【作者】 马彦霞；

【导师】 郁继华；

【作者基本信息】 甘肃农业大学 ， 设施作物， 2013， 博士

【摘要】 随着生态农业和可持续循环农业的发展，日光温室番茄有机生态型无土栽培发展迅速。但是，由于各地追求连片种植、规模经营和降低基质成本的需要，日光温室番茄无土栽培基质的重复利用较为普遍，导致了病虫害加重、果实品质和产量下降等连作障碍问题，这些已成为制约日光温室番茄有机生态型无土栽培可持续发展的瓶颈。自毒作用是导致作物产生连作障碍的主要因子之一，普遍存在于设施蔬菜栽培中。因此，探究日光温室番茄不同茬口无土栽培基质的根际环境和化感作用以及化感消减技术对连作障碍的研究有重要的理论和实践意义。本文研究了日光温室番茄无土栽培不同茬口基质的理化性质和酶活性；以番茄“粉冠一号”为受体材料，以基质浸提液为供体材料，验证了基质化感作用的存在，分析了基质化感作用的影响因素，分离鉴定了基质所含的化感物质；在此基础上，研究了抗坏血酸对番茄自毒现象的缓解效应。得出了以下主要结果：1.连茬栽培基质的蛋白酶、碱性磷酸酶、脲酶、过氧化氢酶、蔗糖酶和脱氢酶活性下降，有机质、全氮、铵态氮、碱解氮、全磷、速效磷、全钾和速效钾等主要养分含量降低，而容重和pH值增加，正茬栽培对基质容重、孔隙度、酶活性、有机质和主要养分含量的影响较小。基质酶活性与理化性质的相关性分析表明，番茄无土栽培中，连茬、迎茬和正茬条件下基质的理化性质与酶活性密切相关，引起了番茄连茬基质微生态环境的改变，最终导致植株生长不良、病虫害加重、品质降低和产量下降等危害。连茬栽培后基质酶活性下降、有机质和主要养分含量降低，提供给番茄的营养源减少，不利于番茄植株生长，而正茬栽培对基质酶活性和主要养分的影响较小。2.基质水浸液处理后较对照显著降低了番茄种子的发芽率、发芽势、发芽指数、主根长、上胚轴长和干鲜重，且随基质水浸液浓度的升高抑制作用增强。连茬基质浸提液处理明显降低了番茄幼苗的株高、茎粗、叶长和叶宽的增幅，说明连茬基质水浸液抑制了番茄生长。不同茬口基质水浸液处理降低了番茄幼苗的叶绿素含量和根系活力，其中连茬的降幅最大。基质浸提液处理的叶片SOD活性先降后升，APX活性呈“降-升-降”的变化趋势，连茬的SOD、APX活性始终低于其它处理。可见，连茬基质浸提液的化感作用强度最大。此外，基质水浸液的化感作用存在浓度效应，0.05g/mL的浸提液化感抑制作用最强。3.利用连茬基质水浸液和水浸液醇溶组分模拟研究了不同化感物质成分和含量对番茄的化感作用。结果表明，不同浓度基质水浸液、水浸液醇溶组分和灭菌水浸液对番茄种子萌发表现为化感抑制作用，且随着水浸液浓度的增大，化感作用增强。水浸液对番茄的化感作用大于水浸液醇溶组分，且浓度越高化感抑制作用越大，说明化感物质的成分越多、含量越高，其化感作用越强。化感物质在高浓度时，微生物可降低或抑制化感物质的作用，使化感物质的抑制作用减弱，但灭菌与未灭菌处理的敏感指数基本一致，可见化感作用中起主要作用的是化感物质。4.对各组分进行生物检测表明，1:1的“乙醚+乙酸乙酯”洗脱组分的化感作用最强，其发芽率、发芽势、发芽指数、主根长、上胚轴长和干鲜重显著低于对照和其它组分。经过对基质化感优势组分“乙醚+乙酸乙酯”洗脱组分的GC-MS检测后发现，不同茬口基质所含的化感物质种类、数量和峰面积大小不同。其中，正茬基质共检测到化感物质14种、迎茬20种、连茬19种，连茬基质中检测到的化感物质峰面积显著高于正茬和迎茬。5.与单一基质水浸液处理相比，基质水浸液和不同浓度抗坏血酸共同处理番茄种子的发芽率、发芽势和发芽指数均增大，促进了幼苗主根和上胚轴的生长，抗氧化酶活性和抗氧化剂含量升高，内源激素ABA含量下降，IAA、GA3和ZT含量增加。说明外源抗坏血酸能有效缓解番茄连茬基质水浸液对番茄的自毒作用，其中1mmol/L的抗坏血酸缓解效果最佳。更多还原

【Abstract】 With the development of ecological agriculture and sustainable circular agriculture,greenhouse tomato in organic media culture develops rapidly. However, due to the requirementof habits of plant and reduction of production costs, the reuse of medium become commonly. Itis more and more extrude that diseases and pets get heavier, the yield and quality of fruitsdecreased, both physical and chemical character become declined, and so on, which becomes amain bottleneck that restricts the sustainable development of the greenhouse tomato in organicmedia culture. The self-allelopathy is one of the most important reasons of continuous croppingobstacle, commonly found in protected vegetable cultivation. Therefore, in protected tomatocultivation system, to explore the different cropping rotation organic ecotype soilless culturemedia of environmental effects, allelopathy and allelopathic decreases the technique has animportant theoretical and practical significance. In this paper, to study the biological charactersand physicochemical characters, verified autotoxicity on cultivation, analyzes influencingfactors of allelopathy, isolation and identification of allelochemicals in four cropping rotations(i.e. the normal cropping, alternate cropping, continuous cropping2years and continuouscropping for3years). Meanwhile, the roles of ascorbic acid in the alleviation mechanism ofautotoxicity in tomato were studied. The main results were as follows:1. In continuous cropping media, the activity of protease, phosphatase, urease, catalase,invertase and dehydrogenase decreased, and organic matter content, nitrogen, ammoniumnitrogen, available nitrogen, total phosphorus, available phosphorus, total potassium andavailable potassium decreased too, but media bulk density and pH increased. While in normalcropping media, the media bulk density and pH, the activity of enzymes, the content of organicmatter and major nutrient were affected slightly. The chemical properties closely related with thephysical properties in the organic media under the normal cropping, alternate cropping andcontinuous cropping, thus led to the change of micro-ecological environment, which resultedthat the growth of plant was lowest, the diseases and pets get heavier, the yield and quality offruits decreased. The result indicated that the enzyme activity correlated with the content oforganic matter and main nutrients in rhizosphere media of greenhouse tomato under differentcropping rotations. Enzyme activity, the content of organic matter and main nutrients might beimportant factors in the material cycle of media. Therefore, the enzyme activity can be used tocharacterize the status and changes of organic matter and nutrient to some extent, whichreflected the intensity and direction of various biological activities in media. After continuouscropping, the activity of enzyme, content of organic matter and major nutrients so decreased,that nutrient source provided to tomato was reduced. It goes against the growth of tomato plants.While in first-planting treatment, the activity of enzymes and main nutrients of media were affected slightly. The biological and physicochemical characters of replanting media and newmedia has little difference.2. When the tomato seed was treated with different rotation systems and differentconcentions of aqueous extracts, the seed germination rate, germination energy and germinationindex, seedling root and epicotyl length, dry weight and fresh weight were significantlydecreased compared to the control, and the inhibition was increased with the increase ofconcentration. The plant height, stem diameter, increase amplitude of leave length and widthdecreased significantly after treatment with extracts of continuous cropping media aqueous, theresults show that the continuous cropping media aqueous extracts inhibit leaf growth. When theplant was treated with different media aqueous extracts, chlorophyll content in leaves and rootactivity of tomato seedlings decreased rapidly, the activity of superoxide dismutase dropped atfirst and rose later, the ascorbate peroxidase activity increased at first and then decreased anddecreased lastly, but also the activities of superoxide dismutase and ascorbate peroxidase werehigher than other treatments. The results indicated that the aqueous extract of3medias couldinhibit seed germination and seedling growth in tomato, and the aqueous extracts of continuouscropping media was greatly inhibited than other media, and inhibition effect is concentrationdependent, increasing with the increase of concentration. When the concentration of aqueousinfusion0.05g/mL had the largest effect on the inhibition of seed germination and seedlinggrowth.3. Allelopathy of various components and contents of allelochemicals on tomato wasstudied by aqueous extracts and methanol soluble components of continuous cropping media.The results indicated that the more allelochemicals content and composition, the stronger theinhibition effects of seed germination and seedlings growth, vice versa.The differentconcentrations of aqueous extracts, methanol soluble fractions of aqueous extracts and sterilizedaqueous extracts all inhibit seed germination, and with the increasing of concentration, theinhibition effect increases gradually. Lower concentration of continuous cropping mediaaqueous extracts sterilization or not had little effect on the seed germination and seedling growthof tomato, while the seed germination and seedling growth were affected by highconcentration(0.05g/mL) of aqueous extracts sterilization or not, but no obvious differenceunder the same concentration. It seemed that micro-organisms play a role in the allelopathicsystem, in which allelochemicals were the main affecting factors, microorganisms weresubsidiary.4. The results of each fraction bioassay showed that allelopathy of50%aether+50%ethylacetate fraction were the strongest in there cropping rotations media, in which the seedgermination rate, germination energy and germination index, seedling root and epicotyl length,dry weight and fresh weight were significantly decreased compared to the control. Furthermore, many organic compounds found in the extracts from50%aether+50%ethyl acetate fraction byGC-MS analysis, and it shows that the numbers of allelochemicals were significantly differentcropping rotations(normal cropping, alternate cropping, continuous cropping) media, they were14、20and19separately.5. The seed germination rate, germination energy and germination index are increased,seedling root and epicotyl grew faster, the protective enzyme activity and antioxidants contentincreased, the content of abscisic acid decreased, and the contents of glutathione, ascorbic acid,auxin, gibberellin and zeatin were significantly increased under treated by ascorbic acid of0.25,0.5and1mmol/L and media aqueous extracts of0.05g/mL compared with those treated by wateror aqueous media extracts only. It was illustrated that there were certain alleviate effects ofexogenous ascorbic acid on autotoxicity caused by aqueous extracts of continuous croppingmedia, among the ascorbic acid concentrations used,1mmol/L was the optimum concentrations.更多还原