A three-dimensional hydro-geochemical model to assess lake acidification risk

Biogeochemical and hydrological fluxes from riparian zones to lake environments can be significant, particularly for shallow systems experiencing large variations in water level, yet they are not considered in water quality models. To address this challenge we dynamically coupled a three-dimensional surface water model with a soil hydro-geochemical model of the riparian zone and used the coupled system to simulate the impacts of acid sulfate soils on the water quality of a morphologically complex coastal lake system in South Australia. A 3-yr simulation was undertaken to capture a period of exposure and re-flooding of pyrite-bearing sediments and acid fluxes to the lake. Model performance was assessed against data from several acidification events that occurred and the simulations reproduced the observed spatio-temporal variation in the expression of soil and water acidity. The model approach introduced here has potential for simulating systems where the terrestrial–aquatic linkage is important in shaping water quality.     

Sweet sorghum for bioethanol production: Crop responses to different water stress levels

Cultivation of sweet sorghum for the production of bioenergy is an attractive option to cope with the challenges of climate change and variability. In fact, on one hand it represents an interesting strategy of mitigation and, on the other, the use of drought resistant species could be considered as an opportunity of adaptation to the change of precipitation patterns. Anyway, when considering the production of agricultural feed stocks, particular attention should be addressed to the environmental sustainability of field production in order to avoid trade-offs in relation to food production, land use and pressure on the water resources. In this context, the cultivation of drought-tolerant energy crops as sweet sorghum (Sorghum vulgare (L.) var. Saccharatum) could be an interesting option. On the bases of these considerations, the current study had the aims i) to monitor the sweet sorghum growth and productive responses to different water treatments, in order to assess the extent of tolerance to constant water stress and ii) to assess the potential for first and second-generation bioethanol production obtainable from soluble sugars and residual biomass at two different development stages, flowering and physiological maturity.Results show that the length of the growing period should be decided on the bases of the objective pursued.If the objective is just the production of bioethanol, a longer cultivation period could be more suitable, but, on the contrary, if the objective is more addressed to an optimization of water, flowering should be considered the best harvest time.     

Ecophysiological Analysis Of Drought And Salinity Stress Of Quinoa (Chenopodium Quinoawilld.)

We assessed the relative influence of drought or salinity stress with similar soil water potentials on growth, plant water relations, and photosynthesis rate of Chenopodium quinoaWilld., as well as the suitability of common techniques used in stress physiology studies. Our results from greenhouse pot experiments showed that salt stress induced better absolute and relative growth rates, and that the plant developed adaptation mechanisms to drought through high water use efficiency and high root shoot ratios. The stomatal resistance and the leaf water potential increased with an increased stress level. Variable to maximal chlorophyll fluorescence (Fv/Fm) and quenching analysis (qP and qN) showed that dehydrated plants are less protected from photoinhibition. The dynamic diffusion porometer is of limited use in leaves with salt glands.     

架空输电线路生态防风技术

结合输电线路防风工作经验,总结出一套适用于沙地输电线路的生态防风技术.采用插埋防风障、铺设稻草袋、装设围栏和种植耐旱植物的方法,较以往的铺垫石块护坡方法具有节省工期、材料、人力和可持续性防护的优点,尤其适用于北方农牧区沙地输电线路的防风治理.     

The driest continent and the greediest water company: newspaper reporting of drought in Sydney and London

Analysis of press reports of the onset of drought in Sydney in 2002 and London in 2006 shows different understandings of the relationship between infrastructure provision, individual behaviour and the environment. Drought is both a natural and cultural phenomenon requiring urban water managers to consider social as well as technical considerations in preparing for future droughts.     

引进烤烟品种的抗旱性生理评价

通过盆栽试验 ,研究了我国引进的V 2 ,RG 1 1 ,K 32 6 ,K 34 6共 4个烤烟品种在干旱胁迫条件下抗旱性的差异。对干旱胁迫下各烤烟品种生长损失率的比较以及叶绿素含量、细胞膜透性、过氧化氢酶活性和丙二醛含量等有关生理指标的研究表明 :在土壤干旱条件下 ,不同烤烟品种抗旱能力不同 ,其大小顺序为K34 6 >RG1 1 >V2 >K32 6。随着干旱程度的加深 ,各品种的抗旱能力差异逐渐减弱     

印度梨形孢真菌促进芝麻生长并提高芝麻抗旱性

将印度梨形孢（Piriformospora indica,Pi）真菌接种芝麻幼苗根部,分别在大田及温室条件下研究供试真菌对芝麻生长和抗旱性的效应。大田试验主要调查产量性状,温室试验在芝麻初花期进行15d的持续干旱处理,测定株高等形态性状、过氧化氢酶活性等生理指标。结果表明,接种及未接种只真菌的芝麻植株在干旱处理前后叶长、叶宽差异达到极显著水平,株高、全展叶片数、基部茎粗、叶绿素含量、根颈粗差异达到显著水平;在人工干旱胁迫条件下,接种尉真菌后芝麻植株能维持较高的过氧化氢酶（CAT）活性和较高含量的脯氨酸（Pro）,降低丙二醛（MDA）含量,从而减轻干旱胁迫伤害。在千粒重及单株籽粒重两个产量性状上,大田和温室接种的芝麻与未接种的差异均达到显著水平。接种成真菌不仅能促进芝麻的生长,而且在干旱条件下,使得芝麻表现出较强的抗旱性,显著提高芝麻产量。     

干旱逆境下不同品种水稻叶片有机渗透调节物质变化研究

通过聚乙二醇 (PEG)模拟水稻短期干旱胁迫研究表明 ,干旱胁迫条件下 4个水、陆稻品种叶片中可溶性有机渗透调节物质如游离氨基酸总量 (TFA)、脯氨酸 (Pro)和可溶性糖 (SS)含量及Pro/TFA比值变化上具有种间一致性 ,均呈显著上升趋势 ,且巴西陆稻的变化较为明显 ;可溶性渗透调节物质适宜作为水稻抗旱能力筛选的参考指标。     

干旱生境中VA菌根对宿主植物的影响及其机制

试验研究证明VA菌根可以影响宿主植物的水分关系。文章综述了VA菌根在干旱胁迫条件下对宿主植物形态、代谢、渗透适应的影响以及VA菌根可能提高宿主抗/耐旱性的机制。文章认为,VA菌根有利于宿主植物抗/耐旱性的作用是由于物理的、化学的、生理的、细胞的综合作用的结果。