆期不同程度的干旱处理 ,均有利于产量的形成 ,促进物质运输 ,提高千粒重 ,同时减少水分消耗 ,提高WUE ;孕穗期干旱处理后 ,灌浆期复水 ,会造成减产 ,和灌浆期相比 ,孕穗期是水分敏感的时期 ,而灌浆期对水分亏缺不敏感 .两种小麦相比较 ,宁春 10号耗水量大、产量低、抗旱性较强 .图 2表 2参

不同水分处理下冬小麦旗叶叶绿素荧光参数的变化研究

用叶绿素荧光诱导动力学技术研究了变水条件对冬小麦旗叶叶绿素荧光参数:初始荧光(Fo)、最大荧光(Fm)、光系统Ⅱ(PSⅡ)的原初光能转化效率(Fv/Fm)和潜在活性(Fv/Fo)以及qP和qNP等的影响。结果表明,干旱胁迫使Fo和qNP值增加,Fv、Fm、Fv/Fm、Fv/Fo、qP、ETR值降低,但在拔节期和灌浆期干旱或复水处理下与干旱处理结果相反,这说明干旱可引起PSⅡ反应中心的破坏,而不同生育期的干湿交替环境条件可以增加PSⅡ反应中心开放部分的比例,将更多的光能用于推动光合电子传递,从而提高光合电子传递能力,同时qNP的提高,有助于耗散过剩的激发能,以保护光合机构,缓解环境对光合作用的影响。

Long-term variability of air temperature and precipitation conditions in the Polish Carpathians

Mountain regions are sensitive to climate changes, which make them good indicators of climate change. The aim of this study is to investigate the spatial and temporal variability of air temperature and precipitation in the Polish Carpathians. This study consists of climatological analyses for the historical period 1851-2010 and future projections for 2021-2100. The results confirm that there has been significant warming of the area and that this warming has been particularly pronounced over the last few decades and will continue in the oncoming years.Climate change is most evident in the foothills;however, these are the highest summits which have experienced the most intensive increases in temperature during the recent period. Precipitation does not demonstrate any substantial trend and has high year-to-year variability. The distribution of the annual temperature contour lines modelled for selected periods provides evidence of the upward shift of vertical climate zones in the Polish Carpathians,which reach approximately 350 meters, on average,what indicates further ecological consequences as ecosystems expand or become extinct and when there are changes in the hydrological cycle.

First and Second Laws Analyses of a Closed Latent Heat Thermal Energy Storage System

First and Second Law analyses were conducted to evaluate the performance of a closed latent heat thermal energy storage (LHTES) system employing calcium chloride hexahydrate (CaCl2·6H2O). The First and the Second Laws of thermodynamics were applied to the system from viewpoint of energy and exergy analyses, respectively. The energy storage tank in the system is neither fully mixed nor fully stratified. It may be considered as semithermal stratified. Experimente that include both charging and discharging periods were performed on sunny winter days in 1996. The energy and exergy variations and the overall energy and exergy efficiencies of the closed LHTES system were calculated for the complete charging and discharging cycle of the selected fifteen clear-sky winter days. Mean energy and exergy efficiencies were found to be 55.20% and 34.83%, respectively.

Potential Impacts of Climate Change on Water and Public Health in Alberta, Canada

A warming climate may affect the well-being through impacts on health and sustainability of its natural resources. Climate change, population growth, and agricultural and industrial development are increasing demand and pressure on Alberta＇s water supplies, and the risk to the health and well-being of Albertanso its economy and its aquatic ecosystems. An analytic framework was developed to help determine the adaptive capacity of the public health sector and its ability to cope with changes in climate and water quality and quantity. The framework includes possibilities for changes in public health processes, management, inputs, outputs, structure, financing, institutions, and policies. Research gaps and priorities related to impacts on the health sector from changed conditions of climate and water supply are offered.

Automatic detection of oceanic mesoscale eddies in the South China Sea

This study focuses on the spatial and temporal distribution characteristics of mesoscale eddies in the South China Sea(SCS). An automatic eddy detection method,based on the geometry of velocity vectors,was adopted to obtain an eddy dataset from 21 years of satellite altimeter data. Analysis revealed that the number of anticyclonic eddies was nearly equal to cyclonic eddies; in the SCS,cyclonic eddies are generally stronger than anticyclonic eddies and anticyclonic eddies are larger and longer-lived than cyclonic eddies. Anticyclonic eddies tend to survive longer in the spring and summer,while cyclonic eddies have longer lifetimes in the autumn and winter. The characteristics and seasonal variations of eddies in the SCS are strongly related to variations in general ocean circulation,in the homogeneity of surface wind stress,and in the unevenness of bottom topography in the SCS. The spatial and temporal variation of mesoscale eddies in the SCS could,therefore,be an important index for understanding local hydrodynamics and regional climate change.

Nonlinear coupling analysis of coal seam floor during mining based on FLAC^3D

Based on the hydro-geological conditions of 1028 mining face in Suntuan Coal Mine, mining seepage strain mechanism of seam floor was simulated by a nonlinear coupling method, which applied fluid-solid coupling analysis module of FLAC^3D. The results indicate that the permeability coefficient of adjoining rock changes a lot due to mining. The maximum value reaches 1 379.9 times to the original value, where it is at immediate roof of the mined-out area. According to the analysis on the seepage field, mining does not destroy water resistance of the floor aquiclude. The mining fissure does not conduct lime-stone aquifer, and it is less likely to form damage. The plastic zone does not exactly correspond to the seepage area, and the scope of the altered seepage area is much larger than the plastic zone.

Morpho-Anatomical Changes in Roots of Chickpea （Cicer arietinum L.） under Drought Stress Condition

Chickpea （Cicer arietinum L.） is a crop cultivated in semi-arid and rainfed areas of Pakistan and it experiences terminal drought stress. In this paper, the morpho-anatomical study regarding roots of chickpea was carried out to investigate the drought adaptation strategies. Twelve cultivars of chickpea were grown in pots under drought stress of 70% and 35% field capacity in addition to control （100%）. Root segments of mature chickpea plants were sectioned in 2 cm from root-shoot junction and used for making transverse sections. The development of sleeve and stele tissues and their proportion were markedly influenced by moisture availability to the root system. Roots length, flesh and dry weight, and number of secondary roots were decreased under field capacity of 70% and 35% as compared to control in 12 cultivars of chickpea. Root epidermis and cortex of CH47/04 consisted of cells with thickened walls and with 2-3 cell layers of sclerenchymatous cells below the epidermis. Increased number of medullary rays and high vascular region was observed in cultivars CH120/04, CH47/04, CH587/05 and CH87/02. Anatomical studies showed that CH47/04 was highly tolerant among 12 cultivars of chickpea, while CH587/05 and CH87/02 behaved moderately under both levels of drought stress （70% and 35% field capacity）.

Study on Landslide Surge in Reservoir Area

Landslide surge is a fluid-solid coupling problem involving multidisciplinary intersections such as landslide dynamics, fluid mechanics and mechanics along the way, which has important research value. The construction of the reservoir will affect the natural geological conditions of the slope of the reservoir area, slope rock under the joint effect of the waves and the reservoir water level changes, which will cause the reservoir bank collapse and even landslides. The occurrence of landslide will cause some loss. In this paper, the types of landslide generation, disaster classification, research methods and existing problems are reviewed. It makes people understand the basic research ideas of landslide surge. Through the analysis and discussion of the different research methods of landslide surges, the shortcomings of these analytical methods are analyzed, which provide important basis for future research and indicate the future research methods and direction.

Polymorph and morphology of CaCO_3 in relation to precipitation conditions in a bubbling system

Simulating the typical carbonation step in a mineral CO_2 sequestration, precipitated calcium carbonate(PCC) was prepared by bubbling CO_2 gas into a rich Ca solution. These carbonation reactions were conducted at three p H ranges, namely 10.0–9.0, 9.0–8.0, and 8.0–7.0, in which temperature and CO_2 flow rate are additional experimental variables. The PCC obtained in experiments was examined by Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD). It was found that supersaturation determined by p H value and flow rate of CO_2 has significant influence on polymorph of PCC. Vaterite was preferably formed at high supersaturation, while dissolution of metastable vaterite and crystallization of calcite occurred at low supersaturation. High temperature is a critical factor for the formation of aragonite. At 70 °C, vaterite, calcite and aragonite were observed to coexist in PCC because transformation from vaterite to aragonite via calcite occurred at this temperature. Scanning electron microscopy(SEM) technology was performed on prepared PCC, and various morphologies consistent with polymorphs were observed.

Lake-margin ecosystems of saline lakes of the Borzya group(Zabaikalsky Krai, Russia) during the initial filling phase

This article presents the results of hydrochemical and hydrobiological studies of shallow saline lakes of the Borzya group(Zabaikalsky Krai, Russia) at the initial filling phase. The lake-margin ecosystems of the studied lakes are characterized by varying degrees of salinity from polyhaline to brine water. Cyclical variations of meteorological conditions and high salinity determined that the compositions of the aquatic organisms are specific, mostly between stenohaline and euryhaline species, the quantities are low, and the community structures are simple.

Study of the Influence of Critical Radius on the Cloud Drops Formation in the Seeding Operations

In the seeding operations in order to mitigate the climatic changes or to intervene beneficently on the precipitations process, it is very important to know the roll of the critical radius size of the cloud drops formation and its posterior evolution. In the seeding operations programs, the fundament is to determinate the critical radius in order to obtain efficient results. So, it must consider （a） the critical radius size necessary in order to get the better results; （b） the atmospheric conditions that determine it. In order to get a methodology to calculate the critical radius in each atmospheric condition, the present work has been developed. And with them, it can estimate the nuclei size necessary in order to assure good seeding. The authors had obtained approximate values that were good enough to the goals.

Characteristics of the lower layer of sandstorms in the Minqin desert-oasis zone

By measuring the sand-dust flux,vertical deposition,and the wind velocity throughout 19 sandstorms in the Minqin region,we quantitatively analyzed the horizontal distribution and vertical variation in sandstorm characteristics under different land cover conditions.The effect of different land cover on mitigating sandstorms was also investigated.The results indicated that,in the surface layer ranging from 0-50 m,the intensity of sand-dust horizontal flux and concentration of sand-dust decreased with the increase of the height in the desert and the edge of oasis,whereas the two physical quantities increased slightly with the increase of the height in the oasis.The two physical quantities obey power function well under all three cover conditions.Moreover,in the desert and at the edge of oasis,the sand-dust vertical deposition decreased with the increase of the height.But a partial unimodal distribution at the oasis site and the maximum deposition occurred at the height of 9 m,which corresponds to the middle height of farmland protection forest.The annual flux that passed through a section of 1 m in width and 50 m in height was 9169 kg in the desert,5318 kg at the edge of oasis,and 2345 kg in the oasis.And the annual fluxes at the edge of oasis and in the oasis are 42% and 74% less,respectively,than that in the desert.This implies that the wind break forest significantly reduced the intensity of sandstorms.

Spatio-temporal changes in agricultural hydrothermal conditions in China from 1951 to 2010

Based on the daily observation data of 824 meteorological stations during 1951-2010 released by the National Meteorological Information Center, this paper evaluated the changes in the heat and moisture conditions of crop growth. An average value of ten years was used to analyze the spatio-temporal variation in the agricultural hydrothermal conditions within a 1 km2 grid. Next, the inter-annual changing trend was simulated by regression analysis of the agricultural hydrothermal conditions. The results showed that the contour lines for temperature and accumulated temperatures(the daily mean temperature ≥0°C) increased significantly in most parts of China, and that the temperature contour lines had all moved northwards over the past 60 years. At the same time, the annual precipitation showed a decreasing trend, though more than half of the meteorological stations did not pass the significance test. However, the mean temperatures in the hottest month and the coldest month exhibited a decreasing trend from 1951 to 2010. In addition, the 0°C contour line gradually moved from the Qinling Mountains and Huaihe River Basin to the Yellow River Basin. All these changes would have a significant impact on the distribution of crops and farming systems. Although the mechanisms influencing the interactive temperature and precipitation changes on crops were complex and hard to distinguish, the fact remained that these changes would directly cause corresponding changes in crop characteristics.

The Rain on Underground Porous Media Part Ⅰ:Analysis of a Richards Model

The Richards equation models the water flow in a partially saturated underground porous medium under the surface.When it rains on the surface,boundary conditions of Signorini type must be considered on this part of the boundary.The authors first study this problem which results into a variational inequality and then propose a discretization by an implicit Euler's scheme in time and finite elements in space.The convergence of this discretization leads to the well-posedness of the problem.