水杨酸提高香蕉幼苗的抗冷性与H2O2代谢有关

探讨了水杨酸(salicylic acid,SA)提高香蕉幼苗抗冷性的可能机理。在常温下(30／22℃)用不同浓度(0—3．5mmol／L)的SA水溶液喷洒叶片1d,置于7℃低温下冷胁迫3d,随后于常温下恢复2d后测定电解质泄漏率,结果表明：SA0．3～0．9mmol／L能显著提高香蕉幼苗的抗冷性,以0．5mmol／L效果最佳。若把冷胁迫温度降到5℃,SA0．5mmol／L预处理可显著减少幼苗叶片的萎蔫面积。但当SA浓度高于1．5mmol／L时,恢复期间的电解质泄漏甚至高于对照(蒸馏水处理),表明它们加剧了冷害。SA提高香蕉幼苗的抗冷性可能需要H2O2的参与：1)SA0．5mmol／L常温处理诱导了H2O2的积累和活性氧造成的膜脂过氧化——三氯乙酸反应物质(TBARS)的增加,这可能与H2O2的清除酶——过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性的受抑和H2O2的产生酶—超氧化物歧化酶(SOD)活性几乎不受影响有关;2)外源H2O2(1．5—2．5mmoL／L)也能显著降低低温胁迫期间的电解质泄漏,表明也能提高抗冷性;3)而用H2O2的捕捉剂——二甲基硫脲(DMTU)可明显抑制SA诱导的抗冷性;4)在低温胁迫与恢复期间,SA预处理明显提高了CAT和APX的活性,抑制了H2O2与TBARS的快速上升。     

外源亚精胺对盐胁迫下白刺幼苗叶片抗氧化酶系统的影响

为进一步阐明盐生植物白刺耐盐性与多胺的关系,通过水培试验研究了叶面喷施亚精胺(Spd)对不同浓度NaCl胁迫下西伯利亚白刺幼苗叶片丙二醛(MDA)和超氧阴离子(O2)产生速率,以及抗氧化物酶系统和根系活力的影响.结果表明:叶面喷施0.1 mmol·L1 Spd 5 d后,可显著提高100和200 mmol·L1 NaCl胁迫下白刺幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性以及根系活力,降低了叶片MDA含量和O2的产生速率;而在0、50、300 mmol·L-1 NaC1处理下,外施Spd对白刺幼苗叶片上述指标无显著影响.研究结果证实,在100～200 mmol·L-1 NaCl胁迫范围内,外施亚精胺可能通过增强体内保护酶活性来显著降低活性氧水平,有效减轻盐胁迫对盐生植物白刺幼苗造成的过氧化伤害,从而增强白刺对盐环境的适应性.     

Spd浸种对盐胁迫下番茄（Solanum lycopersicum)幼苗的保护效应

通过水培试验,研究了100 mmol/L NaCl盐浓度下,0.25 mmol/L Spd浸种处理对两个番茄品种白果强丰(耐盐基因型)和江蔬14号(盐敏感基因型)植株干重、根冠比(R/T)、幼苗叶片和根系抗氧化酶活性及活性氧含量的影响.具体试验处理如下:(a) 对照(蒸馏水浸种+ 0 mmol/L NaCl),(b) NaCl (蒸馏水浸种+ 100 mmol/L NaCl),(c) Spd(0.25 mmol/L Spd浸种 +100 mmol/L NaCl).结果表明,在盐胁迫下,两个番茄品种幼苗叶片和根系内超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性升高,H2O2含量和O·-2产生速率增高,幼苗生长受到抑制,幼苗地上部、地下部干重均明显低于对照,R/T增大,且江蔬14号的变化幅度大于白果强丰.Spd浸种处理降低了盐胁迫下番茄幼苗叶片和根系内O·-2产生速率和H2O2含量,进一步提高了SOD、POD和CAT活性,促进幼苗干重增加,缓解了盐胁迫对植株的伤害.与耐盐基因型番茄品种白果强丰相比,Spd浸种处理对盐敏感基因型番茄品种江蔬14号的作用效果更为明显.总之,Spd浸种处理通过提高盐胁迫下植株体内抗氧化酶活性,降低ROS水平来缓解盐胁迫对番茄幼苗的伤害,提高幼苗耐盐能力.     

亚精胺浸种对番茄幼苗抗盐碱的生理特性研究

以番茄耐盐碱品种‘金鹏一号’和盐碱敏感品种‘中杂9号’为试验材料,采用营养液水培的方法,设置正常营养液栽培(对照CK)、100mmol/L盐碱溶液胁迫、100mmol/L盐碱溶液胁迫+0.1mmol/L亚精胺(Spd)浸种、100mmol/L盐碱溶液胁迫+0.25mmol/L Spd浸种4种处理,研究外源Spd对番茄幼苗株高和茎粗的相对生长率、叶片和根系含水量、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性以及丙二醛(MDA)、脯氨酸(Pro)、叶绿素含量的影响。结果显示:(1)单独盐碱胁迫下,两品种番茄幼苗叶绿素含量、株高和茎粗的相对生长率、叶片和根系相对含水量较对照均降低,而其MDA、Pro含量、SOD和POD活性显著增加。(2)外源Spd浸种处理较盐碱胁迫下能够增加番茄幼苗的株高和茎粗的相对生长率、叶片和根系的相对含水量、Pro及叶绿素含量,进一步提高SOD和POD的活性,降低其MDA含量,能有效缓解盐碱胁迫对番茄幼苗的伤害。(3)在100mmol/L盐碱胁迫条件下,0.25mmol/L Spd浸种处理对番茄幼苗受到的盐碱胁迫伤害的缓解效果更佳,并且这种缓解作用对盐碱敏感品种‘中杂9号’幼苗的效果更加明显。研究表明,在盐碱胁迫下,番茄幼苗的生长受到一定程度的抑制,但外源Spd浸种能够通过调节渗透调节物质含量、增强抗氧化酶活性来减轻盐碱胁迫的伤害,维持植物体的正常生理代谢功能,从而提高番茄幼苗抵抗盐碱胁迫能力,有效缓解盐碱胁迫的伤害,并以0.25mmol/L Spd浸种处理缓解效果更佳,且这种缓解作用对盐碱敏感品种‘中杂9号’幼苗效果更明显。     

NaCl胁迫下亚精胺对番茄种子萌发及幼苗抗氧化系统的影响

采用盆栽试验,研究了NaCl胁迫下外源亚精胺（Spd）浸种处理对“白果强丰”番茄种子萌发、幼苗生长及叶片抗氧化系统的影响.结果表明：Spd浸种处理的番茄种子发芽率（G_r）、发芽指数（G_i）和活力指数（V_i）均显著增加,分别比单纯NaCl处理增加了104.90%、142.31%和122.22%,而番茄种子的平均发芽时间（MGT）缩短了4.97%;Spd浸种处理提高了NaCl胁迫下番茄幼苗叶片超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性,降低了O₂^-·产生速率和过氧化氢（H₂O₂）含量,进而降低了丙二醛（MDA）含量和质膜电解质渗漏率,增加了叶片可溶性蛋白质含量,促进了番茄幼苗生长.表明Spd浸种促进了NaCl胁迫下番茄种子的萌发及幼苗生长,增强了植株的抗盐性.     

外源亚精胺对盐胁迫下黄瓜幼苗游离态多胺含量和多胺合成酶基因表达的影响

以黄瓜品种‘津春2号’（Cucumis sativusL.cv.Jinchun No.2）为材料,采用营养液栽培,研究了外源亚精胺（Spd）对NaCl胁迫下黄瓜幼苗叶片游离态多胺含量和多胺合成酶基因表达的影响。结果表明,75 mmol/LNaCl胁迫下,幼苗株高、茎粗和干鲜重显著降低,外源喷施1 mmol/L Spd处理可明显缓解盐胁迫对幼苗生长的抑制。盐胁迫下叶片游离态多胺含量显著增加,外源Spd进一步促进了游离态Spd和精胺（Spm）的积累,降低了游离态腐胺（Put）的积累。多胺合成酶基因表达分析表明,盐胁迫上调了adc、odc、samdc和spds基因的表达,施用外源Spd后进一步上调了samdc基因,下调了adc、odc、spds基因的表达。表明外源Spd参与了黄瓜幼苗体内多胺代谢的调节,通过下调盐胁迫下adc、odc基因的表达,抑制游离态Put的积累,上调samdc基因的表达促进游离态Spd和Spm的积累,进而缓解盐胁迫对植物生长的抑制。     

水杨酸提高香蕉幼苗的抗冷性与H2O2代谢有关

探讨了水杨酸(salicylic acid, SA)提高香蕉幼苗抗冷性的可能机理.在常温下(30/22 ℃)用不同浓度(0～3.5 mmol/L)的SA水溶液喷洒叶片1 d,置于7 ℃低温下冷胁迫3 d,随后于常温下恢复2 d后测定电解质泄漏率,结果表明:SA 0.3～0.9 mmol/L能显著提高香蕉幼苗的抗冷性,以0.5 mmol/L效果最佳.若把冷胁迫温度降到5 ℃,SA 0.5 mmol/L 预处理可显著减少幼苗叶片的萎蔫面积.但当SA浓度高于1.5 mmol/L时,恢复期间的电解质泄漏甚至高于对照(蒸馏水处理),表明它们加剧了冷害.SA提高香蕉幼苗的抗冷性可能需要H2O2的参与:1)SA 0.5 mmol/L常温处理诱导了H2O2的积累和活性氧造成的膜脂过氧化--三氯乙酸反应物质(TBARS)的增加,这可能与H2O2的清除酶--过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性的受抑和H2O2的产生酶-超氧化物歧化酶(SOD)活性几乎不受影响有关;2)外源H2O2(1.5～2.5 mmol/L)也能显著降低低温胁迫期间的电解质泄漏,表明也能提高抗冷性;3)而用H2O2的捕捉剂--二甲基硫脲(DMTU)可明显抑制SA诱导的抗冷性;4)在低温胁迫与恢复期间,SA预处理明显提高了CAT和APX的活性,抑制了H2O2与TBARS的快速上升.     

格木幼苗对硝普钠-酸铝互作的生理响应

以格木（Erythrophleum fordii Oliv.）幼苗为材料,采用双因素完全随机设计实验方法,测定不同处理幼苗的光合色素和可溶性糖等生理指标,研究格木幼苗对硝普钠（SNP）-氯化铝（AlCl₃）互作的生理响应。结果显示,格木幼苗叶片中叶绿素a、叶绿素b和类胡萝卜素含量均在处理4（0.2 mmol/L AlCl₃、0.1 mmol/L SNP）时最高,在处理9（0.8 mmol/L AlCl₃、0 mmol/L SNP）时含量最低,而叶片中丙二醛（MDA）、游离脯氨酸含量则相反;叶片可溶性糖、可溶性蛋白含量在处理4时最高,在处理9时最低;处理10（0.8 mmol/L AlCl₃、0.1 mmol/L SNP）的超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性最高。施加SNP后,格木幼苗叶片中的叶绿素a、叶绿素b、类胡萝卜素、可溶性糖、可溶性蛋白含量及SOD、POD、CAT活性均显著高于未施加SNP处理。相关性分析表明,叶绿素a、类胡萝卜素、总叶绿素和可溶性蛋白含量等指标间均呈极显著正相关（P < 0.01）。本研究结果得出,低浓度AlCl₃（0.2 mmol/L）胁迫可促进格木幼苗的生长,添加外源SNP对高浓度AlCl₃（0.8 mmol/L）胁迫格木幼苗产生的毒害具有一定的缓解作用,可在格木幼苗的培育及抗性研究中推广应用。     

茉莉酸甲酯对水稻幼苗抗冷性的影响

测定茉莉酸甲酯（MJ）对冷胁迫条件下水稻幼苗生长和与抗冷性相关生理生化指标影响的结果表明：较高浓度的MJ（10^-3mol·L^-1）明显抑制冷胁迫下的水稻幼苗生长,增加细胞膜的渗透性;浓度低一些的MJ（10^-4、10^-5、10^-6、10^-7mol·L^-1）对冷胁迫下水稻幼苗的生长和细胞膜有不同程度的保护作用,其中以10～mol·L^-1MJ的效果为佳。10～mol·L^-1 MJ处理的叶中叶绿素降解程度小,可溶性糖、可溶性总蛋白和脯氨酸的含量以及超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的活性均增加,丙二醛（MDA）含量降低,因而水稻幼苗的抗冷性提高。     

外源亚精胺对不同盐浓度下黄瓜幼苗可溶性蛋白表达的影响

采用营养液水培的方法,以黄瓜品种‘津春2号’为试材,研究了叶片喷施外源亚精胺(Spd)对不同浓度NaCl(0、50、75、100 mmo.lL-1)胁迫下幼苗植株可溶性蛋白表达的影响。结果表明,50 mmol.L-1NaCl胁迫下植株叶片和根系中可溶性蛋白含量提高;75 mmol.L-1和100 mmol.L-1NaCl胁迫明显降低了幼苗植株叶片和根系中可溶性蛋白的含量。不同浓度NaCl胁迫下喷施Spd后可溶性蛋白含量在根系中没有明显变化规律,而叶片可溶性蛋白含量提高。SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)对黄瓜幼苗根系可溶性蛋白分析表明,至少有3种分子量约为61.5、50、47 kD蛋白在50 mmo.lL-1和75 mmol.L-1NaCl胁迫下表达量增强,但100 mmo.lL-1NaCl胁迫下变化不明显;50 mmol.L-1和75 mmol.L-1NaCl胁迫下喷施Spd后61.5 kD和47 kD蛋白表达量明显减弱,50 kD蛋白甚至消失,100 mmol.L-1NaCl胁迫下61.5 kD和47 kD蛋白无明显变化,50 kD蛋白反而增强。     

基于主成分-聚类分析构建甜瓜幼苗耐冷性综合评价体系

为了构建甜瓜(Cucumis melo)种质耐冷性的评价体系并筛选耐冷种质,以19份遗传背景差异明显的甜瓜种质为实验材料,测定低温胁迫下幼苗的9个形态指标和8个生理指标,利用主成分分析、聚类分析及回归分析等多元统计方法对各指标的耐冷系数(α值)进行综合评价。结果表明,低温胁迫下甜瓜幼苗的形态和生理指标发生了明显的变化,其α值的变异系数均大于10%,生理指标的α值变化更为明显。利用主成分分析将原有的17个指标转换为7个独立的综合指标,其累计贡献率达84.64%,以此计算各种质的隶属函数值,并以主成分的贡献率进行加权,最终获得所有种质耐冷性的综合评价值(D值)。基于D值的聚类分析将所有种质按耐冷性强弱划分为3类,其中Oujin为耐冷性最强的种质,Xujin1等11份种质具有中等耐冷性,Qiuxiang等7份种质耐冷性较弱。通过逐步回归分析建立了甜瓜幼苗耐冷性评价的数学模型:D=0.048+0.048POD–0.119SOD+0.097PRO+0.042CRI+0.084RDW+0.206OFW。模型的预测精度大于93.0%。该耐冷性评价体系可广泛用于不同甜瓜种质耐冷性的快速鉴定和预测。     

Association of polyamines in governing the chilling sensitivity of maize genotypes

Chilling stress is an important constraint of global production of maize. This study was undertaken to compare the chilling responses of different maize seedling tissues and to analyze changes in polyamines as a result of chilling stress. Reponses to chilling were characterized in two maize (Zea mays L.) inbred lines, ‘HuangC’ and ‘Mo17’, that putatively differ in chilling sensitivity. Seedlings were exposed to low temperature (5°C) and chilling injury was estimated by electrical conductivity (EC), malonaldehyde (MDA) concentration, and by changes in putrescine (Put), spermidine (Spd) and spermine (Spm) concentrations in root, mesocotyl, and coleoptile tissues. Membrane permeability (as measured by EC), MDA concentrations and Put concentrations in the three tissue of maize seedlings increased after chilling stress, except for the Put concentration in roots. Spd and Spm concentrations in the three tissues of seedlings decreased after chilling stress. The EC for cold stressed tissues were lower in HuangC than Mo17. Also, the EC of coleoptile tissues were lower than for mesocotyl in both inbred lines. We suggest that mesocotyl tissue can be used to evaluate cold tolerance in maize. Stepwise regression analyses showed that chilling injury in roots was generally correlated with Spd concentration while in the mesocotyl injury was mainly correlated with Put and Spd concentrations. Spermidine and Spm concentrations in the coleoptile were correlated with chilling injury. Characteristics changes of polyamines in chill-tolerant maize seedling combined with regression analysis are a reliable method for evaluating chill tolerance in maize lines.     

用体内叶绿素a荧光诱导动力学鉴定番茄的抗冷性

研究了冷害温度对具有不同抗冷性品种的番茄叶片的体内叶绿素a荧光诱导动力曲线的影响。实验结果指出,在低温处理(8℃,5℃,2℃下,暗中24小时)后,番茄叶片的体内叶绿素a荧光诱导动力学曲线有了明显的改变,Fv／Fo值、Rfd值降低了,光系统II原初光能转换效率和潜在的光合活力均受到抑制。我们在苗期和开花期得到的实验结果均表明,在番茄叶片的叶绿素a荧光诱导动力学曲线和这些荧光参数改变的程度与该品种的已知抗冷性之间呈现较好的相关性。我们认为,体内叶绿素a荧光诱导动力学方法是鉴定番茄抗冷性的一个快速、灵敏和可靠的方法,并可用于其他绿色植物的抗冷性鉴定中。     

Comparative proteomic analysis reveals the positive effect of exogenous spermidine on photosynthesis and salinity tolerance in cucumber seedlings

Key message

Our results based on proteomics data and physiological alterations proposed the putative mechanism of exogenous Spd enhanced salinity tolerance in cucumber seedlings.

Abstract

Current studies showed that exogenous spermidine (Spd) could alleviate harmful effects of salinity. It is important to increase our understanding of the beneficial physiological responses of exogenous Spd treatment, and to determine the molecular responses underlying these responses. Here, we combined a physiological analysis with iTRAQ-based comparative proteomics of cucumber (Cucumis sativus L.) leaves, treated with 0.1 mM exogenous Spd, 75 mM NaCl and/or exogenous Spd. A total of 221 differentially expressed proteins were found and involved in 30 metabolic pathways, such as photosynthesis, carbohydrate metabolism, amino acid metabolism, stress response, signal transduction and antioxidant. Based on functional classification of the differentially expressed proteins and the physiological responses, we found cucumber seedlings treated with Spd under salt stress had higher photosynthesis efficiency, upregulated tetrapyrrole synthesis, stronger ROS scavenging ability and more protein biosynthesis activity than NaCl treatment, suggesting that these pathways may promote salt tolerance under high salinity. This study provided insights into how exogenous Spd protects photosynthesis and enhances salt tolerance in cucumber seedlings.

     

Contents of polyamines during vernalization in wheat and the effect of zearalenone

The contents of endogenous free and conjugated polyamines, putrescine (Put) and spermidine (Spd), were determined during 9 week of vernalization (at 5 °C) in winter wheat seedlings cultivated on Murashige and Skoog media without (MS0) and with 2 mg dm⁻³ zearalenone (MSZEN). At the 4^th week of chilling treatment, which is sufficient to induce generative development in 30 % of plants, the marked increase in free and conjugated forms of Put and free Spd were observed. The presence of ZEN in medium significantly accelerated the vernalization. About 20 % of plants treated with ZEN flowered already after 2 weeks and 40 % after 3 weeks of chilling. Significantly higher content of free Put was determined in roots grown on MSZEN compared with MS0 during the first 5 weeks of vernalization with maximum at the 4^th week. After germination, a marked decrease in free Spd content was observed both in plants grown on MS0 and MSZEN. Application of ZEN significantly slowed down the Spd decline in leaves and roots during the first and second week of vernalization. The content of Spd and its conjugates decreased in vernalized plants after 1 week of cultivation at 20 °C.     

Chilling stress--the key predisposing factor for causing Alternaria alternata infection and leading to cotton (Gossypium hirsutum L.) leaf senescence

Leaf senescence plays a vital role in nutrient recycling and overall capacity to assimilate carbon dioxide. Cotton premature leaf senescence, often accompanied with unexpected short-term low temperature, has been occurring with an increasing frequency in many cotton-growing areas and causes serious reduction in yield and quality of cotton. The key factors for causing and promoting cotton premature leaf senescence are still unclear. In this case, the relationship between the pre-chilling stress and Alternaria alternata infection for causing cotton leaf senescence was investigated under precisely controlled laboratory conditions with four to five leaves stage cotton plants. The results showed short-term chilling stress could cause a certain degree of physiological impairment to cotton leaves, which could be recovered to normal levels in 2-4 days when the chilling stresses were removed. When these chilling stress injured leaves were further inoculated with A. alternata, the pronounced appearance and development of leaf spot disease, and eventually the pronounced symptoms of leaf senescence, occurred on these cotton leaves. The onset of cotton leaf senescence at this condition was also reflected in various physiological indexes such as irreversible increase in malondialdehyde (MDA) content and electrolyte leakage, irreversible decrease in soluble protein content and chlorophyll content, and irreversible damage in leaves' photosynthesis ability. The presented results demonstrated that chilling stress acted as the key predisposing factor for causing A. alternata infection and leading to cotton leaf senescence. It could be expected that the understanding of the key factors causing and promoting cotton leaf senescence would be helpful for taking appropriate management steps to prevent cotton premature leaf senescence.     

Chilling stress response of postemergent cotton seedlings

Early season development of cotton is often impaired by sudden episodes of chilling temperature. We determined the chilling response specific to postemergent 13-day-old cotton (Gossypium hirsutum L. cv. Coker 100A-glandless) seedlings. Seedlings were gradually chilled during the dark period and rewarmed during the night-to-day transition. For some chilled plants, the soil temperature was maintained at control level. Plant growth, water relations and net photosynthesis (P(n)) were analyzed after one or three chilling cycles and after 3 days of recovery. Three chilling cycles led to lower relative growth rate (RGR) compared with controls during the recovery period, especially for plants with chilled shoots and roots. Treatment differences in RGR were associated with net assimilation rate rather than specific leaf area. Both chilling treatments led to loss of leaf turgor during the night-to-day transition; this effect was greater for plants with chilled compared with warm roots. Chilling-induced water stress was associated with accumulation of the osmolyte glycine betaine to the same extent for both chilling treatments. Inhibition of P(n) during chilling was related to both stomatal and non-stomatal effects. P(n) fully recovered after seedlings were returned to control conditions for 3 days. We conclude that leaf expansion during the night-to-day transition was a significant factor determining the magnitude of the chilling response of postemergent cotton seedlings.     

Chilling tolerance in <Emphasis Type="Italic">Nicotiana tabacum</Emphasis> induced by seed priming with putrescine

Chilling stress is one of primary constraints to tobacco production in many parts of the world. The present study was conducted to induce chilling tolerance in tobacco by seed priming with putrescine (Put) in relation to physiological changes, using seeds from two tobacco varieties, MSk326 (chilling sensitive variety) and Honghuadajinyuan (HHDJY, chilling tolerant variety). Seed germination, seedling antioxidant enzyme activities and malondialdehyde (MDA) concentration, as well as polyamine concentration were determined under low temperature. During chilling stress at 11°C, seed priming with 0.01 mM Put for 48 h (Put0.01mM48 h) and seed priming with 0.1 mM Put for 48 h (Put0.1mM48 h) significantly increased germination percentage, germination index, seedling length and dry weight of both varieties compared to the controls without Put treatment. When seedlings of 4-leaf stage suffered a short chilling stress (5°C), Put 0.1 mM 48 h improved the activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX), increased endogenous Put, Spd and Spm concentration and decreased the MDA concentration. The results showed that Put priming treatments were available to enhance the chilling tolerance of tobacco seedlings. The optimal treatment of Put was Put0.1 mM48 h.     

亚精胺和丛枝菌根真菌对黄瓜生长的影响

以黄瓜品种‘津春2号’为材料,在育苗基质中添加亚精胺(Spd)和丛枝菌根真菌(AMF),研究外源Spd和AMF对黄瓜幼苗生长、光合作用、果实产量和品质以及根际微生物和酶活性的影响.结果表明:育苗基质中同时添加Spd和AMF,可促进黄瓜幼苗生长,提高根系活力和果实产量,改善品质,并促进养分吸收;Spd和AMF提高黄瓜幼苗净光合速率、实际光化学效率、表观量子效率、羧化效率和光呼吸速率,增加基质中细菌和放线菌数量,而降低真菌数量,并提高蔗糖酶、中性磷酸酶、过氧化氢酶和脲酶的活性.说明育苗基质中同时添加Spd和AMF,可提高黄瓜植株光能利用效率,促使黄瓜幼苗根际微生物区系从低肥力的"真菌型"向高肥力的"细菌型"转化,加速有机磷和有机态氮的分解与转化,为黄瓜生长发育提供比较充足的N、P等养分,从而促进黄瓜植株生长,提高产量并改善品质.Spd可提高AMF侵染率,两者对黄瓜幼苗生长具有明显的叠加效应,说明在接种AMF的基质中添加Spd,是一种可增强AMF侵染率的有效方法.     

外源亚精胺对盐胁迫下黄瓜植株氮化合物含量和硝酸还原酶活性的影响

研究了外源亚精胺(Spd)在营养液栽培中,对盐胁迫下耐盐性不同的两品种黄瓜幼苗体内硝态氮、铵态氮、脯氨酸(Pro)含量和硝酸还原酶(NR)活性的影响。结果表明,外源Spd显著减小了盐胁迫引起的铵态氮、Pro含量的升高幅度和NR活性、硝态氮含量的降低幅度,且对盐敏感型黄瓜品种影响幅度较大。表明Spd可明显减缓盐胁迫对黄瓜幼苗氮素营养代谢的影响。