郭瑞華羅 琌張騰昊,2劉滿強陳小云?胡 鋒
(1 南京農(nóng)業(yè)大學(xué)資源與環(huán)境科學(xué)學(xué)院土壤生態(tài)實驗室,南京 210095)
(2 河北省環(huán)保產(chǎn)品質(zhì)量監(jiān)督檢驗院,石家莊 050000)
地上和地下植食者互作對水稻氮分配及土壤活性氮的影響*
郭瑞華1羅 琌1張騰昊1,2劉滿強1陳小云1?胡 鋒1
(1 南京農(nóng)業(yè)大學(xué)資源與環(huán)境科學(xué)學(xué)院土壤生態(tài)實驗室,南京 210095)
(2 河北省環(huán)保產(chǎn)品質(zhì)量監(jiān)督檢驗院,石家莊 050000)
植物莖葉和根系植食者雖然在空間上隔離,但二者的相互作用被認為是聯(lián)系地上和地下部生態(tài)系統(tǒng)的基礎(chǔ)。土壤氮素有效性通過植物影響植食者已得到大量研究的證實,但有關(guān)地上和地下部植食者互作對土壤氮素影響的研究卻鮮有報道。以水稻褐飛虱和潛根線蟲分別作為地上和地下的植食者,采用兩因素交互試驗設(shè)計,兩個褐飛虱水平(未接種褐飛虱、接種褐飛虱),兩個潛根線蟲水平(未接種潛根線蟲、接種潛根線蟲),探討二者的交互作用對水稻氮吸收和土壤活性氮(微生物生物量氮、可溶性有機氮以及銨態(tài)氮和硝態(tài)氮)的影響。結(jié)果表明,褐飛虱和潛根線蟲相互抑制,二者的共存加劇了對水稻莖葉和根系生長的危害。褐飛虱未影響水稻莖葉和根系含氮量,而潛根線蟲顯著降低了水稻根系含氮量(p<0.05)。褐飛虱和潛根線蟲對土壤活性氮的影響表現(xiàn)出強烈的交互作用,在未接潛根線蟲的處理中,褐飛虱顯著提高了微生物生物量氮含量(p< 0.05),顯著降低了硝態(tài)氮含量(p< 0.05);潛根線蟲顯著影響了微生物生物量氮含量和土壤活性氮總量??傊?,褐飛虱和潛根線蟲的相互抑制關(guān)系對土壤活性氮的影響格局較為復(fù)雜,相比褐飛虱,潛根線蟲趨向于提高土壤活性氮水平,這可能影響與氮轉(zhuǎn)化有關(guān)的土壤生態(tài)功能。
褐飛虱;潛根線蟲;氮分配;微生物生物量氮;可溶性有機氮;礦質(zhì)氮
在陸地生態(tài)系統(tǒng)中,地上部與地下部的生物通過植物作為橋梁而密切關(guān)聯(lián)[1-3]。其中,植物與植食者的關(guān)系是聯(lián)接生態(tài)系統(tǒng)地上和地下部的基石[2]。地上部植食者的取食會引起光合作用產(chǎn)物向根系轉(zhuǎn)移,增加土壤中資源有效性;植食者引起的植物系統(tǒng)防御響應(yīng)也會影響根系分泌物的組成,通過根系輸入土壤的資源數(shù)量和質(zhì)量的改變則進一步影響土壤生物群落和功能的發(fā)展[4]。雖然對地下部根系植食者關(guān)注較晚,但越來越多的證據(jù)表明根系植食者同樣會通過宿主植物影響地上部的植食者[5-6]。迄今,雖然理論上推測地上部和地下部植食者存在普遍的關(guān)系,但是以往的研究往往集中在地上或地下部植食者,二者互作關(guān)系的研究仍較少。
植物化學(xué)組成和養(yǎng)分含量是影響植食者種群發(fā)展的關(guān)鍵因素。大量的研究表明,植物體元素組成尤其是氮素含量對地上部植食者有決定性作用[7-8]。相比之下,有關(guān)植食者特別是根系植食者對土壤養(yǎng)分有效性的影響卻鮮見報道。理論上,地上部植食者的取食導(dǎo)致植物生長功能受損,因而根系對土壤養(yǎng)分的吸收能力減弱,土壤氮素有效性會相對增加;此外,地上部植食者的取食會促進根系分泌物的分泌,刺激微生物生長發(fā)育,加速土壤氮素的周轉(zhuǎn)。因此,在地上部植食者的影響下,土壤氮素有效性增加或減少的可能性均存在[9-10]。對于根系植食者而言,除了有可能影響根系吸收及刺激微生物生長改變土壤氮水平外,根系損傷導(dǎo)致的含氮物質(zhì)的泄漏勢必也會引起土壤氮素有效性增加[11]。迄今對土壤氮素有效性在作物和地上/地下部害蟲直接影響下的變化了解甚少。實際上,研究土壤氮素有效性在植食者作用下的改變對于進一步了解植食者互作機制,特別是植食者互作引發(fā)的一系列后續(xù)效應(yīng),如對植物之間競爭、土壤生物群落的影響及對地上部的反饋作用均有重要意義。
水稻是我國重要的糧食作物,褐飛虱(Nilaparvata lugens St?l)和潛根線蟲(Hirschmanniella oryzae)分別是水稻地上和地下的重要害蟲。雖然褐飛虱與潛根線蟲在自然條件下共存,并且均可能對水稻生長及土壤養(yǎng)分產(chǎn)生影響,但目前關(guān)于二者交互作用的研究尚未見報道。土壤活性氮(微生物生物量氮、可溶性有機氮以及銨態(tài)氮和硝態(tài)氮)是土壤生態(tài)系統(tǒng)中氮循環(huán)最活躍的部分,在土壤氮素轉(zhuǎn)化和生態(tài)系統(tǒng)氮循環(huán)中具有重要的作用。因此,研究水稻害蟲相互作用對水稻氮吸收及土壤氮的影響對于深入了解地上地下部植食者對土壤生態(tài)系統(tǒng)結(jié)構(gòu)和功能的影響具有重要意義。
1.1 實驗材料
盆栽所用土壤采自江西進賢紅壤研究所內(nèi)的雙季稻田耕層(0~18 cm),土壤母質(zhì)為第四紀紅黏土,屬于潴育型水稻土。鮮土過5 mm篩,剔除其中大中型土壤動物及根茬等,在121℃下滅菌;然后按1%比例接入原土配制的土壤菌懸液(水土比5∶1,孔徑0.023 mm篩網(wǎng)濾去線蟲),調(diào)節(jié)至60%田間含水量,室溫黑暗培養(yǎng)60 d以恢復(fù)和穩(wěn)定土壤微生物群落[12],獲得除去線蟲的原位土壤。培養(yǎng)后土壤的理化性質(zhì)為:有機碳9.7 g kg-1,全氮1.7 g kg-1,有效磷38.3 mg kg-1,速效鉀52.0 mg kg-1。
供試水稻品種為TN1(臺中1號Taichung Native 1),褐飛虱(N. lugens)在室內(nèi)以TN1水稻苗飼養(yǎng)數(shù)代備用,潛根線蟲(H. oryzae)由江西進賢潴育型水稻土中挑選并經(jīng)歷多個世代富集而來[12]。
1.2 盆栽實驗
采用兩因素(褐飛虱和潛根線蟲)完全交互的盆栽實驗。褐飛虱處理包括2水平:未接褐飛虱(CK-N)和接種褐飛虱(N);潛根線蟲處理2水平:未接潛根線蟲(CK-H)和接種潛根線蟲(H);每處理設(shè)4個重復(fù)。
實驗用盆缽裝入相當于1.0 kg干土的上述除去線蟲的培養(yǎng)土壤,待水稻在營養(yǎng)液內(nèi)育苗30 d后,挑選長勢一致的水稻苗,每盆缽移栽8株,定期澆水保持盆缽內(nèi)水面高度為1cm左右,盆缽在玻璃溫室內(nèi)隨機排列并用60目紗網(wǎng)(80 cm×25 cm× 25 cm)罩住防蟲。水稻移栽后15 d、25 d時,分別接潛根線蟲(每盆缽500條,基于田間調(diào)查密度)和褐飛虱(每株10頭,即每盆接80頭4齡若蟲[13]),對照不接蟲。接褐飛虱10 d,植株顯示出危害癥狀,則進行破壞性采樣。
1.3 采樣及分析方法
采樣時將所有褐飛虱用吸蟲器吸取至50 ml塑料離心管中。沿土表剪去水稻植株地上部分,并迅速分離根系與土壤,褐飛虱、莖葉、根系及土壤樣品分別保存。
將采集的褐飛虱樣品在60℃下烘48h后稱量生物量并計數(shù);對于與根系分離后的鮮土樣,用淺盤法分離潛根線蟲,并在體視顯微鏡(Motic SMZ-168,中國)下計數(shù)[14];將水稻莖葉和根系清洗干凈分別稱量鮮重后,放置于烘箱中105℃殺青2 h,60℃下烘72 h,然后取出稱重。水稻莖葉和根系全氮用濃H2SO4-H2O2法消化并用半微量凱氏定氮法測定[15];土壤微生物生物量氮用氯仿熏蒸-K2SO4浸提法,濾液中氮含量測定用半微量凱氏定氮法,熏蒸土樣與未熏蒸土樣的有機氮差值除以轉(zhuǎn)換系數(shù)(KN= 0.45)[16]即為微生物生物量氮;可溶性有機氮用超純水浸提(土∶水=1∶5),過孔徑0.45 μm的醋酸纖維素濾膜后,通過連續(xù)流動分析儀(Skalar,荷蘭)測定;礦質(zhì)氮用2 mol L-1KCl浸提(土∶水=1∶5)后,通過連續(xù)流動分析儀(Skalar,荷蘭)測定。
1.4 數(shù)據(jù)分析
采用SPSS 20.0進行數(shù)據(jù)分析,分析前檢驗數(shù)據(jù)的正態(tài)分布及方差齊性,并在必要時利用對數(shù)轉(zhuǎn)換。以多因素方差分析評估褐飛虱和潛根線蟲對水稻和土壤變量的主效應(yīng)和交互效應(yīng),以獨立樣本T檢驗分析有無褐飛虱的差異,均值的比較檢驗采用最小顯著極差法(LSD)(p<0.05)。
2.1 褐飛虱和潛根線蟲的變化
接入同等數(shù)量的褐飛虱后,與對照相比,潛根線蟲顯著降低了褐飛虱的生物量(圖1A);與對照相比,褐飛虱的存在顯著降低了潛根線蟲的數(shù)量(圖1B)。即地上部植食者褐飛虱與地下部植食者潛根線蟲之間是互相抑制的作用。
2.2 褐飛虱和潛根線蟲互作下水稻生長的變化
與無褐飛虱的對照相比,褐飛虱有降低水稻莖葉生物量的趨勢(圖2A);與無潛根線蟲的對照相比,潛根線蟲有降低水稻莖葉和根系生物量的趨勢(表1,圖2A,圖2B)。
圖1 褐飛虱生物量和潛根線蟲數(shù)量的變化Fig. 1 Biomass of N. lugensand population of H. oryzae
表1 褐飛虱和潛根線蟲互作對水稻性狀和土壤活性氮影響的方差分析結(jié)果(F值)Table 1 ANOVA(F-values)of the effects of N. lugens and H. oryzae on rice performance and soil labile nitrogen
圖2 褐飛虱與潛根線蟲對水稻莖葉和根系生物量的影響Fig. 2 Effects of N. lugens and H. oryzae on rice shoot and root biomass
2.3 褐飛虱和潛根線蟲互作下植株含氮量的變化
與無褐飛虱的對照相比,褐飛虱對水稻地上部和地下部含氮量的影響不顯著(圖3A,圖3B);與無潛根線蟲的對照相比,潛根線蟲顯著降低了水稻地下部含氮量(表1,圖3B)。
2.4 褐飛虱和潛根線蟲互作下土壤活性氮的變化
土壤微生物生物量氮和可溶性有機氮顯著受到兩種植食者的交互影響(表1),無潛根線蟲時,與對照相比,褐飛虱提高了土壤微生物生物量氮和可溶性有機氮;而有潛根線蟲時,褐飛虱對微生物生物量氮和可溶性有機氮的作用不明顯(圖4A,4B)。與無潛根線蟲的對照相比,潛根線蟲顯著影響了微生物生物量氮(表1,圖4A)。潛根線蟲與褐飛虱的共同取食有提高土壤銨態(tài)氮含量的趨勢(圖4C)。無潛根線蟲時,與無褐飛虱的對照相比,褐飛虱顯著降低了土壤硝態(tài)氮含量(圖4D)。總體上,相比褐飛虱,潛根線蟲有提高土壤活性氮總量的趨勢(表1,圖5)。
圖3 褐飛虱與潛根線蟲對水稻莖葉和根系含氮量的影響Fig. 3 Effects of N. lugens and H. oryzae on nitrogen content in shoot and root of the rice plant
圖4 褐飛虱和潛根線蟲對土壤微生物生物量氮、可溶性有機氮、銨態(tài)氮和硝態(tài)氮的影響Fig. 4 Effects of N. lugens and H. oryzae on microbial biomass nitrogen,dissolved organic nitrogen,ammonium nitrogen and nitrate nitrogen
圖5 褐飛虱和潛根線蟲對土壤活性氮的影響Fig. 5 Effects of N. lugens and H. oryzae on soil labile nitrogen
3.1 地上和地下植食者互作對水稻生物量和氮分配的影響
越來越多的研究表明地上和地下部生物雖然有距離上的分隔,但可通過宿主植物相互影響[17-18]。本研究結(jié)果發(fā)現(xiàn),褐飛虱和潛根線蟲存在相互抑制的作用,這與已有研究結(jié)果一致[19-20]。水稻受到潛根線蟲的侵染后生物量減少,即對于褐飛虱而言,其食物資源減少,因此,與對照相比生長發(fā)育受到影響,生物量也隨之下降。此外,根系植食者的取食可能提高了宿主植物莖葉內(nèi)抗性物質(zhì)如萜類物質(zhì)和酚類物質(zhì)的含量,或通過刺激植物揮發(fā)物質(zhì)的釋放,吸引地上部植食者的天敵,進而對地上部植食者產(chǎn)生了消極的作用[21]。潛根線蟲數(shù)量的降低可能由于一方面褐飛虱的取食嚴重損傷了地上部植株,降低了水稻光合作用,減少了運輸?shù)礁档臓I養(yǎng)物質(zhì)含量[22],另一方面可能是植食者的取食改變了根系分泌物的數(shù)量和質(zhì)量,從而抑制了根系植食者[21]。
水稻在植株生長發(fā)育過程中根系主要吸收水分和養(yǎng)分,莖葉則主要進行光合作用。本研究結(jié)果顯示,褐飛虱降低了水稻莖葉生物量,而潛根線蟲同時降低了水稻莖葉和根系的生物量,這與已有研究結(jié)果一致[23-24]。褐飛虱可直接通過刺吸水稻莖葉組織的汁液,阻礙稻株體內(nèi)水分和養(yǎng)分的運輸,降低水稻同化作用,進而影響水稻的生長[25],也可間接通過影響根系分泌物的數(shù)量和質(zhì)量,改變土壤微生物的群落結(jié)構(gòu)和根際土壤有效養(yǎng)分[26],進而影響水稻的生長。潛根線蟲的取食能直接危害水稻根系,降低根系對水分和養(yǎng)分的吸收功能,抑制水稻莖葉和根系的生長,也可間接通過根系損傷引起物質(zhì)泄漏,促進根際土壤有效養(yǎng)分的增加,影響土壤微生物的群落結(jié)構(gòu)和功能[27],進一步通過影響土壤養(yǎng)分的供應(yīng)和吸收改變水稻的生長。
氮作為生物體必需大量元素之一,是核酸、蛋白質(zhì)和葉綠體的組成元素。本研究結(jié)果顯示,褐飛虱對水稻莖葉和根系氮含量的影響不明顯,潛根線蟲降低了水稻根系含氮量,這與潛根線蟲抑制水稻生長的趨勢一致,與已有研究結(jié)果一致[28]。有關(guān)植物對植食者耐受性的實驗表明,植物受到侵害后會將新攝取的氮資源運移受害部位以減輕自身損害[29],但是植物對這部分資源的利用方式多樣,如將資源儲存起來,用于其他部位代謝性增長,產(chǎn)生抗性物質(zhì),或通過根系分泌到土壤中[30]。潛根線蟲的取食會損傷水稻根系,可能導(dǎo)致含氮物質(zhì)的泄漏[27]。根系分泌物的增加和含氮物質(zhì)的泄漏都會刺激土壤微生物的發(fā)展[31],從而可能影響土壤微生物參與的礦化和硝化過程,進一步影響植物對養(yǎng)分的吸收。
3.2 褐飛虱和潛根線蟲互作對土壤活性氮的影響
土壤微生物生物量氮是土壤中最活躍的氮庫之一,轉(zhuǎn)化較快、有效性高[32]。土壤可溶性有機氮代表了土壤生態(tài)系統(tǒng)中活躍的有機物組分,來自于外源有機物的分解和土壤有機質(zhì)的微生物礦化過程,是土壤微生物可直接利用的主要氮素來源,也是土壤微生物代謝活動的中間產(chǎn)物[33]。本研究發(fā)現(xiàn),褐飛虱與潛根線蟲均有提高土壤微生物生物量氮的趨勢,與已有研究結(jié)果一致[34]。這是因為一方面根系植食者的取食能夠通過對植物根系的機械性損傷,引起根系內(nèi)營養(yǎng)物質(zhì)“滲漏”到土壤中,促進根際土壤有效養(yǎng)分的增加,另一方面植食者的取食可直接增加根系分泌物,促進根際土壤有效養(yǎng)分的增加和土壤生物群落的發(fā)展[35],也可誘發(fā)植物的耐受性反應(yīng),間接地促進其地上部營養(yǎng)物質(zhì)向根系的分配,進一步促進了根際土壤資源和生物群落的發(fā)展[36]。褐飛虱與潛根線蟲對土壤微生物生物量氮存在交互作用,這是因為在水稻已經(jīng)受到潛根線蟲侵害的情況下,褐飛虱的取食作用會加劇植食者對植物的負面影響,使其受到抑制,可能會減少根系分泌物數(shù)量,土壤生物活性也隨之降低。
氮的轉(zhuǎn)化尤其是有機氮向礦質(zhì)氮的轉(zhuǎn)化是生態(tài)系統(tǒng)中養(yǎng)分循環(huán)的重要過程。目前,已有研究發(fā)現(xiàn),植食者對礦質(zhì)氮的作用可以是積極的、中性的,也可以是消極的[9,35,37]。本研究中,褐飛虱和潛根線蟲均影響了土壤礦質(zhì)態(tài)氮水平。二者的取食作用有提高土壤銨態(tài)氮含量的趨勢,這與已有研究結(jié)果一致[23],原因可能主要是植食者的取食降低了根系吸收能力。褐飛虱有降低土壤硝態(tài)氮含量的趨勢,這與已有研究結(jié)果一致[35],由于土壤礦質(zhì)氮受到多種因素的交互影響,特別是與植物吸收以及微生物的競爭和礦化能力有關(guān),所以其中的機制還很難解釋。植食者對土壤礦質(zhì)氮作用的影響存在爭議,可能與取食強度、植物種類及土壤生物群落結(jié)構(gòu)等有關(guān)??傊诛w虱和潛根線蟲對土壤活性氮各組分的影響存在差異,但總體上看,潛根線蟲對土壤活性氮有促進趨勢,其原因涉及復(fù)雜的氮素轉(zhuǎn)化和植物吸收過程,今后需要利用氮同位素標記技術(shù)及對氮素不同形態(tài)的細致分析深入探究。
褐飛虱和潛根線蟲之間表現(xiàn)出相互抑制作用,二者共存加劇了對水稻生長的危害。潛根線蟲的取食顯著降低了植株根系生物量和含氮量。褐飛虱和潛根線蟲對土壤活性氮的影響格局較為復(fù)雜,相比褐飛虱,潛根線蟲有促進土壤活性氮提高的趨勢,這可能會促進以氮轉(zhuǎn)化過程為主的土壤生態(tài)功能的發(fā)揮。今后需要采用同位素示蹤技術(shù)和質(zhì)譜技術(shù)進一步了解植食者作用下地上和地下部的養(yǎng)分轉(zhuǎn)化與分配的聯(lián)動機制。
[1]Wardle D A,Bardgett R D,Klironomos J N,et al. Ecological linkages between aboveground andbelowground biota. Science,2004,304(5677):1629—1633
[2]Bardgett R D,Wardle D A. Aboveground-belowground linkages. New York:Oxford University Press,2010
[3]Bardgett R D,van der Putten W H. Belowground biodiversity and ecosystem functioning. Nature,2014,515(7528):505—511
[4]Bardgett R D,Wardle D A. Herbivore-mediated linkages between aboveground and belowground communities. Ecology,2003,84(9):2258—2268
[5]Kafle D,Kr?hmer A,Naumann A,et al. Genetic variation of the host plant species matters for interactions with above-and belowground herbivores. Insects,2014,5(3):651—667
[6]Huang W,Siemann E,Carrillo J,et al. Below-ground herbivory limits induction of extrafloral nectar by aboveground herbivores. Annals of Botany,2015,115 (5):841—846
[7]Barber N A,Kiers E T,Theis N,et al. Linking agricultural practices,mycorrhizal fungi,and traits mediating plant-insect interactions. Ecological Applications,2013,23(7):1519—1530
[8]栗治,劉小俠,張青文. 不同氮水平對麥二叉蚜生長發(fā)育和繁殖的影響. 應(yīng)用昆蟲學(xué)報,2014,51(2):353—359
Li Z,Liu X X,Zhang Q W. Effects of nitrogen fertilizer on the development and fecundity of Schizaphis graminum(Rondani)(In Chinese). Chinese Journal of Applied Entomology,2014,51(2):353—359
[9]Bagchi S,Ritchie M E. Herbivore effects on aboveand belowground plant production and soil nitrogen availability in the Trans-Himalayan shrub-steppes. Oecologia,2010,164(4):1075—1082
[10]Noboru K,Alessandro O S,Osamu K,et al. Herbivorous insect decreases plant nutrient uptake:The role of soil nutrient availability and association of below-ground symbionts. Ecological Entomology,2014,39(4):511—518
[11]Treonis A M,Murray P J,Dawson L A. Effects of root feeding,cranefly larvae on soil microorganisms and the composition of rhizosphere solutions collected from grassland plants. Applied Soil Ecology,2005,28 (3):203—215
[12]毛小芳,李輝信,龍梅,等. 不同食細菌線蟲取食密度下線蟲對細菌數(shù)量、活性及土壤氮素礦化的影響. 應(yīng)用生態(tài)學(xué)報,2005,16(6):1112—1116
Mao X F,Li H X,Long M,et al. Effects of bacteria-feeding nematode at its different density on bacterial number,bacterial activity and soil nitrogen mineralization(In Chinese). Chinese Journal of Ecology,2005,16(6):1112—1116
[13]Huang J H,Liu M Q,Chen X Y,et al. Effects of intraspecific variation in rice resistance to aboveground herbivore brown planthopper,and rice root nematodes on plant yield,labile pools of plant and rhizosphere soil. Biology and Fertility of Soils,2015,51(4):417—425
[14]Alef K,Nannipieri P. Methods in applied soil microbiology and biochemistry. London:Academic Press,1995
[15]魯如坤. 土壤農(nóng)業(yè)化學(xué)分析方法. 北京:中國農(nóng)業(yè)科技出版社,2000
Lu R K. Analytical methods for soil and agro-chemistry (In Chinese). Beijing:China Agricultural Science and Technology Press,2000
[16]Witt C,Biker U,Galicia C C,et al. Dynamics of soil microbial biomass and nitrogen availability in a flooded rice soil amended with different C and N sources. Biology and Fertility of Soils,2000,30(5):520—527
[17]Johnson S N,Clark K E,Hartley S E,et al. Aboveground-belowground herbivore interactions:Ameta-analysis. Ecology,2012,93(10):2208—2215
[18]Olga K,Patrick P J M,Bezemer T M. Effects ofroot herbivory on pyrrolizidine alkaloid content and aboveground plant-herbivore-parasitoid interactions in Jacobaea vulgaris. Journal of Chemical Ecology,2013,39(1):109—119
[19]Kaplan I,Sardanelli S,Rehill B J,et al. Toward a mechanistic understanding of competition in vascularfeeding herbivores:An empirical test of the sink competition hypothesis. Oecologia,2011,166(3):627—636
[20]Magdalene K,Marcus P,Caroline M. Effects of root herbivory by nematodes on the performance and preference of a leaf-infesting generalist aphid depend on nitrate fertilization. Journal of Chemical Ecology,2014,40(2):118—127
[21]Bezemer T M,van Dam N M. Linking aboveground and belowground interactions via induced plant defenses. Trends in Ecology and Evolution,2005,20(11):617—624
[22]Meldau S,Woldemariam M,F(xiàn)atangare A,et al. Using 2-deoxy-2-[18F]fluoro-D-glucose([18F]FDG)to study carbon allocation in plants after herbivore attack. BMC Reaearch Notes,2015,8(1):1—9
[23]Huang J H,Liu M Q,Chen X Y,et al. Intermediate herbivory intensity of an aboveground pest promotes soil labile resources and microbial biomass via modifying rice growth. Plant and Soil,2013,367(1/2):437—447
[24]Tsunoda T,Kachi N,Suzuki J I. Effects of belowground vertical distribution of a herbivore on plant biomass and survival in Lolium perenne. Ecological Research,2014,29(2):351—355
[25]Senthil-Nathan S,Choi M Y,Paik C H,et al. Toxicity and physiological effects of neem pesticides applied to rice on the Nilaparvata lugens,St?l,the brown planthopper. Ecotoxicology and Environmental Safety,2009,72(6):1707—1713
[26]Frost C J,Hunter M D. Herbivore-induced shifts in carbon and nitrogen allocation in red oak seedlings. New Phytologist,2008,178(4):835—845
[27]Dromph K M,Cook R,Ostle N J,et al. Root parasite induced nitrogen transfer between plants is density dependent. Soil Biology &Biochemistry,2006,38 (8):2495—2498
[28]Kaplan I,Sardanelli S,Denno R F. Field evidence for indirect interactions between foliar-feeding insect and root-feeding nematode communities on Nicotianatabacum. Ecological Entomology,2009,34 (2):262—270
[29]Haase J,Brandl R,Scheu S,et al. Above and belowground interactions are mediated by nutrient availability. Ecology,2008,89(11):3072—3081
[30]Xoaquín M,Rafael Z,Luis S. Genetic variation and phenotypic plasticity of nutrient re-allocation and increased fine root production as putative tolerance mechanisms inducible by methyl jasmonate in pine trees. Journal of Ecology,2012,100(3):810—820
[31]Rogers C D,Evans K A. Wheat bulb fly,Delia coarctata,larval attraction to phenolic components of host-plant root exudates. Entomologia Experimentalis Et Applicata,2014,150(2):166—173
[32]張奇春,王光火,方斌. 不同施肥處理對水稻養(yǎng)分吸收和稻田土壤微生物生態(tài)特性的影響. 土壤學(xué)報,2005,42(1):116—121
Zhang Q C,Wang G H,F(xiàn)ang B. Influence of fertilization treatment on nutrients uptake by rice and soil ecological characteristics of soil microorganism in paddy field(In Chinese). Acta Pedologica Sinica,2005,42(1):116—121
[33]趙滿興,Kalbitz Karsten,周建斌. 黃土區(qū)幾種土壤培養(yǎng)過程中可溶性有機碳、氮含量及特性的變化. 土壤學(xué)報,2008,45(3):476—484
Zhao M X,Karsten K,Zhou J B. Variation of content and structural characteristics of dissolved organic carbon and nitrogen in soluble organic matter during mineralization of several soils in the loess region(In Chinese).Acta Pedologica Sinica,2008,45(3):476—484
[34]Klumpp K,F(xiàn)ontaine S,Attard E,et al. Grazing triggers soil carbon loss by altering plant roots and their control on soil microbial community. Journal of Ecology,2009,97(5):876—885
[35]Olsen Y S,Dausse A,Garbutt A,et al. Cattle grazing drives nitrogen and carbon cycling in a temperate salt marsh. Soil Biology &Biochemistry,2011,43(3):531—541
[36]Nalam V J,Shah J,Nachappa P. Emerging role of roots in plant responses to aboveground insect herbivory. Insect Science,2013,20(3):286—296
[37]Liu Y S,Pan Q M,Liu H D,et al. Plant responses following grazing removal at different stocking rates in an Inner Mongolia grassland ecosystem. Plant and Soil,2011,340(1/2):199—213
Effects of Interactions of Above- and Below-ground Herbivores on Nitrogen Distribution in Rice Plant and Labile Nitrogen in Soil
GUO Ruihua1LUO Ling1ZHANG Tenghao1,2LIU Manqiang1CHEN Xiaoyun1?HU Feng1
(1 Soil Ecology Laboratory,College of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095,China)
(2 Hebei Province Instituteof Supervision and Inspection Product Quality,Shijiazhuang 050000,China)
【Objective】Interactions between aboveground and belowground herbivores sharing the same host plantare regarded as the basic linkage between aboveground and belowground ecosystems,though they are separated in space. Much work has been done demonstrating that soil nitrogen availability affects the herbivores via plant by regulating chemical composition,such as nitrogen content of the plant. However,little has been reported on effects of the interactions between the two groups of herbivores on soil nitrogen. In this paper,a microcosm experiment was designed to investigate effects of the interactions between the herbivores on nitrogen distribution in the plant and labile nitrogen(microbial biomass nitrogen,dissolved organic nitrogen,ammonium nitrogen and nitrate nitrogen)in the soil. 【Method】In this study,Nilaparvata lugens and Hirschmanniella oryzae were selected as representative of the two groups,aboveground and belowground herbivores,respectively,and a pot experiment was designed to have two rates of Nilaparvata lugens,(zero or eight individuals per plant),and two rates of Hirschmanniella oryzae(zero or 500 individuals per pot),totaling four treatments and four replicates for each treatment. The soil used in the pot was first sterilized under 121℃ to kill all the native nematodes,and then was inoculated with the soil bacterial suspension prepared out of the original soil that had been deprived of soil nematodes,and put into a dark incubator for 60 days of incubation under indoor temperature to restore and stabilize microbial communities in the soil. Rice seedlings were transplanted into the pots after 30 days of seedling nursing in nutrient solution. Hirschmanniella oryzae and Nilaparvata lugens was inoculated separately on the fifteenth and twenty fifth day after rice seedlings were transplanted. Ten days after the inoculation of Nilaparvata lugens,samples of the plants and soil were collected. Plant samples were separated into shoot and root for measurement of biomass and nitrogen content,separately. Soil samples were analyzed,separately,for microbial biomass nitrogen,dissolved organic nitrogen,ammonium nitrogen and nitrate nitrogen.【Result】Results showed that Nilaparvata lugens and Hirschmanniella oryzae negatively affected each other. Nilaparvata lugens tended to decrease shoot biomass,but did not affect much root biomass,while Hirschmanniella oryzae significantly reduced shoot and root biomass(p< 0.05). Nilaparvata lugens showed no significant effect on shoot and root nitrogen content,while Hirschmanniella oryzae significantly reduced root nitrogen content(p< 0.05),though they did not affect much shoot nitrogen content. Significantly interactive effects of aboveground and belowground herbivores on soil labile nitrogen were observed. In the absence of Hirschmanniella oryzae,Nilaparvata lugens significantly increased the content of microbial biomass nitrogen(p< 0.05)and decreased nitrate content significantly(p< 0.05),but did not have much effect on dissolved organic nitrogen and ammonium nitrogen,whereas in the presence of Hirschmanniella oryzae,they did not affect the content of soil labile nitrogen significantly. On the other hand,Hirschmanniella oryzae significantly and positively affected the content of microbial biomass nitrogen and total soil labile nitrogen(p<0.05). 【Conclusion】To sum up,the effects of the interactive suppressions between the aboveground and belowground herbivores on nitrogen content in shoot and root of the rice plants and on soil labile nitrogen are rather complicated. Moreover,compared with Nilaparvata lugens,Hirschmanniella oryzae tends to increase total soil labile nitrogen,which may in turn improve N-transformation-related ecological functions of the soil.
Nilaparvata lugens;Hirschmanniella oryzae;Nitrogen allocation;Microbial biomass nitrogen;Dissolved organic nitrogen;Inorganic nitrogen
S154.1
A
10.11766/trxb201605110159
(責(zé)任編輯:陳榮府)
* 國家自然科學(xué)基金項目(31170487)和江蘇高校優(yōu)勢學(xué)科建設(shè)工程(PAPD)資助 Supported by the National Natural Science Foundation of China(No. 31170487)and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PADA)
? 通訊作者 Corresponding author,E-mail:xychen@njau.edu.cn
郭瑞華(1986—),女,河南周口人,碩士研究生,主要研究地上與地下部生態(tài)系統(tǒng)之間的聯(lián)系。E-mail:ruizhognrui@163.com
2016-05-11;
2016-07-04;優(yōu)先數(shù)字出版日期(www.cnki.net):2016-07-22