周開勝
(1.南京師范大學地理科學學院,江蘇 南京 210023;2.蚌埠學院應(yīng)用化學與環(huán)境工程系,安徽 蚌埠 233030)
西瓜在中國夏季水果中占有十分重要的地位,其種植面積和產(chǎn)量約占世界的1/2 ,隨著西瓜生產(chǎn)的產(chǎn)業(yè)化、規(guī)模化發(fā)展,西瓜專化型尖孢鐮刀菌引起的西瓜枯萎病日漸突出。西瓜枯萎病防治方法,主要有曝曬土壤[6]、嫁接[7]、藥劑熏蒸土壤[7]、高溫悶棚殺菌[8]、深翻改土[9]、與其他作物套作或間作[10]、秸稈反應(yīng)堆技術(shù)[11]、施用生物有機肥[12]、生物制劑[13]、生物防治[14]、加強作物殘余物管理和有機改良[15]等,但均未能有效地抑制西瓜?;图怄哏牭毒?。
21 世紀初在日本[16]和荷蘭[17]分別獨立發(fā)展起來的厭氧還原土壤滅菌法,目前在日本[16,18-26]、荷蘭[17,27-28]、美國[29-32]和意大利[33]得到廣泛運用和發(fā)展,但各國對該方法命名不盡相同。在日本叫生物土壤滅菌法(Biological soil disinfestation,BSD),也稱還原土壤滅菌法(Reductive soil disinfestation,RSD);在荷蘭叫生物土壤滅菌法,也稱厭氧土壤滅菌法(Anaerobic soil disinfestation,ASD);在美國稱之為厭氧土壤滅菌法[19]。厭氧還原土壤滅菌法基本步驟是:在土壤中添加易分解的有機物料(常用有機物料有蕓苔、麥麩、米糠、糖漿等),灌溉淹水,上覆不透氣塑料薄膜,密封3周,創(chuàng)造強還原土壤環(huán)境,達到改良土壤理化性質(zhì)和殺滅土傳植物病原菌目的[16,26]。
本研究采用厭氧還原土壤滅菌法,試圖抑制土壤中西瓜?;图怄哏牭毒?,使得短時間內(nèi)土壤中西瓜專化型尖孢鐮刀菌(FON)數(shù)量下降,從而達到防治西瓜枯萎病的目的。
本研究于2013年3月,在蚌埠市李樓鄉(xiāng)張巷村采集連作10年西瓜土約18 kg,用于土壤處理試驗。稻草和玉米秸稈分別取自蚌埠市李樓鄉(xiāng)張巷村和鳳陽縣臨淮鎮(zhèn)南小莊,粉碎成粉末后用于土壤處理,稻草和玉米秸稈碳、氮含量如表1所示。
表1 稻草和玉米秸稈碳、氮含量Table 1 The carbon and nitrogen contents in rice straw and corn stalk
根據(jù)厭氧還原土壤滅菌法,試驗共設(shè)8個處理:不添加物料不加水處理(對照)、只淹水處理、少量稻草+淹水處理、高量稻草+淹水處理、少量玉米秸稈+淹水處理、高量玉米秸稈+淹水處理、高量稻草+飽和水處理、高量玉米秸稈+飽和水處理,其中,少量稻草、玉米秸稈用量均為0.35%(質(zhì)量比),高量稻草、玉米秸稈均為0.70%(質(zhì)量比),30℃恒溫箱密封培養(yǎng),每組設(shè)3個平行樣,總共24份處理樣品,每份處理土壤樣品平均為0.75 kg。每5 d取樣分析1次,共取樣6次。
細菌、放線菌、真菌和尖孢鐮刀菌分別采用牛肉膏蛋白胨瓊脂培養(yǎng)基、高氏1號培養(yǎng)基、孟加拉紅培養(yǎng)基[34]、改良 Komada’s 培養(yǎng)基[35],30 ℃ 恒溫培養(yǎng),細菌培養(yǎng)2 d后平板涂布計數(shù)法計數(shù),放線菌、尖孢鐮刀菌和真菌培養(yǎng)4 d后平板涂布計數(shù)法計數(shù)。
土壤銨態(tài)氮、硝態(tài)氮用2 mol/L的KCl溶液提取(2 mol/L KCl溶液與土壤比為5∶1),連續(xù)流動儀(Skalar San++,Holland)測定;硫酸根離子用去離子水提取(水土比為 5∶1),離子色譜(Thermo Dionex ICS 1100,USA)測定;氧化還原電位(Eh)(原位監(jiān)測)、pH值(水土比為 2.5∶1.0)用 METTLER TOLEDO SevenCompact pH/Lon氧化還原電位儀(Mettler S220K,Switzerland)測定;電導率(Ec,水土比為5∶1)用DDS-320型電導率儀(上海大普儀器有限公司生產(chǎn))測定。
數(shù)據(jù)用Microsoft Excel2003處理,并用SPSS16.0軟件進行差異顯著性分析。
添加有機物料淹水,30℃恒溫密封培養(yǎng),可降低土壤Eh值[15],培養(yǎng)1 d后,除對照和只淹水處理的土壤Eh值為正值外,其他各處理的Eh值均為負值,但這些負值均高于-100 mV,屬弱還原環(huán)境。培養(yǎng)5 d后,除對照和只淹水處理的土壤Eh值仍為正值外,其他各處理樣品的Eh值全部是負值,均低于-100 mV,屬強還原環(huán)境(圖1)。厭氧還原土壤滅菌法可調(diào)節(jié)土壤pH值[36-40],培養(yǎng)20 d時,各處理樣品的pH值均顯著高于對照pH值,之后各處理土壤樣品pH值雖有所降低,但仍顯著高于對照(圖2)。在整個培養(yǎng)過程中,對照和各處理土壤樣品的電導率(Ec)值,多在0.10 ms/cm上下波動(圖3)。
圖1 不同處理下土壤氧化還原電位的變化Fig.1 The changes of redox potentials in differently treated soils
圖2 不同處理下土壤p H值的變化Fig.2 The changes of pH values in differently treated soils
圖3 不同處理下土壤電導率的變化Fig.3 The changes of electrical conductivities in differently treated soils
由于所采集的西瓜連作土壤源自西瓜水稻輪作土(即每年各種一季西瓜和水稻),此次取的土是在水稻種植收獲完成后的稻田土,該連作10年西瓜土壤中尖孢鐮刀菌含量達1 g土1×104CFU,高于1 g土1×103CFU的治病臨界濃度[42]。經(jīng)過處理后,只淹水處理土壤樣品中尖孢鐮刀菌數(shù)量與對照相比,在整個處理過程中變化不大,而其他處理中尖孢鐮刀菌含量均顯著低于對照和只淹水處理(圖5)。真菌數(shù)量在整個處理過程中呈遞減趨勢,但各處理與對照相比,差異均不顯著。
圖4 土壤中主要離子濃度的變化Fig.4 The changes of main ion concentrations in differently treated soils
圖5 土壤微生物數(shù)量的變化Fig.5 The microbiological changes in differently treated soils
厭氧還原土壤滅菌法殺滅土壤中土傳病原菌的可能機理有:強還原環(huán)境[17],有機物料厭氧腐解產(chǎn)生的乙酸、丁酸和丙酸等有機酸[24]及 NH3和H2S[38-39]等揮發(fā)性物質(zhì)對病原菌具有毒害作用,還原條件下形成的Fe2+和Mn2+離子是抑制尖孢鐮刀菌的誘導因子[23],能有效地抑制土傳病原菌。厭氧還原土壤滅菌法處理后的土壤pH值升高,對于酸性土壤的改良具有很好的效果[38-39],低Eh和高pH值可使土壤有益菌增加,尖孢鐮刀菌減少。已有的 研究結(jié)果表明,厭氧還原土壤滅菌法能有效地抑制西紅柿?;图怄哏牭毒?Fusarium oxysporum f.sp.Lycopersici),青 枯 雷 爾 氏 菌 (Ralstonia solanacearum)[22]、棉花根腐病菌(Phytophthora cactorum)[43]及香蕉?;图怄哏牭毒?Fusarium oxysporum f.sp.Cubense)[44]。
本研究使用的有機物料為稻草和玉米秸稈,二者對土壤Eh、pH值的影響及對尖孢鐮刀菌抑制作用的差異不顯著;采用淹水和飽和水處理對土壤真菌和尖孢鐮刀菌的抑制作用及對土壤理化性質(zhì)影響來看效果都很好,就節(jié)約水資源而言,飽和水處理可節(jié)約大量水資源,而且使用起來也比較便利。2種不同有機物料對土壤NH+4-N、NO-3-N影響的差異性不顯著,就同一處理方法、同一處理時段而言,均表現(xiàn)出相似的變化規(guī)律,但用玉米秸稈處理后的土壤NH+4-N含量略高于稻草處理的土壤,這與玉米秸稈的碳氮比值較稻草低有關(guān),另外,在處理西瓜連作土壤防治西瓜枯萎病時,可因地制宜,就地取材,選取最便利的有機物料。就同一種有機物料而言,高量稻草(或玉米秸稈)較低量稻草(或玉米秸稈)對尖孢鐮刀菌的抑制效果更好。以上結(jié)果表明,厭氧還原土壤滅菌法處理西瓜連作土壤,可抑制西瓜專化型尖孢鐮刀菌。
[1] 吳洪生.西瓜連作土傳枯萎病微生物生態(tài)學機理及其生物防治[D].南京:南京農(nóng)業(yè)大學,2008.
[2] 趙玉強,田艷麗,高杜娟,等.pyrG基因?qū)ξ鞴鲜伤峋虏⌒院徒M氨酸利用的影響[J].江蘇農(nóng)業(yè)學報,2014,30(6):1309-1315.
[3] 孫海燕,魏君革,徐錦華,等.PEG介導gus基因轉(zhuǎn)化西瓜枯萎病菌[J].江蘇農(nóng)業(yè)學報,2014,30(2):275-281.
[4] 尚霄麗,張建鵬,李曉慧,等.不同類型肥料對西瓜葉片生長、膨瓜速度及產(chǎn)量的影響[J].江蘇農(nóng)業(yè)科學,2014,42(7):158-159.
[5] 蘇衛(wèi)國,郭 軍,鄭佳秋,等.西瓜與水生蔬菜水旱輪作模式栽培技術(shù)要點[J].江蘇農(nóng)業(yè)科學,2014,42(6):205-206.
[6] MANSOORIB,JALIANINK H.Control of soilborne pathogens of watermelon by solar heating[J].Crop Protection,1996,15(5):423-424.
[7] MIGUEL A,MAROTO JV,BAUTISTA A S,et al.The grafting of triploid watermelon is an advantageous alternative to soil fumigation by methyl bromide for control of Fusarium wilt[J].Scientia Horticulturae,2004,103(1):9-17.
[8] 蔡 貞,姚春霞,周 瑛,等.西瓜設(shè)施栽培連作病害枯萎病防治技術(shù)研究[J].江蘇農(nóng)業(yè)科學,2005(3):69-70,97.
[9] 張學偉,黃學森,古琴生,等.西瓜連作障礙及其防治方法[J].中國西瓜甜瓜,1993(2):21-23.
[10] REN L,SU S,YANGX,et al.Intercropping with aerobic rice suppressed Fusarium wilt in watermelon[J].Soil Biology& Biochemistry,2008,40(3):834-844.
[11]宋尚成,朱鳳霞,劉潤進,等.秸稈生物反應(yīng)堆對西瓜連作土壤微生物數(shù)量和土壤酶活性的影響[J].微生物學通報,2010,37(5):696-700.
[12] LING N,ZHANG W,TAN S,et al.Effect of the nursery application of bioorganic fertilizer on spatial distribution of Fusarium oxysporum f.sp.niveum and its antagonistic bacterium in the rhizosphere of watermelon[J].Applied Soil Ecology,2012,59:13-19.
[13] DE C A,SZTEJNBERG A,SABUQUILLO P,et al.Management Fusarium wilt on melon and watermelon by Penicillium oxalicum[J].Biological Control,2009,51(3):480-486.
[14] ALABOUVETTE C,OLIVAIN C,STEINBERG C.Biological control of plant diseases:the European situation[J].European Journal of Plant Pathology,2006,114:329-341.
[15] BAILEY K L,LAZAROVITS G.Suppressing soil-borne diseases with residue management and organic amendments[J].Soil and Tillage Research,2003,72(2):169-180.
[16] SHINMURA A.Causal agent and control of root rot of welsh onion[J].Phytopathological Society of Japan,Soilborne Disease Workshop Report,2000,20:133-143.
[17] BLOK W J,LAMERSJ G,TERMORSHUIZEN A J,et al.Control of soilborne plant pathogens by incorporating fresh organic amendments followed by tarping[J].Phytopathology,2000,90(3):253-259.
[18] EBIHARA Y,UEMATSU S.Survival of strawberry-pathogenic fungi Fusarium oxysporum f.sp.fragariae,Phytophthora cactorum and Verticillium dahliae under anaerobic conditions[J].J Gen Plant Pathol,2014,80:50-58.
[19] MOMMA N,KOBARA Y,UEMATSU S,et al.Development of biological soil disinfestations in Japan[J].Appl Microbiol Biotechnol,2013,97:3801-3809.
[20] MOWLICK S,TAKEHARA T,KAKU N,et al.Proliferation of diversified clostridial species during biological soil disinfestation incorporated with plant biomass under various conditions[J].Appl Microbiol Biotechnol,2013,97:8365-8379.
[21] MOWLICK S,INOUE T,TAKEHARA T,et al.Changes and recovery of soil bacterial communities influenced by biological soil disinfestation as compared with chloropicrin-treatment[J].AMB Express,2013,3:46.
[22] MOMMA N,YAMAMOTO K,SIMANDI P,et al.Role of organic acids in the mechanisms of biological soil disinfestation(BSD)[J].J Gen Plant Pathol,2006,72:247-252.
[23] MOMMA N,KOBARA Y,MOMMA M.Fe2+and Mn2+,potential agents to induce suppression of Fusarium oxysporum for biological soil disinfestation[J].J Gen Plant Pathol,2011,77:331-335.
[24] MOMMA N,MOMMA M,KOBARA Y.Biological soil disinfesta-tion using ethanol:effect on Fusarium oxysporum f.sp.lycopersici and soil microorganisms[J].J Gen Plant Pathol,2010,76:336-344.
[25] MOMMA N.Biological soil disinfestation(BSD)of soilborne pathogens and its possible mechanisms[J].Japan Agric Research Quarterly,2008,42:7-12.
[26] SHINMURA A.Principle and effect of soil sterilization method by reducing redox potential of soil[J].Phytopathological Society of Japan,Soilborne Disease Workshop Report,2004,22:2-12.
[27] OVERBEEK L V,RUNIA W,KASTELEIN P,et al.Anaerobic disinfestation of tare soils contaminated with Ralstonia solanacearum biovar 2 and Globodera pallida[J].Eur J Plant Pathol,2014,138:323-330.
[28] MESSIHA N A S,DIEPENINGEN A D,WENNEKER M,et al.Biological soil disinfestation(BSD),a new control method for potato brown rot,caused by Ralstonia solanacearum race 3 biovar 2[J].Eur JPlant Pathol,2007,117:403-415.
[29] BUTLER D M,ROSSKOPF E N,KOKALISB N,et al.Exploring warm-season cover crops as carbon sources for anaerobic soil disinfestation(ASD)[J].Plant Soil,2012,355:149-165.
[30] BUTLER D M,KOKALIS-BURELLE N,Albano J P,et al.Anaerobic soil disinfestation(ASD)combined with soil solarization as a Methyl bromide alternative:vegetable crop performance and soil nutrient dynamics[J].Plant Soil,2014,378:365-381.
[31] HEWAVITHARANA S S,RUDDELL D,MAZZOLA M.Carbon source-dependent antifungal and nematicidal volatiles derived during anaerobic soil disinfestation[J].Eur J Plant Pathol,2014,140:39-52.
[32] DOMINGUEZ P,MIRANDA L,SORIA C,et al.Soil biosolarization for sustainable strawberry production[J].Agron Sustain Dev,2014,34:821-829.
[33] COLLA P,GILARDI G,GULLINO M L.A review and critical analysis of the European situation of soilborne disease management in the vegetable sector[J].Phytoparasitica,2012,40:515-523.
[34]方中達.植病研究方法[M].3版.北京:中國農(nóng)業(yè)出版社,1998.
[35] SUN E J,SU H J,KO W H.Identification of Fusarium oxysporum f.sp.cubense Race4 from soil or host tissue by cultural characters[J].Phytopathology,1978,68:1672-1673.
[36]朱同彬,張金波,蔡祖聰.淹水條件下添加有機物料對蔬菜地土壤硝態(tài)氮及氮素氣體排放的影響[J].應(yīng)用生態(tài)學報,2012,23(1):109-114.
[37]朱同彬,孟天竹,張金波,等.強還原方法對退化設(shè)施蔬菜地土壤的修復[J].應(yīng)用生態(tài)學報,2013,24(9):2619-2624.
[38]黃新琦,溫 騰,孟 磊,等.土壤快速強烈還原法對尖孢鐮刀菌的抑制作用[J].生態(tài)學報,2014,34(16):4526-4534.
[39]黃新琦,溫 騰,孟 磊,等.土壤厭氧還原消毒對尖孢鐮刀菌的抑制研究[J].土壤,2014,46(5):851-855.
[40] BAUHUSJ,MEYER A C,BRUMME R.Effect of the inhibitors nitrapyrin and sodium chlorate on nitrification and N2O formation in an acid forest soil[J].Biology and Fertility of Soils,1996,22:318-325.
[41] WOLF I,RUSSOW R.Different pathways of formation of N2O,N2and NO in black earth soil[J].Soil Biology and Biochemistry,2000,32:229-239.
[42]何 欣,黃啟為,楊興明,等.香蕉枯萎病致病菌篩選及致病菌濃度對香蕉枯萎病的影響[J].中國農(nóng)業(yè)科學,2010,43(18):3809-3816.
[43] GAXIOLA S J A,BALAGURUSAMY N.Survival of soil-borne fungus Phymatotrichopsis omnivore after exposure to volatile fatty acids[J].J Gen Plant Pathol,2013,79:105-109.
[44] HUANGX Q,WEN T,ZHANG JB,et al.Toxic organic acids produced in biological soil disinfestation mainly caused the suppression of Fusarium oxysporum f.sp.cubense[J].Bio Control,2015,60:113-124.