盐度胁迫下口虾蛄Mn-SOD基因的表达分析

利用实时定量PCR技术,分析了Z9～Z11期口虾蛄Oratosquilla oratoria Mn-SOD基因在不同盐度胁迫下的表达情况.试验共设置8组,盐度分别为12.8、16.3、19.8、23.3、26.8（对照组）、30.3、33.8、37.3,各组均在盐度胁迫后的1.5、3、6、9、12、24、36、48、72 h取样.结果表明：在盐度胁迫时间为6、9、12、48、72 h时,各盐度组口虾蛄Mn-SOD基因的表达量总体上极显著或显著低于对照组（P＜0.01或P＜0.05）,且与对照组盐度差值小的23.3、30.3两个盐度组,Mn-SOD基因表达量总体上均高于极高盐度（37.3）和极底盐度（12.8）组,在胁迫时间为24、36 h时,除12.8、16.3两个低盐度组外,其余盐度组Mn-SOD基因的表达量总体上极显著高于对照组（P＜0.01）;除极高和极低盐度组外,其余盐度组Mn-SOD基因的表达量均随着胁迫时间的延长总体上呈先降低再升高再逐步降低的变化趋势,盐度为12.8、16.3、19.8、23.3、30.3、33.8、37.3的各试验组,Mn-SOD基因最大表达量的时间点分别为6、12、24、24、24、24、24h.研究表明,各试验盐度组口虾蛄在72 h内对盐度胁迫的适应总趋势为不适应—最不适应—逐步适应—不适应.     

高盐废水人工湿地处理中耐盐植物的筛选

天津塘沽作为滨海新区核心区,是目前天津发展最快的地区之一。由于本区盐碱土壤等自然条件,污水中盐分含量较高,制约了废水的回用。本文通过模拟人工湿地实验,比较了芦苇(Phragmites australis)、盐地碱篷(Suaeda salsa)、碱蒿(Artemisia anethifolia)、黄花鸢尾(Iris wilsonii)、盐角草(Salicornia europaea)和大米草(Spartina anglica)等耐盐植物对轻污染水体中高浓度氯离子的去除能力,筛选出去除能力较强的植物,并确定植物对盐分去除率达到最大时的生态系统条件。结果表明,适合人工湿地的耐盐碱植物对氯离子的去除效果依次为:芦苇>盐地碱篷>碱蒿>黄花鸢尾>盐角草>大米草,停留时间一般在第4 d时可达到平衡。该研究为利用人工湿地处理高盐废水提供了科学依据。     

生物炭对盐碱土氮淋溶的影响

生物炭对某些高度风化的热带土壤和温带酸性土壤有改善土壤结构,减少营养元素淋失的作用,但关于温带干旱区的盐碱土的改良效果却很少报道。以新疆绿洲盐碱土为对象,研究玉米秸秆生物炭对氮淋溶的影响。采用室内土柱淋滤试验,土柱包含炭土比(W/W)0%、1%、5%和10%四个处理,模拟大气降雨,定期收集淋滤液,分析其中的氮素指标。结果显示,5%和10%添加比例分别减少了土壤氨态氮的淋失量31.14%和52.43%,1%的添加比例增加了铵态氮淋失。对比空白,10%处理的铵态氮、硝态氮和总氮减少淋失量分别达到52.43%、50.01%和33.83%,1%和5%处理土柱的硝态氮和总氮在试验10 d内(降雨量140 mm)就基本淋失完,而10%处理土柱则显得较为平缓,几乎到25 d(降雨量290 mm)时才基本淋失完。四个土柱的铵态氮的淋失都较为平缓。另外,生物炭可以减少土柱的溶液淋失量(20.95%),增加土壤持水能力。上述结果表明,生物炭施用于干旱区盐碱土能明显减少硝态氮和总氮淋失并延长其在土壤中的停留时间,增强土壤的持续供氮能力。     

Low Root Zone Temperature Exacerbates the Ion Imbalance and Photosynthesis Inhibition and Induces Antioxidant Responses in Tomato Plants Under Salinity

The combined effects of salinity with low root zone temperature （RZT） on plant growth and photosynthesis were studied in tomato （Solanum lycopersicum） plants. The plants were exposed to two different root zone temperatures （28/20℃, 12/8℃, day/night temperature） in combination with two NaC1 levels （0 and 100 mmol L-l）. After 2 wk of treatment, K＋ and Na~ concentration, leaf photosynthetic gas exchange, chlorophyll fluorescence and leaf antioxidant enzyme activities were measured. Salinity significantly decreased plant biomass, net photosynthesis rate, actual quantum yield of photosynthesis and concentration of K＋, but remarkably increased the concentration of Na＋. These effects were more pronounced when the salinity treatments were combined with the treatment of low RZT conditions. Either salinity or low RZT individually did not affect maximal efficiency of PSII photochemistry （Fv/Fm）, while a combination of these two stresses decreased Fv/Fm considerably, indicating that the photo-damage occurred under such conditions. Non-photochemical quenching was increased by salt stress in accompany with the enhancement of the de-epoxidation state of the xanthophyll cycle, in contrast, this was not the case with low RZT applied individually. Salinity stress individually increased the activities of SOD, APX, GPOD and GR, and decreased the activities of DHAR. Due to the interactive effects of salinity with low RZT, these five enzyme activities increased sharply in the combined stressed plants. These results indicate that low RZT exacerbates the ion imbalance, PSII damage and photosynthesis inhibition in tomato plants under salinity. In response to the oxidative stress under salinity in combination with low RZT, the activities of antioxidant enzymes SOD, APX, GPOD, DHAR and GR were clearly enhanced in tomato plants.     

Irrigation effects of cooling tower effluent on soil chemistry and alfalfa in the Rio Grande river basin

Development of alternative sources through wastewater reuse is important to meet water demands in arid regions. However, effects of wastewater irrigation on soil properties and crop performance must be evaluated before advocating its widespread use. Objectives of this study were to evaluate: (i) effects of prior evaporative disposal of saline‐sodic blowdown water (BW) on soil (fine‐loamy, mixed, and thermic Typic Calciorthods) properties in the disposal area, and (ii) effects of flood irrigation with three water qualities (control, BW 1X, and BW 2X) on soil salinity and alfalfa performance using a greenhouse soil column study (soil collected from same study area as objective (i)). Results indicated that although prior land disposal of BW had increased salinity and sodicity of soil, they were within the tolerance limits of the intended crop, alfalfa. Mass balance calculations indicated measured (15·6 Mg ha⁻¹) and calculated (13·2 Mg ha⁻¹) salt accumulation at the test site used for evaporative disposal were similar. Alfalfa grown using BW under greenhouse conditions produced prime quality hay and biomass yield similar to the control treatment (8·3 g column⁻¹ vs. 10·5 g column⁻¹ in control). Although 3·6 years equivalent of flood irrigation with BW 1X did not result in saline soil (BW 1X irrigated soils EC ranged from 2·2 to 3·5 dS m⁻¹), BW 2X irrigation resulted in saline soils. Sodicities of irrigated soils were greater in fine textured deep soils than coarse textured surface soils (e.g., SAR of 6·1 at 0–5 cm vs. 19·5 mmol^1/2 L^−1/2 at 30–60 cm in BW 1X), indicating the need for high solubility Ca amendments for long‐term irrigation with BW on fine texture soils within the soil profile. Copyright © 2010 John Wiley & Sons, Ltd.     

基于PLSR方法的青海茶卡-共和盆地土壤盐分高光谱遥感反演

摘要：对青海省茶卡地区盐渍土实地调查、采集土壤样品及土壤理化分析的基础上,于实验室测量土样光谱数据,通过PLSR(Partial Least Squares Regression)方法,充分地利用多个与土壤盐分相关的波段组合,综合所有波段信息来定量地估算土壤盐分含量,建立了PLSR土壤盐分反演模型。利用25个土壤样品建模的均方根误差RMSEC = 4.74 mg kg−1(R2 = 0.97),17个独立的检验样本的均方根误差RMSEV=5.72g kg-1(R2 = 0.92)。将模型用于Hyperion星载髙光谱数据进行土壤盐分含量空间分布估算研究,并综合地形及地下水的因素对土壤盐分含量空间分布信息的估算结果进行了评价,结果与实地调查及前人的文献较为一致。揭示了PLSR方法的有效性及Hyperion星载髙光谱数据进行土壤盐渍化探测、土壤盐分定量估算的潜力。     

气候变暖对宁夏引黄灌区土壤盐分及其灌水量的影响

气候变暖加剧了土壤水分蒸发,带动土壤盐分向上移动,引起土壤盐分增加,导致土壤盐碱危害加剧。采用近35 a来的土壤盐分定位观测资料和气象资料,研究气候变暖对宁夏引黄灌区土壤盐分变化的影响。研究结果表明：近 35 a随着全球变暖,宁夏引黄灌区土壤全盐含量呈明显的增加趋势,轻盐化土壤、中盐化土壤和重盐化土壤全盐质量分数分别增加0.08、0.13和0.19 g/kg;当温度增加0.5～3.0℃时,宁夏引黄灌区轻盐化土壤、中盐化土壤和重盐化土壤淋洗土壤增加盐分所需的灌水量分别增加8.2%～9.1%、8.2%～8.7%和8.3%～8.8%,总灌水量增加1.29～1.40亿m3。     

基于Markov链的土壤盐渍化动态变化预测

为揭示银川平原土壤盐渍化演变规律,该研究从2000年4月份TM影像、2004年4月份中巴资源卫星影像、2009年4月份中国环境卫星影像分别提取银川平原土壤盐渍化信息,获得三个时期的银川平原土壤盐渍化分布图;以2000年数据作为模型的初始状态、2000年—2004年数据建立银川平原土壤盐渍化概率转移矩阵,模拟银川平原土壤盐渍化变化趋势并进行精度检验。对模型的X2检验表明,模型2009年预测结果与实际值无显著性差异,两者吻合良好。模型结果表明,在当前驱动力下,100多年后,各盐渍化土壤面积趋于稳定,重度盐渍化     

含盐砂土中5TE传感器应用的影响因素探究

5TE传感器由于其可以同时测量土壤温度、体积含水率和体积电导率的优势,越来越多地被应用于土壤评估中.为了更好地将5TE应用到盐渍化及低温等区域,通过室内砂柱正交实验探究含水率、盐分、温度这3个因素对5TE体积介电常数和体积电导率的影响.实验结果表明:①5TE体积介电常数除受含水率影响外,温度和盐分也会对其产生影响.饱和...     

中度嗜盐菌Halomonas sp. STSY-3的耐盐特性研究

[目的]通过对中度嗜盐菌Halomonas sp.STSY-3的耐盐特性研究,为工程嗜盐菌的筛选提供方法和参数指导,同时为高盐废水的生化处理过程中工程菌的选用、问题诊断和工艺优化等提供必要的理论基础。[方法]以中度嗜盐菌Halomonas sp.STSY-3试验材料,利用吸光光度法测定盐度、接种量、阴阳离子和渗透冲击对该菌株生长特性的影响。[结果]Halomonas sp.STSY-3具有较强适应盐度变化的能力,菌株生长的盐度范围为1%～11%(NaCl,W/V),最适生长盐度为7%(NaCl,W/V);在系列NaCl浓度下,菌液接种量的增加可以有效地加强菌株在不同盐度下的生长;在12种不同的阴、阳离子中,仅有Cl-和Na+最适宜其生长,该菌株对SO42-也具有较强的耐受能力。[结论]该研究为高盐废水的生化处理提供了基础数据和耐盐特性测定方法。