摘""要:由古巴專(zhuān)化型尖孢鐮刀菌(Fusarium"oxysporum"f."sp."cubense)引起的枯萎病是目前影響全球香蕉產(chǎn)業(yè)可持續(xù)健康發(fā)展最嚴(yán)重的病害。為篩選到對(duì)香蕉組培苗具有顯著促生和抗病作用的優(yōu)勢(shì)叢枝菌根(arbuscular"mycorrhizal,"AM)真菌菌株,本研究在盆栽試驗(yàn)條件下對(duì)比了從廣西香蕉主產(chǎn)區(qū)香蕉根際土壤分離的5種AM真菌對(duì)香蕉組培苗生長(zhǎng)和枯萎病的影響。結(jié)果表明:接種AM真菌的香蕉組培苗根系菌根侵染率為15.00%~95.00%,依次為BNMJ-1"(C."etunicatum)gt;BNTJ-6"(G."mosseae)gt;HTJ2-60"(C."lamellosum)gt;BDQJ-2"(G."fulvum)gt;GZXJ-10"(Paraglomus"sp.);除GZXJ-10處理外,其他接種處理均能顯著促進(jìn)香蕉組培苗生長(zhǎng),隸屬函數(shù)綜合分析結(jié)果顯示,BNMJ-1處理的促生效果最為顯著,其株高、莖徑、葉片數(shù)、最大根長(zhǎng)、總生物量較對(duì)照組分別增加68.60%、44.54%、40.67%、12.05%和65.15%,BNTJ-6處理的促生效果次之;BNMJ-1處理的枯萎病防治效果最佳,其次是BNTJ-6處理,較對(duì)照組病情指數(shù)分別下降93.37%和89.03%,防效分別達(dá)93.64%和88.85%。綜上所述,供試的5種AM真菌中對(duì)香蕉組培苗促生、抗病效果較好的菌株為BNMJ-1和BNTJ-6。因此,本研究篩選獲得香蕉組培苗的促生抗病優(yōu)勢(shì)AM真菌菌株,為后期開(kāi)發(fā)香蕉菌根種苗以及專(zhuān)用菌根真菌菌劑、菌肥等產(chǎn)品奠定基礎(chǔ)。
關(guān)鍵詞:香蕉;土壤;叢枝菌根真菌;促生;枯萎病中圖分類(lèi)號(hào):S668.1""""""文獻(xiàn)標(biāo)志碼:A
Effects"of"Five"Arbuscular"Mycorrhizal"Fungi"Species"on"the"Growth"and"Fusarium"Wilt"Disease"of"Banana"Tissue"Culture"Seedlings
WANG"Liang1,2,"ZHANG"Jinlian2,"KANG"Yihao2,"HUANG"Haisi2,"QIN"Xiaojuan2*,"JIANG"Jinping1*,"CHEN"Tingsu2
1."College"of"Environmental"Science"and"Engineering,"Guilin"University"of"Technology,"Guilin,"Guangxi"541004,"China;"2."Microbiology"Research"Institute,"Guangxi"Academy"of"Agricultural"Sciences,"Nanning,"Guangxi"530007,"China
Abstract:"Wilt"caused"by"Fusarium"oxysporum"f."sp."Cubense"is"currently"the"most"serious"disease"affecting"the"sustainable"and"healthy"development"of"the"global"banana"industry."To"screen"superior"arbuscular"mycorrhizal"(AM)"fungi"that"significantly"promote"the"growth"and"disease"resistance"of"banana"tissue"culture"seedlings,"this"study"compared"the"effects"of"five"dominant"AM"fungi"isolated"from"the"main"banana"producing"areas"in"Guangxi"on"the"growth"and"Fusarium"wilt"of"banana"tissue"culture"seedlings"under"pot"conditions."The"results"showed"that"the"mycorrhizal"infection"rate"of"banana"tissue"culture"seedlings"inoculated"with"AM"fungi"ranged"from"15.00%"to"95.00%,"they"were"asnbsp;follows:"BNMJ-1"(C."etunicatum)"gt;"BNTJ-6"(G."mosseae)"gt;"HTJ2-60"(C."lamellosum)"gt;"BDQJ-2"(G."fulvum)"gt;"GZXJ-10"(Paraglomus"sp.)."All"the"inoculation"treatments"significantly"promoted"the"growth"of"banana"tissue"culture"seedlings"except"for"the"GZXJ-10"treatment,"and"the"results"of"membership"function"comprehensive"analysis"showed"that"the"BNMJ-1"treatment"had"the"most"significant"growth-promoting"effect,"which"increased"plant"height,"stem"diameter,"number"of"leaves,"maximum"root"length"and"total"biomass"by"68.60%,"44.54%,"40.67%,"12.05%"and"65.15%,"respectively,"compared"with"the"control,"followed"by"the"BNTJ-6"treatment."BNMJ-1"treatment"was"the"most"effective"in"wilt"control,"followed"by"BNTJ-6"treatment,"which"decreased"the"disease"index"by"93.37%"and"89.03%"compared"to"the"control"and"the"preventive"efficacy"reached"93.64%"and"88.85%."In"summary,"among"the"five"AM"fungi"for"testing,"the"strains"with"better"disease-promoting"resistance"to"banana"seedlings"grown"in"tissue"culture"were"BNMJ-1"and"BNTJ-6."Therefore,"screening"to"obtain"the"advantageous"AM"fungal"strains"for"banana"tissue"culture"seedlings"lays"the"foundation"for"the"later"development"of"banana"mycorrhizal"seedlings"as"well"as"special"mycorrhizal"fungal"fungicides"and"fungal"fertilizers.
Keywords:"banana;"soil;"arbuscular"mycorrhizal"fungi;"growth"promoting;"Fusarium"wilt"disease
DOI:"10.3969/j.issn.1000-2561.2025.06.020
香蕉(Musa"nana"Lour.)是熱帶、亞熱帶地區(qū)重要的果糧兼用作物,是世界鮮果貿(mào)易量最大的水果[1],2021年全球香蕉收獲面積達(dá)533.69萬(wàn)hm2[2]。我國(guó)是世界重要的香蕉生產(chǎn)國(guó),香蕉種植面積位居世界第六,產(chǎn)量居第二[3],已成為熱帶作物產(chǎn)值最高的產(chǎn)業(yè)之一[4]。香蕉枯萎病是一種由古巴專(zhuān)化型尖孢鐮刀菌(Fusarium"oxysporum"f."sp."cubense)侵染香蕉根部引起植株凋萎的毀滅性真菌土傳病害[5],可使香蕉植株黃化萎蔫、維管束褐變至整株枯亡[6],在無(wú)寄主的情況下,病原菌以厚垣孢子的形式在土壤中能存活長(zhǎng)達(dá)30"a[7-8],目前尚無(wú)有效的化學(xué)農(nóng)藥和優(yōu)質(zhì)高抗香蕉品種對(duì)該病害進(jìn)行徹底防控[9],是當(dāng)前全球香蕉產(chǎn)業(yè)可持續(xù)健康發(fā)展的主要制約因素[10]。生物防治是一種安全、環(huán)境友好且有潛力的植物病害防控方法,被認(rèn)為是目前防治香蕉枯萎病的有效工具和重要策略[11],已成為近年香蕉枯萎病防控研究的熱點(diǎn)。
叢枝菌根(arbuscular"mycorrhizal,"AM)真菌是一種具有重要生態(tài)功能的土壤真菌,能與80%的高等植物根系形成互惠共生體——叢枝菌根[12]。AM真菌與植物根系共生后,在植物根際形成龐大的菌絲網(wǎng)絡(luò)系統(tǒng),協(xié)助宿主植物獲取根際的碳、氮養(yǎng)分和水分[13],穩(wěn)定并改善根際土壤團(tuán)粒結(jié)構(gòu),修復(fù)土壤生態(tài)[14],從而促進(jìn)植物生長(zhǎng)、提高植物產(chǎn)量和宿主抗病抗逆性,AM真菌是農(nóng)業(yè)生產(chǎn)上防控土傳病害的重要有益微生物資源[15-16]。已有研究證明,接種摩西球囊霉(G."mo ss eae)、根內(nèi)球囊霉(G."intraradices)和幼套球囊霉(G."etunicatum)可顯著促進(jìn)茅蒼術(shù)苗的營(yíng)養(yǎng)生長(zhǎng),對(duì)根腐病的防效高達(dá)62.94%[17]。接種摩西球囊霉(G."mo ss eae)可顯著增加番茄幼苗地上部鮮質(zhì)量、干質(zhì)量,降低根結(jié)線(xiàn)蟲(chóng)病病情指數(shù)[18]。接種根內(nèi)孢囊霉(R."intraradices)可顯著提高枸杞株高、莖粗、鮮質(zhì)量和總?cè)~綠素含量,對(duì)根腐病的防治效果達(dá)62.79%[19]。接種AM真菌可顯著增加香蕉植株地上部分和根系的干質(zhì)量[20],顯著減少根際土壤周?chē)怄哏牭毒鷶?shù)量,降低香蕉枯萎病發(fā)病率和病情指數(shù)[21-23],且混合接種劑的促生和防病效果好于單一接種劑[24]。
目前已證實(shí)的可有效控制植物土傳病害的AM真菌超過(guò)30種[25],但不同的AM真菌對(duì)同一種植物所表現(xiàn)的效果不同,宿主植物和AM真菌之間存在相互選擇性[26]。廣西是我國(guó)重要的香蕉主產(chǎn)區(qū)及優(yōu)質(zhì)貨源地,本研究從廣西香蕉主產(chǎn)區(qū)的香蕉植株根際土壤中分離獲得5種AM真菌菌株,在溫室盆栽條件下探討其對(duì)香蕉組培苗生長(zhǎng)及枯萎病的影響,篩選獲得目標(biāo)優(yōu)勢(shì)AM真菌菌株,以期為利用AM真菌改善蕉園土壤生態(tài)和實(shí)現(xiàn)香蕉枯萎病的綠色防控提供科學(xué)依據(jù)和技術(shù)支持。
1.1""材料
香蕉組培苗:桂蕉1號(hào),購(gòu)自廣西植物組培苗有限公司。
花盆:盆口直徑12.0"cm、盆高10.5"cm、底部直徑5.0"cm,用多菌靈浸泡處理;基質(zhì):以育苗有機(jī)質(zhì)∶沙∶土=2∶1∶1混勻,然后裝入滅菌袋中進(jìn)行高壓蒸汽滅菌,溫度為121"℃,時(shí)間120"min。
供試菌株:AM真菌由廣西農(nóng)業(yè)科學(xué)院微生物研究所分離、保存、擴(kuò)繁,具體菌株編號(hào)及名稱(chēng)見(jiàn)表1。病原菌(尖孢鐮刀菌古巴專(zhuān)化型4號(hào)生理小種,F(xiàn)OC4)由廣西農(nóng)業(yè)科學(xué)院植物保護(hù)研究所香蕉病害研究團(tuán)隊(duì)提供。
1.2""方法
1.2.1""試驗(yàn)設(shè)計(jì)""2023年8月在廣西農(nóng)業(yè)科學(xué)院微生物研究所溫室進(jìn)行盆栽試驗(yàn)。選取4~5葉齡且長(zhǎng)勢(shì)一致的香蕉苗移栽于花盆。共設(shè)置6個(gè)處理,以未接種AM真菌的處理作為對(duì)照(CK),處理組分別接種5種AM真菌(表1),每個(gè)處理3個(gè)重復(fù),每個(gè)重復(fù)12株蕉苗。移栽時(shí),先在花盆底部墊一張與底部大小一致的紙片,加入花盆1/2滅菌基質(zhì)。在植株根圍放置AM真菌接種體,接種量約為300個(gè)孢子/盆,使其與根系充分接觸,繼續(xù)加入基質(zhì)至花盆3/4,并確?;|(zhì)覆蓋香蕉根系,澆足定根水;CK中加入用于擴(kuò)繁AM真菌的滅菌基質(zhì)。每盆按照菌株編號(hào)做好標(biāo)記,干濕交替法澆水,每2周補(bǔ)充1次Hoagland營(yíng)養(yǎng)液。
1.2.2""項(xiàng)目測(cè)定及方法""(1)香蕉根系采集。用剪刀剪下約1/3香蕉根系,采集老、嫩、粗、細(xì)各種根段,用自來(lái)水清洗干凈后再用去離子水清洗數(shù)次,浸泡于50%酒精中保存,用于觀察AM真菌的侵染情況。
(2)根系染色及侵染率測(cè)定。分別于接種30、60"d后,采集香蕉根系。參考覃曉娟等[27]的墨水醋染色法對(duì)根系進(jìn)行染色,參考TROUVELOT等[28]的方法檢測(cè)根系,使用尼康Eclipse"Ci-L和Ds-Ri2觀察菌根侵染情況。用侵染率、侵染強(qiáng)度、相對(duì)叢枝豐度3個(gè)參數(shù)描述菌根侵染狀況。
(3)生長(zhǎng)性狀。接種60"d后采樣,每處理取12株蕉苗。測(cè)定各處理的株高、莖徑、有效葉片數(shù)和最大根長(zhǎng)。從香蕉植株球莖至最上端葉片分叉處的距離為株高,采用游標(biāo)卡尺測(cè)量距根部5"cm處的莖圍粗為莖徑,有效葉片數(shù)為除子葉外的所有成熟葉片數(shù)量,采用直尺量取最長(zhǎng)主根或側(cè)根垂直長(zhǎng)度為最大根長(zhǎng)。
(4)生物量。接種60"d后,用自來(lái)水將植株洗凈,將植株地上部與地下部分裝至信封袋于105"℃烘箱內(nèi)殺青30"min、70"℃烘干至恒重后稱(chēng)得干質(zhì)量,并在生物量的基礎(chǔ)上,計(jì)算菌根依賴(lài)性指數(shù)(MD)[29]。計(jì)算公式如下:
根據(jù)NEMEC[30]的分類(lèi)方法,可將植物對(duì)菌根的依賴(lài)程度分為3級(jí):MD≥300%,為高強(qiáng)度依賴(lài);200%≤MDlt;300%,為中等強(qiáng)度依賴(lài);100%≤MDlt;200%,為弱依賴(lài)或無(wú)依賴(lài)。
(5)AM真菌的盆栽防效測(cè)定。接種AM真菌60"d后,選取長(zhǎng)勢(shì)良好的蕉苗進(jìn)行病原菌接種,每個(gè)處理設(shè)置3個(gè)重復(fù),每個(gè)重復(fù)取8株蕉苗。接種時(shí),用解剖刀沿香蕉根圍進(jìn)行對(duì)稱(chēng)傷根處理,每株蕉苗接種40"mL孢子濃度為1×106個(gè)/mL的尖孢鐮刀菌分生孢子懸浮液。常規(guī)管理,接種病原菌21"d后,調(diào)查發(fā)病情況,計(jì)算各處理發(fā)病率、病情指數(shù)和防治效果。依據(jù)蕉苗球莖縱剖面的褐變面積占比確定病級(jí):0級(jí)為球莖無(wú)褐變;球莖褐變面積≤25%為1級(jí);25%lt;球莖褐變面積≤50%為3級(jí);50%lt;球莖褐變面積≤75%為5級(jí);球莖褐變面積gt;75%為7級(jí)[31]。1.3""數(shù)據(jù)處理
采用Microsoft"Excel"2021軟件對(duì)數(shù)據(jù)進(jìn)行整理,用SPSS"24.0軟件進(jìn)行方差分析、相關(guān)性分析,采用最小顯著差異(LSD)法進(jìn)行多重比較。
根據(jù)周福平等[32]運(yùn)用的模糊數(shù)學(xué)中的隸屬函數(shù)法對(duì)不同性狀指標(biāo)進(jìn)行綜合分析。首先求出各指標(biāo)隸屬函數(shù)值,然后進(jìn)行累加并求其平均值,平均值越大,則說(shuō)明該菌株的促生效果越好,從而篩選出香蕉優(yōu)勢(shì)AM真菌菌株。隸屬函數(shù)值計(jì)算公式如下:
式中,X為某一指標(biāo)的測(cè)定值,Xmin為某一指標(biāo)測(cè)定值中的最小值,Xmax為某一指標(biāo)測(cè)定值中的最大值。
2.1"nbsp;接種不同AM真菌的香蕉組培苗根系侵染情況
不同AM真菌對(duì)香蕉根系侵染情況如表2所示。供試的5株AM真菌均能侵染香蕉根系,但不同菌株之間的侵染率、侵染強(qiáng)度和叢枝豐度均存在差異。在接種60"d時(shí),菌株BNMJ-1的侵染率、侵染強(qiáng)度和叢枝豐度均最高,分別為95.00%、35.05%和26.82%;其次為菌株BNTJ-6,其侵染率、侵染強(qiáng)度和叢枝豐度分別為80.00%、24.65%和15.07%;菌株GZXJ-10的侵染率、侵染強(qiáng)度和叢枝豐度最低,分別為15.00%、3.60%和1.80%,CK未檢測(cè)到AM真菌侵染。AM真菌菌絲、泡囊和叢枝結(jié)構(gòu)的侵染染色情況見(jiàn)圖1。
2.2""不同AM真菌對(duì)香蕉組培苗營(yíng)養(yǎng)生長(zhǎng)的影響
由表3可知,接種菌株BDQJ-2、HTJ2-60的香蕉各項(xiàng)營(yíng)養(yǎng)生長(zhǎng)指標(biāo)均顯著高于CK(Plt;0.05),BNMJ-1、BNTJ-6處理組的株高、莖徑、葉片數(shù)均顯著高于CK(Plt;0.05),其最大根長(zhǎng)略高于CK,但差異不顯著。而GZXJ-10處理的株高、葉片數(shù)和最大根長(zhǎng)均顯著低于CK(Plt;0.05),莖徑略低于CK,差異不顯著??梢?jiàn),接種菌株BDQJ-2、BNMJ-1、BNTJ-6、HTJ2-60均能有效促進(jìn)香蕉組培苗生長(zhǎng),其中以菌株BNMJ-1和BNTJ-6的促生效果最為顯著,與CK相比,株高分別增加了68.60%和76.30%,莖徑分別增加了44.54%和38.05%,葉片數(shù)分別增加了40.67%和44.44%,最大根長(zhǎng)分別增加了12.05%和4.48%。
接種菌株BDQJ-2、BNMJ-1、BNTJ-6、HTJ2-60均能顯著增加香蕉組培苗地上干質(zhì)量、地下干質(zhì)量和生物量,其中BNMJ-1、BNTJ-6處理的地上干質(zhì)量增加效果顯著(Plt;0.05),較CK分別提高了61.45%和62.79%;以BNMJ-1、BNTJ-6和HTJ2-60處理的地下干質(zhì)量增加效果顯著(Plt;"0.05),較CK分別提高了65.71%、62.50%和66.67%;以BNMJ-1處理的生物量增加效果顯著(Plt;0.05),較CK提高了65.15%。GZXJ-10處理的地上干質(zhì)量和生物量略低于CK,但無(wú)顯著差異,地下干質(zhì)量顯著低于CK(Plt;0.05)。香蕉組培苗對(duì)不同接種處理的菌根依賴(lài)性存在差異,以接種菌株BDQJ-2、BNMJ-1、BNTJ-6、HTJ2-60處理的菌根依賴(lài)性較高,達(dá)到中度依賴(lài)級(jí)別,MD指數(shù)依次為224%、287%、248%、222%,而GZXJ-10的菌根依賴(lài)級(jí)別較弱,MD指數(shù)僅為78%(表4)。
通過(guò)對(duì)各處理的蕉苗生長(zhǎng)指標(biāo)和生物量等進(jìn)行隸屬函數(shù)分析,除GZXJ-10處理外,其他接菌處理的隸屬函數(shù)平均值均高于CK(表5)??梢?jiàn),除了菌株GZXJ-10對(duì)香蕉組培苗生長(zhǎng)具有抑制作用外,其余菌株均能促進(jìn)植株生長(zhǎng),促生效果依次為BNMJ-1gt;BNTJ-6gt;BDQJ-2gt;HTJ2-60(圖2)。
2.3""不同AM真菌對(duì)香蕉組培苗枯萎病發(fā)生和防效的影響
香蕉組培苗接種枯萎病菌21"d后,CK的病情指數(shù)最高,為53.33,接種AM真菌的各處理的病情指數(shù)均有所下降,其中菌株BNMJ-1、BNTJ-6、HTJ2-60達(dá)到顯著差異(Plt;0.05,表6),病情指數(shù)由低到高為BNMJ-1lt;BNTJ-6lt;HTJ2-"60lt;BDQJ-2lt;GZXJ-10lt;CK。植株枯萎病發(fā)病情況見(jiàn)圖3,5個(gè)AM真菌對(duì)香蕉枯萎病均有一定的防治效果,其中以菌株BNMJ-1和BNTJ-6的防治效果較好,防效分別達(dá)93.64%和88.85%。
2.4""香蕉組培苗生長(zhǎng)和病情指數(shù)與菌根侵染的相關(guān)性
通過(guò)相關(guān)性分析表明(表7),侵染率與株高和生物量呈顯著正相關(guān)(Plt;0.05),與病情指數(shù)呈極顯著負(fù)相關(guān)(Plt;0.01),與莖徑、葉片數(shù)和最大根長(zhǎng)均無(wú)顯著相關(guān)性;侵染強(qiáng)度、叢枝豐度與株高、莖徑、葉片數(shù)、最大根長(zhǎng)、地下干質(zhì)量和生物量均無(wú)顯著相關(guān)性,而與病情指數(shù)呈極顯著負(fù)相關(guān)(Plt;0.01)。
AM真菌和宿主植物之間存在一定的相互選擇性[33],良好的共生關(guān)系是發(fā)揮菌根效應(yīng)的基礎(chǔ)。根系侵染率反映了AM真菌在植物根系內(nèi)的生長(zhǎng)
和發(fā)育情況,是宿主植物與AM真菌共生關(guān)系的重要指標(biāo),侵染率越高說(shuō)明共生關(guān)系越好[34-35]。本研究中的5株AM真菌均能侵染香蕉根系,形成菌根結(jié)構(gòu),其中菌株BNMJ-1和BNTJ-6表現(xiàn)出較高的侵染水平,侵染率分別達(dá)到95.00%和80.00%,說(shuō)明這2株AM真菌與香蕉的共生關(guān)系較強(qiáng),為菌根效應(yīng)的充分發(fā)揮奠定了基礎(chǔ)。
AM真菌能促進(jìn)宿主植物的營(yíng)養(yǎng)生長(zhǎng),改善植物的產(chǎn)量和品質(zhì)[36-39],并在誘導(dǎo)植物抗病性方面作用顯著[40-41]。已有多項(xiàng)研究表明,摩西球囊霉(G."mosseae)對(duì)植物具有顯著的促生抗病作用,有較好的應(yīng)用前景。楊凡等[42]在黃瓜育苗過(guò)程中接種摩西球囊霉,結(jié)果顯示,與未接種處理相比,接種處理的壯苗指數(shù)和最大側(cè)根長(zhǎng)分別增加了46.34%和62.45%,枯萎病的發(fā)病率和病情指數(shù)分別降低了87.14%和80.27%。周昱[16]研究發(fā)現(xiàn),接種摩西球囊霉對(duì)白皮云杉的促生和抗病效果最佳,株高、徑粗、地徑及地上部干質(zhì)量較對(duì)照分別增加了53.31%、25.11%、71.46%、71.42%,根腐病病情指數(shù)下降37.53%。曹敏等[17]研究表明,摩西球囊霉、根內(nèi)球囊霉(G."intraradices)和幼套球囊霉(G."etunicatum)對(duì)茅蒼術(shù)苗均具有促生和抗病效應(yīng),其中幼套球囊霉的促生作用最為顯著,摩西球囊霉對(duì)地下部物質(zhì)積累的促進(jìn)作用更大,摩西球囊霉和幼套球囊霉對(duì)根腐病的防治效果較好。本研究結(jié)果表明,除GZXJ-10外,其他菌株處理均能促進(jìn)香蕉組培苗生長(zhǎng),并降低枯萎病病情指數(shù),從隸屬函數(shù)分析來(lái)看,促生效果最好的菌株為BNMJ-1,其株高、莖徑、葉片數(shù)、最大根長(zhǎng)、總生物量比CK分別增加68.60%、44.54%、40.67%、12.05%和65.15%,菌株BNTJ-6的促生作用次之,本結(jié)果與前人的研究[16-17,"42]具有一定的相似性。菌根依賴(lài)性是一種衡量植物對(duì)菌根真菌生長(zhǎng)效應(yīng)的指標(biāo),MD值越大,說(shuō)明菌根真菌對(duì)植物的生長(zhǎng)促進(jìn)效應(yīng)就越顯著[43]。本研究中,促生作用較明顯的菌株BDQJ-2、BNMJ-1、BNTJ-6和HTJ2-60,其MD值均大于200,達(dá)到中度依賴(lài)級(jí)別,進(jìn)一步表明這些菌株對(duì)香蕉組培苗的生長(zhǎng)具有促進(jìn)效應(yīng),能積累更多的生物量;防治效果最好的菌株是BNMJ-1,其次是BNTJ-6,其病情指數(shù)比CK分別下降93.37%、89.03%,防效分別達(dá)到93.64%和88.85%。梁昌聰?shù)萚44]研究表明,接種AM真菌能夠降低巴西蕉枯萎病的發(fā)病率和病情指數(shù),且混合接種摩西球囊霉、聚叢球囊霉(G."aggregatum)、幼套球囊霉比單接種摩西球囊霉的抗病效果要明顯,其病情指數(shù)較對(duì)照降低70.00%,病情指數(shù)的降幅略低于本研究,其原因可能是不同AM真菌與特定植物的親和性不同導(dǎo)致其侵染率存在差異,進(jìn)而造成對(duì)植物生物量和抗病性的影響存在明顯差異。
本研究相關(guān)分析顯示,侵染率與株高、生物量呈顯著正相關(guān),與病情指數(shù)呈極顯著負(fù)相關(guān),說(shuō)明隨著侵染率的增加,植物菌根化程度也隨之提高,AM真菌對(duì)植物生長(zhǎng)的促進(jìn)作用也越明顯[45],該結(jié)果與張延旭等[29]和李俠等[46]的研究結(jié)果一致。有研究表明,AM真菌抵御植物土傳病害的前提是在病原物入侵之前AM真菌與植物間已形成菌根并發(fā)育良好[47],且AM真菌抗病性的誘導(dǎo)依賴(lài)于較高的菌根侵染率(gt;50%)[48-49]。本研究中抗病效果較好的菌株BNMJ-1、BNTJ-6在香蕉根系的侵染率均遠(yuǎn)高于50%,抗病效果較差的菌株BDQJ-2、HTJ2-60和GZXJ-10的侵染率均低于50%,與前人研究結(jié)果[48-49]一致。綜上所述,可選擇BNMJ-1、BNTJ-6作為香蕉綠色生態(tài)栽培應(yīng)用的備選優(yōu)勢(shì)AM真菌菌株。
本研究在盆栽條件下,以從香蕉根際土壤中分離篩選到的5種AM真菌為供試菌株,對(duì)比了不同AM真菌對(duì)香蕉組培苗的促生和抗病作用,結(jié)果表明,接種AM真菌可顯著促進(jìn)香蕉組培苗的生長(zhǎng),降低香蕉植株枯萎病病情指數(shù),提高枯萎病的防控效果,以供試菌株BNMJ-1和BNTJ-6的促生和抗病效果最佳。因此,今后可將菌株BNMJ-1和BNTJ-6作為香蕉促生和枯萎病防控的備選AM真菌優(yōu)勢(shì)菌株,為后期開(kāi)發(fā)菌根種苗以及專(zhuān)用菌根真菌菌劑、菌肥產(chǎn)品,實(shí)現(xiàn)香蕉產(chǎn)業(yè)的綠色生態(tài)健康發(fā)展奠定基礎(chǔ)。
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