混合盐碱胁迫对芹菜种子萌发的影响

NaCl、Na2SO4、NaHCO3和Na2CO3按不同比例混合,模拟盐度和pH变化规律与天然盐碱地相似的15种盐碱条件,探讨混合盐碱胁迫对芹菜(Apium graveolens)种子萌发的影响.结果表明:芹菜种子的发芽率、发芽势、发芽指数和活力指数均随盐浓度的升高,pH的增大呈下降趋势.芹菜种子的萌发主要受盐浓度的影响,不同盐浓度间的影响差异大;当盐浓度为200 mmol/L时,基本不萌发.     

长穗薄冰草（Thinopyrum ponticum）对盐碱胁迫的生理响应

实验采用不同浓度（以干土重0.3%、0.5%、0.7%和0.9%计）Na2SO4、NaCl、NaHCO3、Na2CO3,Na2SO4：NaCl=1：1、NaHCO3：Na2CO3=1：1和Na2SO4：NaCl：NaHCO3：Na2CO3=1：1：1：1对长穗薄冰草进行胁迫,研究长穗薄冰草对盐碱胁迫的生理响应.结果表明：根系活力、SOD活性随盐碱浓度的增加逐渐下降,脯氨酸含量呈上升趋势,叶绿素含量除Na2SO4处理组外,呈先上升后下降的趋势.其中碱性盐（NaHCO3、Na2CO3、NaHCO3：Na2CO3=1：1、Na2SO4：NaCl：NaHCO3：Na2CO3=1：1：1：1）对长穗薄冰草的胁变效应较中性盐（Na2SO4、NaCl、Na2SO4：NaCl=1：1）大,以Na2SO4处理组对长穗薄冰草的影响最小,0.7% Na2CO3是长穗薄冰草正常生长的临界浓度.     

牛叠肚幼苗对盐碱胁迫的生理响应及其耐盐阈值

以盆栽牛叠肚组培苗为试材,比较研究了不同浓度中性盐(NaCl、Na2SO4)和碱性盐(NaHCO3、Na2CO3)胁迫对其生长和生理指标的影响。结果显示:(1)牛叠肚幼苗生长在碱性盐(NaHCO3、Na2CO3)处理下表现出"低促高抑"现象,而在中性盐(NaCl、Na2SO4)处理下均受到不同程度的抑制。(2)随着盐碱胁迫浓度的升高,牛叠肚叶片的相对电导率呈增加趋势,丙二醛(MDA)积累波动变化;Na2SO4和NaHCO3处理下二者之间的变化趋势相似,而NaCl和Na2CO3处理下二者之间变化趋势则不同。(3)牛叠肚叶片中超氧化物歧化酶(SOD)活性随胁迫浓度增加先升高后下降,而过氧化物酶(POD)活性呈先下降后升高趋势,说明牛叠肚主要通过SOD和POD的互补作用来降低氧化伤害。(4)以相对株高生长量下降50%为标准,求得牛叠肚幼苗对NaCl、Na2SO4、NaHCO3、Na2CO34种单盐的耐受阈值分别为85.18(0.50%,W/V)、40.77(0.58%,W/V)、171.00(1.44%,W/V)、114.20(1.21%,W/V)mmol·L-1。研究表明,各盐碱胁迫使牛叠肚幼苗的生长受到不同程度的抑制,但其在一定浓度范围内通过提高抗氧化酶(SOD、POD)活性来减轻盐碱伤害,维持植株的正常生理代谢;牛叠肚幼苗对碱性盐(NaHCO3、Na2CO3)的耐受能力强于中性盐(NaCl、Na2SO4)。     

盐碱协同胁迫对向日葵抗氧化酶系统的影响

根据中国东北盐碱土壤特点,将4种盐NaCl、NaHCO3、Na2SO4和Na2CO3按不同比例混合,模拟出25种盐度和pH值各不相同的复杂盐碱条件(盐浓度为50～250 mmol/L,pH值为712～1046),并对向日葵苗进行盐碱混合胁迫处理,研究了向日葵超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)酶等抗氧化酶系统和丙二醛(MDA)的盐碱协同胁迫效应．结果表明, 向日葵抗氧化物酶活性强弱同时与盐度和碱度密切相关,3种抗氧化物酶活性对于盐浓度的反应相似,均为其含量随着盐浓度的升高开始逐渐升高然后下降,而对于pH的影响,不同酶反应结果不同．即随着pH值升高,SOD酶活性和CAT酶活性降低,而POD酶活性反应则是随着pH值升高活性也升高．双向方差分析(ANOVA)结果表明：盐碱效应对于3种酶活力的影响是显著的．其中,盐效应对POD和SOD活性的影响比pH值的影响大,而pH值对CAT活性的影响效应比盐效应大．除SOD外,盐碱效应的交互作用显著 (P<0001)．抗氧化酶系统和MDA含量两者间相关性和逐步回归分析表明,3种酶对MDA的影响效应随其强度不同呈现显著不同．其中SOD是1个主导因子,CAT 处于次位, 而POD的影响不大,甚至可以忽略．     

NaCl和Na2CO3胁迫对栓皮栎种子萌发及幼苗生长的影响

为了阐明栓皮栎种子萌发期对盐碱胁迫的耐受性,研究了不同浓度(0、50、100、200和400 mmol/L)NaCl和Na2CO3胁迫对其种子萌发、生长、保护酶活性和有机渗透调节物质等的影响,结果表明:(1)盐碱胁迫对栓皮栎种子的萌发率和发芽指数均没有显著影响;随着Na+浓度的升高,NaCl和Na2CO3处理下的胚根长度、胚根生长速率、胚根鲜重均受到抑制,呈现下降趋势;活力指数和耐盐指数在NaCl胁迫下表现为较低浓度(50 mmol/L)促进,较高浓度(100,200,400 mmol/L)抑制,而在Na2CO3处理下则不断下降;相对盐害率在两种处理下均表现波动趋势。(2)通过建立活力指数、胚根长度等与Na+浓度的回归方程,发现在NaCl胁迫下栓皮栎种子活力指数、胚根鲜重、胚根长度和胚根生长速率的临界值分别为300.0、300.0、333.6、369.6 mmol/L。(3)在NaCl和Na2CO3胁迫下,随Na+浓度的增加,丙二醛含量增幅显著;NaCl处理下的SOD(superoxide dismutase)活性呈现先升高后降低的趋势,而Na2CO3处理下则均低于对照;POD(peroxidase)活性变化不显著;CAT(catalase)活性均表现为先降低后升高;脯氨酸、可溶性蛋白和可溶性糖含量均随着Na+浓度的升高而呈现不同程度上升趋势。(4)等Na+浓度时,NaCl处理下的各项生长指标均高于Na2CO3处理,丙二醛、保护酶活性及渗透调节物质含量均低于Na2CO3处理,说明Na2CO3对栓皮栎种子的影响比NaCl更为显著。     

盐碱胁迫对赤霞珠葡萄幼苗生长及相关生理指标的影响

【目的】了解不同盐分配比和不同浓度梯度复合盐碱胁迫对‘赤霞珠’葡萄（Vitis vinfera ‘Cabernet Sauvignon’）幼苗生长和抗逆生理指标的影响，确认其耐盐碱性范围及其耐盐碱能力。【方法】 以1年生‘赤霞珠’自根苗为试材，用NaCl、Na2SO4、NaHCO3、Na2CO3按不同比例混合配置中性盐、弱碱性盐、强碱性盐3组复合盐溶液，每组各设置50、100、150 mmol/L3个浓度梯度，以不做处理的溶液作为对照，于幼苗生长期间进行定期浇灌处理，通过室内盆栽试验来模拟不同类型、不同程度盐碱胁迫，在处理后不同时期测定幼苗生长形态、生理及光合指标。【结果】（1）茎粗和叶面积随盐胁迫浓度增大，呈现先增大后减小的趋势， 而‘赤霞珠’幼苗的株高基本呈现下降趋势。其中，中性、弱碱性、强碱性盐胁迫组间相比，‘赤霞珠’幼苗株高在强碱性盐胁迫组150 mmol/L处理10 d、150 mmol/L处理40 d都较同期中性、弱碱性组相应浓度显著降低；（2）随着盐浓度的增大，SOD活性及MDA含量呈先增大后减小的趋势，而‘赤霞珠’幼苗叶片的POD活性呈现缓慢增加的趋势，强碱性盐胁迫组叶片POD活性在处理30-50d时均高于相同浓度的中性、弱碱性盐胁迫处理组，但随着时间处理延长，到处理60 d后逐渐低于同浓度其他两处理组，其中150 mmol/L浓度表现得更明显。；（3）‘赤霞珠’葡萄幼苗胞间CO2浓度、净光合速率、蒸腾速率随着盐碱浓度的增加主要呈下降趋势，其胞间CO2浓度与净光合速率均为50 mmol/L浓度处理时较高。在同期相同盐浓度处理下，叶片净光合速率在强碱性盐胁迫150 mmol/L浓度处理75 d时显著低于同期中性、弱碱性处理组。（4）在相同浓度条件下，强碱性盐胁迫处理的幼苗株高及最大叶面积都显著低于中性盐和弱碱性盐处理组；叶片SOD活性在50 mmol/L中性盐胁迫处理下较CK显著提高了27%；叶片MDA含量在150 mmol/L强碱性盐胁迫下随着时间延长显著逐渐增加。【结论】‘赤霞珠’幼苗生长在盐碱胁迫下受到一定限制，但其株高、叶面积、胞间CO2浓度、净光合速率、蒸腾速率在50 mmol/L浓度处理下均呈现较好的增长趋势，而其株高及茎粗在强碱性盐胁迫150 mmol/L盐碱溶液处理下均增长最不明显；在一定低浓度浓度范围内50 mmol/L盐碱处理有利于赤霞珠葡萄幼苗生长。     

盐碱胁迫对小麦幼苗生长和根际细菌群落结构的影响

【背景】植物可通过改变根际微生物群落结构来减轻胁迫,但盐碱胁迫下小麦生长和根际细菌群落结构变化尚待明晰。【目的】明确盐碱胁迫下小麦幼苗生长及根际细菌群落结构变化。【方法】以添加NaCl和Na2CO3调节Hoagland营养液Na+浓度和pH来模拟盐碱胁迫,通过MiSeq高通量测序分析细菌群落结构。【结果】与无胁迫对照相比,单纯盐胁迫使小麦幼苗地上和地下部干重、叶绿素和根际土壤速效氮含量分别显著降低了25.0%、57.1%、21.2%和42.9%(P<0.05);小麦幼苗生长指标和根际土壤速效氮、速效磷、有机质含量及酶活性(除过氧化氢酶)随碱度升高而降低;所有处理的小麦幼苗根际优势菌门(丰度7.1%-71.5%)均为变形菌门(Proteobacteria)、放线菌门(Actinobacteria)和厚壁菌门(Firmicutes),优势属(丰度0.5%-5.1%)有肠杆菌属(Enterobacter)、嗜多甲基菌属(Methyloversatilis)、固氮菌属(Azotobacter)、假单胞菌属(Pseudomonas)和异根瘤菌属(Allorhizobium)。盐碱胁迫未显著...     

盐碱胁迫对巨菌草根际土壤微生物多样性及酶活性的影响

为探明盐碱胁迫对巨菌草根际土壤微生物多样性及酶活性的影响,该文设置了7个盐碱梯度,利用SPSS和Illumina高通量测序分析巨菌草根际土壤生理指标和微生物多样性.结果表明:(1)各处理间,巨菌草根际土壤真菌和细菌结构均存在差异;12‰盐碱浓度下,真菌优势菌纲为粪壳菌纲(68.5％)、散囊菌纲(16.3％),细菌优势菌...     

可培养盐碱菌多样性的研究进展

存在于高盐强碱极端环境的微生物因其独特的生命方式,引起了广泛的关注。根据盐碱环境所含的可溶性盐成分,可分为"NaCl型"和"苏打型(Na_2CO_3/NaHCO_3)"两大类,前者的碱性pH值较低而后者碱性pH值较高。本文总结了盐碱菌适宜生长条件在盐度0.5 mol/L和碱性pH 9.0之上且有效发表的标准菌株,并对这些菌株的生物多样性及生理特性进行了阐述;可培养盐碱细菌的数量及其多样性远远大于盐碱古菌,但是盐碱细菌对高盐度和强碱性p H依赖程度相对较低。盐碱细菌主要组成依次为芽孢杆菌纲(Bacilli,占总数约40%)、γ-变形菌纲(γ-Proteobacteria,30%)、梭菌纲(Clostridia,11%)、δ-变形菌纲(δ-Proteobacteria,6%)和放线菌纲(Actinobacteria,6%),而盐碱古菌主要组成为盐古菌纲(Halobacteria,92%)和甲烷微菌纲(Methanomicrobia,8%)。这些极端微生物在生物地球化学过程中或生态循环中扮演着重要的角色和功能,挖掘和利用盐碱菌具有重要意义。     

悬浮培养发状念珠蓝细菌对盐碱胁迫的生理应答研究北大核心CSCD

天然发状念珠蓝细菌是荒漠化土壤中的"先锋生物",具有极强的耐旱、耐碱、耐高温等能力。本研究旨在揭示悬浮培养发状念珠蓝细菌的抗盐碱能力,为发状念珠蓝细菌的人工培养提供基础。25℃,80μmol/(m2·s)光照下,BG-11培养液培养发状念珠蓝细菌,利用不同浓度(0、60、120、180、240 mmol/L)混合的Na2SO4和Na2CO3胁迫发状念珠蓝细菌细胞,处理时间分别为24 h和72 h,测定其质膜透性、超氧化物歧化酶活性、丙二醛、脯氨酸、可溶性蛋白以及可溶性多糖含量,分析发状念珠蓝细菌细胞对盐碱胁迫的响应。盐碱胁迫下,随着胁迫程度的加重,发状念珠蓝细菌细胞的质膜相对透性增加,丙二醛含量上升;超氧化物歧化酶活性和脯氨酸含量先上升后下降;可溶性蛋白含量逐渐下降;可溶性多糖含量不断升高。悬浮培养的发状念珠蓝细菌细胞对盐碱胁迫产生结构和生理的应激响应,增强了发状念珠蓝细菌抗盐碱能力。     

Bioremediation of HMX-Contaminated Soil Using Soil Slurry Reactors

Soil in some parts of the Iowa Army Ammunition Plant in Burlington, Iowa, was contaminated with cyclotetramethyleneter-anitramine, commonly known as high melting explosive (HMX). A laboratory treat-ability study was conducted to find out the ability of the native soil bacteria present in the contaminated site to degrade HMX. The results indicated that the HMX can be removed effectively from soil by native soil bacteria through a co-metabolic process. Molasses, identified as an effective co-substrate, is inexpensive, and this factor makes the treatment system cost-effective. The successful operation of aerobic-anoxic soil slurry reactors in batch mode with HMX-contaminated soil showed that the technology can be scaled up for field demonstration. The HMX concentration in the contaminated soil was decreased by 97% in 4 months of reactor operation. The advantage of the slurry reactor is its simplicity of operation. The method needs only mixing and the addition of molasses as co-substrate.     

Compost Soil Piles for Treatment of Oil-Contaminated Soil

A number of diverse technological options are being considered for the remediation of soil contaminated with weathered crude oil in Kuwait. The bioremediation technique involving the use of composting soil piles was selected from among the most appropriate methods and evaluated on a pilot scale. The field test was conducted from November 1992 to September 1993 at the Burgan oil field. Soil piles were constructed from the contaminated soil after amendment with necessary soil additives. The piles were subjected to regular irrigation and turning, and a monitoring program was carried out, including monthly soil sample collection from each pile for the measurement of petroleum hydrocarbon PAHs, soil microbial counts, mineral and metal concentrations. The results obtained showed that the composting soil pile treatment resulted in the reduction of up to 59% total extractable matter of oil contamination within 8 months. This article describes the technology used and summarizes the results obtained.     

Dependence of Soil Respiration on Soil Temperature and Soil Moisture in Successional Forests in Southern China

The spatial and temporal variations in soil respiration and its relationship with biophysical factors In forests near the Tropic of Cancer remain highly uncertain. To contribute towards an Improvement of actual estimates, soil respiration rates, soil temperature, and soil moisture were measured In three successional subtropical forests at the Dlnghuahan Nature Reserve （DNR） In southern China from March 2003 to February 2005. The overall objective of the present study was to analyze the temporal variations of soil respiration and Its biophysical dependence in these forests. The relationships between biophysical factors and soil respiration rates were compared In successional forests to test the hypothesis that these forests responded similarly to biophysical factors. The seasonality of soil respiration coincided with the seasonal climate pattern, with high respiration rates in the hot humid season （April-September） and with low rates In the cool dry season （October-March）. Soil respiration measured at these forests showed a clear Increasing trend with the progressive succession. Annual mean （± SD） soil respiration rate In the DNR forests was （9.0 ± 4.6） Mg CO2-C/hm^2 per year, ranging from （6.1 ± 3.2） Mg CO2-C/hm^2 per year in early successional forests to （10.7 ± 4.9） Mg CO2-C/hm^2 per year in advanced successional forests. Soil respiration was correlated with both soil temperature and moisture. The T/M model, where the two biophysical variables are driving factors, accounted for 74%-82% of soil respiration variation In DNR forests. Temperature sensitivity decreased along progressive succession stages, suggesting that advanced-successional forests have a good ability to adjust to temperature. In contrast, moisture Increased with progressive succession processes. This increase is caused, in part, by abundant respirators In advanced-successional forest, where more soil moisture is needed to maintain their activities.     

土壤酸化过程的土壤化学分析

要了解自然的抑或农业的土壤生态系统,认识和研究土壤酸化过程是必要的。土壤酸化过程在自然界是固然存在的,它们是地壳表面     

提高赤红壤旱地生态系统土壤肥力问题的研究

提高赤红壤旱地生态系统土壤肥力问题的研究高志强（福建农业大学土地与环境学系,福州３５０００２）ＳｏｉｌＦｅｒｔｉｌｉｔｙＩｍｐｒｏｖｅｍｅｎｔｏｆＵｐｌａｎｄＬａｔｅｒｉｔｉｃＲｅｄＳｏｉｌＥｃｏｓｙｓｔｅｍ．￥ＧａｏＺｈｉｑｉａｎｇ（Ｄｅｐａｒｔｍ...     

Remediation of Metal-Contaminated Soil by an Integrated Soil Washing-Electrolysis Process

Chelating agents such as EDTA and DTPA are often used to remove metals from soil. However, their toxicity, bio-recalcitrance, and problems with recovery of heavy metal and chelating agents severely limit their applications. A biodegradable chelating agent, LED3A, and two surfactants, SDS and Triton X 100, were evaluated as potential alternatives for remediation of metal-contaminated soil.

LED3A alone only removed 40% of cadmium the addition of surfactant significantly enhanced its cadmium removal capacity up to 80% for a wide range of pH (5 to 11). The enhancement increased with both surfactant concentrations and LED3A concentrations. Because LED3A had a much higher removal capacity for copper, the synergistic effect of surfactant-LED3A mixture was less obvious. Sequential extraction analysis indicated that the LED3A not only removed copper from carbonate and Fe-Mn oxide fraction, but also from organic fractions. A three-dimension electrolysis reactor could effectively recover both metals and LED3A-SDS within thirty minutes. The combined soil washing by LED3A-surfactants and electrolysis provides a potential approach for remediation of copper- and cadmium-contaminated soils.     

Negative Effects of Chelants on Soil Qualities of Five Soil Series

Due to the low phytoavailability of some heavy metals (HMs), a prolonged period is required when phytoextraction is used to remove these HMs from contaminated soils. The use of chelants and other chemical compounds are often used to increase the phytoavailability of the HMs for plant uptake. Negative effects of chemical agents on the soil and groundwater have rarely been reported during chemical-enhanced phytoextraction. This research applied chelants to various soil series with different characteristics to assess their impacts on soil quality. The experimental results showed that the application of 5 mmol kg^?1 of all chelants had a negative effect on the soil quality. This was especially true for electrical conductivity (EC) when diethylene trinitrilo pentaacetic acid (DTPA) was used as the chemical extracting agent.