生态学报  2014, Vol.34 Issue (4): 847-852

文章信息

刘恩太, 李园园, 胡艳丽, 孙传香, 毛志泉
LIU Entai, LI Yuanyuan, HU Yanli, SUN Chuanxiang, MAO Zhiquan
棉隆对苹果连作土壤微生物及平邑甜茶幼苗生长的影响
Effects of dazomet on edaphon and growth of Malus hupehensis rehd. under continuous apple cropping
生态学报, 2014, 34(4): 847-852
Acta Ecologica Sinica, 2014, 34(4): 847-852
http://dx.doi.org/10.5846/stxb201306091546

文章历史

收稿日期:2013-6-9
修订日期:2013-10-21
棉隆对苹果连作土壤微生物及平邑甜茶幼苗生长的影响
刘恩太1, 3, 李园园2, 胡艳丽1, 孙传香1, 毛志泉1     
1. 山东农业大学园艺科学与工程学院/作物生物学国家重点实验室, 泰安 271018;
2. 青岛明月蓝海生物科技有限公司, 青岛 266400;
3. 山东银香伟业集团有限公司, 菏泽 274400
摘要:以生产上常用苹果砧木——平邑甜茶为试材,盆栽条件下研究了棉隆微粒剂对苹果连作土壤微生物及平邑甜茶幼苗生长的影响。结果表明:与重茬(对照CK)相比,棉隆处理极显著(P <0.01)降低了连作土壤中真菌数量,降幅达58.8%,细菌和放线菌数量分别显著(P <0.05)降低15.3%、8.5%,细菌/真菌增加108.8%,放线菌/真菌增加124.2%;棉隆使连作条件下平邑甜茶单株幼苗根系长度、根表面积、根体积和根系活力分别提高421.4%、426.5%、171.7%、48.8%。平邑甜茶植株叶面积以及叶片中叶绿素a、b含量、净光合速率均极显著提高,分别增加162.6%、14.9%、15.0%、24.0%,叶片同化能力增强;植株长势增强,株高和地径均极显著提高,植株地上干鲜重和地下干鲜重也得到了极显著性增加,最高增加幅度达2.2 倍。综上,棉隆处理后苹果连作土壤中微生物数量降低,而细菌与真菌比值、放线菌与真菌比值增加,平邑甜茶幼苗植株长势增强,棉隆可有效减轻苹果连作障碍发生。
关键词棉隆    连作    平邑甜茶    微生物    
Effects of dazomet on edaphon and growth of Malus hupehensis rehd. under continuous apple cropping
LIU Entai1, 3, LI Yuanyuan2, HU Yanli1, SUN Chuanxiang1, MAO Zhiquan1     
1. College of Horticultural Science and Engineering, Shandong Agriculture University/State Key Laboratory of Crop Biology, Taian 271018, China;
2. Qingdao Bright Moon Bluesea Bio-Tech Co, LTD, Qingdao, Shandong 266400, China;
3. Good Earth Group, Heze, Shandong 274400, China
Abstract:ARP (Apple replant problem, ARP), which is also known as the continuous cropping obstacles of apple, influences the cultivation of replanted fruit trees. It occurs in all major apple planting regions throughout the world. Generally, it is believed that both biotic and abiotic factors act together to cause ARP, and that the biotic factors are recognized as the main cause of continuous cropping obstacles. This study aims to examine the responses of Malus hupehensis Rehd. and edaphon to dazomet, which was used to alleviate ARP, and to develop an effective method to prevent and cure ARP. The study was carried out in 2012 at the State Key Laboratory of Crop Biology and College of Horticulture of Shandong Agricultural University. The trees were planted in pairs in containers filled with loamy sand. The apple sick soil was originated from a remediate 20-year-old apple orchard. The soil was mixed with dazomet at the ratio of 0.5 g/kg before tree planting. Trees grown in the soil untreated with dazomet served as the control. Trees were dripirrigated consistently. The results showed that compared with the control, dazomet inhibited the growth of fungi, actinomycetes and bacteria under continuous cropping conditions. Dazomet treatments noticeably decreased the numbers of fungi, bacteria and actinomycetes by 58.8% (P <0.01), 15.3% and 8.5% (P <0.05), respectively. Therefore, dazomet had the most inhibition effect on fungi, and the lowest on actinomycetes. With respect to the ratio of bacteria (actinomycetes) to fungi,the ratio of bacteria and actinomycetes to fungi increased by 108.8% and 124.2%, respectively. Compared with control, the dazomet had significantly increased the length of roots, surface area of roots, total roots volume and root activity by 4.2, 4.3, 1.7, 0.49 times, respectively. The dazomet generally enhanced root biomass and improved the function of root under continuous cropping conditions. All these differences in content were statistically significant (P <0.01). The roots play crucial roles in plant. The roots affect the growth and development of aboveground plant, which inclued the growth of foliage, starkrimsom of leaves, forming of flower buds and the reproductive growth of trees. The assimilation ability of leaves increased upon treated with dazomet under continuous cropping conditions. Compared with the control, the area of leaves, content of chlorophyll a, content of chlorophyll b and net photosynthetic rate significantly (P <0.01) increased by 162.6%, 14.9%, 15.0%, 24.0%, respectively, after treated with dazomet. Plant height, geoxyl, root and shoot biomass showed a general growth (P <0.01). The dry weight of the plant above the ground and underground also had extremely significant increase (P <0.01). The highest increase rate was up to 2.2 times. In conclusion, the above-mentioned parameters show that dazomet improved vigor of trees by inhibiting the growth of fungi, actinomycetes, bacteria on replant disease sites.
Key words: dazomet    continuous cropping    Malus hupehensis Rehd.    edaphon    

随着苹果园进入老龄化阶段,果园更新和连作(重茬)栽培在所难免。苹果连作障碍是在原地连作栽培时所发生的综合病症,主要表现为苹果植株新梢生长发育迟钝、生长势减弱,甚至植株死亡,果园寿命缩短,苹果连作障碍在世界各苹果主产区普遍发生[1, 2],其发病原因复杂,常归因于非生物因素和生物因素,且生物因素是主要原因[3, 4]。Rumberger等[5]研究也发现在老苹果园中,根际细菌和真菌群落结构发生了一定变化。Mazzola等[6]研究发现苹果再植园土壤中微生物系统随着栽培时间的增加而发生变化,认为导致苹果连作障碍直接原因为土壤微生物群落组成的变化。van Schoor等[7]研究发现镰刀菌、疫霉菌、丝核菌、腐霉菌等有害真菌与苹果连作障碍有一定的关系。目前,客土、轮作、施用有机物料、选择抗性砧木及土壤熏蒸等可减轻苹果连作障碍。而在生产中,客土成本高[8],轮作不宜长期使用且防治效果不如土壤熏蒸,施用有机物料在一些地区取材不便等种种因素限制着其在生产中的应用。土壤化学熏蒸是克服连作病害有效措施,在生产中广泛应用[9, 10]。而一些化学物质由于对环境存在危害逐渐被禁止,如溴甲烷[11]。因此寻找高效、低毒、低成本的环保型土壤熏蒸措施非常重要。棉隆,又名必速灭、垄鑫、二甲噻嗪,分子式C5H10N2S2,为环保型广谱性土壤熏蒸消毒剂,可杀灭土壤中真菌、细菌、线虫、杂草种子等[12, 13, 14, 15, 16]。本研究以生产常用苹果砧木平邑甜茶为试材,探讨棉隆对苹果连作土壤微生物及平邑甜茶幼苗生长的影响,为减缓苹果连作障碍提供新方法及理论依据。

1 材料与方法 1.1 实验材料与处理

试验于2012 年在山东农业大学园艺科学与工程学院/作物生物学国家重点实验室进行。供试材料为平邑甜茶(Malus hupehensis Rehd.),于4 ℃左右将平邑甜茶种子层积30 d,种子露白后在育苗盘播种育苗。幼苗长至6 片真叶将其移至装有7.5 kg苹果连作土的外径29 cm,内径25 cm,深20 cm的泥瓦盆中。试验用连作土取自山东省泰安市宁阳县磁窑镇20 年生红富士苹果园,砧木为八棱海棠(M. micromalus),土壤类型为褐土,土壤pH为7.4,硝态氮含量为11.39 mg/kg,铵态氮含量为2.32 mg/kg,速效钾含量为70.0 mg/kg,速效磷含量为25.4 mg/kg,有机质含量为5.1 g/kg。苹果连作土收集于距树干1 m,深5—40 cm范围内的土壤,多点取样,混匀使用。苹果连作土均匀装盆,设为CK;于栽植幼苗前45 d将棉隆(98%微粒剂)施入苹果连作土壤中,每盆施入棉隆3.75 g,充分混匀后装盆,设为T,放置45 d后(4 月27 日)种植幼苗。每盆栽植幼苗2 株,每处理30 盆。采样时,各处理随机选取3 盆,每盆选取1 棵植株进行测定,即每处理3 次重复。

1.2 测定方法 1.2.1 植株生物量的测定

于7 月15 日、8 月15 日、9 月15 日用常规方法测定幼苗植株株高和地径。于8 月15日完整取出植株地上部和根系,清洗干净,阴凉处晾干后测定地上部干重和根系干重;再将地上部和根系烘干后测定干重。

1.2.2 叶绿素含量的测定

参照赵世杰等[17]的方法于8 月15 日统一选取幼苗同一部位6—9 片健康成熟叶片,洗净,擦干后用剪刀切碎,取样品0.2 g,加20 mL,80%丙酮,置于暗处浸提24 h,于665、649、470 nm下比色,由下列公式求得叶绿素、类胡萝卜素的含量[17]

式中,D470D649D665分别为提取液在波长470 nm、649 nm、665 nm下的光密度;CaCb分别为叶绿素a、叶绿素b。

1.2.3 叶面积和净光合速率的测定

于8 月15 日统一选取幼苗同一部位健康成熟叶片,利用PP-Systems公司生产的CIRAS-2型便携式自动光合仪测定叶片净光合速率。于9:30—10:30天气晴朗时测定。用常规法测定叶面积。

1.2.4 根系相关指标的测定

于8 月15 日将幼苗取出,根系小心用水洗净后,将根系放于盛有水的硬塑料板中,并将根系展开,用专业版WinRHIZO(2007 年版)根系分析系统分析处理样品图像,记录根系表面积、体积、长度和根尖数。采用赵世杰等[17]TTC比色法测定根系活力。

1.2.5 土壤微生物的测定

8 月15 日采集土样,细菌采用牛肉膏蛋白胨培养基,真菌采用马丁氏培养基,放线菌常用高氏1 号培养基。微生物的培养采用平板梯度稀释培养法[18]

1.2.6数据处理

采用SPSS 18统计分析软件进行t检验:P<0.05,有显著差异;P<0.01,有极显著差异。

2 结果与分析 2.1 棉隆对连作条件下植株株高、地径及生物量的影响

图 1所示,CK和T处理之间株高、地径在7、8、9 月份表现出相同的趋势:T > CK,差异均达到极显著性水平(不同大写字母代表处理间达到0.01水平极显著差异)。棉隆处理均提高了连作条件下平邑甜茶幼苗的株高和地径,株高增幅为63%—100%,地径增幅为59%—117%。

图1 棉隆对植株株高、地径的影响 Fig. 1 Effects of dazomet on plant height and geoxyl

表 1可知,CK与T之间地上干、鲜重、地下干、鲜重均存在极显著性差异。植株地上、地下干鲜重增加幅度为160.6%—223.9%。因此,棉隆处理极显著提高了连作条件下平邑甜茶幼苗生物量。

表1 棉隆对单株幼苗干鲜重的影响 Table 1 Effects of dazomet on fresh weight and dry weight
指标Index棉隆Dazomet对照CK增长率Growth rate/%
*P < 0.05,差异显著;**P <0.01,差异极显著;CK:重茬对照
鲜重Fresh weight/g地上shoot40.00±1.11* *15.35±0.33160.6
地下root49.05±1.53* *17.51±1.58180.1
干重Dry weight/g地上shoot20.06±1.07* *6.66±0.23201.2
地下root22.25±1.33* *6.87±0.10223.9
2.2 棉隆对植株叶面积、叶片叶绿素含量和净光合速率的影响

棉隆处理对连作条件下平邑甜茶幼苗叶片相关指标的影响如表 2所示,T处理叶面积、叶绿素含量及净光合速率均高于CK。与CK相比,T处理植株叶片叶面积、净光合速率、叶绿素a含量、叶绿素b含量显著上升,叶面积分别增加162.6%、24.0%、14.9%、15.0%,差异均达到极显著性水平。

表2 棉隆对单株幼苗叶面积、叶片净光合速率和叶绿素含量的影响 Table 2 Effects of dazomet on area of leaf,net photosynthetic rate and content of chlorophyll
处理
Treatment
叶面积
The area of leaf
/cm2
净光合速率
Net photosynthetic rate
/(μmol CO2·m-2·S-1)
叶绿素a含量
Content of chlorophyll a
/(mg/g鲜重)
叶绿素b含量
Content of chlorophyll b
/(mg/g鲜重)
对照 CK31851±199419.2±0.30.2158±0.00550.0619±0.0029
棉隆 Dazomet83635±3572* *23.8±0.3* *0.2480±0.0010* *0.0712±0.0010* *
2.3 棉隆对连作条件下平邑甜茶根系的影响

表 3所示,CK与T处理之间幼苗根系根长度、根表面积、根体积和根系活力均存在极显著性差异。与CK相比,T处理植株根系根长度、根表面积、根体积和根系活力分别增加421.4%、426.5%、171.7%、48.8%。

表3 棉隆对单株幼苗根系的影响 Table 3 Effects of dazomet on the roots
处理
Treament
根长度
Roots length/cm
根表面积
Roots surface/cm2
根体积
Roots volume/cm3
根系活力
Root activity/(μg·h-1·g-1 鲜重)
对照 CK812.6±78.4118.7±10.42.05±0.7376.9±9.3
棉隆 Dazomet4236.5±208.8* *625.0±60.8* *5.57±1.29* *114.4±10.2* *
2.4 连作条件下不同处理对土壤微生物的影响

表 4可知,CK与T处理土壤中细菌和放线菌数量存在显著差异,而真菌数量存在极显著差异。与CK相比,T处理土壤中细菌、放线菌和真菌数量分别降低15.3%、8.5%、58.8%,真菌降低幅度远远大于细菌和放线菌。因此,T处理使连作土壤中细菌/真菌和放线菌/真菌增加,增加幅度分别为108.8%、124.2%。

表4 棉隆对土壤微生物的影响 Table 4 Effects of dazomet on edaphon
处理
Treatment
细菌
Bacteria
/(×105CFU/g)
放线菌
Actinomyces
/(×105CFU/g)
真菌
Fungi
/(×105CFU/g)
细菌/真菌
Bacteria/
Fungi
放线菌/真菌
Actinomyces/
Fungi
对照CK217.3±12.5*76.2±2.4*2.38±0.27* *91.6±5.732.2±3.6
棉隆Dazomet184.0±14.769.7±3.10.98±0.12191.3±37.3* *72.2±11.5* *
3 结论与讨论

苹果连作障碍是国内外苹果主产区普遍存在的问题。苹果连作条件下,苹果植株根系数量减少、功能减弱,生长势减弱。苹果连作障碍是由生物和非生物因素引起。有研究认为苹果连作障碍主要原因为土壤中微生物群落组成发生变化、有害真菌数量增加等生物因素。目前,土壤熏蒸消毒是克服苹果连作障碍的有效方法之一。棉隆是一种环保型广谱性土壤熏蒸消毒剂,其消毒原理为:当棉隆同潮湿土壤接触时能转化成具有土壤消毒特性的挥发性物质如异硫氰酸甲酯气体[12, 14],能够杀死土壤中线虫、有害昆虫、真菌、细菌、杂草种子等。Mao等[11]研究

发现,棉隆能够大幅度降低黄瓜连作土壤中Fusarium spp.和Phytophthora spp. 2 种主要有害真菌。同时,Fusarium spp.和Phytophthora spp.也是引起苹果连作障碍的主要有害真菌[7]。土壤中微生物与土壤系统稳定性和功能发挥存在重要关系。土壤中真菌、细菌、放线菌三大类微生物数量直接影响着土壤生化活性及土壤养分的组成和转化,其中多数真菌是重要的植物病原菌,同时也有与植株共生或为植物提供营养、水分等的有益真菌。一般而言,土壤中放线菌和细菌数量越多,真菌数量越少,细菌/真菌越高,就越有利于作物生长[19, 20]。本研究表明棉隆极显著性降低了苹果连作土壤中真菌、细菌和放线菌数量,降低幅度由大到小依次为:真菌 > 细菌 > 放线菌。因此,棉隆使苹果连作土壤中细菌/真菌和放线菌/真菌增加。同时棉隆处理后根系长度、表面积、体积等显著增加,可能由于棉隆处理后土壤中真菌数量大幅度降低,细菌与真菌比值极显著增加,从而改善了连作土壤环境,为平邑甜茶植株根系创造了良好的生长环境。棉隆处理后根系数量和功能增加进而有利于地上部生理活动的进行。本研究地上相关数据显示,棉隆处理后,叶片中叶绿素含量显著增加,净光合速率显著提升,光合作用是果树植株营养生长和生殖生长的基础和重要生理功能,净光合速率是衡量植株叶片光合生产能力的主要参数,光合作用主要依赖于叶绿体内的色素,而叶片中叶绿素含量的高低能够反映叶片光合作用能力,影响着植株叶片净光合速率和同化物的积累,棉隆处理后植株叶片中叶绿素含量及净光合速率均显著增加,因此植株活力增强,从而使得连作条件下平邑甜茶植株株高、地径和植株干鲜重显著提高。应用棉隆进行土壤熏蒸消毒简便易行、低毒高效,但棉隆具有灭生性,对植物也有一定毒害,故使用时应在种植作物前进行,且注意使用浓度及熏蒸时间,熏蒸后确保充分透气,保证无残留药害。

棉隆微粒剂处理苹果连作土壤使土壤中真菌数量显著减少,细菌与真菌比值增加,植株根系数量和功能增加,光合作用增强,植株生物量增加1.6 至2.2 倍。因此,棉隆微粒剂可有效减轻苹果连作障碍。

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