不同抗性泡核桃对褐斑病病原菌侵染的生理生化响应北大核心CSCD

以抗病和感病泡核桃无性系为实验材料,人工接种褐斑病病原菌后测定不同时期叶片中保护酶活性、总酚、类黄酮、叶绿素含量等相关生理生化指标,探讨不同抗性泡核桃响应褐斑病病原菌侵染的生理生化差异。结果表明:(1)接种病原菌后,感病无性系64叶片带菌率随着侵染时间的增加而升高,且显著高于抗病无性系199(P<0.05)。(2)抗病无性系199和感病无性系64叶片的SOD、POD、CAT、APX和PPO活性随着侵染时间均呈现先升高后降低的变化趋势,其中SOD、POD和APX活性均在16 d时达到最大值;与较感病无性系相比,接种后抗病无性系的POD和APX活性较强;在接种前期(1~16 d),感病无性系PPO活性高于抗病无性系,后期(16~34 d)CAT活性也较抗病无性系高。(3)抗病无性系叶片叶绿素含量始终高于感病无性系;抗病无性系MDA含量在接种后无明显变化,而感病无性系先增加后降低,其细胞膜脂过氧化较重。(4)两个无性系叶片可溶性蛋白和可溶性糖含量变化较平缓,且差异不显著,在接种后期(34 d)有升高的趋势;接种5 d以后,感病无性系叶片类黄酮和总酚含量始终显著高于抗病无性系。研究发现,泡核桃抗病无性系叶片带菌率较低,较难受到侵染,并且通过提高POD和APX活性以及积累较多叶绿素、可溶性蛋白和可溶性糖来应对病原菌侵染引起的氧化胁迫,抑制病原菌的繁殖,从而提高其抗病能力。     

辣椒感染疫病后生化指标的响应研究

采用生理生化分析方法研究了辣椒感染疫病后叶片中几个生化指标的变化。结果表明,染病前后感病品种叶片中可溶性总糖含量持续高于抗病品种;抗病类型品种和感病类型品种的可溶性蛋白含量变化规律均表现为先升高后下降,但接种前其叶片中可溶性蛋白含量两者间无明显差异;抗病类型和感病类型辣椒接种后保护酶活性均升高,而且感病类型的POD和ASP酶活性在接种后120h显著高于抗病类型;高抗类型叶片中PPO活性增加幅度显著大于感病类型,但抗病类型品种PPO活性上升趋势比较平缓。接种后,感病品种PAL活性上升幅度小于高抗品种,接种后96h PAL活性开始逐渐下降。可溶性总糖含量和苯丙氨酸解氨酶可以作为辣椒苗期抗疫病鉴定的生化指标。     

薇甘菊萎蔫病毒感染对薇甘菊光合特性和4种酶活性的影响

为明确薇甘菊萎蔫病毒(Mikania micrantha wilt virus,MMWV)对薇甘菊(Mikania micrantha)叶片生理生化的影响,探讨了MMWV侵染对薇甘菊叶片超氧化物岐化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)、多酚氧化酶(polyphenol oxidase,PPO)和苯丙氨酸解氨酶(phenylalanine ammonia-lyase,PAL)活性及叶绿素总含量和光合特性的影响.结果表明:MMWV感染薇甘菊16d内叶片的SOD活性均比对照组高,其中第16天达最大值,但接种后第24和32天SOD活性分别比对照低了13.28％和25.37％;POD活性在接种后16-32d均显著高于对照.PPO和PAL变化趋势相似,在接种后第8天这两个酶的活性分别比对照高了77.75％和23.58％,而在第32天分别比对照减少了14.27％和20.53％.随着侵染时间的增加,感病薇甘菊叶片中叶绿素含量减少,叶绿素a/b值逐步降低;同时最大净光合速率(Pmax)和光饱和点(LSP)分别比健康对照减少了32.34％和12.52％,而对暗呼吸速率(Rd),光补偿点(LCP)和表观量子效率(AQY)无显著影响.表明MMWV侵染可减低薇甘菊叶片光合作用的效率.     

腐烂病菌侵染对苹果愈伤组织防御酶活性及丙二醛含量的影响

以苹果树腐烂病菌LXS080601、感病苹果品种‘富士’和抗病砧木‘平邑甜茶’愈伤组织为材料,测定腐烂病菌侵染后,愈伤组织内过氧化物酶（POD）、多酚氧化酶（PPO）、超氧化物歧化酶（SOD）和苯丙氨酸解氨酶（PAL）活性及丙二醛（MDA）含量的动态变化。结果显示,接种LXS080601后,‘富士’愈伤组织的发病严重度和病情指数均明显大于‘平邑甜茶’;感病品种MDA含量上升速度快,于接种后3 d增幅为28.02%,且变幅较大,为–0.32%~36.39%,而抗病砧木MDA含量变化较小,仅为–2.17%~7.46%。同时,腐烂病菌侵染提高了愈伤组织内4种防御酶活性,接种后1~2 d,PPO和POD酶活性达到高峰,接种后3~4 d,PAL和SOD酶到达活性高峰;除PPO外,‘平邑甜茶’PAL、SOD和POD酶活性变化均明显高于‘富士’,且整个侵染过程酶活性维持在较高水平,而‘富士’体内3种酶活性快速下降至对照水平,表明‘平邑甜茶’通过提高抗氧化酶活性减少体内活性氧的积累,降低膜脂过氧化产物MDA的形成,增强了对腐烂病菌侵染的抗性。     

不同品种葡萄抗霜霉病特性与叶片POD、PPO活性关系的研究

在霜霉病盛发期,对8804、梅尔诺、品丽珠3个葡萄品种(系)叶片中的PPO和POD活性变化进行了测定.结果显示,8804的PPO和POD活性较大,并保持相当长时间的高活性值,而梅尔诺、品丽珠叶片中PPO和POD活性较小;8804的PPO酶活性变化范围高于其它2个品种,但POD酶活性变化范围却低于后者.葡萄叶片中PPO和POD活性与葡萄霜霉病抗性之间存在一定的相关性,且不同抗感品种间PPO和POD酶活性存在极显著差异.研究结果表明,8804较梅尔诺、品丽珠对霜霉病具有较强的抗性.     

梨黑星菌粗毒素对抗病和感病梨离体叶片生理特性的影响

以不同抗病性梨品种为材料,研究了梨黑星菌粗毒素对梨离体叶片的过氧化物酶(POD)活性、苯丙氨酸解氨酶(PAL)活性、丙二醛(MDA)含量、细胞膜相对透性以及叶绿素含量变化的影响.研究表明,毒素接种后抗病和感病品种叶片的POD和PAL活性、MDA含量和相对电导率均呈上升趋势,其间会有1个或2个峰值出现,且抗病品种叶片的POD和PAL活性高于感病品种,而细胞内MDA含量和相对电导率增加比率低于感病品种;同时,毒素使梨离体叶片的叶绿素、类胡萝卜素含量下降,且感病品种的下降幅度大于抗病品种.总之,梨离体叶片POD和PAL的活性变化与梨品种抗病性呈正相关,叶片MDA含量和相对电导率变化与梨品种抗病性呈负相关,抗病品种离体叶片对毒素的毒害有更强的抵抗力.     

不同苹果品种对褐斑病抗性的鉴定及抗性生理研究

对42个苹果栽培品种叶片褐斑病进行了田间发病状况调查与抗性鉴定,分析了叶片气孔密度和大小与抗病性之间的关系,同时研究了不同抗性品种离体叶片接种病原菌后超氧化物歧化酶（SOD）、多酚氧化酶（vPo）、过氧化物酶（POD）、苯丙氨酸解氨酶（PAL）活性和木质素含量的差异变化。依照抗性分级标准,供试材料中抗病品种有14个（其中高抗品种2个）,感病品种有28个（其中高感品种7个）;叶片气孔密度与病情指数之间存在显著正相关,相关系数r=0．683;叶片接种后,诱导了4种酶活性和木质素含量的升高,抗病和感病品种的SOD和PP0活性无显著差异,而抗病品种的POD和PAL活性以及木质素含量显著高于感病品种。苹果叶片的气孔密度、POD和PAL的活性以及木质素含量与褐斑病抗性有关。     

水杨酸对苦瓜叶片白粉病抗性及抗氧化酶活性的影响

以‘碧绿3号’苦瓜幼苗为材料,采用100、500和1000μmol.L-1的水杨酸(SA)溶液预处理后进行白粉菌的诱导接种,研究了SA处理对苦瓜叶片光合色素含量和4个抗氧化酶活性的影响。结果显示:各浓度SA处理苦瓜植株的病情指数均显著低于对照(蒸馏水处理),并随SA处理浓度增加而逐渐下降;各SA处理苦瓜叶片的光合色素含量均高于其对照,且随SA处理浓度升高而逐渐增加;苦瓜叶片APX、CAT和GR活性随SA处理浓度增加而升高,但GPX活性反而下降,各处理CAT和GR活性增幅均高于病情指数增幅,1000μmol.L-1SA处理的APX活性增幅也高于病情指数增幅。研究发现,SA处理可以提高苦瓜感染白粉病植株叶片的光合色素含量及其抗氧化酶活性,显著降低其病情指数,增强其白粉病抗性,且以1000μmol.L-1SA处理效果最好。     

桃色顶孢霉代谢产物对绿豆白粉病的防治作用

应用桃色顶孢霉发酵液中蛋白粗提物、三唑酮处理感病绿豆叶片和植株,比较分析病斑变化和综合病情指数,并测定不同处理植株新生叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及丙二醛(MDA)含量,探究桃色顶孢霉发酵液粗提蛋白对绿豆白粉病的影响。结果表明,喷施粗提蛋白的感病植株叶片的病斑变化明显,且新生叶片鲜绿,无白粉病菌侵染症状。与喷施无菌水的对照相比,喷施粗提蛋白的感白粉病绿豆植株叶片CAT酶活性提高了71.70%,差异显著,而POD酶活性降低了8.45%,且叶片MDA含量降低了29.81%。试验结果证实了桃色顶孢霉发酵液的蛋白粗提物对绿豆白粉病具有一定的防治效果,并能影响到植物相关抗逆酶的活性。     

黄条金刚竹对高浓度CO2和O3及其复合作用的生理响应

以黄条金刚竹为试材,环境背景大气为对照,应用开顶式气室(OTCs)熏蒸法模拟大气高浓度CO2(700μmol.mol-1)、O3(100nmol.mol-1)及其复合作用情景,分析叶片光合色素、膜脂过氧化及抗氧化酶等的变化规律。结果显示:(1)与对照相比,高浓度O3处理103d的黄条金刚竹叶片叶绿素a、叶绿素b、总叶绿素含量和叶绿素a/b、叶绿素/类胡萝卜素及SOD、POD、CAT活性均显著下降,而超氧阴离子和丙二醛含量、相对电导率、APX活性均显著升高,类胡萝卜素含量变化不明显。(2)与对照相比,同期高浓度CO2处理的叶片叶绿素a、叶绿素b、总叶绿素含量和叶绿素/类胡萝卜素均显著升高,而叶绿素a/b和超氧阴离子、丙二醛含量及SOD、POD、CAT、APX活性显著降低,相对电导率和类胡萝卜素含量变化不明显。(3)高浓度O3和CO2复合作用下,除叶绿素a/b和CAT活性显著下降外,其余测定指标均与对照无明显变化。研究表明:高浓度O3使黄条金刚竹叶片活性氧产生速率提高,抗氧化酶活性和光合色素含量降低,膜脂过氧化程度加剧,膜结构破坏,表现出严重的伤害效应;而高浓度CO2能降低叶片活性氧产生速率,减轻膜脂过氧化程度,提高光合色素含量,表现出保护效应;高浓度O3和CO2复合处理能使叶片维持比高浓度O3处理更高的光合色素含量和抗氧化酶活性,即高浓度CO2能在一定程度上有效地缓解高浓度O3对黄条金刚竹所造成的生理伤害。     

Arbuscular mycorrhiza‐mediated resistance in tomato against Cladosporium fulvum‐induced mould disease

Root colonization with arbuscular mycorrhizal fungi (AMF) enhances plant resistance particularly against soil‐borne pathogenic fungi. In this study, mycorrhizal inoculation with Glomus mosseae (Gm) significantly alleviated tomato mould disease caused by the air‐borne fungal pathogen, Cladosporium fulvum (Cf). The disease index (DI) in local leaves (receiving pathogen inoculation) and systemic leaves (just above the local leaf without pathogen inoculation) was 36.4% and 11.7% in mycorrhizal plants, respectively, whereas DI was 59.6% and 36.4% in the corresponding leaves of AMF non‐inoculated plants, after 50 days of Gm inoculation, corresponding to 15 days after Cf inoculation by leaf infiltration. Foliar spray inoculation with Cf also revealed that AMF pre‐inoculated plants had a higher resistance against subsequent pathogen infection, where the DI was 41.3% in mycorrhizal plants vs. 64.4% in AMF non‐inoculated plants. AMF‐inoculated plants showed significantly higher fresh and dry weight than non‐inoculated plants under both control (without pathogen) and pathogen treatments. AMF‐inoculated plants exhibited significant increases in activities of superoxide dismutase and peroxidase, along with decreases in levels of H₂O₂ and malondialdehyde, compared with non‐inoculated plants after pathogen inoculation. AMF inoculation led to increases in total chlorophyll contents and net photosynthesis rate as compared with non‐inoculated plants under control and pathogen infection. Pathogen infection on AMF non‐inoculated plants led to decreases in chlorophyll fluorescence parameters. However, pathogen infection did not affect these parameters in mycorrhizal plants. Taken together, these results indicate that AMF colonization may play an important role in plant resistance against air‐borne pathogen infection by maintaining redox poise and photosynthetic activity.     

Castor bean growth and rhizosphere soil property response to different proportions of arbuscular mycorrhizal and phosphate-solubilizing fungi

A pot culture experiment was performed to study the effects of infection with different proportions of arbuscular mycorrhizal fungus (AMF) and phosphate-solubilizing fungus (PSF) on the rhizosphere soil property of castor bean (Ricinus communis L.). One AMF, Glomus mosseae, and one PSF, Mortierella sp. (Ms), were applied to non-sterilized coastal saline soil. The plant dry mass, leaf chlorophyll content, and P-uptake of castor bean were assessed. In coastal saline soil, the different proportions of both fungi-inoculated seedlings showed significantly greater shoot and root dry weight than the controls, which had lower root-to-shoot ratios than the inoculated seedlings. An increase in phosphorus (P) and chlorophyll contents was also observed in the inoculated seedlings compared with the controls. The appropriate Ms proportion seemed to be advantageous for AMF colonization. However, available P content of fungi-treated soil increased in proportion to the increase in Ms population and AMF colonization. By contrast, the pH of inoculated soil decreased because of the increased proportion of Mortierella, and electrical conductivity values showed a negative correlation with AMF colonization. Soil enzyme activities (i.e., urease, invertase, neutral phosphatase, and alkaline phosphatase) and soil organic matter were also stimulated by inoculation with different proportions of both fungi. However, the catalase activities of inoculated soil were inhibited compared with those of the control soil. Results from this study prove that castor bean planting associated with an appropriate proportion of AMF and PSF will benefit the amelioration of coastal saline soils of eastern China.     

Oxidative enzymes activities of mycorrhizal inoculated pepper plant infected with phytophthora infestans

The activities of polyphenol oxidase, peroxidase and catalase were investigated in Glomus etunicatum an arbuscular mycorrhizal inoculated pepper plant infected with Phytophthora infestans. Pepper plant inoculated with pathogen alone, simultaneously inoculated with mycorrhizal and pathogen or dually inoculated with pathogen before mycorrhizal had increased level of the oxidative enzymes activities especially at 4 weeks after planting. Of the three oxidases investigated catalase had the highest level of activities in all the treatments while the level of peroxidase was the lowest. The results showed that pathogen alone, build up the level of the oxidases in the inoculated pepper plant while inoculation of the pepper plant with AM mycorrhizal either simultaneously or dually with pathogen lower the activity of the oxidases indicating a passive protective effect of mycorrhizal.     

Potential of Bacillus species against Meloidogyne javanica parasitizing eggplant (Solanum melongena L.) and induced biochemical changes

Aims

The biocontrol potential of three Bacillus species, namely Bacillus subtilis (BS), Bacillus firmus (BF), and Bacillus coagulans (BC) was tested against the root-knot nematode Meloidogyne javanica (Treub) Chitwood in eggplants (Solanum melongena L.). Plant growth and biochemical effects were also measured in these interactions.

Methods

Bacillus species were inoculated in soil around the seedlings of eggplants (Solanum melongena L.) with and without nematodes in a greenhouse experiment. Plant growth, biochemical changes, and nematode parasitism were observed at 15 and 45 days after inoculation (DAI).

Results

BC significantly enhanced plant growth, chlorophyll “b” and total chlorophyll contents, and polyphenol oxidase (PPO) activity in the leaves of eggplants, while BS showed greatest reduction in root-knot nematode parasitism. Non-infected and untreated control (C?) plants showed lesser chlorophyll “b,” carotenoids, soluble protein contents, and guaiacol peroxidase but higher catalase and PPO activities compared to infected and untreated controls (C+) at 15 and 45 DAI. Superoxide dismutase activity declined in most of the treated plants at 45 DAI following rise at 15 DAI. Ascorbate peroxidase activity increased at 45 DAI compared to 15 DAI in C? and C+ plants. PAL activity was greatly enhanced at 45 DAI in all treatments and controls over that at 15 DAI.

Conclusions

BC is a potentially plant growth-promoting bacteria although it was less effective against nematode infection compared to BS. Enzymes activities varied with infection and DAI. BC at 15 DAI in general increased the activity of most of the stress enzymes and thereby overcoming the effect of nematode parasitism.     

大田增温对夏玉米光合特性的影响

在大田条件下研究了增温对两个夏玉米品种农大108(ND108)和掖单13号(YD13)光合特性及产量的影响.结果表明:大喇叭口期到成熟期增温显著降低了夏玉米籽粒产量,ND108和YD13的籽粒产量分别较对照降低了46.6%和45.1%;叶面积指数平均值分别降低了15.4%和11.5%;穗位叶叶片光合速率平均值分别降低了22.85%和18.14%;两个玉米品种叶片的叶绿素a和叶绿素b含量显著降低,但对叶绿素a的影响更显著.增温后玉米叶片的磷酸烯醇式丙酮酸羧化酶(PEPCase)和核酮糖二磷酸羧化酶(RuBPCase)活性都显著降低,ND108、YD13叶片的PEPCase和RuBPCase活性分别较对照降低了51.1%、32.4%和29.5%、7.7%.     

红皮云杉外生菌根菌单接种及混合接种对苗木生长的影响

以提高外生菌根真菌对红皮云杉苗木促生长效果为目的,在前期研究的基础上,采用菌株配对培养的方法对获得的云杉外生菌根真菌进行混合接种菌株组合筛选;采用沟施菌剂方法,对3年生红皮云杉移床苗进行外生菌根菌菌株组合野外混合接种试验,同时以各菌株野外单接种作为对照,研究外生菌根真菌单接种及混合接种对红皮云杉苗木生长的影响。试验结果表明:供试菌株及菌株组合对红皮云杉苗木生长均有一定的促进作用。菌株L15促生长效果最佳,接种100d苗木高生长高于对照30.88%,地径高于对照15.29%。组合L15/025与L15/009促苗木生长效果低于单接种L15的效果,高于单接种009和025的效果。接种菌株010和组合L15/025的苗木与对照相比,叶绿素含量提高差异显著,叶绿素a水平分别高于对照59.15%、54.61%,叶绿素b水平分别高于对照76.34%和67.78%。除接种菌株010的苗木外,其他处理苗木其过氧化氢酶活性与对照相比均有所降低。所有处理苗木的根系活力均低于对照。综上,外生菌根菌高效菌株与一般菌株混合接种会弱化高效菌株自身接种效果;苗木过氧化氢酶活性、苗木根系活力与苗木的生物量间无相关性。     

羊草草原群落6种植物叶片功能特性对氮素添加的响应

 该文比较了羊草草原群落中包括建群种和优势种在内的6种植物,羊草（Leymus chinensis）、西伯利亚羽茅（Achnatherum sibiricum）、大 针茅（Stipa grandis）、 冰草（Agropyron cristatum）、糙隐子草（Cleistogenes squarrosa）和黄囊苔草（Carex korshinskyi）的比叶 面积(Specific leaf area, SLA)、叶片含氮量和叶绿素含量等叶片功能特性( Leaf functional trait)对氮素添加的响应,旨在探讨草原生态 系统中,不同物种对氮素可利用性改变的响应和适应对策。结果表明：随着氮素添加量的增加,物种对光资源的竞争增强,不同物种在光资源 的竞争策略和竞争力间存在着显著的差异。羊草通过提高SLA、单位质量叶片的叶绿素含量和含氮量,使单位面积叶片含氮量和叶绿素含量均呈 线性提高,进而增强了其对光的竞争力。西伯利亚羽茅主要通过提高SLA增加光合总面积,来增强自身的光竞争力。冰草在SLA和单位质量叶片 的叶绿素和氮含量均有一定的可塑性,但对光的竞争力明显弱于羊草和西伯利亚羽茅。大针茅和黄囊苔草对SLA的调节能力较低,加之大针茅 SLA较低,而黄囊苔草处于群落的下层,这两种植物的光竞争力较弱。糙隐子草具有较高的SLA,对单位质量叶片叶绿素和氮含量的调节能力相 对较强,其光竞争力高于黄囊苔草。同时,糙隐子草叶片叶绿素a与叶绿素b的比值沿氮素添加梯度显著降低,进一步证实氮素添加改变了群落 的光环境。     

铜胁迫条件下AMF对海州香薷光合色素含量、抗氧化能力和膜脂过氧化的影响

以盆栽海州香薷为研究对象,模拟Cu胁迫条件下,接种丛枝菌根真菌(AMF)对海州香薷叶片光合色素含量、抗氧化酶活性、抗氧化剂含量、膜脂过氧化程度的影响。结果表明:(1)与对照相比,Cu胁迫使海州香薷叶片叶绿素a(Chl a)、叶绿素b(Chl b)、总叶绿素(Chl(a+b))、类胡萝卜素(Car)含量以及叶绿素a/b(Chl a/b)均显著降低,抗氧化酶活性和抗氧化剂含量也显著下降,质膜相对透性(MRP)和丙二醛(MDA)含量显著增大。(2)与Cu胁迫相比,Cu胁迫下接种AMF可使海州香薷叶片叶绿素含量显著增加;超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)活性显著提高;还原型谷胱甘肽(GSH)、抗坏血酸(As A)含量显著增加;MDA含量、MRP显著下降。总之,接种AMF可提高Cu胁迫下海州香薷叶片光合色素含量和抗氧化能力,降低膜脂过氧化水平,从而缓解Cu胁迫对植株造成的伤害,增强海州香薷对Cu胁迫的适应性,提高了植株的生物量。     

Nonstructural carbohydrate metabolism during leaf ageing in tobacco (Nicotiana tabacum)

Nonstructural carbohydrate status and activities of ADP-glucose pyrophosphorylase (EC 2.7.7.27, ADPG pyrophosphorylase) and sucrose phosphate synthase (EC 2.4.1.14, SPS) were determined during ageing of tobacco ( Nicotiana tabacum L., cvs KY 14 and Speight G28) leaves sampled from control plants and from plants that had the apical meristem and subsequent axillary growth removed (detopped plants). Over the 30-day period shoot growth increased much more for control compared to detopped plants, but the increase in root growth was similar for both treatments. Dry matter and leaf area of the individual leaf used for enzyme and metabolite analysis were constant over time for controls but increased 5-fold for detopped plants. Ageing of control leaves was indicated by a progressive loss of chlorophyll and ribulose 1, 5-bisphosphate carboxylase (EC 4.1.1.39, Rubisco) activity; loss of these components was diminished for detopped plants. In contrast to chlorophyll and Rubisco activity, activities of ADPG pyrophosphorylase and SPS remained relatively constant over time for controls. Thus, under normal ageing conditions, changes in activities of ADPG pyrophosphorylase and SPS were not closely associated with changes in the standard senescence indicators chlorophyll and Rubisco activity. The activities of ADPG pyrophosphorylase and SPS were enhanced, relative to controls, within 6 days after applying the detopping treatment and activities remained high for the duration of the 30-day period. Detopping also led to increased concentrations of starch and sucrose, but the increases were not well correlated with changes in enzyme activities. The data indicated that the leaves of detopped plants functioned as both source leaves, with enhanced ability to synthesize carbohydrate, and sink leaves, with enhanced growth. Therefore, activities of ADPG pyrophosphorylase and SPS were more responsive to changes within an individual leaf than to changes in whole plant growth.     

水分胁迫下AM真菌对沙打旺生长和抗旱性的影响

利用盆栽试验研究了水分胁迫条件下接种AM真菌对优良牧草和固沙植物沙打旺(Astragalus adsurgens Pall.)生长和抗旱性的影响。在土壤相对含水量为70%、50%和30%条件下,分别接种摩西球囊霉(Glomus mosseae)和沙打旺根际土著菌,不接种处理作为对照。结果表明,水分胁迫显著降低了沙打旺植株(无论接种AM真菌与否)的株高、分枝数、地上部干重和地下部干重,并显著提高了土著AM真菌的侵染率,对摩西球囊霉的侵染率无显著影响。接种AM真菌可以促进沙打旺生长和提高植株抗旱性,但促进效应因土壤含水量和菌种不同而存在差异。不同水分条件下,接种AM真菌显著提高了植株菌根侵染率、根系活力、地下部全N含量和叶片CAT活性。土壤相对含水量为30%和50%时,接种株地上部全N、叶片叶绿素、可溶性蛋白、脯氨酸含量和POD活性显著高于未接种株;接种AM真菌显著降低了叶片MDA含量;接种土著AM真菌的植株株高、分枝数、地上部和地下部干重显著高于未接种株。土壤相对含水量为30%时,接种AM真菌显著增加了地上部全P含量和叶片相对含水量;接种摩西球囊霉的植株株高、分枝数、地上部和地下部干重显著高于未接种株。水分胁迫40d,接种AM真菌显著提高了叶片可溶性糖含量。水分胁迫80d,接种株叶片SOD活性显著增加。菌根依赖性随水分胁迫程度增加而提高。沙打旺根际土著菌接种效果优于摩西球囊霉。水分胁迫和AM真菌的交互作用对分枝数、菌根侵染率、叶片SOD、CAT和POD活性、叶绿素、脯氨酸、可溶性蛋白、地上部全N和全P、地下部全N和根系活力有极显著影响,对叶片丙二醛和地下部全P有显著影响。AM真菌促进根系对土壤水分和矿质营养的吸收,改善植物生理代谢活动,从而提高沙打旺抗旱性,促进其生长。试验结果为筛选优良抗旱菌种,充分利用AM真菌资源促进荒漠植物生长和植被恢复提供了依据。