贝莱斯芽孢杆菌BG-2对厚皮甜瓜贮藏品质及防御酶活性的影响

【背景】厚皮甜瓜白霉病主要由尖孢镰刀菌引起,严重影响厚皮甜瓜品质,从而造成经济损失。【目的】研究贝莱斯芽孢杆菌BG-2对尖孢镰刀菌的抑制作用,以及对采后厚皮甜瓜贮藏品质的影响。【方法】以贝莱斯芽孢杆菌为供试菌株,研究其对2种不同贮藏温度（25℃和4℃）下厚皮甜瓜果实腐烂率、失重率、果肉硬度、可滴定酸、可溶性固形物含量和维生素C含量的影响,同时测定过氧化氢酶（catalase,CAT）、过氧化物酶（peroxidase,POD）和超氧化物歧化酶（superoxide dismutase,SOD）防御酶活性,进而探究Bacillus velezensis BG-2对尖孢镰刀菌的抑制作用及对厚皮甜瓜贮藏品质的影响。【结果】贝莱斯芽孢杆菌BG-2菌悬液能有效抑制尖孢镰刀菌的生长,菌悬液浓度为1×10⁷ CFU/mL时抑菌圈直径为（20.45±0.39） mm,抑菌效价为144.48 mm/mL;同时,B. velezensis BG-2能有效减缓果肉硬度、维生素C含量、可溶性固形物含量和可滴定酸的下降,抑制果实失重和腐烂,能较好地保持果实的品质,抑制防御酶活性的下降。【结论】B. velezensis BG-2能显著抑制尖孢镰刀菌的生长,延缓厚皮甜瓜的后熟,维持采后甜瓜果实较高的品质和防御酶活性,对甜瓜腐烂有较好的防治效果。     

尖孢镰刀菌致病机理和化感作用研究进展

尖孢镰刀菌引起的枯萎病在生产中的防控相当困难。通过总结国内外相关文献,综述近年来有关尖孢镰刀菌致病机理和化感作用的研究进展。尖孢镰刀菌通过分泌毒素和细胞壁降解酶共同致病,谱系特异性区域的存在是其致病性强和宿主范围广的主要原因;在尖孢镰刀菌各专化型中已分离出大量致病相关基因;其他植物和拮抗微生物(木霉菌、丛枝菌根真菌、非致病性尖孢镰刀菌以及植物生长促生菌)可以分泌化感物质,作用于宿主植物和尖孢镰刀菌,直接抑制尖孢镰刀菌的生长或激活宿主植物的防御反应。未来有关尖孢镰刀菌致病机理研究应该在基因组测序基础上构建精细的遗传图谱;对化感作用的研究应当深入探讨分子机理,利用高通量测序等技术在转录组或蛋白组水平上明确宿主植物抗枯萎病相关基因,同时利用分子标记辅助育种来筛选新的抗枯萎病品种。     

链格孢菌毒素对紫茎泽兰的致病机理

以叶圆片法分析链格孢菌[Alternaria alternata(Fr.)Keissler]毒素对紫茎泽兰（Eupatorium adenophorum Spreng.)叶组织细胞膜透性、过氧化物酶（POD）、抗坏血酸过氧化物酶（APX）和过氧化氢酶（CAT）活性以及丙二醛（MDA）含量的影响,结果表明,链格孢菌毒素使紫茎泽兰叶组织细胞膜透性上升,Na^ 和K^ 渗漏量增加,膜脂过氧化加强,MDA含量上升;链格孢菌毒素处理的紫茎泽兰叶片中POD、APX和CAT的活性均较对照降低。     

月腺大戟根总黄酮对尖孢镰刀菌抑制作用的研究

采用生长速率法和孢子萌发法分别测定月腺大戟根总黄酮对尖孢镰刀菌菌丝生长和分生孢子萌发的抑制率,显微观察总黄酮处理尖孢镰刀菌后菌丝体形态结构的变化,并测定菌丝体相对电导率,菌丝体内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性。结果表明:月腺大戟根总黄酮对尖孢镰刀菌菌丝生长和分生孢子萌发均有显著的抑制作用,抑制率随总黄酮浓度增加而增高,20 mg/L时抑制率达100%。总黄酮处理后的尖孢镰刀菌菌丝较细,分支减少,透明度差,液泡数量增多且形成较大的液泡;菌丝体细胞膜透性增加,SOD、CAT活性呈先上升后下降的趋势。以上实验结果可为植物病害生物防治及开发植物源农药方面提供理论依据和实验技术。     

我国部分地区蔬菜镰孢菌的分离及鉴定

对采自我国6省18市（县）的蔬菜根茎样本进行了组织分离和形态学鉴定,共鉴定出镰孢菌10个种.其中尖镰孢（Fusarium oxysporum）为优势茵,占镰孢菌总量的73.42％,其他种类的镰孢菌为锐顶镰孢(F.acuminatum)、弯角镰孢（F.camptoceras）、蓝色镰孢（F.coeruleunm）、木贼镰...     

独蒜兰提取物对植物病原真菌的抑菌活性

【目的】研究独蒜兰假鳞茎乙醇提取物对植物病原真菌的抑菌作用,为植物源杀菌剂的开发提供依据。【方法】采用菌丝生长速率法,研究独蒜兰假鳞茎乙醇提取物对15种植物病原菌的抑制活性;以西瓜尖孢镰刀菌作为供试菌,进一步研究该提取物对病原真菌的菌丝干重、细胞膜、过氧化氢酶（CAT）、过氧化物酶（POD）和超氧化物歧化酶（SOD）等的影响。【结果】独蒜兰假鳞茎提取物对辣椒疫霉病菌、西瓜尖孢镰刀菌、番茄灰霉病菌和非洲隐地疫霉菌的抑菌效果明显,其EC₅₀值分别为0.849、0.782、0.813和1.161 mg·mL^-1;经独蒜兰提取物处理后的西瓜尖孢镰刀菌菌丝干重随着药剂浓度的增加而减少;细胞膜丙二醛含量和相对电导率增加;菌丝体细胞内CAT、POD和SOD 3种保护酶活性增加。【结论】独蒜兰假鳞茎提取物对植物病原真菌具有较好的抑菌活性,其抑菌作用可能与其干扰菌丝生长、使菌丝细胞膜正常功能受损等有关。     

甘肃大葱贮藏期镰孢菌腐烂病病原鉴定

【目的】大葱在贮藏期频繁发生镰孢菌腐烂病,损失严重。明确该病害病原种类对病害防治具有重要意义。【方法】利用组织分离法对采集自甘肃省兰州市(区)蔬菜市场的16份大葱贮藏期镰孢菌腐烂病病样进行病原物的分离、纯化培养,经单孢分离后根据形态学特征,再结合r DNA-ITS、EF-1a(tef)基因序列分析的方法进行鉴定。【结果】共分离得到80株镰孢菌,经鉴定分属3个种,即层出镰孢菌(Fusarium proliferatum)、尖孢镰孢菌(F.oxysporum)和燕麦镰孢菌(F.avenaceum),其中层出镰孢菌为大葱镰孢菌腐烂病的优势致病菌,分离频率为52.50%。对兰州白葱不同部位进行致病性测定,结果表明层出镰孢菌对大葱鳞茎的致病力最强,而燕麦镰孢菌对大葱鳞茎的致病力最弱。【结论】3种镰孢菌作为该病害的病原,属国内首次报道。     

岷江百合WRKY转录因子基因的克隆与功能分析

WRKY转录因子家族在植物应对非生物和生物胁迫的防卫反应中起重要作用。岷江百合(Lilium regale Wilson)是高抗枯萎病的野生百合,该研究基于前期转录组测序分析,采用RT PCR方法从岷江百合中克隆得到WRKY转录因子基因LrWRKY4并分析其功能,以探讨岷江百合对枯萎病菌尖孢镰刀菌(Fusarium oxysporum)侵染的转录调控机制,为进一步研究岷江百合WRKY基因家族的功能奠定基础。结果显示：(1)LrWRKY4开放阅读框为993 bp,编码330个氨基酸,LrWRKY4含有一个高度保守的‘WRKYGQK’七肽序列和一个C₂H₂锌指基序,属于Ⅱc类WRKY转录因子。(2)成功构建GFP LrWRKY4融合载体并通过根癌农杆菌介导转化洋葱表皮细胞,激光共聚焦显微观察发现,GFP LrWRKY4融合蛋白表达的绿色荧光特异性地分布在洋葱表皮细胞的细胞核中。(3)成功构建了过表达载体pCAMBIA2300s LrWRKY4并转化烟草,得到11个T₂代转基因烟草株系,且转LrWRKY4基因烟草与野生型烟草(WT)在表型上无明显差异;尖孢镰刀菌接种根部和叶片的实验结果显示,转LrWRKY4基因烟草对尖孢镰刀菌的抗性较WT明显增强;qRT PCR分析显示,岷江百合LrWRKY4基因在11个转基因烟草株系中均有表达,且转基因烟草中JA/SA信号途径相关基因的表达上调,并诱导了部分病程蛋白相关基因以及抗氧化相关基因的表达上调。(4)岷江百合鳞片浸染LrWRKY4 RNAi载体后的腐烂程度和病变面积均远大于RNAi空载转化的鳞片;瞬时表达LrWRKY4 RNAi载体的岷江百合鳞片中LrWRKY4基因的表达水平较对照下降了约45.7%,接种尖孢镰刀菌72 h后表达水平下降了93.8%;瞬时表达LrWRKY4 RNAi后,一些JA/SA信号途径相关基因的表达水平明显下降。研究表明,岷江百合LrWRKY4编码一个定位于植物细胞核的Ⅱc类WRKY转录因子;LrWRKY4基因能够在转基因烟草中稳定表达,且过表达LrWRKY4基因提高了烟草对尖孢镰刀菌的抗性;但瞬时表达LrWRKY4 RNAi降低了岷江百合JA/SA信号途径相关基因的表达并增强了对尖孢镰刀菌的敏感性。推测LrWRKY4基因是岷江百合抗尖孢镰刀菌防卫反应中的正调控因子,可能通过参与JA/SA介导的信号传导途径,诱导防卫相关基因的表达从而调节其对尖孢镰刀菌的抗性。     

采用EF-1α序列及气生菌丝上的孢子形态特征对九州镰孢菌、拟枝孢镰孢菌和厚垣镰孢菌的鉴定

对九州镰孢菌Fusarium kyushuense、厚垣镰孢菌F. chlamydosporum 和拟枝孢镰孢菌F. sporotrichioides在气生菌丝上产生的孢子进行了比较。九州镰孢菌在气生菌丝上产生多隔孢子（即中型分生孢子）;厚垣镰孢菌在气生菌丝上产生的主要是0隔针叶状分生孢子;拟枝孢镰孢菌在气生菌丝上产生两种类型的分生孢子：芜菁形、单胞分生孢子以及椭圆形、0－1隔的分生孢子。多隔的气生孢子（中型分生孢子）在厚垣镰孢菌和拟枝孢镰孢菌这两个种中偶尔可以观察到,但是不应作为对这两个种进行鉴定的主要     

尖孢镰刀菌FoHeli转座元件的结构特征及功能验证

Helitron是一种广泛存在于真核生物中的可移动遗传元件。与其他转座子不同,自主Helitron元件可编码具有复制引发（Rep）和解旋酶（Hel）结构域的转座酶,并通过滚环复制的方式在基因组中进行扩张。本研究对9种尖孢镰刀菌中的自主Helitron元件进行系统分析,结果表明尖孢镰刀菌中存在两类自主Helitron元件FoHeli1与FoHeli2。其中FoHeli1成员间序列高度相似,并具有明晰的边界特征：3’端为保守的“TATTTT”序列,其上游可形成稳定的发夹结构,且发夹上游可与5’端形成12bp的反向互补结构。基于上述分析结果,从尖孢镰刀菌Fo4287菌株中克隆获得完整的FoHeli1元件,并通过构建双元转座系统及PEG介导的原生质体转化,证明尖孢镰刀菌中的FoHeli元件可在禾谷镰刀菌PH-1菌株的基因组中发生跳转。     

大豆内生细菌的分离及根腐病拮抗菌的筛选鉴定

内生细菌存在于健康植物体内,一些内生细菌具有促生长、抗病和固氮等生物学功能.本项研究采用化学药剂表面灭菌方法从黑龙江省大豆品种合丰25的根、茎、叶和种子中分离到大量内生细菌,其种群数量在根部最多,为3.4×103CFU/g,在叶部次之,为2.8×103CFU/g,在茎部和种子中最少,为2.9×102 CFU/g和1.4×102CFU/g.从121株内生细菌中筛选到31株对大豆根腐病菌Fusarium oxysporum f. sp.soybean具有较强抑制作用的拮抗内生细菌,其中菌株TF28抑菌谱广,抑菌率高,对不同植物的病原菌F. oxysporum的抑菌率为80.2%～96.7%.经形态、生理生化和16S rRNA鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens).     

一株溶藻细菌对海洋原甲藻的溶藻效应

从深圳大鹏湾南澳赤潮爆发海域的表层海水中分离得到1株对海洋原甲藻(Prorocentrum micans)具有溶藻活性的海洋细菌,菌株编号为N10。利用液相感染法研究了该溶藻细菌的溶藻效果和溶藻作用方式。结果表明,菌株N10能使藻细胞失去运动活性,并膨胀变形,细胞膜内物质聚集于一端,藻细胞最终破裂死亡。菌悬液接种到藻液中的量越大,初始细菌密度越高,其溶藻效果越强。菌悬液以1∶10的体积比接种到藻液中时,藻细胞在24 h的死亡率为83%,至72 h全部溶解死亡;体积比为1∶20的藻细胞在24 h的死亡率为71%,之后藻细胞密度略有波动,120 h时死亡率达77%;而体积比为1∶100的藻细胞密度在前24 h有所下降,死亡率达39%,之后藻细胞密度又开始明显上升;对照组的藻细胞密度均呈明显上升趋势。菌悬液过滤液和高温加热处理后的菌悬液过滤液对海洋原甲藻均无溶藻活性,表明菌株N10的溶藻方式为直接溶藻。通过16S rRNA序列分析并与GenBank数据进行同源性检索,并结合细菌形态及生理生化特征,菌株N10隶属于黄杆菌科(Flavobacteriaceae)中的Muricauda sp.。     

Field evaluation of different application methods of the mixture of Bacillus cereus strain AR156 and Bacillus subtilis strain SM21 on pepper growth and disease resistance

The mixture of Bacillus subtilis strain SM21 and Bacillus cereus strain AR156, referred to as ASB, is a biopesticide in the process of registration in China, which has the capacity of controlling root-knot nematode in cucumber, Phytophthora wilt in pepper and Ralstonia wilt in tomato. In this study, we tested its effects on a range of physiological indicators of plant growth including biomass, yield, chlorophyll content and fruit nutrients of pepper, as well as, its efficacy in controlling bacterial wilt caused by Ralstonia solanacearum under field conditions in 2009 and 2010 by a variety of inoculation methods. Three application methods – soaking seeds, drenching soil around seeds right after sowing and drenching the rhizosphere of transplanted seedling with the aqueous solution (as a soil drench) –and three concentrations of ASB (1.0 × 10⁶ CFU/mL, 1.0 × 10⁷ CFU/mL, and 1.0 × 10⁸ CFU/mL) were employed. The results showed that both soaking seeds with ASB at 1.0 × 10⁷ CFU/mL as well as drenching rhizosphere with ASB at 1.0 × 10⁶ CFU/mL and 1.0 × 10⁷ CFU/mL promoted growth, increased yield and fruit nutrient contents of pepper. The combination of these two inoculation methods led to significant increases in growth and fruit nutrient contents. We found that the most effective way was the combination of soaking seeds with the ASB at 1.0 × 10⁷ CFU/mL and drenching rhizosphere with it at 1.0 × 10⁶ CFU/mL, which is also easy for Chinese farmers to implement.     

Antagonistic interactions between fungal pathogens and phylloplane fungi of guava

Dominant phylloplane fungi of guava (Psidium guajava L.) were screened for their antagonistic activities against the two pathogens,Colletotrichum gloeosporioides andPestalotia psidii, bothin vitro andin vivo. Culture filtrates ofAspergillus niger, Fusarium oxysporum andPenicillium citrinum caused more than 50% growth inhibition ofC. gloeosporioides. Filtrates ofCephalosporium roseo-griseum andF. oxysporum were most effective in reducing the growth ofP. psidii. Volatiles produced from the cultures ofA. niger, F. oxysporum, P. citrinum andP. oxalicum inhibited the growth ofC. gloeosporioides, whereas volatiles fromC. roseo-griseum, F. oxysporum andTrichoderma harzianum inhibited the growth ofP. psidii. The inhibitory effect of volatiles decreased with increase in incubation time. In general, the maximum effect of volatiles was noticed after 48 h incubation. Different grades of colony interactions in dual cultures were recognised between the two pathogens and the phylloplane fungi examined. Maximum inhibition ofC. gloeosporioides was caused byAureobasidium pullulans, Cladosporium cladosporioides, epicoccum purpurascens, F. oxysporum andMyrothecium roridum, whereasAspergillus terreus, C. roseo-griseum andP. oxalicum significantly reduced the growth ofP. psidii. Application of a spore suspension of each test fungus inhibited lesion development of guava leaves caused by the test pathogensin vitro. Inhibition was more pronounced when the spore concentration was increased.A. pullulans, C. cladosporioides, E. purpurascens, F. oxysporum, andT. harzianum were found to be strongly antagonistic toC. gloeosporioides. A. niger, A. terreus, C. roseo-grisem andT. harzianum were strongly antagonistic toP. psidii.     

Pseudomonas aeruginosa FARP72 Offers Protection Against Aeromonas hydrophila Infection in Labeo rohita

Use of probiotics as the biocontrol agent for disease prevention in aquaculture is gaining importance as an alternative to the indiscriminate use of antibiotics and other chemotherapeutics. In view of this trend, the probiotic properties of a potent antagonistic bacterium, Pseudomonas aeruginosa FARP₇₂, was characterized in terms of safety, antagonistic activities, in vitro immunomodulation, and in vivo disease resistance. Immunomodulatory activity was ascertained by measuring the production of intracellular superoxide anion, nitric oxide, total leukocyte peroxidase content, and the leukocyte proliferation in head kidney leukocytes. The bacterium isolated from the skin mucus of freshwater catfish Clarias batrachus was harmless to Labeo rohita. It showed inhibitory activity against Aeromonas caviae, A. hydrophila, Edwardsiella tarda, Pseudomonas putida, and Streptococcus agalactiae as revealed by cross and parallel streaking methods. Significantly higher superoxide anion and nitric oxide production, peroxidase content, and proliferative responses of leucocytes delineated the strains’ ability to interact with immune cells to activate the immune system in vitro. Significant growth inhibition of A. hydrophila from 1.55 × 10⁵ CFU/mL was observed when co-cultured with P. aeruginosa FARP₇₂ in phosphate-buffered saline (PBS) at levels ranging from 2.61 × 10⁷ to 2.61 × 10⁹ CFU/mL in 10 days. P. aeruginosa FARP₇₂ increased the survival rate of rohu fingerlings against pathogenic A. hydrophila challenge in biocontrol study in vivo as determined by cohabitation challenge. These results suggest that P. aeruginosa FARP₇₂ is a potential probiotic strain and can be used in aquaculture to improve the health status and disease resistance of fish.

     

花青素对神经退行性疾病保护作用的研究进展

对近年来花青素在神经退行性疾病中的研究进展进行综述,并从抑制氧化应激、缓解神经炎症、缓解兴奋性毒性和抑制蛋白异常聚集等方面对花青素的神经保护作用机制进行探讨,为进一步了解和研究花青素类化合物在神经退行性疾病中的预防作用提供科学依据。     

抗感青枯病番茄的内生细菌数量动态分析及其对青枯病的生物防治

对番茄内生细菌数量动态及其对青枯病的生物防治研究结果表明:番茄内生细菌可来源于种子内部。番茄不同生育期,内生细菌数量最多在成株期,其中抗病品种根、茎分别为24.3×104CFU/g鲜重和22.9×104CFU/g鲜重,感病品种根、茎分别为9.8×104CFU/g鲜重和13.4×104CFU/g鲜重。抗病品种中具有拮抗青枯菌的内生细菌菌株为17个,感病品种中7个。部分内生细菌具促进番茄种子萌发和防治番茄青枯病的作用,其中5R和3R内生菌株的防病效果分别达91.7%和81.3%。     

电解水的抑菌活性及对食品加工表面材料的消毒效果

为了考查应用电解水消除细菌污染的可行性,对氧化电解水的杀菌效果及对食品加工表面材料的消毒效果进行了研究。结果表明,含0.1%NaCl的自来水经7min的电解后所获得的氧化电解水,能在2min内将菌液浓度分别为4.20×106CFU/mL,2.18×106CFU/mL,1.44×106CFU/mL,2.10×106CFU/mL,1.94×106CFU/mL的埃希氏大肠杆菌(Escherichia coliO157:H7)、沙门氏菌(Salmonella enteritidis)、单核细胞增生李斯特菌(Listeria monocytogenes)、摩化摩根菌(Morganella morganii)、副溶血性弧菌(Vibrio parahaemolyticus)几乎全部杀死。另外,对食品加工表面接触材料中的地板砖、不锈钢板、瓷砖进行染菌消毒试验结果表明,含0.1%NaCl的电解水同样能将上述浓度的菌液感染到食品表面接触材料后在5min之内几乎全部将其杀死,是一种理想的食品表面材料消毒剂。     

Endomelanconiopsis microspora发酵产物乙酸乙酯提取物对人参核盘菌的抑制机理

【背景】人参菌核病是人参的主要病害之一,严重影响人参的产量。【目的】探索白花蒲公英内生菌(Endomelanconiopsis microspora)发酵产物乙酸乙酯提取物对人参核盘菌的抑制机理。【方法】采用人参核盘菌菌丝生长和孢子萌发试验测定抑制效果;采用显微镜观察菌丝形态变化,通过电导率和核酸含量的变化测定细胞膜通透性,通过丙二醛(malondialdehyde,MDA)含量和超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)和过氧化氢酶(catalase,CAT)活力的变化测定膜脂过氧化程度。【结果】内生菌E. microspora发酵产物乙酸乙酯提取物能显著抑制人参核盘菌菌丝生长,最小抑菌浓度为3.75 mg/mL,培养6 d后抑制率为76.22%。该提取物能显著抑制人参核盘菌孢子萌发,15.00 mg/mL时抑制效果最好,抑制率达90.69%。提取物影响菌丝形态,增加人参核盘菌细胞膜通透性,造成菌丝内含物外渗,7.50 mg/mL处理10 h后电导率和核酸含量分别比对照组增加30.11%和62.85%。同时提取物显著增加人参核盘菌MDA含量和SOD、POD、CAT活力,7.50 mg/mL处理组呈现先上升后下降的变化趋势,并在12 h时达到最高值。【结论】内生菌E. microspora发酵产物乙酸乙酯提取物通过改变人参核盘菌细胞膜通透性,加剧膜脂过氧化,破坏细胞膜完整性,导致细胞内含物流失,显著抑制孢子萌发和菌丝生长。     

Effect of 24-epibrassinolide on growth, protein content and antioxidative defense system of Brassica juncea L. subjected to cobalt ion toxicity

Brassica juncea L. plants were subjected to cobalt (Co) ion (0, 5?×?10^?4, 10^?3, 1.5?×?10^?3 and 2?×?10^?3?M) toxicity and were sprayed with different concentrations of 24-epibrassinolide (24-EBL) (0, 10^?10, 10^?8 and 10^?6?M) at 15-day stage after sowing. They were sampled at 30 and 60?days after sowing and analyzed for growth parameters in terms of shoot length and number of leaves. Thereafter, leaves were excised and content of proteins and the activities of antioxidative enzymes (superoxide dismutase (SOD) (EC 1.15.1.1) catalase (CAT) (EC 1.11.1.6), ascorbate peroxidase (APOX) (EC 1.11.1.11), guaiacol peroxidase (POD) (EC 1.11.1.7) glutathione reductase (GR) (EC 1.6.4.2), monodehydroascorbate reductase (MDHAR) (EC 1.1.5.4) and dehydroascorbate reductase (DHAR) (EC 1.8.5.1)) were analyzed. The plants exposed to cobalt ion exhibited a significant decline in growth in terms of shoot length and number of leaves. However, foliar spray treatment with 24-EBL was able to alleviate the stress generated by cobalt ion and significantly improved the above parameters. The activities of antioxidative enzymes (SOD, CAT, POD, GR, APOX, MDHAR and DHAR) and protein content were also regulated considerably in leaves of plants treated with 24-EBL alone, 10^?8?M concentration being the most effective. The activities of antioxidative enzymes also increased in leaves of B. juncea plants by the application of cobalt ion to soil and consequently sprayed with 24-EBL. Similarly, the protein content was also regulated in leaves of B. juncea plants treated with 24-EBL as compared to untreated control plants, thereby revealing stress-protective properties of 24-EBL.