干旱胁迫下AMF对云南蓝果树幼苗生长和光合特征的影响

采用盆栽试验与称重控水法,将土壤相对含水量分别控制在田间最大持水量的100%、91.68%、82.85%、60.00%、41.86%和21.28%,并在这6个不同的土壤相对含水量条件下,分别设添加苯菌灵(杀真菌剂)(低AMF)和不添加苯菌灵(高AMF)处理,研究干旱胁迫下AMF对极小种群野生植物云南蓝果树幼苗生长和光合特征的影响,揭示云南蓝果树濒危的微生物学机制,为云南蓝果树保护措施的制定与实施奠定基础。结果表明,添加苯菌灵处理显著降低了不同水分条件下的AMF侵染率,说明试验中AMF处理的实生苗在生长和光合特征上的差异是苯菌灵处理下侵染率下降导致的;随着干旱胁迫的加剧,云南蓝果树幼苗的根部AMF侵染率显著降低、叶面积等生长指标和净光合速率(Pn)等光合参数都发生显著变化;高AMF处理可以显著增加水分充足和轻度干旱胁迫条件下云南蓝果树幼苗的大部分生长指标和光合参数,而对重度胁迫下的云南蓝果树幼苗没有显著影响,说明重度干旱胁迫对其影响大于AMF的影响;另外,整合了可塑性指数分析和隶属函数分析两种方法对其抗旱性进行评价,云南蓝果树幼苗基本上无法通过调节形态和光合能力来适应水分环境的变化,但是高AMF处理可使云南蓝果树幼苗具有较强的可塑性和更强的抗旱性。实验结果为云南蓝果树的科学保育及种苗繁育提供了理论依据。     

水分胁迫和杀真菌剂对黄顶菊生长和抗旱性的影响

利用盆栽试验研究水分胁迫下AM真菌对黄顶菊生长和抗旱性的影响,揭示黄顶菊入侵过程中的微生物学机制。以苯菌灵为杀真菌剂,在土壤相对含水量为120%、80%、40%和20%条件下,分别设灭菌和不灭菌两种处理。结果表明,水分胁迫显著降低了黄顶菊株高、干重和主根长,而对AM真菌侵染率无显著影响。施用苯菌灵显著降低了菌根侵染率、叶片保水力、保护酶活性、可溶性糖和可溶性蛋白含量,提高了MDA含量。不灭菌处理下黄顶菊植株对土壤有效N和有效P的利用率较高,且植株全N、P含量显著高于灭菌处理,菌根贡献率随土壤相对含水量降低而逐渐提高,重度胁迫分别是渍水条件下的1.84和1.88倍。土壤水分状况和AM真菌的交互作用对黄顶菊生物量和生理指标影响显著。AM真菌共生能够促进黄顶菊根系对土壤水分和矿质营养吸收,改善植物代谢活动,提高抗旱性。实验结果为黄顶菊合理防控措施的制定提供了依据,同时作为丛枝菌根的基础性研究也具有重要的意义。     

保水剂和丛枝菌根真菌异形根孢囊霉对紫花苜蓿生长与抗旱性的影响

为探讨保水剂（super absorbent polymers,SAP）和丛枝菌根真菌（arbuscular mycorrhizal fungi,AMF）对植物生长和抗旱性的影响,以紫花苜蓿Medicago sativa为供试植物,开展了温室盆栽试验。植物播种时设置土壤添加和不添加聚丙烯酰胺型SAP（BJ2101）处理,以及接种和不接种异形根孢囊霉Rhizophagus irregularis处理,通过称重法维持12%的土壤含水量（正常供水）,植物生长30d,各处理一半植物接受干旱胁迫（6%的土壤含水量）,另一半仍正常供水,持续30d后收获。结果表明,在干旱胁迫下,接种AMF显著增加了紫花苜蓿的植株干重,促进了植物对矿质元素的吸收,提高了叶片中叶绿素和脯氨酸含量,增强了植物的抗旱性。SAP抑制了R. irregularis对植物根系的侵染;与单接种AMF相比,SAP和AMF的联合施用降低了紫花苜蓿的生物量,影响了植物对矿质元素的吸收。本研究中,SAP和AMF的联合施用并没有表现出协同增效作用,这一方面可能是因为研究设定的土壤水分管理模式,另一方面SAP与AMF共同施用的适宜条件还需进一步探索优化。     

丛枝菌根真菌接种与磷添加对干旱胁迫燕麦土壤微生物生物量及酶活性的影响

研究丛枝菌根真菌(AMF)接种与磷添加对干旱胁迫燕麦根系AMF侵染率、土壤微生物生物量和酶活性的影响,探讨其与燕麦产量的关系,为旱作区燕麦磷肥合理施用的菌根调控技术提供依据。试验采用盆栽控水,设置2个水分水平(正常供水,75%土壤相对含水量,W1;干旱胁迫,55%土壤相对含水量,W2)、3个施磷水平(0、20、40 mg·kg^-1,P0、P1、P2)、2个AMF水平(接种,AMF;不接种,NAMF),共12个处理。于燕麦拔节期、灌浆期、成熟期采集根系和土样,检测根系AMF侵染率,测定土壤MBC、MBN、MBP,土壤蔗糖酶、脲酶、碱性磷酸酶活性,及成熟期燕麦产量。结果表明：水分处理、磷处理和AMF处理均对各指标有显著影响,三因子在土壤MBN和土壤蔗糖酶活性上存在显著交互作用。干旱胁迫下,与未接种处理相比,接种AMF后,各指标均显著提高。P1下,燕麦生育期内AMF侵染率,土壤MBC、MBN、MBP,土壤蔗糖酶、脲酶、碱性磷酸酶活性及产量较P0显著提高的最大幅度分别达13.21%、52.26%、47.07%、88.94%、23.15%、15.44%、11.15%、17....     

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。     

干旱条件下接种AM真菌对小马鞍羊蹄甲幼苗根系的影响

为了探讨岷江干旱河谷丛枝菌根真菌(AMF)对寄主植物幼苗根系的影响,通过接种购买的AMF摩西球囊霉菌(Funneliformis mosseae)到优势乡土灌木小马鞍羊蹄甲(Bauhinia faberi var.microphylla)幼苗,在重度、中度和轻度干旱条件下培养3个月,研究不同干旱条件下AMF对幼苗根系形态特征、结构特征、功能性状的影响。方差分析结果表明:(1)3种干旱胁迫条件下,接菌均显著增加了幼苗的根总长、根表面积、根分枝数、根尖数(P0.001),在中度胁迫和轻度胁迫下,接菌显著促进根鲜重、根体积的增加(P0.001),轻度胁迫条件下接菌幼苗的根鲜重、根总长、根表面积、根体积、根尖数最高并显著高于其它处理,但接菌与未接菌的根平均直径之间没有显著差异;(2)接菌幼苗根系趋向于叉状分支结构,在重度胁迫时,叉状分支趋势更显著(P0.001);(3)接菌幼苗的根比例都显著小于未接菌的,但幼苗比根长不存在显著差异。相关分析结果表明:菌根侵染率与根鲜重、根总长、根表面积、根体积、根分枝数、根尖数呈极显著正相关(P0.001),与拓扑指数、根比例呈极显著负相关(P0.001)。研究表明,在干旱条件下,AMF虽然没有提高生长初期的根系的吸收效率,但接种AMF显著影响幼苗根系形态特征和结构特征,更利于植物适应干旱环境,并且AMF对幼苗根系的促生作用随着干旱胁迫程度减轻而提高。     

干旱胁迫下AM真菌对矿区土壤改良与玉米生长的影响

以神东矿区塌陷区退化土壤为供试基质,以玉米为宿主植物,研究在干旱胁迫下,丛枝菌根真菌(arbuscular mycorrhizalfungi)对玉米生长和养分吸收的影响,以及对矿区退化土壤的改良作用.结果表明:干旱胁迫下,接种AMF显著提高了玉米根系侵染率和生物量,玉米叶片相对含水量和叶色值明显高于对照组;接种组玉米地上部分磷、氮、钙和根系部分磷、钾、钙含量显著增加;接种AMF后,玉米根际土壤总球囊霉素和易提取球囊霉素含量分别增加了36.2％和33％,且根际土壤中有机质含量显著增加.由此可见,接种AMF促进了玉米对矿质养分的吸收,缓解了干旱造成的玉米生长的不利影响,提高了根际土壤中有机质含量,对矿区退化土壤改良有重要意义.     

干旱胁迫条件下AMF促进小马鞍羊蹄甲幼苗生长的机理研究

采用温室水分控制试验,在干旱胁迫条件下,定量化研究优势丛枝菌根真菌(AMF)影响优势乡土植物小马鞍羊蹄甲(Bauhinia faberi var.microphylla)幼苗生长的机理,主要通过研究干旱胁迫条件下摩西球囊霉菌(Funneliformis mosseae)与小马鞍羊蹄甲的共生关系,阐明AMF在植物生长初期的作用。结果表明,干旱胁迫条件下,摩西球囊霉菌能够很好地侵染幼苗,侵染率高达89%—97%,并且不受水分条件影响。接种的幼苗最大光合速率、水分利用效率随着干旱胁迫程度从重度到轻度(水分从低到高)逐渐增大,相反地,叶片脯氨酸含量逐渐减小。接种显著地促进幼苗株高、叶片数、叶面积、根长、根面积等生长指标,提高幼苗各部分生物量、地上地下磷(P)含量。当含水量为60%田间持水量时,AMF促进小马鞍羊蹄甲幼苗吸收P的效果最好。接种还显著影响幼苗的生物量分配,在重度干旱胁迫时影响P分配,水分条件也显著影响幼苗的生物量分配。此外,接种和水分的交互作用对叶生物量、总生物量、生长指标以及地上部氮(N)总量影响显著。结果表明干旱胁迫条件下菌根效应显著,并在干旱条件下显著促进了小马鞍羊蹄甲幼苗的生长,这为进一步干旱河谷植被恢复提供了理论依据。     

山杜英和黧蒴幼苗对干旱胁迫(PEG)的生理响应

以山杜英(Elaeocarpus sylvestris)和黧蒴(Castanopsis fissa)幼苗为试验材料,利用聚乙二醇6000(PEG-6000)人工模拟水分胁迫环境,设置三个胁迫强度处理(轻度、中度、重度)、三个胁迫持续时间处理(12h、24h、36h),以不加PEG-6000的1/2Hoagland营养液中的苗木作为对照,对2个树种幼苗的叶片相对含水量、相对电导率、脯氨酸含量、叶绿素含量、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量和可溶性糖含量进行了测定,研究了水分胁迫对这2种幼苗的影响。结果表明:随着水分胁迫强度的加深及持续时间的延长,2种幼苗叶片相对含水量出现下降趋势,黧蒴的含水量下降更为显著;2种树种幼苗叶片内相对电导率呈波动性上升,黧蒴在轻度胁迫时相对电导率有大幅增加;2种幼苗的脯氨酸含量显著增加,叶绿素含量呈小幅波动,SOD活性先升后降,可溶性糖含量呈现波动性上升;山杜英叶片的MDA含量增加较缓慢,而黧蒴叶片的MDA含量大幅度增加。研究表明幼苗山杜英比黧蒴抗旱性强,叶片相对含水量、相对电导率和MDA含量可作为评价这2种苗木抗旱性的依据。     

水分胁迫下AM真菌对柠条锦鸡儿(Caragana korshinskii)生长和抗旱性的影响

利用盆栽实验研究了水分胁迫条件下AM真菌对柠条锦鸡儿(Caragana korshinskii)生长和抗旱性的影响.在土壤相对含水量为80%、60%和40%条件下,分别接种摩西球囊霉(Glomus mosseae)和柠条锦鸡儿根际土著菌,结果表明,水分胁迫对AM真菌的接种效果有显著影响.不同水分条件下,接种AM真菌显著提高了宿主植物根系菌根侵染率.土壤相对含水量为40%～60%时,接种株的株高、茎粗、生物干重和叶片保水力明显高于不接种株;接种AM真菌提高了植株对土壤有效N和有效P的利用率,增加了植株全P、叶片叶绿素和可溶性糖含量以及SOD、POD、CAT等保护酶活性.土壤相对含水量为40%时,叶片MDA含量明显下降.水分胁迫条件下,以接种柠条锦鸡儿根际土著菌的效果最佳.AM真菌增强宿主植物的抗旱性可能源于促进宿主植物根系对土壤水分和矿质元素吸收的直接作用和改善植物体内生理代谢活动、提高保护酶活性的间接作用.     

Arbuscular Mycorrhizal Fungi Alter Fractal Dimension Characteristics of Robinia pseudoacacia L. Seedlings Through Regulating Plant Growth,Leaf Water Status,Photosynthesis, and Nutrient Concentration Under Drought Stress

The influence of arbuscular mycorrhizal fungi (AMF), Funneliformis mosseae and Rhizophagus intraradices, on plant growth, leaf water status, chlorophyll concentration, photosynthesis, nutrient concentration, and fractal dimension (FD) characteristics of black locust (Robinia pseudoacacia L.) seedlings was studied in pot culture under well-watered, moderate drought stress, and severe drought stress treatments. Mycorrhizal seedlings had higher dry biomass, leaf relative water content (RWC), and water use efficiency (WUE) compared with non-mycorrhizal seedlings. Under all treatments, AMF colonization notably enhanced net photosynthetic rate, stomatal conductance, and transpiration rate, but decreased intercellular CO₂ concentration. Leaf chlorophyll a and total chlorophyll concentrations were higher in AM seedlings than those in non-AM seedlings although there was no significant difference between AMF species. AMF colonization improved leaf C, N, and P concentrations, but decreased C:N, C:P, and N:P ratios. Mycorrhizal seedlings had a larger FD value than non-mycorrhizal seedlings. The FD value was positively and significantly correlated to the plant growth parameters, photosynthesis, RWC, WUE, and nutrient concentration but negatively correlated to leaf/stem ratio, C:N and C:P ratios, and intercellular CO₂ concentration. We conclude that AMF lead to an improvement of growth performance of black locust seedlings under all growth conditions, including drought stress via improving leaf water status, chlorophyll concentration, photosynthesis, and nutrient uptake. Moreover, FD technology proved to be a powerful non-destructive method to characterize the effect of AMF on the physiology of host plants during drought stress.     

Synergistic effect of colonization with arbuscular mycorrhizal fungi improves growth and drought tolerance of Plukenetia volubilis seedlings

The objective of this study was to investigate the effects of arbuscular mycorrhizal fungus (AMF) inoculation on plant growth and drought tolerance in seedlings of a promising oilseed crop, Sacha Inchi (Plukenetia volubilis L.), under well-watered or drought conditions. AMF inoculation was applied in four treatments: without AMF inoculation, Glomus versiforme, Paraglomus occultum, or combination of both microorganism inoculations. The results showed that AMF colonization significantly enhanced the growth of Sacha Inchi seedlings regardless of soil water conditions, and the greatest development was reached in plants dually inoculated under well-watered conditions. G. versiforme was more efficient than P. occultum. Plants inoculated with both symbionts had significantly greater specific leaf area, leaf area ratio and root volume when compared with the uninoculated control, G. versiforme, and P. occultum treatments alone, indicating a synergistic effect in the two AMF inoculation. Photosynthetic rate and water-use efficiency were stimulated by AMF, but not stomatal conductance. Inoculation with AM fungus increased antioxidant enzymes activities including guaiacol peroxidase and catalase, thus lowering hydrogen peroxide accumulation and oxidative damage, especially under drought stress conditions. However, proline content showed little change during drought stress and AMF colonization conditions, which suggested that proline accumulation might not serve as the main compound for osmotic adjustment of the studied species. These results indicate that AMF inoculation stimulated growth and enhanced drought tolerance of Sacha Inchi seedlings, through alterations in morphological, physiological and biochemical traits. This microbial symbiosis might be an effective cultivation practice in improving the performance and development for Sacha Inchi plants.     

干旱胁迫下接种丛枝菌根真菌对七子花非结构性碳水化合物积累及C、N、P化学计量特征的影响

以濒危植物七子花二年生幼苗为研究材料,采用盆栽试验方法,研究干旱胁迫和接种丛枝菌根真菌(AMF)处理对幼苗不同器官C、N、P化学计量关系和非结构性碳水化合物(NSC)含量的影响。试验共设计4个处理:对照(CK)、干旱胁迫(D)、接种AMF(AMF)、干旱胁迫和接种AMF(D+AMF)。结果表明: 在干旱胁迫下七子花根系AMF的侵染率显著下降,但接种AMF处理植株的株高、叶片数显著高于未接种处理。接种AMF显著提高了干旱胁迫下植株根、叶可溶性糖和NSC含量及茎、叶淀粉含量,且茎和叶可溶性糖与淀粉比显著下降。干旱胁迫导致植株C含量在根和叶中显著增加,P含量在茎中显著减少;与干旱胁迫相比,胁迫下接种AMF植株根、茎、叶P含量及叶C含量显著提高,而根C、N含量及茎C含量显著降低。胁迫下接种AMF植株根、茎C∶N、C∶P、N∶P和叶N∶P均显著低于单一胁迫处理。NSC与C∶N∶P计量比的相关性分析表明,根、叶P含量与可溶性糖和NSC含量呈显著正相关,茎P含量与淀粉和NSC含量呈显著正相关,各器官N∶P与NSC含量呈显著负相关。综上,干旱胁迫显著抑制了七子花幼苗的生长,接种AMF通过提高植株根和叶的可溶性糖含量、根的可溶性糖/淀粉,增加地上部分淀粉含量,促进P元素吸收和降低各器官N∶P来增强植株耐旱性,从而提高七子花幼苗在干旱环境中的存活率。     

水分胁迫下烯效唑对百日草幼苗光合特性及叶解剖结构的影响

以百日草‘芳菲1号’为试材,研究不同水分胁迫下烯效唑(S3307)对其幼苗生长、光合特性及叶解剖结构的影响,以明确S3307对百日草的抗旱作用及其机理。结果显示:(1)在水分胁迫下,百日草的生长均受到不同程度的抑制,叶绿素含量显著降低,光合作用受到抑制,叶解剖结构有所变化。(2)S3307处理后,均能够显著降低所对应的不同程度水分胁迫下百日草的株高,显著增加茎粗、叶面积、叶片厚度、栅栏组织厚度和根冠比,显著增加叶绿素含量,提高百日草的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和水分利用效率(WUE)。研究表明,S3307能够提高百日草的抗旱性,而且在轻度和中度水分胁迫下Pn的下降主要是由气孔因素引起,而在重度水分胁迫下光合速率的下降是由非气孔因素引起的。     

Effects of drought stress and N supply on the growth, biomass partitioning and water-use efficiency of Sophora davidii seedlings

A greenhouse experiment was conducted in order to understand the adaptation responses to different water and N conditions, and further explore if additional N supply could improve the water-use efficiency (WUE) and adaptability of Sophora davidii seedlings under dry conditions. Two-month-old seedlings were subjected to a completely random design with three water (80, 40 and 20% water field capacity (FC)) and three N supply (N0: 0, Nl: 92 and Nh:184 mg N kg⁻¹ soil) regimes. Drought stress dramatically decreased seedlings height, basal diameter, leaf number, leaf area, root length, and biomass production. An increase in below-ground biomass was observed indicating a higher root/shoot ratio (R/S) under drought stress conditions, and drought further decreased relative water content (RWC) and WUE. On the other hand, S. davidii seedlings exhibited strong responses to N supply, but the responses were inconsistent with the various N supply levels. Low N supply (Nl) increased seedlings height, basal diameter, leaf number, leaf area, and biomass production, but decreased root length. In contrast, high N supply (Nh) decreased or had little effect on these growth characteristics. N supply increased leaf percentages, but decreased fine root percentages. In addition, Nl rather than the other two N treatments increased leaf area ratio (LAR), leaf/fine root mass ratio (L/FR), R/S and RWC under severe drought stress (20% FC), even though these parameters could increase with the Nh treatment under well-watered condition (80% FC). Moreover, Nl also increased WUE under three water conditions, but Nh had little effect on WUE under drought stress conditions (40% FC and 20% FC). The results suggested that water and N co-limited the growth of S. davidii seedlings, and the seedlings exhibited great positive responses to Nl in this study. Appropriate or low N supply, therefore, would be recommended to stimulate growth, enhance WUE, alleviate drought stress, and consequently contribute to S. davidii seedling establishment under dry condition, but excess N supply should be avoided.