盐分胁迫下棉花幼苗对外源甜菜碱的生理响应

通过研究盐分胁迫下棉花幼苗对外源甜菜碱的生理响应,为盐分胁迫下施用甜菜碱提高棉花幼苗抗逆提供参考。以新疆广泛种植的新陆早18号为试验材料,200 mmol/L氯化钠胁迫,用5、10 mmol/L甜菜碱喷施处理,7 d后测定棉花幼苗体内主要生理指标含量的变化。结果表明非盐胁迫下,甜菜碱处理显著提高脯氨酸和可溶性糖含量,而丙二醛含量和抗氧化酶活性不受甜菜碱影响;盐胁迫下棉花幼苗体内丙二醛含量显著高于对照,并且脯氨酸、可溶性糖含量增加,抗氧化酶活性提高,盐分胁迫下棉花幼苗经过甜菜碱处理后,有效抑制丙二醛的产生,同时脯氨酸、可溶性糖和抗氧化酶含量进一步提高。甜菜碱处理有效缓解盐胁迫对棉花幼苗的伤害,以施用5 mmol/L甜菜碱(glycine betaine/GB)效果较好。     

Exogenous proline mitigates the inhibition of growth of Nicotiana tabacum cultured cells under saline conditions

The addition of exogenous proline (10 mm) to Na100-saline culture medium, modified LS medium (Linsmaier and Skoog 1965: Physiol. Plant., 18, 100–127) with 100 mm NaCl promoted the growth of tobacco (Nicotiana tabacum L., cv. Bright Yellow-2) suspension cells unadapted to salt stress without maintaining a high ratio of K⁺ to Na⁺ ions under salinity conditions. The addition of exogenous glutamic acid or alanine were not comparable to that of exogenous proline. The proline contents of the NaCl-unadapted cells became much higher when the cells were grown in Na100-saline culture medium with 10 mm proline than when the cells were cultured without proline. The accumulation of K⁺, Na⁺, counter ions was sufficient to compensate for the increase of the water potential of the cells caused by salinity. These results suggest that exogenous proline does not act as a nitrogen store and that proline may act as a protectant for enzymes and membranes against salt inactivation rather than as a compatible solute in tobacco suspension cells.     

高温干旱共胁迫下外源甜菜碱和CaCl2对烟草生理响应的影响

以烤烟品种云烟85为材料,采用盆栽试验研究了对高温干旱共胁迫的反应,以及外源甜菜碱（GB）和CaCl2对烟草抗高温干旱共胁迫方面的作用。结果表明,叶面喷施GB和CaCl2能显著提高烟草植株生物量。在高温干旱共胁迫下,叶面喷施GB较蒸馏水处理能极显著提高烟草叶片叶绿素含量、SOD和POD活性,维持较高的脯氨酸含量及较低的丙二醛（MDA）含量和质膜相对透性;叶面喷施CaCl2较蒸馏水处理能极显著提高烟草叶片叶绿素含量、SOD和POD活性,极显著降低质膜相对透性,显著降低丙二醛（MDA）含量,维持较高的脯氨酸含量。高温干旱共胁迫恢复生长后,GB、CaCl2和蒸馏水处理的烟草其叶绿素含量、SOD和POD活性均有不同程度回升,丙二醛含量、脯氨酸含量、细胞质膜透性都有所下降。因此,GB和CaCl2对有效减轻双逆境胁迫引起的伤害,提高烟草的抗高温干旱胁迫能力具有积极的作用。     

干旱胁迫条件下加工番茄对喷施甜菜碱的生理响应

以新疆广泛种植的加工番茄屯河8号为材料,通过盆栽和田间试验,测定了加工番茄叶片中叶绿素、可溶性蛋白、脯氨酸、可溶性糖和丙二醛含量以及抗氧化酶 [超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）] 活性和加工番茄产量,研究了干旱胁迫下加工番茄对叶面喷施不同浓度甜菜碱的生理响应。结果表明,干旱胁迫下喷施低浓度甜菜碱对加工番茄抵御干旱有一定的作用。干旱胁迫下喷施甜菜碱后,有效抑制了叶绿素和可溶性蛋白含量的下降,协同增加脯氨酸和可溶性糖的含量,抗氧化酶活性也显著增强,膜脂过氧化程度减弱即丙二醛含量下降,田间试验各生理指标的含量变化与盆栽结果相类似,干旱胁迫下喷施甜菜碱促进了加工番茄产量的增加。     

甜菜碱对干旱胁迫下棉花幼苗生理特性的影响

以新疆广泛种植的棉花品种新陆早18号为试材,通过测定棉花幼苗体内脯氨酸、可溶性糖和丙二醛（MDA）的含量及抗氧化酶包括超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）的活性,研究叶面喷施不同浓度甜菜碱（Glycine betaine,GB）对干旱胁迫下棉花幼苗生理特性的影响。结果表明,干旱胁迫下,与对照相比,脯氨酸、可溶性糖、MDA含量及SOD和POD活性都显著提高,喷施甜菜碱后促进脯氨酸和可溶性糖含量进一步提高,酶活也显著升高,同时有效抑制了丙二醛含量的增加,CAT活性受干旱胁迫及甜菜碱的影响较小。研究表明喷施低浓度甜菜碱在一定程度上可以缓解干旱胁迫对棉花幼苗的伤害。     

干旱处理下不同烤烟品系的生理差异研究

为培育抗性优良的烤烟品种,探究烤烟的耐旱特性及机理,以烤烟品系LY1306、中烟100和红花大金元为试验材料,研究在聚乙二醇6000(PEG-6000)模拟干旱胁迫和水分控制的干旱处理下,各烤烟品系叶片抗氧化酶类活性,丙二醛(MDA)和脯氨酸含量变化,以及光合生理特性和叶片细胞超微结构的差异。结果表明,25%PEG-6000胁迫下,LY1306能保持较好的生理状态,具有较高的SOD活性和较强的脯氨酸渗透调节能力;中烟100的个别叶片出现萎蔫,SOD活性较LY1306低,较对照组POD和CAT活性显著降低,MDA含量较高;红花大金元叶片出现严重萎蔫,CAT活性降低幅度最大,脯氨酸积累量较高。在反复缺水干旱条件下,LY1306能够维持较高的CAT活性,MDA积累量少,水分利用率较高,蒸腾速率较低,细胞中叶绿体数量和叶绿体形态维持正常。红花大金元的POD活性增长明显,脯氨酸含量显著增长,但MDA积累量较大,叶绿体变形且数量明显减少。中烟100的POD活性较高,脯氨酸积累量较大,叶绿体结构较完整。综上,LY1306在干旱胁迫下具有较强的清除活性氧和脯氨酸渗透调节能力,综合抗旱能力较好。本研究结果为培育抗旱烤烟品种提供了理论依据。     

Silicon Increases Tolerance to Boron Toxicity and Reduces Oxidative Damage in Barley

ABSTRACT

Silicon (Si) protects plants from multiple abiotic and biotic stresses The effect of exogenous Si levels (50, 75, and 100 mg kg^?1) on the growth, boron (B) and Si uptake, lipid peroxidation (MDA), lipoxygenase activity (LOX; EC 1.13.11.12), proline, and H₂O₂ accumulation, non-enzymatic antioxidant activity (AA) and the activities of major antioxidant enzymes (superoxide dismutase, SOD, EC 1.15.1.1; catalase, CAT, EC 1.11.1.6 and ascorbate peroxidase, APX, EC 1.11.1.11) of barley (Hordeum vulgare L.) were investigated under glasshouse conditions. Increasing levels of Si supplied to the soil with 20 mg kg^?1 B counteracted the deleterious effects of B on shoot growth. Application of B significantly increased the B concentration in barley plants. However, Si application decreased B concentrations. Increasing application of Si increased the Si concentration in barley plants. The concentration of H₂O₂ was increased by B toxicity but decreased by Si supply. Boron toxicity decreased proline concentrations and increased lipid peroxidation (MDA content) and LOX activity of barley. Compared with control plants, the activities of AA, SOD, CAT, and APX in B stressed plants grown without Si decreased, and application of Si increased their activities under toxic B conditions. The LOX activity was decreased by Si. Based on the present work, it can be concluded that Si alleviates B toxicity by possibly preventing oxidative membrane damage, both through lowering the uptake of B and by increasing tolerance to excess B within the tissues.     

干旱胁迫对紫苏生长及品质的影响

为了明确适于紫苏种植的水分灌溉条件,以紫苏实生苗为材料,正常供水为对照(CK),研究干旱胁迫(轻度干旱、中度干旱、重度干旱)对紫苏生长及品质的影响。结果表明,轻度和中度干旱胁迫可显著提高紫苏叶片丙二醛(MDA)含量和相对电导率,并使其抗氧化酶活性、脯氨酸(Pro)、可溶性糖和可溶性蛋白含量维持在较高水平;重度干旱胁迫也显著提高了紫苏叶片MDA含量和相对电导率,但其抗氧化酶活性、Pro、可溶性糖和可溶性蛋白含量显著低于CK,且随着胁迫处理时间的延长,叶片MDA含量和相对电导率呈逐渐上升趋势,而抗氧化酶活性、脯氨酸、可溶性糖和可溶性蛋白含量则呈逐渐下降趋势。随着干旱胁迫程度的增加,紫苏地上部生物量显著下降;叶片中总挥发油含量呈先上升后下降的趋势。由此可见,干旱胁迫处理不利于紫苏的生长,但适当的干旱胁迫可促进紫苏叶片挥发油的合成,显著提高苏叶药材品质。本研究结果为紫苏规范化栽培提供了依据。     

不同植烟区土壤对中上部烟叶抗氧化系统及部分质量指标的影响

试验于2010年和2011年在贵州省开阳县龙岗镇烤烟良种繁育基地进行,设置3个不同植烟区土壤处理(天柱砂壤土、威宁粉壤土和龙岗壤黏土),研究相同气候条件下贵州不同区域植烟土壤对烤烟中上部叶抗氧化系统及烟叶外观质量和感官质量的影响。结果表明:烤烟生长发育中期,天柱砂壤土和威宁粉壤土处理烟叶多酚氧化酶、超氧化物歧化酶及过氧化物酶活性较高,后期龙岗壤黏土处理较高;烤烟生长发育中后期,天柱砂壤土和威宁粉壤土处理烟叶丙二醛含量均高于龙岗壤黏土处理,因此,天柱砂壤土和威宁粉壤土处理烟叶进入成熟衰老的时间较龙岗壤黏土早。天柱砂壤土处理烟叶外观质量和感官质量均较好,其次是龙岗壤黏土,威宁粉壤土较差。天柱土利于优质烟叶的形成。     

硅作用下铜对小麦幼苗生理特性影响研究

通过水培试验,研究了在不同加硅量(0,30,60,90,120,150 mg/L,以SiO2计)作用下,铜(10 mg/L,以Cu计)对小麦幼苗叶绿素含量、抗氧化酶系统活性(SOD、POD、CAT)、脯氨酸含量、可溶性蛋白含量以及MDA含量的影响,结果表明:在加硅量(30,60,90 mg/L,以SiO2计)作用下,小麦幼苗叶绿素a含量、抗氧化酶系统(SOD、POD)活性、脯氨酸含量、可溶性蛋白含量的升高以及MDA含量的降低,减轻了铜对小麦幼苗的毒害作用;在加硅量150 mg/L作用下,小麦幼苗叶片可溶性蛋白含量的降低,MDA含量的升高,加重了铜对小麦幼苗的毒害作用。研究结果表明,加硅处理能够在一定浓度范围内缓解铜对小麦幼苗的毒害作用,从而为铜毒害的小麦区域增施硅肥提供理论依据。     

铝胁迫下外源抗坏血酸对水稻幼苗抗氧化性能的影响

为探讨外源抗坏血酸(AsA)对铝胁迫下水稻抗氧化损伤的效应,以滇优35号(杂交稻,粳稻)为试验材料,采用溶液培养法研究外源AsA对不同铝浓度(0、50、100、200、400 μmol·L^-1)胁迫下水稻根尖H₂O₂含量及抗氧化酶活性等生理生化指标的影响。结果表明,水稻根尖氧化损伤程度随铝浓度的递增而加剧,与对照相比,400 μmol·L^-1铝胁迫可导致水稻根尖H₂O₂和MDA含量增加1.53和3.16倍,脯氨酸含量、SOD、POD、APX和CAT活性分别增加1.73、1.39、1.42、1.76和1.56倍,内源AsA含量减少0.53倍;而施用外源AsA处理的根尖H₂O₂和MDA含量只增加1.04和2.69倍,内源AsA含量减少0.46倍,脯氨酸含量增加1.96倍,SOD、POD、APX和CAT活性分别增加1.48、1.63、1.90和1.89倍。综上所述,外源AsA可通过增强渗透调节物质含量来维护质膜结构的完整性,增强抗氧化酶活性和内源AsA含量,降低根尖H₂O₂的积累和质膜过氧化程度,促进水稻在铝胁迫条件下的生长。本研究结果为进一步探索外源AsA缓解水稻铝毒的机理提供了一定的理论依据。     

水分胁迫下氮、钾对不同基因型夏玉米氮代谢的影响

采用盆栽试验研究了水分胁迫和适量供水条件下,氮、钾对2种基因型夏玉米陕单9号(抗旱品种)和陕单911(不抗旱品种)各生育期体内硝酸还原酶活性、脯氨酸、甜菜碱和可溶性蛋白质积累的影响,旨在从氮代谢方面揭示这些因子的抗旱机理。试验结果表明,水分胁迫下,硝酸还原酶活性显著降低,不抗旱品种降低更甚;脯氨酸、甜菜碱和可溶性蛋白质有不同程度累积,抗旱品种含量和变幅大于不抗旱品种。2品种苗期对水分胁迫响应较弱,脯氨酸、甜菜碱和可溶性蛋白质含量低;拔节和抽雄期响应强烈,这些化合物含量增高,其中甜菜碱含量达到高峰时间比脯氨酸晚。水分胁迫下,施用氮肥能显著提高硝酸还原酶活性及脯氨酸、甜菜碱和可溶性蛋白质含量,改善氮代谢。不抗旱品种2种氮肥用量的效果有显著差异;抗旱品种在低氮用量时效果显著,低、高氮肥用量间无显著区别。适量供水下,氮肥作用明显下降,表明氮肥不仅在于供应养分,而且还能通过改善氮代谢而增强作物的抗旱性能。钾肥对受水分胁迫的夏玉米表现出比氮肥更突出的效果,而在适量供水时效果消失,表明在作物受旱条件下,显著改善作物氮代谢是钾增强作物抗旱性的主要机理之一。     

Protective role of proline against salt stress is partially related to the improvement of water status and peroxidase enzyme activity in cucumber

A salt-sensitive cucumber cultivar "Jinchun No. 2" ( Cucumis sativus L.) was used to investigate the role of proline in alleviating salt stress in cucumber. Proline was applied twice (day 0 and day 4 after salt treatment) as a foliar spray, with a volume of 25 mL per plant at each time. Plant dry weight, leaf relative water content, proline, malondialdehyde (MDA), Na⁺, K⁺ and Cl⁻ contents, as well as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) activities in the plants were determined at day 8 after salt treatment. The results showed that 100 mmol L^–1 NaCl stress significantly decreased plant dry weight, leaf relative water and K⁺ contents, and increased leaf MDA, Na⁺ and Cl⁻ contents and SOD, POD, CAT and APX activities. However, leaf proline accumulation was not affected by salinity. The exogenous application of proline significantly alleviated the growth inhibition of plants induced by NaCl, and was accompanied by higher leaf relative water content and POD activity, higher proline and Cl⁻ contents, and lower MDA content and SOD activity. However, there was no significant difference in Na⁺ and K⁺ contents or in CAT and APX activities between proline-treated and untreated plants under salt stress. Taken together, these results suggested that the foliar application of proline was an effective way to improve the salt tolerance of cucumber. The enhanced salt tolerance could be partially attributed to the improved water status and peroxidase enzyme activity in the leaf.     

种植与组培9年的转AhDREB1基因毛白杨耐盐性比较

为了对栽培9年后转AhDREB1基因毛白杨的耐盐性进行评价,并探究田间种植与组培继代2种不同生长条件对转基因毛白杨耐盐性的影响,以从大田种植9年的转AhDREB1基因杂种毛白杨[(Populus tomentosa×Populus bolleana)×P.tomentosa]中获得的株系(T46-F)和组培继代9年的2个转基因杂种毛白杨株系(T46、T12),以及非转基因杂种毛白杨株系(CK)为试材,通过对外源基因进行PCR检测,发现9年后AhDREB1基因仍然稳定整合在转基因植株中。通过不同浓度的Na Cl胁迫试验,对各株系的相对电导率进行分析,进一步选择测定0.6%浓度Na Cl处理水平下各株系的株高、地径生长量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、丙二醛(MDA)含量、脯氨酸含量和叶绿素相对含量,对不同转AhDREB1基因毛白杨株系的耐盐性进行分析和比较。结果表明,所有株系的相对电导率、MDA含量均随Na Cl浓度增加而增大,但高盐浓度下转基因株系T46-F、T46、T12的相对电导率、MDA含量均显著低于CK。无论是在非盐条件,还是0.6%Na Cl胁迫下,AhDREB1基因的导入均能显著提高毛白杨植株的SOD、POD活性,脯氨酸含量。其中0.6%浓度Na Cl胁迫下,T46-F、T46、T12的SOD活性分别是CK的2.51倍、3.20倍、2.55倍;POD活性分别是CK的1.23倍、1.63倍、1.10倍;脯氨酸含量分别是CK的1.51倍、1.69倍、1.62倍。此外,转AhDREB1基因毛白杨叶绿素含量下降显著低于CK,同时株高、地径生长量显著高于CK。组培继代9年的转基因株系的脯氨酸含量、株高生长量显著高于在大田种植9年的转基因毛白杨,而相对电导率显著低于大田种植转基因株系,说明组培继代培养更有利于保持转基因毛白杨的耐盐性。综上可知,转AhDREB1基因显著提高了毛白杨的抗氧化酶活性,调控渗透调节物质的积累,从而减轻细胞膜的氧化损伤,降低了相对电导率,提高了毛白杨的耐盐性,综合考虑各个指标,各株系耐盐性的大小顺序为T46T12T46-FCK。本研究为通过转AhDREB1基因提高植物耐盐性提供了理论参考。     

海藻酸钠寡糖提高水稻幼苗对镉胁迫的抗性

通过水培试验,研究了海藻酸钠寡糖对水稻镉(Cd)毒害的缓解效果,并从Cd的吸收分布、非蛋白巯基(NPT)含量和抗氧化酶活性等方面,初步探讨了其可能的生理机制。结果表明,海藻酸钠寡糖预处理一定程度上可缓解水稻Cd毒害,其中20 mg/L处理的效果较明显,表现为促进了幼苗生长,提高了光合色素含量。进一步分析显示,海藻酸钠寡糖处理的水稻地上部和地下部Cd含量及转移效率均显著降低,Cd在根部细胞壁中的含量及所占比例则显著增加,叶片和根中NPT含量也分别提高了23.5%和14.9%,植物螯合肽(PCs)含量分别增加28.0%和15.0%,抗氧化酶活性和脯氨酸含量也有不同程度提高,丙二醛含量显著下降27.1%。这些结果初步说明细胞壁固持、巯基分子螯合和抗氧化系统均参与了海藻酸钠寡糖对水稻Cd毒害的缓解。     

Amelioration of cadmium stress in gladiolus (Gladiolus grandiflora L.) by application of potassium and silicon

Gladiolus corms were grown in media contaminated with cadmium (Cd) (50 mg kg^?1) and supplemented with silicon (Si) and potassium (K). The role of Si and K for mitigation of Cd toxicity was evaluated. Cd-induced stress generated significantly increased level of oxidative stress markers including hydrogen peroxide (H₂O₂), and malondialdehyde (MDA) in gladiolus. The application of K and Si improved the production of protein and proline in the treated plants. Moreover, K and Si supplemented plants exhibited an improvement in the activity of antioxidant enzymes and a reduction in the level of MDA, H₂O₂ and Cd uptake under Cd stress. Application of K and Si also enhanced the uptake of mineral nutrients including calcium (Ca), magnesium (Mg), manganese (Mn), sulfur (S) and K. The plants supplemented with K and Si exhibited a higher amount of total phenolics and flavonoids. The combined effect of Si and K was more pronounced regarding beneficial effects on gladiolus plants compared to individual effect of these elements under Cd stress. The current research reveals that Si and K may improve gladiolus growth by decreasing the oxidative stress and Cd uptake and by increasing the activity of antioxidant defense enzymes, the quantity of secondary metabolites and plant nutrition.     

荞麦对酸铝胁迫生理响应的研究

铝毒害是限制酸性土壤中植物生长的重要因素,以荞麦(FagopyrumesculentumMoench.)为实验材料,在沙培条件下,用不同浓度(0,10,100,1000mg/L)、不同pH(3,4,5)的铝溶液处理,在出苗后的第14d和28d测试与铝胁迫有直接关系的5个生理指标。结果表明,溶液的铝浓度和pH的变化对荞麦生理都有明显的影响,最低浓度的铝处理10mg/L在不同pH下已经影响了荞麦的正常生长,和对照相比根系活力(RA)下降、根质膜透性(MP)增大、叶片内丙二醛(MDA)和游离脯氨酸(Pro)的含量以及过氧化物酶(POD)的活性升高,并且随着铝处理浓度的升高,荞麦体内各生理指标和对照差异性加大;同一铝浓度下pH5和pH3相比,MP降低、RA增强、叶片内MDA和Pro的含量以及POD的活性有所下降。铝胁迫下荞麦体内各生理指标的变化有显著的相关性。随着荞麦的生长,铝毒害有所缓解。     

Protective role of proline against salt stress is partially related to the improvement of water status and peroxidase enzyme activity in cucumber

Abstract

A salt-sensitive cucumber cultivar “Jinchun No. 2” (Cucumis sativus L.) was used to investigate the role of proline in alleviating salt stress in cucumber. Proline was applied twice (day 0 and day 4 after salt treatment) as a foliar spray, with a volume of 25?mL per plant at each time. Plant dry weight, leaf relative water content, proline, malondialdehyde (MDA), Na⁺, K⁺ and Cl^? contents, as well as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) activities in the plants were determined at day 8 after salt treatment. The results showed that 100?mmol?L^–1 NaCl stress significantly decreased plant dry weight, leaf relative water and K⁺ contents, and increased leaf MDA, Na⁺ and Cl^? contents and SOD, POD, CAT and APX activities. However, leaf proline accumulation was not affected by salinity. The exogenous application of proline significantly alleviated the growth inhibition of plants induced by NaCl, and was accompanied by higher leaf relative water content and POD activity, higher proline and Cl^? contents, and lower MDA content and SOD activity. However, there was no significant difference in Na⁺ and K⁺ contents or in CAT and APX activities between proline-treated and untreated plants under salt stress. Taken together, these results suggested that the foliar application of proline was an effective way to improve the salt tolerance of cucumber. The enhanced salt tolerance could be partially attributed to the improved water status and peroxidase enzyme activity in the leaf.     

Influence of Silicon on Sunflower Cultivars under Drought Stress,I: Growth,Antioxidant Mechanisms,and Lipid Peroxidation

Abstract: Understanding plant responses to drought stress is essential, and there is a need to know possible physiological mechanisms of damage and drought avoidance for the genetic improvement of crops. Therefore, we investigated the effects of silicon (Si) on shoot and root growth, leaf relative water content (RWC), stomatal resistance (SR), lipid peroxidation (MDA), membrane permeability (MP), proline and hydrogen peroxide (H₂O₂) accumulation, nonenzymatic antioxidant activity, and the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) of 12 sunflower cultivars grown under drought conditions. Silicon applied to the soil counteracted the deleterious effects of drought in 6 of the 12 sunflower cultivars. In general, SR and H₂O₂, proline, and MDA content were increased in all the cultivars under drought stress. However, application of Si decreased their levels and alleviated membrane damage (MP) significantly by increasing leaf RWC. The CAT activity was significantly decreased by drought stress, but supplemental Si increased it. In general, SOD and APX activities of the cultivars were increased by drought and decreased by application of Si. The nonenzymatic antioxidant activity of the cultivars was significantly increased by Si under drought stress. Based on the present work, it can be concluded that applied Si alleviates drought stress in sunflower cultivars by preventing membrane damage, although the cultivars showed genotypic variation in response to applied Si.     

施肥和外源砷对小白菜生长和抗性生理的影响

通过盆栽试验,研究了施用有机肥料与氮、 磷、 钾肥以及不同浓度砷对小白菜（Brassica campestris L. ssp. Chinensis L.）株高、 根长、 单株鲜重、 砷含量以及小白菜植株脯氨酸（Pro）、 丙二醛（MDA）、 超氧化物歧化酶（SOD）、 过氧化物酶（POD）等的影响。结果表明: 在施肥条件下外源砷10 mg/kg促进小白菜生长,鲜重最高,株高、 根长增加,外源砷继续提高则抑制小白菜生长; 小白菜砷含量随外源砷提高而增加,施肥则促进砷吸收; 小白菜Pro和MDA含量随外源砷提高而增加,施肥则有助于降低Pro和MDA含量; 小白菜POD活性在不施肥处理下随砷浓度的提高呈上升下降的变化趋势,且以砷 50 mg/kg时最高; 在施肥条件下随砷浓度的增加而增强; 小白菜SOD活性在有机肥处理下随砷浓度的增加而增强,在不施肥、 施氮磷钾肥以及氮磷钾肥和有机肥混施处理下随砷浓度的升高呈上升下降的变化趋势,均以砷 50 mg/kg处理最高。