干旱胁迫对藜麦幼苗组织解剖结构和生理特性的影响

为探究藜麦幼苗不同组织对干旱胁迫的响应,本试验采用盆栽方法设定不同田间持水量(100％、50％、25％)和不同处理时间(0、48、96 h),分别对藜麦幼苗根、茎、叶组织的解剖结构、脯氨酸含量以及吡咯啉-5-羧酸合成酶(P5CS)、脯氨酸脱氢酶(PDH)、过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CA...     

外源水杨酸对盐胁迫下棉花幼苗光合作用的影响

为了探究水杨酸(SA)对盐胁迫下棉花幼苗的缓解机理,以2个对盐胁迫敏感程度不同的棉花品种中棉所41号和中棉所49号为材料,研究SA浸种和叶面喷施对盐胁迫下棉花幼苗光合作用的影响。结果表明,0.05、0.06 mmol·L~(-1) SA浸种和0.08、0.12、0.18 mmol·L~(-1) SA叶面喷施均可提高棉花幼苗的株高、干物质积累、叶绿素含量、净光合速率、胞间CO_2浓度和气孔导度,能有效缓解0.6%NaCl的胁迫。中棉所41号在0.05 mmol·L~(-1)SA浸种处理和0.08 mmol·L~(-1) SA叶面喷施处理表现最好,中棉所49号在0.06 mmol·L~(-1) SA浸种处理和0.18 mmol·L~(-1) SA叶面喷施处理表现最好。主成分分析表明,单株鲜重、叶干重、净光合速率和气孔限制值可以作为评价不同浓度的SA对盐胁迫缓解效果的主要指标。综上所述,SA浸种与叶面喷施2种处理方式均可缓解0.6%NaCl带来的伤害,但存在浓度效应,适宜的浓度与棉花的基因型与耐盐性密切相关。本研究为进一步揭示外源SA对棉花盐胁迫的缓解机理提供了参考,同时也为新疆盐碱地棉花种植提供了理论依据。     

ROLE OF SALICYLIC ACID IN REGULATION OF CADMIUM TOXICITY IN WHEAT (TRITICUM AESTIVUM L.)

The present study is focused on the possible mediatory role of salicylic acid (SA) under cadmium (Cd⁺²) toxicity. Cadmium treatments resulted in the inhibition of root dry biomass, root elongation and increased Cd accumulation in roots. Pretreatment of seeds with SA (500 μM) for 20 hrs resulted in protection against Cd, increased root dry biomass, root elongation and minimal accumulation of cadmium. Cadmium chloride (CdCl₂; 0.0, 100, 400 and 1000 μM) produced a significant inhibition in chlorophyll, photosynthetic efficiency [carbon dioxide (¹⁴CO₂)-fixation], relative water content (RWC) and abscisic acid (ABA) content. Pretreatment of seeds with SA alleviated the Cd negative effect on these parameters. A drop in the activities of carboxylating enzymes, phosphoenol pyruvate carboxylase (PEPC, EC 4.1.1.31), and ribulose1,5-bisphosphate carboxylase (RuBPC, EC 4.1.1.39) were observed in Cd treated plants. Pretreatment with SA ameliorated the inhibitory effect of Cd on the studied enzymatic activities. Cadmium applied to salicylic acid free plants increased the level of stress metabolites, malondialdehide (MDA), hydrogen peroxides, and free proline content. Salicylic acid pretreatment decreased the toxic effect level of cadmium manifested by lower lipid peroxidation, lesser production of H₂O₂ and reduction in free proline content. The ultrastructural investigation of the root cells of wheat exposed to different concentrations of Cd for 15 days was carried out. The results indicated that Cd induced several obvious ultrastructural changes such as increased vacuolation, condensed cytoplasm with increased density of the matrix, reduction of mitochondrial cristae, severe plasmolysis, highly condensed nuclear chromatin and increment of disintegrated organelles. Electron dense granules appeared between the cell wall and plasmalemma. In vacuoles, electron dense granules encircled by the membrane were aggregated and formed into larger precipitates, which increase in number and volume as a consequence of excessive Cd exposure. An important issue arising from this study was how the short-term treatment with SA affected several physiological processes, such as plant growth, photosynthesis, and antioxidant defense system. We assume that the beneficial effect of SA during an earlier growth period could be related to avoidance of cumulative damage upon exposure to cadmium. One of the important roles of SA in inducing resistance to various environmental stresses is manifested by its ability to express genes that code for pathogenesis-related proteins or defense-related enzymes. Also, SA could form a complex with Cd that may provide Cd tolerance.     

外源水杨酸对冷藏枇杷果实木质化及相关酶活性的影响

以“解放钟”枇杷为试材,研究了外源水杨酸(SA)对4℃冷藏枇杷果实木质化的影响。试验结果表明：采用1.0 g/L SA浸果20 min处理能抑制枇杷果实苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、肉桂醇脱氢酶(CAD)和过氧化物酶(POD)的活性,从而抑制果实木质素的形成,降低果实硬度,说明SA具有减缓冷藏枇杷果实木质化的作用。     

锌铬复合胁迫对大豆根际土壤酶活性的影响

为研究不同Zn、Cr复合胁迫对大豆根际土壤酶活性的影响,在盆栽条件下,采用添加外源Zn、Cr的方法,测定了大豆根际和非根际土壤脲酶活性、过氧化氢酶活性、蔗糖酶活性。结果表明,不同Zn、Cr处理对大豆根际土壤脲酶活性有显著抑制效果,在Zn、Cr浓度分别为500、400 mg/kg时,大豆根际土壤脲酶活性为最低。随Zn、Cr浓度的增加,大豆根际土壤过氧化氢酶活性呈现先升高后降低的趋势,在Zn、Cr浓度分别为0、300 mg/kg时,达最大值,比对照提高14.80%;在Zn、Cr浓度分别为500、400 mg/kg时,仅为2.38 ml/(g·h),是最小值,比对照降低44.38%。随Zn、Cr浓度增加,大豆根际土壤蔗糖酶活性也呈现类似趋势,在Zn、Cr浓度分别为0、90 mg/kg时,达最大值3.65(mg/g·d),比对照提高9.87%;在Zn、Cr浓度分别为500、400 mg/kg时,达到最小值1.80(mg/g·d),比对照降低45.8%。同时结合偏相关分析结果发现,Zn、Cr对3种土壤酶活性均产生了协同抑制效应,且Zn的抑制作用大于Cr。     

水杨酸对废电池胁迫下绿豆幼苗抗氧化酶活性及生理特性的影响

采用室内有培养土的纸杯培养方法,研究了不同浓度水杨酸（SA）处理对废电池胁迫下,绿豆幼苗抗氧化酶及生理特性的影响。结果表明,废电池胁迫下,超氧化物歧化酶（SOD）活性升高,过氧化物酶（POD）活性降低,光合色素、可溶性蛋白含量下降,脯氨酸和丙二醛（MDA）含量升高,电导率增大,膜稳定性降低,显示出一定的毒害效应;低浓度（≤100mg·L-1）的外源SA处理能够明显增强废电池胁迫下绿豆叶片SOD、POD活性,改善多项指标,但随着SA浓度升高,SOD和POD酶活性逐渐降低。说明低浓度SA能通过刺激抗氧化酶活性,减轻氧化胁迫,缓解废电池对绿豆幼苗的毒害作用,但高浓度SA（≥100mg·L-1）缓解作用降低。     

Critical Toxic Ranges of Chromium in Spinach Plants and in Soil

ABSTRACT

Long-term irrigation with untreated industrial sewage effluents causes accumulation of high concentrations of chromium (Cr) and other heavy metals in soil and subsequently in crop plants (especially leafy vegetables), which can be phytotoxic to plants and/or a health hazard to animals and humans. Greenhouse experiments were conducted to determine the effects of Cr application on the growth of spinach (Spinacia oleracia L.) and to develop critical toxic ranges of Cr in plants and in soil. The study involved growing of spinach variety ‘Punjab Green’ in a greenhouse on silty clay loam and sandy soils equilibrated with different levels of applied Cr (0, 1.25, 2.5, 5, 10, 20, 40, 80, 160, and 320 mg Cr kg^{? 1} soil). Plants were harvested at: three growth stages 45, 60, and 90 days after sowing (DAS). Critical toxic ranges were estimated by regressing and plotting data on ammoniumbicarbonate-diethylenetriaminepenta-acetic acid (AB-DTPA) extractable Cr in soil or Cr concentration in plants versus dry-matter yield (DMY) of spinach at the three growth stages. Toxic ranges, i.e., slightly toxic (80%–90%), moderately toxic (70%–80%), and extremely toxic (< 70%) in terms of DMY relative to the attainable maximum DMY, were established for both soils and for plants at all three growth stages. There was no germination of spinach with applied Cr at 320 mg Cr kg^{? 1} rate in silty clay loam soil and at 40 mg Cr kg^{? 1} rate in sandy soil due to Cr toxicity. Roots accumulated more Cr in comparison with shoots. Chromium concentrations of 0.47–1.93 mg Cr kg^{? 1} soil in silty clay loam soil, 0.13–0.94 mg Cr kg^{? 1} soil in sandy soil, 1.08–5.40 mg Cr kg^{? 1} plant DM in silty clay loam soil and 0.54–11.7 mg Cr kg^{? 1} plant DM in sandy soil were found to be toxic. The critical toxicity ranges of Cr thus established in this study could help in demarcating Cr toxicity in soils and in plants such as spinach and other leafy vegetables due to irrigation of soils with untreated sewage water contaminated with chromium.     

冷激结合水杨酸处理对黄瓜果实冷害及能量和脯氨酸代谢的影响

为探讨冷激结合水杨酸处理减轻黄瓜果实冷害的作用及其机理,本试验分别研究了冷激(0℃冰水混合物)、水杨酸(1 mmol·L-1)以及二者结合(含有1 mmol·L-1水杨酸的0℃冰水混合物)3种处理方式对黄瓜果实低温贮藏期间能量和脯氨酸代谢的影响.结果表明,冷激、水杨酸以及二者结合处理均能抑制黄瓜果实冷害程度、相对电导率...     

六价铬对玉米幼苗生长及抗氧化系统的影响

为系统研究六价铬[C（rVI）]对玉米幼苗生长及抗氧化系统的影响,采用水培方法,在培养液中加入不同浓度重铬酸钾（0、10-6、10-5、10-4mol.L-1）,胁迫不同时间（6、12、18d）后对幼苗进行各项指标检测。结果表明,低浓度铬（10-6mol.L-1）对幼苗生长有一定刺激作用,且对地上部分刺激作用更明显;对叶片抗氧化酶活性及抗坏血酸含量没有显著影响。中浓度铬（10-5mol.L-1）胁迫明显抑制根部生长（n=15,P〈0.01）,对地上部分干重积累无显著影响,使幼苗含水量有明显下降（n=15,P〈0.01）;MDA含量明显升高（n=5,P〈0.01）;18d后,SOD和ASA-POD活性分别升高50.9和125.0,POD活性下降72.3,抗坏血酸含量上升约2倍。高浓度铬（10-4mol.L-1）胁迫下幼苗生长几乎停止,含水量明显下降（n=15,P〈0.05）。铬在玉米幼苗中的积累明显影响其生长,造成植株含水量下降,冠根比增大,叶片抗氧化酶活性剧烈变化并受到严重的氧化胁迫。     

硒处理对薄壳山核桃幼苗生长的影响

为探究硒对薄壳山核桃幼苗生长的影响,利用不同浓度亚硒酸钠[0(CK)、0.5、5、10、20、40、80 μmol·L^-1]对薄壳山核桃幼苗进行处理,并测定相关生理指标。结果表明,低浓度硒对薄壳山核桃幼苗生长发育、生物量积累、酶活性均有促进作用,而高浓度硒抑制了幼苗生长、干物质的积累、酶活性、光合速率,且硒浓度越高,抑制作用越明显。80 μmol·L^-1 硒浓度处理后的根长较CK显著降低了55.36%(P<0.05),其他形态指标均无显著差异。硒处理显著提高了幼苗体内的硒含量,且根系>叶片。随着硒浓度的增加,叶、根内的硒含量呈先升高后降低的趋势,硒浓度≥0.5 μmol·L^-1时,其他处理均与CK存在显著差异。40 μmol·L^-1硒浓度处理下叶中的硒含量较CK显著增加了1 682倍,根中的硒含量提高了482倍。低硒浓度(≤10 μmol·L^-1)处理可以促进根中Mn²⁺、Mg²⁺含量和叶中的Zn²⁺含量的积累。当硒浓度≥5 μmol·L^-1时,会促进根中Zn²⁺含量的积累,硒浓度≥10 μmol·L^-1,促进茎中Mn²⁺含量的积累,其中在80 μmol·L^-1硒浓度处理下茎中Mn²⁺含量为CK的9.29倍。过氧化物酶(POD)、超氧化物歧化酶(SOD)活性随着硒浓度增加均呈先增后减的趋势,且在0.5 μmol·L^-1硒浓度处理下达到最高,明显高于CK,分别为1 698.63、1 912.28 U·mg prot^-1。综上,低浓度硒处理和施硒时间长短对幼苗光合作用影响不大,而高浓度硒处理会抑制光合作用。本研究结果为进一步揭示硒富集机理和硒的科学使用提供了理论依据。     

外源水杨酸对锰污染红壤中玉米的生长与抗氧化酶活性的调节作用

采用盆栽实验方法研究了外源水杨酸（SA）对锰污染红壤中玉米的生长、脂质过氧化程度、活性氧水平以及抗氧化酶活性的影响。结果表明,过量锰明显降低玉米植株干重,显著提高了茎叶和根中锰的含量。SA促进锰胁迫下玉米的生长,但对植株中锰的含量与分布无影响。过量锰处理下,玉米叶片超氧阴离子（O.2-）和过氧化氢积累显著增加,脂质过氧化、电解质渗透率和脯氨酸含量显著升高;而SA和过量锰复合处理下,这些指标则显著降低。过量锰诱导超氧化物歧化酶（SOD,EC1.15.1.1）、过氧化物酶（POD,EC1.11.1.7）活性升高,抑制过氧化氢酶（CAT,EC1.11.1.6）和抗坏血酸过氧化物酶（APX,1.11.1.11）活性;SA处理促进锰胁迫下SOD和POD活性进一步升高,减小CAT和APX活性下降的程度。这些结果提示,SA调节抗氧化酶活性,保护组织细胞免遭氧化损伤,是SA缓解过量锰对玉米毒害作用的重要生理原因。     

开花后水分胁迫对冬小麦旗叶光合作用和保护酶活性的影响

为了解干旱对冬小麦光能利用与耗散机制的影响,研究了花后水分胁迫对冬小麦光合作用参数、叶绿素荧光参数及保护酶与光合作用相关酶活性的影响.结果表明,水分胁迫增加了旗叶可溶性糖和丙二醛含量,提高了叶片的渗透调节和抗氧化能力.中度水分胁迫下旗叶的光合速率和蒸腾速率与充分供水处理的相近,而重度胁迫处理的光合速率和蒸腾速率则降低较为明显.适度的水分胁迫可诱导叶片保护酶活性升高,从而减轻干旱伤害.适度的水分胁迫可增强PSⅡ反应中心的电子捕获效率,增强光呼吸作用,较好的保护光合机构.水分胁迫促进了冬小麦灌浆前期的蔗糖合成能力,但同时也导致灌浆中后期旗叶衰老的加剧,使得叶片的蔗糖合成能力急剧下降.水分胁迫降低了旗叶的RuBP羧化酶活性,除非受旱严重,否则RuBP羧化酶活性的降低不会限制叶片的光合作用.     

Decontamination of Chromium by Farm Yard Manure Application in Spinach Grown in Two Texturally Different Cr-Contaminated Soils

ABSTRACT

Chromium (Cr) is an environmental pollutant and its accumulation up to toxic levels in the soil and plants by applying irrigation with untreated industrial effluents has become a major problem throughout the world, especially in developing countries like India. Various inorganic as well as organic compounds are known for their ability to reduce mobilization of heavy metals in soils for plant uptake and leaching to ground water. The present study was undertaken under controlled glasshouse conditions to assess the effectiveness of farm yard manure (FYM) applications (equivalent to 0, 1, and 2% organic matter on w/w basis) to ameliorate Cr toxicity in spinach grown in two texturally different soils (silty loam and sandy) contaminated artificially with five levels of Cr (0, 1.25, 2.5, 5.0, and 10.0 mg Cr kg^{? 1} soil as K₂Cr₂O₇). The diethylene triamine pentaacetic acid (DTPA)-extractable Cr in soil (before seeding and after harvest), Cr concentration, and its uptake by shoots and roots of spinach increased with increasing level of applied Cr. Roots accumulated more Cr than shoots, which depicts limited translocation of Cr from roots to shoots. A significant decrease was observed in dry matter yield (DMY) of shoots as well as roots by raising levels of applied Cr (0 to 10 mg Cr kg^{? 1} soil) in both soils, but the extent of the DMY decrease was higher in the sandy loam soil. Application of FYM showed mitigating effects on Cr toxicity. The DMY was higher in the presence of FYM, than its absence, at all rates of applied Cr in both soils. The FYM application caused decline in the DTPA-extractable Cr in soil, and concentration of Cr and its uptake by shoots and roots of spinach at a given level of applied Cr. The magnitude of Cr toxicity and its amelioration by FYM application was higher in sandy soil compared to silty loam soil. The results of this study indicated that FYM application to the soil could be used as an effective measure for reducing Cr toxicity to crop plants in Cr-contaminated soils irrigated by untreated industrial effluents.     

重金属富集植物黑麦草对Zn的响应

采用根袋土培试验研究了重金属Zn胁迫对黑麦草（Loliurn perenne L．）生长、抗氧化酶活性、游离脯氨酸含量、根系活力及锌积累的影响。结果表明,黑麦草对重金属锌有很强的抗性和耐性．即使在高锌下（16mmol Zn／kg）。黑麦草生长也未受到抑制。黑麦草地上部干重、根系千重在8mmol Zn／kg下达到最大值。分别较对照增加48．8％,52．2％;高锌处理（16mmol Zn／kg）的植株地上部千重也较对照增加11．2％。黑麦草POD活性随Zn胁迫增加,先下降,然后回升SOD活性则随锌胁迫增加而下降。随Zn胁迫增加,叶脯氨酸、根系活力先增加,然后下降。地上部、根系Zn含量随Zn胁迫增加而增加,最大值分别为746．5,521．0mg／kg DW（16mmol Zn／kg）。高锌处理下（≥4mmol／kg）Zn转运率（S／R）〉1．0。     

Cs对菠菜叶片光合作用影响的研究

为了揭示Cs对植物光合作用的影响机理,本文采用不同浓度的CsCl(0、1、5、10、20 mmol·L-1)和石英砂培处理菠菜幼苗15 d,分析测定了Cs在菠菜中的积累分布以及Cs对菠菜叶片叶绿素含量、光合气体交换参数、叶绿素荧光参数、类囊体膜电子传递速率、类囊体膜吸收光谱和77k低温荧光光谱的影响.结果表明:Cs处理显著降低菠菜叶片的叶绿素含量;随着Cs处理浓度的增加,尤其在处理浓度大于10 mmol·L-1时,叶片净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)以及蒸腾速率(Tr)显著下降;叶片叶绿素荧光参数分析表明,Cs处理浓度大于10 mmol· L-1时,光系统Ⅱ(PSⅡ)反应中心遭到破坏;类囊体膜电子传递活性分析表明高浓度Cs处理抑制PSⅡ放氧侧的电子传递活性;类囊体膜室温吸收光谱和77K低温荧光光谱分析表明高浓度Cs会破坏类囊体膜的结构,导致叶绿素的结合状态受损,从而使类囊体膜光能的吸收、传递和分配受到抑制,并且会导致类囊体膜上PSⅡ和PSⅠ的色素蛋白发生不同程度的降解.本研究可为Cs污染的植物修复提供一定理论依据.     

不同氮钙营养对菠菜安全品质与抗氧化酶活性的影响

通过溶液培养研究了氮钙营养对菠菜生长、安全品质和抗氧化酶活性的影响。结果表明,在Ca2+浓度相同时,菠菜在供N浓度为12 mmol/L时产量最高;相同供N水平下,Ca2+浓度为5 mmol/L时,菠菜可获得较高产量。菠菜可食部位的硝酸盐含量随着N和Ca2+浓度的升高明显上升。当N浓度为8 mmol/L时,菠菜可食部位可溶态草酸含量最低;在Ca2+浓度为5 mmol/L时,草酸总量最低。N浓度相同时,以5 mmol/L Ca2+处理的叶片POD活性最低;当供N浓度为8 mmol/L时,5 mmol/L Ca2+处理的叶片SOD活性最高,而CAT活性则随着N和Ca2+浓度的提高而显著下降。相同Ca2+浓度下,丙二醛的含量随着供N浓度的升高而明显增加;而在相同N水平下,Ca2+浓度为5 mmol/L处理的叶片丙二醛含量最低。叶片游离脯氨酸的含量均随着Ca2+浓度的增加而明显降低,低N处理的脯氨酸含量也较低。说明在本试验条件下,N浓度为8 mmol/L和Ca2+浓度为5 mmol/L,是菠菜生长较适宜的氮钙浓度。     

腐植酸和氮肥用量及其互作对植烟土壤质量的影响

以中烟100为材料,采用腐植酸和氮肥双因子盆栽试验,研究了腐植酸和氮肥用量及其互作对植烟土壤团聚体组成、养分及酶活性的影响。结果表明:干、湿筛法测定的土壤团聚体的平均重量直径均以T3处理(腐植酸900 mg/kg+氮肥40 mg/kg)最高,与其他处理相比提高幅度分别为15.3%~23.2%和6.5%~20.0%;方差分析显示,腐植酸与氮肥互作对土壤pH、有机质影响不显著,但对土壤碱解氮、有效磷、速效钾含量的影响达到极显著水平(P0.01);二者互作对烤烟各生育期土壤脲酶、蔗糖酶活性影响不同。由此,腐植酸和氮肥用量及其互作对提高土壤团聚体稳定性、土壤主要养分含量及酶活性具有显著效果。