叶面喷施褪黑素对干旱及复水下玉米光合特性和抗氧化系统的影响

为揭示叶面喷施外源褪黑素(MT)在干旱胁迫及复水下调控玉米的生理机制,该研究以玉米‘陕科9号’为试验材料,叶面喷施100 μmol·L^-1褪黑素,在重度干旱胁迫和复水后测定叶片相对含水量(RWC)、叶面积、地上部生物量、光合机构活性以及抗氧化酶活性等指标。结果表明：(1)外源喷施褪黑素能有效缓解干旱胁迫诱导的玉米生长发育抑制,同时显著提高干旱胁迫下玉米叶片光系统(PSⅡ和PSⅠ)有效量子产量［Y(Ⅱ)和Y(Ⅰ)］,并降低干旱胁迫下叶片PSⅠ 受体侧和供体侧限制引起的非光化学能量耗散的量子产量Y(ND)和Y(NA)。(2)喷施外源褪黑素显著增强了干旱胁迫玉米植株叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)及谷胱甘肽还原酶(GR)活性,显著降低了其丙二醛(MDA)和过氧化氢(H₂O₂)含量;同时外源褪黑激素也显著上调了其相应抗氧化酶活性相关基因的表达量。(3)复水后,干旱胁迫下经褪黑素处理的玉米植株叶片上述各参数恢复速度较单独干旱胁迫处理植株更快。研究认为,叶面喷施褪黑素有效缓解了干旱胁迫对玉米叶片的光合机构的损伤,增强了叶片抗氧化酶活性及相关基因的表达,显著降低了膜脂过氧化伤害程度,且复水后显著促进叶片生理功能的恢复,表明外源褪黑素可通过改善干旱及复水下玉米叶片光合效率和抗氧化能力,从而促进植株生长以适应干旱多变的环境。     

外源褪黑素对干旱胁迫下牡丹幼苗生理特性的影响

为探究褪黑素(Melatonine,MT)对牡丹幼苗抗旱性的影响及生理机制,以牡丹品种凤丹(Paeonia ostii Fengdan)幼苗为试材,研究不同浓度外源褪黑素(50、100和200 μmol/L)对干旱胁迫下牡丹幼苗生长及生理特性的影响。结果表明,干旱胁迫严重限制了牡丹幼苗的生长和光合作用,叶片细胞脂质过氧化及伤害指数增加,引起氧化应激及渗透调节反应。经外源褪黑素预处理能够减轻干旱胁迫对牡丹幼苗的伤害,具体表现为根系、茎叶及总干物质量提高;减少叶绿素a、叶绿素b及类胡萝卜素等光合色素降解,改善光合作用及PSⅡ电子传输能力;降低丙二醛(MDA)、过氧化氢(H_2O_2)、超氧阴离子(O_2~-)含量及细胞膜质伤害指数(MII),提高超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)及谷胱甘肽还原酶(GR)等抗氧化酶活性减少脂质过氧化;促进渗透调节物质积累。总之,以100 μmol/L MT处理对牡丹幼苗抗旱性提高效果最好。外源褪黑素预处理能提高干旱胁迫下牡丹幼苗光合荧光特性、抗氧化和渗透调节能力,促进干旱胁迫下牡丹幼苗生长。     

褪黑素对玉米幼苗根系发育和抗旱性的影响

褪黑素是一种在生物体内广泛存在的吲哚胺类化合物,参与植物的多种生理和生化过程。近年来研究认为褪黑素可以不同程度地增强植物的抗逆性,但对其作用机理仍知之甚少。通过两种褪黑素的施用方法,详细研究了褪黑素对于玉米根系发育和抗旱性的影响。首先,采用水培根灌褪黑素的方法对玉米幼苗的根系和生长状况进行分析,结果表明施加褪黑素显著提高多种玉米幼苗根系参数,包括根长、根表面积、根体积和侧根数目等。其次,采用盆栽浸种褪黑素的方法,对叶片相对含水量、光合作用、抗氧化酶活性、地上部分生物量等进行测定,结果表明在干旱胁迫条件下,褪黑素浸泡种子的处理方式能够提高植株的光合速率、气孔导度和蒸腾速率,增强抗氧化酶活性以及降低活性氧和丙二醛含量,证明褪黑素促进植物根系发育,减轻氧化损伤,缓解光合抑制,改善植物水分状况,从而提高植物抗旱性。     

花后干旱对冬小麦光合、抗氧化特性和C4光合酶活性的影响

干旱是限制小麦增产最主要的非生物胁迫之一。为探究不同抗旱性冬小麦品种对花后干旱的响应,本试验以干旱敏感型品种“京冬18”和抗旱型品种“农大211”为材料,调查了花后干旱及复水后冬小麦的旗叶光合特性、丙二醛含量、抗氧化酶活性、渗透调节物质含量以及各器官C4光合酶活性的变化。结果表明：花后干旱显著降低了“京冬18”的千粒重,而对“农大211”的千粒重无显著影响;与“京冬18”相比,“农大211”在干旱胁迫下叶片的SPAD值和净光合速率相对较高,F_v/F_m值相对稳定,丙二醛含量的增幅相对较小,SOD和POD活性及可溶性蛋白和脯氨酸含量的增幅相对较大;穗部(颖壳和籽粒)C4光合酶(PEPC、NADP-ME和PPDK)活性高于旗叶,且在干旱胁迫下被诱导增强;复水后,各项指标得到不同程度的恢复;相关分析表明,花后干旱下穗部C4光合酶活性增幅与旗叶脯氨酸含量及抗氧化酶活性增幅呈显著正相关。综上,花后干旱胁迫降低了小麦旗叶光合能力,加速了膜脂过氧化和叶绿素降解,最终影响到籽粒产量;抗旱性较强的品种在干旱胁迫下通过增强穗部C4光合酶活性、旗叶渗透调节及抗氧化能...     

外源褪黑素对干旱胁迫下大豆结荚期光合及生理的影响

以"绥农26"为供试大豆品种,采用盆栽方式,研究外施100μmol·L~(-1)褪黑素对干旱胁迫下大豆结荚期光合及生理的影响。结果表明:与正常供水相比,随时间延长,干旱胁迫处理大豆植株生长受到抑制,结荚数量减少,并最终造成产量降低,光合作用和叶绿素荧光不断降低,抗氧化酶活性和渗透调节物质则呈先上升后下降趋势,而膜脂过氧化水平则不断升高;外源褪黑素提高了干旱胁迫下大豆结荚期地上部和地下部鲜干重、株高、叶面积和结荚数量并提高产量,缓解光合及叶绿素荧光下降,增加大豆叶片抗氧化酶(SOD、POD、CAT、APX)活性和渗透调节物质(可溶性糖、可溶性蛋白、脯氨酸)含量,调节膜脂过氧化平衡(MDA、H2O2和相对电导率);褪黑素处理提高了干旱胁迫下大豆叶片Pn、Tr、Gs,分别提高14.1%～30. 0%、7. 3%～19. 6%、12. 4%～20. 3%,Fv/Fo、Fv/Fm、ΦPSⅡ和ETR分别提高3.5%～15.5%、5.4%～9.4%、2.6%～5.9%、3.0～18.2%;褪黑素处理籽粒鲜重、籽粒干重、籽粒数量、结荚数量和株高较干旱胁迫处理分别提高37.5%～51.4%、35.2%～150.0%、23.4%～42.1%、6.6%～28.7%、2.6%～9.6%,褪黑素处理单株荚数、单株粒数、单株粒重和百粒重较干旱胁迫处理分别提高8.6%、7.1%、10.5%和6.5%。综上所述,外源褪黑素可以提高干旱胁迫条件下光合和抗氧化酶活性并能缓解生长抑制,增强了大豆抵御干旱的能力并提高其产量。     

外源褪黑素对干旱胁迫下黑麦草和苜蓿抗氧化能力及养分吸收的影响

以黑麦草和苜蓿为对象,分别叶面喷施和根施100 μmol·L^-1的褪黑素溶液,在干旱胁迫下测定了生物量、丙二醛(MDA)含量、相对电导率、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性、养分含量(有机碳C、全氮N、全磷P)等指标,研究外源褪黑素对干旱胁迫下植物抗氧化能力及养分吸收的影响。结果表明: 干旱胁迫下,黑麦草和苜蓿的地上、地下生物量显著降低,外施褪黑素能够有效缓解干旱胁迫对黑麦草和苜蓿生长的抑制作用,叶面喷施和根施褪黑素使干旱胁迫下黑麦草的生物量分别增加14.5%和29.6%,苜蓿的生物量分别增加36.6%和49.1%。干旱胁迫下,黑麦草的SOD、POD活性和苜蓿的SOD活性显著降低,外施褪黑素显著提高黑麦草和苜蓿的SOD、POD、CAT活性,减少叶片中MDA的积累,使叶片相对电导率显著下降,抗氧化能力显著提高。干旱和外施褪黑素对黑麦草和苜蓿有机碳含量无显著影响。干旱胁迫下,黑麦草叶片和根中的N、P含量以及苜蓿根中的N含量降低,外施褪黑素提高黑麦草和苜蓿根和叶片中的N、P含量,这表明褪黑素对干旱胁迫下黑麦草和苜蓿的养分吸收有一定的调节作用。施用褪黑素不仅能改善植物的抗氧化能力,还能调节养分吸收以增强植物对干旱胁迫的适应性,而且叶面喷施褪黑素效果好于根施。     

干旱下接种根际促生细菌对苹果实生苗光合和生理生态特性的影响

本试验研究了接种根际促生细菌(PGPR)对干旱条件下植物光合和生理生态特性的影响,以期为PGPR在植物抗旱中的应用提供理论依据.采用盆栽试验,以苹果实生幼苗为供试植物,以经过筛选得到的既具有1-氨基环丙烷-1-羧酸(ACC)脱氨酶活性又具有较强溶磷能力的根际促生菌YX₂为供试菌株,设置正常水分(CK)、轻度干旱(LD)、中度干旱(MD)和重度干旱(SD),其相应含水量分别为田间持水量的70%～80%、55%～65%、40%～50%、25%～35%,研究不同程度干旱胁迫条件下接种YX₂对苹果实生幼苗光合和生理生态特性的影响.结果表明: 与未接种处理相比,干旱环境下接种YX₂提高了苹果幼苗叶片的相对含水量、叶绿素含量、抗氧化酶活性、叶绿素荧光值、气孔导度和光合性能,降低了相对电导率、渗透调节物质和丙二醛的积累,缓解了干旱胁迫对净光合速率的抑制,增强了抗氧化系统的防御能力,减少了细胞膜过氧化伤害,提高了植株抗旱性能.     

干旱对番茄幼苗光合和某些生理指标的影响

干旱缺水已成为植物光合作用和生长发育主要的限制因素,在干旱胁迫下,作物的生长发育受到影响,依据作物的形态变化进行浇灌属于延后性灌溉,未必能完全补偿对作物生长造成的影响。确定灌溉时间点,既确保植物正常生长不受影响,也可以提高水分利用效率,减少水资源浪费,从而达到节水灌溉的目的。该研究以温室土槽栽培番茄幼苗为材料,设定土壤含水量为30.00%(对照)、21.00%、18.00%、15.00%、12.00%、9.00%,研究了干旱胁迫对番茄叶片光合特性、抗氧化酶(超氧化物歧化酶、过氧化物酶、过氧化氢酶)、碳酸酐酶活性变化的影响,并以此表征番茄幼苗需水信息。结果表明:随着干旱胁迫程度的增加,叶片水势逐渐降低。超氧化物歧化酶、过氧化物酶及过氧化氢酶等抗氧化酶在番茄幼苗耐受水分胁迫中起到重要的作用;超氧化物歧化酶、过氧化物酶在干旱胁迫条件下反应更迅速,但过氧化氢酶相对于超氧化物歧化酶、过氧化物酶对干旱胁迫的耐受能力更强;干旱胁迫条件下抗氧化酶活性的转折点在15.00%土壤含水量左右;水分胁迫条件下碳酸酐酶参与了对光合作用的调节,并在15.00%土壤含水量时活性升至最高,使得番茄仍能维持较高的光合速率,以维持正常的生理机能;随着干旱胁迫程度的加剧(12.00%土壤含水量),碳酸酐酶活性与净光合速率都迅速下降。综上分析,当土壤含水量低于15.00%并高于12.00%时,对作物进行灌溉最为合适。抗氧化酶及碳酸酐酶活性可为作物最佳灌溉时间点的预测提供科学依据。     

干旱胁迫及复水对红松针叶和树皮绿色组织光合特性及抗氧化系统的影响

以红松为材料,研究了干旱及复水对红松针叶和树皮绿色组织的光合特性和抗氧化酶活性等生理生化指标的影响。结果表明:干旱胁迫下,红松针叶和树皮绿色组织叶绿素总量和叶绿素a/b值均有显著下降,这样可以通过降低PSII天线捕获的光能,减少发生光抑制的危险;针叶净光合速率(Pn)下降主要由非气孔因素造成,树皮绿色组织Pn下降主要由气孔因素造成;红松针叶和树皮绿色组织非光化学猝灭(NPQ)均升高,表明热耗散是植株重要光保护机制;红松针叶和树皮绿色组织丙二醛(MDA)含量明显升高,发生了氧化胁迫,超氧化物歧化酶(SOD)等抗氧化酶活性的提高对红松的干旱胁迫起到了积极的防御作用;复水后,红松针叶和树皮绿色组织Pn恢复到对照水平,叶绿素荧光参数和抗氧化酶活性也表现出不同程度恢复。以上研究结果表明,干旱胁迫下红松针叶和树皮绿色组织均通过减少光捕获、热耗散和酶活性调节协同作用,稳定光合机构功能,复水后红松光合特性表现较好的恢复能力,红松对干旱具有较强的适应能力。     

接种菌根真菌对青冈栎幼苗耐旱性的影响

利用丛枝菌根真菌摩西球囊霉(Glomus mosseae)、根内球囊霉(Glomus intraradices)和外生菌根真菌彩色豆马勃(Pisolithus tinctorius)对石漠化地区造林树种青冈栎(Cyclobalanopsis glauca)幼苗进行接种试验。在大棚盆栽条件下模拟土壤干旱胁迫,研究菌根真菌对青冈栎生长和耐旱性的影响。结果表明:在土壤干旱条件下,接种菌根处理植株生物量显著高于未接种处理(P0.05),菌根依赖性随土壤水分含量降低而升高;未接种处理植株叶绿素含量在土壤干旱条件下显著降低(P0.05),除接种Pisolithus tinctorius处理外,其它接种处理叶绿素含量无显著变化。土壤干旱使植株体内脯氨酸和可溶性糖含量上升,在中度干旱条件下,接种处理可溶性糖含量均显著高于对照处理,接种Glomus intraradices、Pisolithus tinctorius处理脯氨酸含量显著低于对照(P0.05);在重度干旱条件下,接种Glomus mosseae和Glomus intraradices处理可溶性糖含量显著高于对照处理(P0.05),而相应的脯氨酸含量显著低于对照处理。当土壤水分含量在田间持水量55%—65%时,接种处理植株SOD、POD和CAT酶活性显著高于未接种处理(P0.05),在土壤水分含量降至35%—45%时,Glomus mosseae和Glomus intraradices处理SOD酶活性显著高于对照,并且所有接种处理POD酶活性均显著高于对照。此外,在水分干旱条件下,植株全磷和全钾含量也显著高于未接种处理(P0.05)。研究表明,丛枝菌根真菌和外生菌根真菌均能够侵染青冈栎幼苗根系;在干旱胁迫条件下,接种菌根真菌能够提高青冈栎植株生物量、抗氧化酶活性、增加植株可溶性糖含量和促进植株养分吸收,提高植株耐旱性,从而使青冈栎幼苗在岩溶干旱环境下更容易存活。     

干旱胁迫对蒙古柞表观资源利用率的影响

比较研究了模拟干旱及自然水分梯度条件下蒙古柞树种光合生理指标,模拟干旱处理试验土壤含水量分别控制在田间持水量的85％－100％（CK）、65％－85％（MEW）和45％－65％（LW）。结果表明,干旱胁迫对蒙古柞幼树净光合速率、气孔导度、蒸腾速率、水分利用率、表观CO2利用率和表观光能利用率等生理指标均产生明显影响。野外自然条件下水分梯度对蒙古柞大树气孔导度、水分利用率和净光合速率有显著影响,但对蒸腾速率、表观CO2利用率和表观光能利用率的影响不显著,中等水分条件可明显提高蒙古柞大树叶片的气体交换和水分利用率,说明蒙古柞树种叶片气体交换和表观资源利用率对干旱胁迫的响应程度不同。蒙古柞树种是干旱可变植物,长期水分胁迫可提高树种的耐旱能力,特别是中等水分胁迫能保持蒙古柞固有的强劲耐旱能力。     

Physiological Evaluation of Drought Stress Tolerance and Recovery in Cauliflower (Brassica oleracea L.) Seedlings Treated with Methyl Jasmonate and Coronatine

Coronatine (COR) is a chlorosis-inducing phytotoxin that mimics some biological activities of methyl jasmonate (MeJA). Although MeJA has been reported to alleviate drought stress, it is unclear if COR has the same ability. Our objective was to determine the influence of exogenously applied MeJA and COR on the growth and metabolism of cauliflower seedlings under drought stress and recovery. Both MeJA and COR enhanced the growth and accumulation of dry matter in cauliflower seedlings during drought-stressed and rewatering conditions. Treatment with MeJA or COR enhanced tolerance of drought stress through increased accumulation of chlorophyll and net photosynthetic rate. Enzymatic (superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, and glutathione reductase) and nonenzymatic antioxidant (proline and soluble sugar) systems were activated, and lipid peroxidant (malondialdehyde and hydrogen peroxide) was suppressed by MeJA and COR under drought stress. MeJA and COR also increased leaf relative water content and endogenous abscisic acid level under drought-stressed conditions. After rewatering, the contents of leaf water, chlorophyll, abscisic acid, and photosynthetic characteristics as well as enzymatic and nonenzymatic antioxidant systems showed nearly complete recovery. Both MeJA and COR can alleviate the adverse effects of drought stress and enhance the ability for water stress resistance through promotion of defense-related metabolism in cauliflower seedlings.     

Response to drought of Zn-stressed Quercus suber L. seedlings

Zinc is an essential nutrient for higher plants but it becomes toxic as its availability increases. In nature, different stress factors commonly occur concurrently, challenging our ability to predict their impacts. Information on zinc (Zn) effect on plant ability to withstand other sources of stress is scarce. This study examines the effect of zinc supply rate on the response of Quercus suber L. seedlings to water stress. Seedlings were treated with four levels of zinc from 3 to 150 μM, and then exposed to a short severe drought. Zinc concentration in leaves and roots increased with zinc availability. Maximum photosynthetic rate, photochemical efficiency, root length and specific root length decreased as Zn availability increased. The decrease was particularly intense between 50 and 150 μM Zn. The relative effects of drought were less intense in seedlings receiving higher doses of Zn than in those receiving 3 μM. Thus, at severe drought, relative water content of detached leaves decreased to 52% in seedlings receiving the lowest level of Zn. In contrast, relative water content remained above 70% in seedlings exposed to high concentrations of this metal. The pattern was similar for photosynthetic rate and stomatal conductance, as the decrease in these variables resulting from severe drought was 100% and 90% in seedlings receiving 3 μM and 65% and 56% in seedlings receiving the highest Zn dose. Our results suggest that morpho-physiological responses to zinc may foster water conservation strategies and alleviate the effects of drought in the short term, but they may impair seedling ability to root and grow in a longer term.     

苗圃氮加载及水分胁迫对栓皮栎苗木叶片光合氮分配及生物量积累的影响

苗圃科学施氮(N)作为提高苗木N贮存水平与质量的核心手段,能否提高干旱立地苗木造林效果仍存在争议;N贮存水平与干旱如何协同作用影响叶片光合N分配及苗木生物量积累尚不明确。阐明上述问题,能够为干旱立地下的森林植被恢复以及造林苗木科学精准施N提供科学依据。选择栓皮栎(Quercus variabilis Blume)为研究对象,对一年生苗木设置2个苗圃木质化期N加载水平(0、24 mg N/株),翌年春苗木移栽后设置2个灌溉水平(85%、40%田间持水量),取样测定苗木生物量、叶片N、叶绿素与脯氨酸水平、以及气体交换参数,计算光合N分配及光合N利用效率(PNUE)。结果表明,叶片发育完成后,干旱抑制N向光合系统分配,但N加载处理提高了干旱下的光合N含量,从而在一定程度上抵消干旱对生物量积累的抑制;无N加载苗木则向光合系统投入更少的N,而提高脯氨酸水平,生物量积累受抑制更为显著。无N加载苗木在遭受干旱后将N向羧化组分分配,而N加载苗木遭遇干旱后则显著抑制叶片将N向羧化系统以及电子传递系统分配,捕光组分N的分配则不受植物体内N贮存或外部水分状况的影响,栓皮栎苗木通过调整不同功能组分光合N含量和...     

Drought and shade deplete nonstructural carbohydrate reserves in seedlings of five temperate tree species

Plants that store nonstructural carbohydrates (NSC) may rely on carbon reserves to survive carbon‐limiting stress, assuming that reserves can be mobilized. We asked whether carbon reserves decrease in resource stressed seedlings, and if NSC allocation is related to species' relative stress tolerances. We tested the effects of stress (shade, drought, and defoliation) on NSC in seedlings of five temperate tree species (Acer rubrum Marsh., Betula papyrifera Marsh., Fraxinus americana L., Quercus rubra L., and Quercus velutina Lam.). In a greenhouse experiment, seedlings were subjected to combinations of shade, drought, and defoliation. We harvested seedlings over 32–97 days and measured biomass and NSC concentrations in stems and roots to estimate depletion rates. For all species and treatments, except for defoliation, seedling growth and NSC accumulation ceased. Shade and drought combined caused total NSC decreases in all species. For shade or drought alone, only some species experienced decreases. Starch followed similar patterns as total NSC, but soluble sugars increased under drought for drought‐tolerant species. These results provide evidence that species deplete stored carbon in response to carbon limiting stress and that species differences in NSC response may be important for understanding carbon depletion as a buffer against shade‐ and drought‐induced mortality.     

Melatonin Promotes Rice Seed Germination under Drought Stress by Regulating Antioxidant Capacity

Drought stress is a serious threat to the germination of plant seeds and the growth of seedlings. Melatonin has been proven to play an important role in alleviating plant stress. However, its effect on seed germination under drought conditions is still poorly understood. Therefore, we studied the effects of melatonin on rice seed germination and physiological characteristics under drought stress. Rice seeds were treated with different concentrations of melatonin (i.e., 0, 20, 100, and 500 μM) and drought stress was simulated with 5% polyethylene glycol 6000 (PEG6000). The results showed that 100 μM melatonin can effectively improve the germination potential, rate and index; the vigor index of rice seeds; and the length of the shoot and root. In addition, that treatment also increased the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and reduced the content of malondialdehyde (MDA). The grey relational grade between the shoot MDA content and the melatonin seed-soaking treatment was the highest, which could be useful for evaluating the effect of melatonin on drought tolerance. Two-way analysis of variance showed that the effect of single melatonin treatment on rice seeds was more significant than that of single drought stress and interaction treatment of drought and melatonin (p < 0.05). The subordinate function results showed that 100 μM melatonin significantly improved the germination and physiological indexes of rice seeds and effectively alleviated the adverse effects of drought stress on rice seedlings. The results helped to improve the understanding of the morphological and physiological involvement of melatonin in promoting seed germination and seedling development under drought stress.     

Differential physiological and biochemical responses of Quercus infectoria and Q. libani to drought and charcoal disease

The vast oak-dominated forests of the Zagros Mountains in southwestern Iran currently undergo large-scale dieback driven by a combination of drought and increasing incidence of charcoal disease caused by the fungal pathogens Biscogniauxia mediterranea and Obolarina persica. Here, we explore the interactive effects between drought and charcoal disease agents on the physiology and biochemistry of Quercus infectoria and Quercus libani seedlings. The combination of pathogen attack and water limitation hampered plant development, especially in Q. libani seedlings, negatively affecting growth, biomass production, photosynthetic efficiency, and leaf water potential. An increase in markers of oxidative damage together with the upregulation of the antioxidant defense revealed that drought stress and pathogen infection led to pro-oxidative conditions in both oak species, especially in Q. libani, where larger changes in malondialdehyde and hydrogen peroxide occurred. The upregulation of the antioxidant system was more prominent in Q. infectoria than in Q. libani, resulting in enhanced enzyme activity and accumulation of non-enzymatic antioxidants. Fungal infection stimulated the activity of chitinase, phenylalanine ammonia lyase and β-1,3-glucanase in Q. infectoria leaves and this response became more pronounced under water shortage. Our study highlights that drought stress greatly intensifies the effects of the charcoal disease. Moreover, our findings imply superior stress resistance of Q. infectoria conferred by a highly efficient antioxidant system, strong osmotic adjustment (through proline), and increases in resistance enzymes and secondary metabolites (phenols and flavonoids). Future investigations should focus on adult trees in their natural habitat including interactions with soil factors and other pathogens like nematodes, bacteria and other fungi. Because the present research was conducted on oak seedlings, the findings can be considered by forest nursery managers.