玉米萌芽期水分胁迫的抗旱性分析

通过PEG渗透胁迫人工模拟干旱条件,对山西省新近育成和当前常见的18个玉米杂交种进行了萌芽期抗旱性研究。结果表明:萌发期水分胁迫降低了各玉米品种的发芽势和发芽率,阻碍了胚芽和胚根的生长,降低了种子中贮藏物质的运转率。但不同的玉米品种在抗旱性上存在极显著差异,抗旱性强的品种在水分胁迫下仍然保持较高的发芽势和发芽率。活力抗旱指数和萌发抗旱指数可以良好地反映品种间抗旱性的差别。通过对上述指标的测定,可以较好地反映出玉米品种萌芽期的抗旱性。     

商洛主推玉米品种萌发期抗旱性评价

以6份商洛地区主推玉米品种为供试材料,采用聚乙二醇（PEG-6000）模拟干旱胁迫的方法,测定发芽势、发芽率、胚根长、胚芽长等9个萌发指标的变化,并通过加权隶属函数法对供试玉米品种萌发期抗旱性进行综合评价。结果表明：①与清水对照相比,干旱处理后的发芽势、发芽率、胚根长、胚芽长和根体积均有不同程度下降;胚根干重、胚芽干重、贮藏物质转运率呈下降趋势,根冠比呈增加趋势。②隶属函数法计算综合评价值（D值）,供试品种萌发期抗旱性分为2类：万瑞6号、安森7号和秦鑫1708为强抗旱型;兆玉951、正大658和登海11为弱抗旱型。③根体积、储藏物质转运率和根冠比所占权重较大,可作为玉米品种萌发期抗旱性筛选的评价指标。     

不同谷子品种萌发期对干旱胁迫生理响应的变化及抗旱指标筛选

为了探讨干旱胁迫对谷子萌芽期的影响,筛选抗旱谷子新品种及谷子萌芽期抗旱性相关指标,明确干旱胁迫对不同谷子品种萌发期生理特征变化影响,以20%的聚乙二醇（PEG-6000）模拟干旱胁迫对15个谷子品种进行了萌发期抗旱性鉴定,对相关的六个抗旱性指标进行了筛选和相关性研究,并通过测定15个品种在干旱胁迫条件下SOD、POD和CAT的活性来研究其变化情况。结果表明：以萌发抗旱指数为标准指标,15个品种谷子萌发期抗旱性基本可以分为强、中、弱3类,其中抗旱性强的3个品种分别是陇谷10号、长生07、晋谷21号;抗旱性弱的2个品种是济谷20号、长生13。在干旱胁迫条件下谷子SOD、POD和CAT活性均有所升高,其中SOD活性在抗旱性强的3个品种中值最大,在抗旱性较弱的2个品种中值最小;SOD活性升高值与萌发抗旱指数显著正相关,而POD和CAT活性升高程度与萌发抗旱指数相关性不显著。通过相关性分析表明,活力抗旱指数、相对发芽率、相对发芽势与萌发抗旱指数呈极显著正相关,而相对胚芽长、相对胚根长与萌发抗旱指数之间没有明显的相关性。综上,在相关的六个抗旱性指标中,谷子抗旱的标准指标是萌发抗旱指数,谷子萌发期抗旱性鉴定的首要指标为活力抗旱指数和相对发芽率,次级指标则是相对发芽势,参考指标为相对胚芽长和相对胚根长。     

14个玉米杂交种萌发期抗旱性评价

本研究以20%的聚乙二醇溶液(PEG6000)模拟干旱胁迫条件,对14个玉米品种进行了萌发期抗旱性评价。结果表明,在PEG干旱胁迫条件下,玉米的发芽率降低,胚根、胚芽的生长受到不同程度的抑制,活力指数降低。鉴定玉米萌芽期抗旱性以萌发抗旱指数为主,结合其他各项指标进行综合评价。以相对发芽率、相对发芽势、相对活力指数、相对胚根长、相对胚芽长、萌发抗旱指数和胁迫指数为依据,通过隶属函数法综合评价,14个玉米杂交种抗旱性顺序依次是家佳荣2号12正组48×1云瑞8812正组47×1路单8号北玉16会单4号海禾2号迪卡2号12正组535×53412正组536×534珍禾2号12正组238×14112元江2号。     

不同谷子品种萌发期对干旱胁迫生理响应的变化及抗旱指标筛选

为了探讨干旱胁迫对谷子萌芽期的影响，筛选抗旱谷子新品种及谷子萌芽期抗旱性相关指标，明确干旱胁迫对不同谷子品种萌发期生理特征变化影响，以20%的聚乙二醇（PEG-6000）模拟干旱胁迫对15个谷子品种进行了萌发期抗旱性鉴定，对相关的六个抗旱性指标进行了筛选和相关性研究，并通过测定15个品种在干旱胁迫条件下SOD、POD和CAT的活性来研究其变化情况。结果表明：以萌发抗旱指数为标准指标，15个品种谷子萌发期抗旱性基本可以分为强、中、弱3类，其中抗旱性强的3个品种分别是陇谷10号、长生07、晋谷21号；抗旱性弱的2个品种是济谷20号、长生13。在干旱胁迫条件下谷子SOD、POD和CAT活性均有所升高，其中SOD活性在抗旱性强的3个品种中值最大，在抗旱性较弱的2个品种中值最小；SOD活性升高值与萌发抗旱指数显著正相关，而POD和CAT活性升高程度与萌发抗旱指数相关性不显著。通过相关性分析表明，活力抗旱指数、相对发芽率、相对发芽势与萌发抗旱指数呈极显著正相关，而相对胚芽长、相对胚根长与萌发抗旱指数之间没有明显的相关性。综上，在相关的六个抗旱性指标中，谷子抗旱的标准指标是萌发抗旱指数，谷子萌发期抗旱性鉴定的首要指标为活力抗旱指数和相对发芽率，次级指标则是相对发芽势，参考指标为相对胚芽长和相对胚根长。     

PEG胁迫下玉米自交系萌发期抗旱性综合评价

为探索不同玉米自交系的萌发期抗旱性,研究采用15%聚乙二醇(PEG-6000),蒸馏水作对照,以18个玉米自交系为试验材料,在人工气候室内通过渗透胁迫人工模拟干旱条件,测定不同自交系的胚根长、胚芽长、发芽率、发芽势4个形态指标和种子萌发期渗透调节物质游离脯氨酸(Pro)含量、丙二醛(MDA)含量、过氧化物酶(POD)活性和超氧化物歧化酶(SOD)活性4个生理生化指标。采用方差分析、相关性分析、模糊隶属函数分析等方法对不同玉米自交系抗旱性进行综合评价。结果表明：玉米萌芽期干旱胁迫对种子的8个指标影响较大,其中4个形态指标在15%PEG胁迫下均显著降低,4个生理生化指标均显著升高;胚根长、胚芽长、发芽率、发芽势、Pro含量和SOD活性可优先作为不同材料之间鉴定抗旱性差异的重要指标。通过模糊隶属函数法采用3种不同的方法评价抗旱性,表明单独使用一类指标可有效评价具有极端差异的玉米自交系萌发期的耐旱性,而综合使用形态指标和生理生化指标比单一类型指标更能准确评价抗旱性。利用胁迫指数显著性分析和模糊隶属函数法共同筛选出抗旱较强的自交系N958。研究为进一步研究玉米抗旱性机制提供了抗性来源。     

大麦种子萌发期抗旱性鉴定指标的筛选及抗旱性评价

【目的】研究大麦种子萌发期形态指标与抗旱性的关系,构建抗旱性评价方法。【方法】采用20;PEG8000模拟干旱胁迫,测定其9项形态指标。采用相关性分析及因子分析等筛选大麦种子萌发期抗旱性鉴定指标,并运用隶属函数法对101份大麦材料进行抗旱性综合评价。【结果】这9项形态指标与抗旱性均呈显著的相关关系。【结论】发芽势、发芽率、胚根长、胚芽长、胚芽鞘长、胚根干重、胚芽干重、根冠比、物质转运速率等指标均可作为大麦种子萌发期重要的抗旱性鉴定指标。采用隶属函数法筛选出Z027S078T、新引D7为抗旱性极强的材料;垦啤6号、贝赖勒斯为抗旱性极弱的材料。     

小麦抗旱性鉴定方法及评价指标研究Ⅳ萌发期抗旱指标的比较研究

为探讨小麦萌发期的抗旱性鉴定指标,采用PEG-6000高渗溶液胁迫剂在小麦种子萌发期进行渗透胁迫试验,并运用灰色关联分析对品种的抗旱性做出评判,依据抗旱性对有关指标进行相关分析。结果表明,种子萌发期抗旱性鉴定方法结果科学、客观,具有较强的操作性和重复性;相对发芽率、贮藏物质转运率、胚芽鞘长可作为鉴定小麦萌发期抗旱性的可靠指标,初生根数可作为参考指标,芽长、主胚根长不宜作为鉴定指标。     

不同玉米品种萌芽期抗旱性研究

通过PEG渗透胁迫人工模拟干旱条件，对不同的玉米品种川单15号、黔单11号、户单2000、成单19、安单136、黔单13号、三北六号、农大3138、正红6号进行了萌芽期抗旱性研究。结果表明：水分胁迫降低了各玉米品种的发芽势和发芽率，阻碍了胚芽和胚根的生长，降低了种子中贮藏物质的利用效率。但不同的玉米品种在抗旱性上存在极显著差异，抗旱性强的品种在水分胁迫下仍然保持较高的发芽势和发芽率。通过对上述指标的测定可以较好地反映出玉米品种萌芽期的抗旱性。     

PEG模拟干旱胁迫处理辽宁省主栽玉米品种的萌发特性

为了筛选抗旱玉米品种应用于生产,以沈玉35、辽单33等9个辽宁省主栽玉米品种为试验材料,研究不同程度干旱胁迫对玉米种子萌发特性的影响。结果表明:在高浓度PEG(20%)模拟干旱胁迫条件下,相对发芽率抚玉20最高,达95.92%,发芽势相对值富友99和长玉1最高,均为79.59%;萌发抗旱指数长玉1最高,达0.742;贮藏物质转运伤害率富友99最低,为43.34%;对沈玉35胚芽生长的伤害率最低,为78.81%;对抚玉20胚根的伤害率最低,仅3.53%。在干旱胁迫条件下,丹玉39的相对发芽势和萌发抗旱指数均为最低,分别为8.51%和0.103,其次是郑单958,分别为31.25%和0.463;丹玉39胚根生长伤害率最高,为76.32%;其次是郑单958,为49.89%。各品种的发芽率、发芽势、萌发指数、贮藏物质转运率、胚芽长及胚根长在干旱胁迫条件下均明显降低,不同品种间存在差异。抗旱性较强的品种为抚玉20和富友99,干旱敏感品种为丹玉39和郑单958。     

3种园林植物的抗盐光合特性

研究狗牙花、红背桂和花叶假连翘叶片的光合作用对盐胁迫的响应,揭示3种幼苗耐盐胁迫的能力,以便为滨海盐土的园林植物选择提供参考。通过利用人工浇盐的方式模拟野外盐环境,测定植物光合指标,并用主成分方法评定各种园林植株的抗盐性。结果表明,随着盐胁迫时间的延长,在0.3%盐浓度胁迫下,3种幼苗的Pn不断下降;狗牙花与花叶假连翘的Gs和Ci不断下降,红背桂先升后降;狗牙花与红背桂的Tr不断下降,花叶假连翘先降后升。在0.6%盐浓度胁迫下,3种幼苗的Pn持续下降;狗牙花的Gs先降后升,红背桂与花叶假连翘下降。狗牙花、花叶假连翘的Ci先降后升,红背桂持续下降;3种幼苗的Tr先降后升。采用主成分分析法对3种植株的光合指标进行综合评价,显示盐浓度胁迫下的3种植物幼苗的光合指标得分为红背桂狗牙花花叶假连翘。3种苗木中,红背桂叶片能维持较高的光合活性,更适于盐碱地栽培,而花叶假连翘的耐盐胁迫能力弱。     

猪伪狂犬病病毒流行毒株gE/gI缺失突变株的构建及生物学特性研究

【目的】为研制针对猪伪狂犬病病毒流行毒株的疫苗提供候选毒株。【方法】构建针对猪伪狂犬病病毒流行毒株的gE/gI缺失重组转移质粒pMD-LA-RA及携带EGFP标记基因的重组转移质粒pMD-LA-EGFP-RA,将pMDLA-EGFP-RA与伪狂犬病病毒流行毒株PRV AH进行同源重组,利用EGFP为筛选标记,获得携带EGFP基因的gE/gI基因缺失突变株PRV AH gE~–/gI~–/EGFP~+,以此毒株与pMD-LA-RA进行第2次同源重组,筛选去除EGFP基因的gE/gI基因缺失突变株PRV AH gE~–/gI~–,并通过生长曲线、易感细胞连续传代和动物免疫评价其增殖能力、遗传稳定性及免疫原性。【结果】通过2次同源重组,结合荧光观察、空斑纯化和PCR检测,成功获得了PRV AH gE~–/gI~–,经PCR鉴定、荧光观察及测序鉴定,证实该毒株g E和g I基因被成功缺失,且不携带EGFP标记基因。生物学特性研究结果表明,该毒株增殖能力与亲本毒株相当,遗传稳定性及免疫原性良好。【结论】采用同源重组技术成功构建了免疫原性良好的猪伪狂犬病病毒流行毒株gE/gI基因缺失突变株,为研制针对流行毒株的基因缺失疫苗奠定了一定的基础。     

Effects of exogenous spermidine on the photosynthesis of Cucumis sativus L. seedlings under rhizosphere hypoxia stress

With water culture, this paper studied the effects of exogenous spermidine (Spd) on the net photosynthetic rate (P _n), intercellular CO₂ concentrations (C _i), stomatal conductance (G _s), transpiration rate (T _r), apparent quantum yield (Φ _c), and carboxylation efficiency (CE) of cucumber seedlings under hypoxia stress. The results showed that P _n decreased gradually under the hypoxia stress, and reached the minimum 10 days later, which was 63.33% of the control. Compared with that of the hypoxia-stressed plants, the P _n 10 days after the application of exogenous Spd increased by 1.25 times. A negative correlation (R ²=0.473−0.7118) was found between _{P n} and C _i, and G _s and T _r changed in wider ranges, which decreased under the hypoxia-stress, but increased under the hypoxia-stress plus exogenous Spd application. There was a significant positive correlation between G _s and T _r (R ²=0.7821−0.9458), but these two parameters had no significant correlation with P _n. The hypoxia stress induced a decrease of Φ _c and CE by 63.01% and 72.33%, respectively, while the hypoxia stress plus exogenous Spd application made Φ _c and CE increase by 23% and 14%, respectively. The photo-inhibition of cucumber seedlings under hypoxia stress was mainly caused by non-stomatal inhibition, while the exogenous Spd alleviating the hypoxia stress by repairing photosynthesis systems. __________ Translated from Chinese Journal of Applied Ecology, 2006, 17(9): 1609–1612 [译自: 应用生态学报]     

臭氧与干旱胁迫对海南蒲桃和盆架子幼苗光合生理的影响

以海南蒲桃（Syzygium hainanense）和盆架子（Alstonia scholaris）幼苗为材料,置于开顶气室进行人工臭氧熏气和干旱处理。通过测定0 d、15 d、30 d时2种树木幼苗叶片的净光合速率、气孔导度、胞间CO₂浓度及蒸腾速率,计算气孔限制值,分析这些指标在臭氧胁迫和干旱胁迫下的变化情况。结果显示：⑴受臭氧和干旱胁迫的影响,2种幼苗叶片的净光合速率、气孔导度、蒸腾速率随处理时间的延长呈现下降,胞间CO₂浓度和气孔限制值上升或下降,臭氧与干旱交叉胁迫的影响大于臭氧或干旱单一胁迫。在臭氧胁迫下,海南蒲桃幼苗的净光合速率下降以气孔限制为主,干旱胁迫下以非气孔限制为主。（2）盆架子幼苗在臭氧胁迫和干旱胁迫下从气孔限制转为非气孔限制,说明海南蒲桃的抗臭氧能力强于盆架子,抗旱能力不如盆架子;臭氧和干旱交叉胁迫下,2种幼苗的净光合速率下降均以非气孔限制为主,说明他们抗臭氧与干旱交叉胁迫的能力相近。     

双氰胺减少铵态氮肥施用后潮土N2O排放的机制

为探讨双氰胺（DCD）减少铵态氮肥施用后氧化亚氮（N₂O）的排放机制,通过开展好氧培养试验,研究DCD配施铵态氮（NH₄⁺-N）或亚硝态氮（NO₂^--N）对潮土土壤N₂O排放的影响,同时添加不同浓度NO₂^--N模拟NO₂^--N累积对N₂O和CO₂排放的影响。结果表明： DCD仅对NH₄⁺-N氧化过程中N₂O排放有抑制作用,对NO₂^--N还原过程中产生的N₂O没有影响;培养前7 d,DCD显著抑制NH₄⁺-N的氧化过程,降低净硝化速率,而在添加NO₂^--N土壤中加入DCD后净硝化速率显著增加,培养30 d后,DCD对NH₄⁺-N和NO₂^--N氧化过程均没有影响;添加外源NO₂^--N明显促进了N₂O排放,其排放通量显著高于不施肥的对照处理; N₂O累积排放量同NO₂^--N浓度呈正相关,CO₂累积排放量同NO₂^--N浓度呈显著负相关。研究表明,DCD可以避免NO₂^--N大量累积而产生的毒害作用,但仅对氨氧化过程N₂O减排有效果,因此亟待研发适于抑制NO₂^--N产生N₂O的新型抑制剂。     

Adventitious shoot regeneration from the leaves of some pear varieties (Pyrus spp.) grown in vitro

The pear (Pyrus spp.) is one of the most important temperate fruit crops. A complete protocol for adventitious shoot regeneration was developed from the leaves of four pear varieties grown in vitro: Abbe Fetel, Yali, Packham’s Triumph and Aikansui, and the Chinese rootstock variety Duli. Shoot explants were collected from the field and cultured in vitro in Murashige and Skoog (MS) media supplemented with 1.0 mg·L⁻¹ 6-benzylaminopurine (BA) and 0.1 mg·L⁻¹ indole-3-butyric acid (IBA). After four weeks, leaf explants of all 5 varieties grown in vitro were excised and cultured in MS media supplemented with 0.0 mg·L⁻¹, 0.2mg·L⁻¹, 0.5 mg·L⁻¹, 1.0 mg·L⁻¹ and 2.0 mg·L⁻¹ naphthaleneacetic acid (NAA) and 5.0 mg·L⁻¹ BA or with 1.0 mg·L⁻¹, 2.0 mg·L⁻¹ and 4.0 mg·L⁻¹ thidiazuron (TDZ). The cultures were maintained in darkness for 21 days for shoot induction in the shoot induction medium (IM), then transferred to the shoot expression medium (EM) in 1.0 mg·L⁻¹ TDZ without any auxins and kept in a growth room at (25±2)°C under a 16/8 h light/dark photoperiod regime for 8 weeks. Finally, the shoots were transferred to the MS shoot elongation medium (SEM) supplemented with 0.2 mg·L⁻¹ BA, 0.1 mg·L⁻¹ IBA and 0.2 mg·L⁻¹ gibberellic acid (GA₃). A combination of TDZ and NAA had a significant effect on the number of shoot regenerations in all 5 tested varieties. The maximum mean number of shoots and maximum number of shoots per leaf obtained from Yali variety were 11.8 (P⩽0.001) and 22, followed by Aikansui with 6.6 (P⩽0.001) and 4.6, and Duli with 8 (P⩽0.001) and 12, all arising from the combination of 0.2 mg·L⁻¹ NAA with 1.0 mg·L⁻¹ TDZ. For Packham’s Triumph and Abbe Fetel, the maximum mean number of shoots and maximum number of shoots per leaf were 5.6 (P⩽0.001), 4.8 and 8 (P⩽0.001), and 11, respectively, from the combination of NAA (1.0 mg·L⁻¹) and TDZ (2.0 mg·L⁻¹). Abbe Fetel was the only variety which produced significantly higher adventitious shoots from the two different combinations of 1.0 mg·L⁻¹ NAA and 5.0 mg·L⁻¹ BA (P⩽0.05), and 2.0 mg·L⁻¹ NAA and 5.0 mg·L⁻¹ BA (P⩽0.01). Some of the most prominent problems associated with shoot proliferation and regeneration were also observed and discussed in this paper.     

Effect of interactions between carbon dioxide enrichment and NH 4 + /NO 3 − ratio on pH of culturing nutrient solution, growth and vigor of tomato root system

A growth chamber experiment was conducted to investigate the influence of NH₄⁺/NO₃⁻ ratio and elevated CO₂ concentration on the pH in nutrient solution, growth and root vigor system of tomato seedling roots, which attempts to understand whether the elevated CO₂ concentration can alleviate the harmful effects of higher NH₄⁺-N concentration in nutrient solutions on the tomato root system. Tomato (Lycopersicon esculentum Mill. var. Hezuo 906) was grown in pots with nutrient solutions varying in NH₄⁺/NO₃⁻ ratio (0:1, 1:3, 1:1, 3:1 and 1:0) and the growth chambers were supplied with ambient (360 μL·L⁻¹) or elevated CO₂ concentration (720 μL·L⁻¹). The results showed that the pH changed with the growth process and CO₂ concentration increased. At both CO₂ levels, pH increased when 100% NO₃⁻-N was supplied and decreased in other treatments. The pH decrease in the nutrient solution was directly correlated to the NH₄⁺-N proportion. The pH value was more reduced in 100% NH₄⁺-N nutrient solution than increased in the 100% NO₃⁻-N nutrient solution. CO₂ enrichment increased the dry weight of shoots and roots, root vigor system, total absorbing area and active absorbing area of tomato seedlings. All the measurement indexes above were increased in the elevated CO₂ concentration treatment with the NO₃⁻ proportion increase in the nutrient solutions. Thus, under the elevated CO₂ concentration, the dry weights of shoots and roots, root vigor system, total root absorbing area and active absorbing area were found to be inversely correlated to NH₄⁺/NO₃⁻ ratio, leading to about 65.8%, 78.0%, 18.9%, 12.9% and 18.9% increase, respectively, compared with that under the ambient CO₂ concentration. Our results indicated that tomato seedling roots may benefit mostly from CO₂ enrichment when 100% NO₃⁻-N nutrient solutions was supplied, but the CO₂ concentration elevation did not alleviate the harmful effects when 100% NH₄⁺-N was supplied. __________ Translated from Plant Nutrition and Fertilizer Science, 2007, 13(5): 865–870 [译自: 植物营养与肥料学报]     

Identification of blaIMI-mediated carbapenem-resistant Enterobacter from a duck farm in China

Carbapenem- and colistin-resistant Enterobacter has been a clinical and therapy problem in recent years. Here, we report the carbapenem- and colistin-resistant Enterobacter harboring bla_IMI isolated from intestinal samples and the environment of a duck farm in China. Four bla_IMI-positive Enterobacter isolates were resistant to carbapenem and colistin. Three bla_IMI subtypes were detected in different molecular categories of Enterobacter. The detection of the various IMI producers highlights the diversity of carbapenemases in a duck farm. Whole-genome sequencing demonstrated the bla_IMI genes were present in chromosomes or plasmids in these strains. The conjugation experiment demonstrated the ability of bla_IMI-carrying plasmid to transmit horizontally. The molecular evolution characteristics were examined through comparative genetic analysis. The study demonstrated the presence of chromosomal and plasmid bla_IMI and the bla_IMI-carrying plasmid exhibits a horizontal transmission between Enterobacter and Escherichia coli C600. The similar genetic content was discovered between two bla_IMI-16-positive Enterobacter asburiae. In addition, a bla_IMI-16-carrying plasmid is an IncFII(Yp) plasmid, and a substantial amount of mobile genetic elements were identified around bla_IMI-16. The IS-like elements and IncFII(Yp) plasmid are significant in the propagation of bla_IMI. Our study provides evidence for the transmission of diverse bla_IMI genes in China and supplies additional reference data for bla_IMI-positive antimicrobial-resistant Enterobacter. Routine surveys of bla_IMI-positive Enterobacter from animal-raising environments must be given more focus.     

不同光质条件及NH4+-N、Cu2+浓度对栅藻处理沼液的影响

将筛选所得耐污能力强的栅藻作为研究对象,研究不同光质条件对栅藻处理沼液的影响,并且以实际沼液废水中NH₄⁺-N、Cu²⁺浓度为参照设置不同浓度,分别考察NH₄⁺-N、Cu²⁺对栅藻生长的影响。结果表明：在白光、蓝光、红光3种光质下,栅藻生物产率分别是0.21、0.04、0.03 g ·L^-1·d^-1,白光条件下栅藻生长相对较好。50 mg·L^-1低浓度NH₄⁺-N下栅藻生长较好,其生物产率优于BG 11培养基,分别为0.20、0.18 g·L^-1·d^-1;500、2000 mg·L^-1高浓度NH₄⁺-N下,藻细胞生长缓慢,生物产率仅为0.12、0.11 g·L^-1·d^-1。在Cu²⁺浓度分别为0.5、1.0、2.0 mg·L^-1的培养液中,藻细胞生物产率分别为0.18、0.15、0.13 g·L^-1·d^-1。一定浓度NH₄⁺-N存在下,栅藻能耐受较高的Cu²⁺浓度。     

土壤盐分离子对乌鲁木齐小白菜Pb含量的影响研究

为研究土壤中盐分离子对小白菜Pb含量的影响,采取正交试验L₁₆ 4⁵和盆栽试验方法,分析了5种阳离子（Ca²⁺、Mg²⁺、K⁺、Na⁺、Pb²⁺）和3种阴离子（SO₄^2-、Cl^-、NO₃^-）对小白菜地上部和根系中Pb含量的影响。结果表明,试验条件下小白菜地上部Pb含量为0.215~0.930 mg·kg^-1,根系中Pb含量为1.648~24.33 mg·kg^-1,可食用部分超标率达81.3%。土壤盐分离子对小白菜地上部Pb含量影响顺序为： Ca²⁺ > Mg²⁺ > Na⁺ > Pb²⁺ > K⁺。根据相关性分析,土壤中Ca²⁺与小白菜地上部Pb含量呈显著负相关（r=-0.540 3,P<0.05）,Na⁺和Pb²⁺呈正相关但不显著。Mg²⁺和K⁺呈负相关,也不显著。Cl^-和NO₃^-与小白菜地上部Pb含量呈显著负相关（r=-0.540,P<0.05）,SO₄^2-呈正相关,但不显著。对小白菜根系Pb含量影响顺序为： Pb²⁺ > K⁺ > Na⁺ > Ca²⁺ > Mg²⁺,土壤中Pb²⁺对小白菜根系Pb的含量呈显著正相关（r=0.483,P<0.05）,Ca²⁺、Mg²⁺、K⁺、Na⁺、SO₄^2-、Cl^-和NO₃^-相关性不显著。乌鲁木齐土壤中固有的盐分离子对小白菜可食用部分Pb的吸收没有抑制作用。