铝胁迫下外源钙对外生菌根真菌抗氧化保护酶活性的影响

采用液体培养方法,研究了4个不同菌株(Bo 02、Bo 15、Pt 715和Sl 08)的抗铝性及其在铝胁迫下加入0、0.25、0.5、1.0 mmol.-1L-1Ca2+处理后抗氧化保护酶活性的变化,旨在了解钙在缓解外生菌根真菌铝毒方面的作用.结果表明,不同菌株抗铝性不同,Pt 715和Sl 08的抗铝性强于Bo 02和Bo 15.铝胁迫可显著提高外生菌根真菌Bo 02 CAT和SOD活性、Bo 15SOD活性、Sl 08 CAT和POD活性,说明外生菌根真菌中这几种酶活性的提高与铝毒胁迫密切相关.4个菌株中,Bo 02酶活性对外源钙最敏感,外源钙对Bo 02铝胁迫的缓解作用最好.较高浓度的钙(≥0.5 mmol.L-1)可缓解或消除Sl 08铝胁迫造成的抗氧化酶活性上升.     

铝和锰对外生菌根真菌生长、养分吸收及分泌作用的影响

在强酸性土壤和铝锰矿墟上,铝和锰是影响森林生长和植被恢复的主要限制因子,研究它们对外生菌根真菌的影响,筛选优良的抗性菌株,可为开展污染土壤生物修复提供技术支撑及理论依据.试验采用纯培养技术研究了Al3+、Mn2+单独或共存对褐环乳牛肝菌13(Suillus luteus 13,Sl 13)、土生空团菌04(Cenococcum geophilum 04,Cg 04)、彩色豆马勃715(Pisolithustinctorius 715,Pt 715)这3株外生菌根真菌生长、养分吸收、有机酸分泌的影响.结果表明,Mn2+使Sl 13、Cg 04、Pt 715的生物量分别降低了70.35%、52.44%和18.55%;Al3+使Sl 13的生物量下降50.74%,但增加Cg 04的生物量;Al3+和Mn2+共存对3种菌株生长均有协同抑制作用,但对Pt 715的抑制最小,表明Cg 04抗铝,Pt 715对铝、锰的单独污染和复合污染均有较强的抗性.Al3+和Mn2+抑制外生菌根真菌吸收养分,对Sl 13的抑制作用显著大于Pt 715和Cg 04;但提高3个菌株的草酸和H+分泌速率,增加其分泌量,两者共存对Cg 04草酸分泌速率具有协同促进效应,Pt 715不仅能分泌草酸而且还分泌丁二酸.因此,抗性强的外生菌根真菌可通过分泌较多的有机酸络合Al3+和Mn2+而缓解其毒害.     

铝对马尾松幼苗光合作用的若干影响

本工作在溶液培养条件下,研究了铝对马尾松针叶叶绿素含量、叶绿素吸收光谱、光合作用和叶绿体甘油醛-3-磷酸脱氢酶活性的影响。      

磷对超积累植物--东南景天生长和积累锌的影响

通过溶液培养试验,探讨了东南景天植株体内磷锌相互关系.结果表明,在一定范围内供磷(0.5-2.0mmol·L-1)能明显促进东南景天的生长,显著提高叶片、茎和根的生物量适当的增磷(0.5-1.0mmol·L-1)极显著提高东南景天叶片、茎的锌含量和地上部的锌积累量;高磷(2.0mmol·L-1)则降低地上部的锌含量和积累量.无论在何种磷锌水平处理下S(地上部的锌积累量)/R(根系的锌积累量)比值始终大于1,表明在东南景天植株体内可能存在明显的"增磷诱导锌需求(Phosphorusinduced zinc requirement)"现象.从植物修复角度来说,利用增磷手段提高超积累植物东南景天的生物量和地上部锌的积累能力具有重要的应用价值.     

镉对植物光合作用的影响

本文从光合作用色素、光合组织、光合作用过程、光合速率等方面概述了近些年来 Cd对植物光合作用影响的研究进展 ,并结合我们的研究进行了讨论。     

铜镉胁迫对2种菌根真菌生长和细胞壁离子交换量的影响

在离体培养条件下,研究了铜镉胁迫对2种外生菌根真菌美味牛肝菌(Boletus edulis)和铆钉菇(Gomphidius viscidus)生长状况,培养环境pH值和细胞壁离子交换量的影响.结果表明,以对照相比,铜镉处理抑制了菌根真菌的生物量积累.通过半致死浓度评价2种菌根真菌耐受性发现,铆钉菇的Cu耐受性强于美味牛肝菌,而Cd耐受性弱于美味牛肝菌.菌根真菌培养后,基质pH降低与真菌生物量有关.铜镉处理下菌根真菌单位生物量下降的pH单位大于对照,说明菌根真菌在重金属胁迫下能通过调节自身pH环境缓解压力.铆钉菇的离子交换量在780～1 800μmol·g^-1之间,并随重金属处理浓度的增加而增加;美味牛肝菌的离子交换量在500～750μmol·g^-1之间,并随重金属处理浓度的增加而减少.     

丛枝菌根菌丝对重金属元素Zn和Cd吸收的研究

丛枝菌根菌丝对重金属元素Ｚｎ和Ｃｄ吸收的研究陶红群李晓林张俊伶（中国农业大学资源与环境学院，北京１０００９４）关键词丛枝菌根；锌；镉．近年来，由于工业排放及一些农业措施（如污灌等）造成许多土壤中重金属元素的污染．其中锌和镉是两个较为重要的重金属污染...     

三种除草剂对VA菌根真菌的侵染和植物生长的影响

用不灭菌的壤质黄潮土,在盆栽条件下研究了三种除草剂对VA菌根侵染和植物生长的影响。结果表明,三种除草剂的影响程度依次为绿麦隆>二甲四氯>氟乐灵;对菌根侵染的影响只出现在植物生长早期。接种VA菌根后,菌根侵染率、植物生长量、氮磷吸收量都显著大于不接种的对照植物。     

几种纯培养外生菌根真菌对矿物油的降解效果

用紫外分光光度法对4种外生菌根真菌降解矿物油的能力进行了研究.结果表明,这4种外生菌根真菌都具有降解矿物油的能力.但在不同的培养基中其生物量和降解矿物油的能力显著不同,以有机氮作为氮源及提供少量葡萄糖作为启动碳源将大大提高其生物量及矿物油降解率.结果为应用菌根技术修复矿物油污染土壤及优化降解条件提供了依据.     

4种外生菌根真菌对滴滴涕的耐受性及生理响应

在纯培养条件下,研究了外生菌根真菌--美味牛肝菌(Boletus edulis)、铆钉菇(Gomphidius viscidus)、双色蜡蘑(Laccaria bicolor)、褐疣柄牛肝菌(Leccinum scabrum)在不同质量浓度DDT处理下的生长效应、耐受性和生理响应. 结果表明:DDT没有影响外生菌根真菌的生长模式,只是改变了其生长速度和生物量积累. 在5.0 mg/L的DDT处理下,美味牛肝菌、铆钉菇和双色蜡蘑的生长没有受到显著影响. 在25.0 mg/L的DDT处理下,美味牛肝菌的生长没有受到显著影响,显示出了较好的耐受性. 在高ρ(DDT)处理下,铆钉菇的多酚氧化酶、漆酶和过氧化物酶活性显著增强,液体培养基Ph下降幅度较大. 美味牛肝菌和铆钉菇通过不同的方式来响应DDT的胁迫,它们均具有较好地降解DDT的潜力.      

Influences of excessive Cu on photosynthesis and growth in ectomycorrhizal Pinus sylvestris seedlings

Growth and photosynthesis responses were measured for Scots pine( Pinus sylvestris L. cv. ) inoculated with ectomycorrhizal fungi ( Suillus bovinus ) under 6.5 and 25 mg/L Cu treatments to evaluate ectomycorrhizal seedlings‘ tolerance to heavy metal stress. Results showed that excessive Cu can significantly impair the growth and photosynthesis of pine seedlings, but such impairment is much smaller to the ectomycorrhizal seedlings. Under 25mg/L Cu treatment, the dry weight of ectomycorrhizal seedlings is 25% lower than the control in contrary to 53% of the non-mycorrhizal seedlings, and the fresh weight of ectomycorrhizal roots was significantly higher than those of non-mycorrhizal roots, about 25% and 42% higher at 6.5 and 25 mg/L Cu treatments respectively. Furthermore,ectomycorrhizal fungi induced remarkable difference in the growth rate and pigment content of seedlings under excessive Cu stress. At 2.5 mg/L Cu, the contents of total chlorophyll, chlorophyll-a and chlorophyll-b were 30% higher in ectomycorrhizal plants than those in non-mycorrhizal plants. O2 evolution and electron transport of PSI and PSII were restrained by elevated Cu stress. However, no significant improvement was observed in reducing the physiological restraining in ectomycorrhizal seedlings over the non-mycorrhizal ones.     

Combined effects of cadmium and fluoranthene on germination, growth and photosynthesis of soybean seedlings

The single and combinational effects of cadmium (Cd) and fluoranthene (FLT) on germination, growth and photosynthesis of soybean seedlings were investigated. Exposure to 5, 10, or 15 mg Cd/L or 1, 5, or 10 mg FLT/L individually or in combination significantly decreased germination vigor (3 days) and final germination rate of soybean seeds, except at 1 and 5 mg FLT/L. The results of two-way ANOVA analysis and the Bliss independence model showed that at lower concentrations of FLT (1 mg/L), the interaction between Cd and FLT on germination was antagonistic, whereas the interaction was synergistic when the concentration of FLT was 5 or 10 mg/L and the concentration of Cd was 15 mg/L. Growth, expressed as dry weight, length of shoot and root, leaf area, and photosynthesis, expressed as net photosynthetic rate, intercellular CO2 concentration, chlorophyll contents and fluorescence of soybean seedlings were also reduced by exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L, singly or jointly. Significant antagonistic effects of exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L on shoot growth and photosynthesis were observed, whereas synergy and antagonism of Cd and FLT were both observed for root growth.     

Effects of soil water and nitrogen availability on photosynthesis and water use efficiency of Robinia pseudoacacia seedlings

The efficient use of water and nitrogen (N) to promote growth and increase yield of fruit trees and crops is well studied.However,little is known about their effects on woody plants growing in arid and semiarid areas with limited water and N availability.To examine the effects of water and N supply on early growth and water use efficiency (WUE) of trees on dry soils,one-year-old seedlings of Robinia pseudoacacia were exposed to three soil water contents (non-limiting,medium drought,and severe drought) as well as to low and high N levels,for four months.Photosynthetic parameters,leaf instantaneous WUE (WUEi) and whole tree WUE (WUEb) were determined.Results showed that,independent of N levels,increasing soil water content enhanced the tree transpiration rate (Tr),stomatal conductance (Gs),intercellular CO2 concentration (Ci),maximum net assimilation rate (Amax),apparent quantum yield (AQY),the range of photosynthetically active radiation (PAR) due to both reduced light compensation point and enhanced light saturation point,and dark respiration rate (Rd),resulting in a higher net photosynthetic rate (Pn) and a significantly increased whole tree biomass.Consequently,WUEi and WUEb were reduced at low N,whereas WUE i was enhanced at high N levels.Irrespective of soil water availability,N supply enhanced Pn in association with an increase of Gs and Ci and a decrease of the stomatal limitation value (Ls),while Tr remained unchanged.Biomass and WUEi increased under non-limiting water conditions and medium drought,as well as WUEb under all water conditions;but under severe drought,WUEi and biomass were not affected by N application.In conclusion,increasing soil water availability improves photosynthetic capacity and biomass accumulation under low and high N levels,but its effects on WUE vary with soil N levels.N supply increased Pn and WUE,but under severe drought,N supply did not enhance WUEi and biomass.     

NO对Cd2+胁迫下绿豆幼苗DNA及光合作用的影响

以绿豆幼苗为材料,研究了外源一氧化氮(NO)处理对Cd~(2+)胁迫3天和8天时幼苗叶片和根系DNA含量、DNA链间交联程度以及叶片光合参数的影响。结果表明:单独Cd~(2+)胁迫导致叶片和根系DNA含量降低,DNA链间交联程度增加,叶片净光合速率、气孔导度和胞间隙CO2浓度降低,气孔限制值升高;与单独Cd~(2+)胁迫相比,NO和Cd~(2+)复合处理提高了叶片和根系DNA含量,降低了DNA链间交联程度,同时使叶片净光合速率和气孔导度升高,而使胞间隙CO2浓度和气孔限制值降低。结果说明,NO能缓解Cd~(2+)胁迫对绿豆幼苗DNA结构及其代谢的影响;Cd~(2+)胁迫抑制绿豆幼苗光合作用的主要原因是气孔因素,而NO主要通过提高幼苗叶片非气孔因素缓解了Cd~(2+)胁迫对幼苗光合作用的抑制。     

Impact of photosynthesis and transpiration on nitrogen removal in constructed wetlands

To determine the impact of photosynthesis and transpiration on nitrogen removal in wetlands, an artificial wetland planted with reeds was constructed to treat highly concentrated domestic wastewater. Under different meteorological and hydraulic conditions, the daily changes of photosynthesis and transpiration of reeds, as well as nitrogen removal efficiency were measured. It was found that net photosynthesis rate per unit leaf area was maintained on a high level (average 19.0 μmol CO₂/(m²·s)) from 10:00 to 14:00 in July 2004 and reached a peak of 21.1 μmol CO₂/(m²·s) when Photon Flux Density was high during the day. Meanwhile, TN and NH₄ ⁺-N removal efficiency rose to 79.6% and 89.6%, respectively—the maximum values observed in the test. Correlation coefficient analysis demonstrated a positive correlation among photon flux density, net photosynthetic rate, transpiration rate, and TN and NH₄ ⁺-N removal efficiency. In contrast, there was a negative correlation between stomatal conductance and TN and NH₄ ⁺-N removal efficiency. Results suggest that the photosynthesis and transpiration of wetland plants have a great impact on nitrogen removal efficiency of wetlands, which can be enhanced by an increase in the photosynthesis and transpiration rate. In addition, the efficiency of water usage by reeds and nitrogen removal efficiency could be affected by the water level in wetlands; a higher level boosts nitrogen removal efficiency. Translated from China Environmental Science, 2006, 26(1): 30–33 [译自: 中国环境科学]     

植物光合及蒸腾特性对湿地脱氮效果的影响

测定了芦苇光合作用及蒸腾特性随气象和水力条件的变化,及湿地相应的脱氮效率.采用相关系数法分析了芦苇光合及蒸腾特性与脱氮效率之间的关系.结果表明,芦苇的光合作用、蒸腾作用对湿地脱氮效果影响较大,随净光合速率和蒸腾速率的增加,湿地中DO浓度上升,改善了湿地脱氮效果;湿地水深影响芦苇水分利用效率和湿地脱氮效率,与浅水位比较而言,深水位下芦苇的水分利用率和湿地脱氮效率都得到了提高.     

3种工业有机废弃物对铅锌尾矿生物化学性质及植物生长的影响

开展野外田间试验,在铅锌尾矿中添加3种工业有机废物(酒糟、中药渣、蘑菇渣)作为改良剂,从植物生长、营养元素、土壤酶活性、尾矿及植物重金属含量等方面研究其对铅锌尾矿的改良效果.结果表明:①添加酒糟、中药渣、蘑菇渣处理后尾矿中DTPA-Cd、DTPA-Cu、DTPA-Pb和DTPA-Zn含量分别降低了24.2%~27.3%、45.7%~48.3%、18.0%~20.9%和10.1%~14.2%;有机质、铵态氮、有效磷含量分别增加了2.27~2.32倍、12.4~12.8倍和4.04~4.74倍;土壤脱氢酶、β-葡萄糖苷酶、脲酶和磷酸酶活性分别提高了5.51~6.37倍、1.72~1.96倍、6.32~6.62倍和2.35~2.62倍.②添加酒糟、中药渣、蘑菇渣促进了植物种子萌发和种苗生长,植被盖度分别到达了84%、79%和86%;其中,黑麦草的生物量增加了4.2~5.6倍,狗牙根的生物量增加了15.7~17.3倍;黑麦草和狗牙根地上部分重金属含量均显著降低.③植被盖度、生物量与尾矿基质营养元素和土壤酶活性呈极显著正相关,与尾矿重金属有效态含量呈极显著负相关;植物地上部分重金属含量与尾矿基质营养元素、土壤酶活性呈极显著负相关,与尾矿基质重金属有效态含量呈极显著正相关.综合分析表明,可以将酒糟、中药渣、蘑菇渣作为改良剂用于铅锌尾矿废弃地的生态恢复.     

幼刺参不同部位对Zn^2＋、Cu^2＋的蓄积动力学研究

以幼刺参为实验材料,在10℃、15℃、20℃条件下测定其体壁、消化道及呼吸树中Zn2 、Cu2 的蓄积量、蓄积速率及浓缩系数.研究发现,10℃时,Zn2 于第8 d在刺参体壁、消化道达到蓄积顶点,最大蓄积量分别为245.48×10-6和973.35×10-6;Cu2 于15℃,第8 d在幼刺参体壁和消化道达到最大蓄积量,分别为9.34×10-6和 59.65×10-6;20℃时,Cu2 于第8 d在呼吸树达到最大蓄积量,为622.37×10-6.研究表明,刺参消化道对Zn2 的蓄积大于体壁的蓄积,刺参呼吸树对Cu2 的蓄积大于消化道和体壁的蓄积.同时,温度显著影响Zn2 、Cu2 的蓄积.为了更好地理解Zn2 、Cu2 不同温度下在幼参体内的蓄积过程,本研究采用经典的非线性最小二乘估计原理构建数学模型,很好地模拟了重金属在不同的组织中随时间变化的动力学过程.     

Zn、Cd单一及复合污染对黑麦草根分泌物及根际Zn、Cd形态的影响

采用根袋土培试验,研究了锌、镉单一及复合污染对重金属富集植物黑麦草生长、锌镉积累、根分泌物及根际Zn、Cd形态的影响.结果表明,锌镉共存下(8 mmol/kg Zn+2 mmol/kg Cd),黑麦草对锌、镉的吸收为协同效应;仅镉污染时(2 mmol/kg Cd),镉对植株吸收锌为抑制效应.黑麦草吸收的锌、镉主要集中在地上部,以锌、镉复合污染时植株地上部对锌、镉的富集量最大,分别达到3 108.72、73.97 mg/kg,具有作为土壤重金属锌、镉污染植物修复材料的潜力.根际的松结合态锌、镉（交换态、碳酸盐结合态和铁锰结合态）含量大于其非根际的松结合态锌、镉含量.Cd污染和Zn、Cd复合污染的根际和非根际土壤镉形态均以交换态>碳酸盐结合态>铁锰结合态>残渣态>有机结合态.Zn污染及Zn、Cd复合污染根际和非根际土壤各锌形态以铁锰结合态>碳酸盐结合态>残渣态>有机结合态>交换态,而Cd污染的根际和非根际的锌形态则以残渣态>铁锰结合态>有机结合态>碳酸盐结合态>交换态.Zn、Cd污染促进了黑麦草根系氨基酸的分泌,降低了根际土壤的pH值,以Zn、Cd复合污染根际土壤氨基酸总量最大,分别为对照、Zn和Cd污染的1.95、1.54和1.40倍,根际土壤的pH值最低(5.18).根际氨基酸含量在重金属胁迫下明显增加,可能与黑麦草适应重金属胁迫有关.根际pH值高于非根际是根际Zn、Cd有效性大于非根际的重要原因.     

外生菌根真菌对五氯芬的耐受性及生理响应

在纯培养条件下,研究了7种外生菌根真菌--美昧牛肝菌(Boletus edulis)、铆钉菇(Gomphidius viscidus)、双色腊蘑(Laccaria bicolor)、褐疣柄牛肝菌(Leccinum 8cabrum)、红绒盖牛肝菌(Xerocomus chrysenteron)、大毒滑锈伞(Heboloma crustulinifoume)和长柄粘滑菇(Hebeloma longicaudum)在不同五氯酚浓度下的生长速度和耐受性,筛选出具有降解五氯酚潜力的3种外生菌根真菌--铆钉菇、双色腊蘑、褐疣柄牛肝菌;考察了这3种外生菌根真菌在五氯酚胁迫下的生长模式,并采用点试方法对真菌氧化还原酶的产生情况进行了检测.结果表明:低浓度(≤10mg·L-1)条件下,五氯酚并没有改变菌种的生长模式,其中铆钉菇表现出了对五氯酚较强的耐受性,而在较高浓度下(15mg·L-1),所有菌种生长均受到抑制.酶点试结果表明,铆钉菇是3种外生菌根真菌中氧化还原酶活性最强且种类较多的菌种,它表现出较高的漆酶、酪氨酸氧化酶和过氧化物酶活性,是一种具有高效降解芳环结构污染物潜力的菌根真菌.