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马铃薯与玉米复合种植对土壤化感物质及土壤细菌群落结构的影响 总被引:1,自引:0,他引:1
为探究马铃薯与玉米复合种植对化感物质积累与细菌群落结构的影响,分析轮作、间作缓解连作障碍的机制,本研究以马铃薯连作、玉米连作、马铃薯||玉米间作、马铃薯-玉米轮作第8年的土壤为对象,利用GC-MS测定土壤中化感物质含量,并采用Illumina Miseq高通量测序技术对土壤细菌16Sr DNA V4-V5区域进行测序,分析土壤中细菌多样性和群落结构的变化,并对化感物质和优势菌属进行相关性分析。结果表明:玉米连作和马铃薯连作会导致化感物质的积累,玉米连作土壤积累了更多的油酸、亚油酸、花生酸、木焦油酸等脂肪酸,马铃薯连作土壤积累了更多的硬脂醇、二十烷醇等脂肪醇类物质。轮作降低了大部分化感物质的积累,间作降低的化感物质种类相对轮作较少。不同种植方式下土壤细菌群落结构发生了显著变化,相对于连作,间作和轮作Ace指数和Chao指数显著升高。在门水平上,轮作土壤放线菌丰度显著高于马铃薯连作土壤,间作土壤拟杆菌门丰度显著低于玉米连作土壤,两种连作土壤中酸杆菌门丰度都较轮作显著升高。在属水平上,一些有益细菌如节杆菌属、溶杆菌属等在复合种植土壤中相对丰度更高。通过相关性分析发现土微菌属、小梨形菌属与脂肪醇类物质呈显著正相关,黄杆菌属、溶杆菌属、微杆菌属等与脂肪酸类物质呈显著负相关。马铃薯与玉米复合种植降低了化感物质在土壤中的积累,从而抑制了土壤细菌丰度的降低,提高了有益菌属丰度,消减了连作障碍。 相似文献
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菊花不同部位及根际土壤水浸液处理对光合作用的自毒作用研究 总被引:8,自引:1,他引:8
菊花[Dendranthema morifolium(Ramat)Tzvel.]的自毒作用是菊花连作障碍发生机理研究的重要内容之一.本文研究了连作障碍比较明显的菊花栽培种"高压太子"不同部位(枯落物、叶、茎和根系)及根际土壤水浸液处理对盆栽同种菊花光合作用的影响,结果表明:不同部位和根际土壤水浸液处理对叶片叶绿素含量、净光合速率及气孔导度均表现出抑制趋势,而暗呼吸速率却受到促进,尤以地上部水浸液的抑制作用为显著.说明降低自身叶绿素含量、净光合速率及气孔导度,即抑制自身的光合作用,同时促进自身暗呼吸是菊花自毒作用的机制之一. 相似文献
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In order to elucidate the effect of allelochemicals on soil microbial characteristics in the cucumber rhizosphere, the soil microbial biomass and respiration, community functional diversity and RAPD marker diversity as affected by exogenous cinnamic acid were studied. Exogenous cinnamic acid increased soil microbial respiration and the metabolic quotient, but decreased soil microbial biomass-C. Soil microbial community functional diversity and genetic diversity (as indicated by RAPD markers) were also significantly altered by exogenous cinnamic acid. These results suggest that allelochemicals can change soil microbial genetic diversity, biological activity and microbial metabolic activity, which alter soil microbial ecology and accordingly affect the growth of cucumber with accumulation in the soil of allelochemicals. 相似文献
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水稻化感材料的抑草作用及其机制 总被引:25,自引:1,他引:25
水稻化感材料PI312777和化感1号在田间能显著地抑制杂草,而且其抑草作用与栽培方式相关,抛秧和移栽方式对杂草的抑制作用明显地优于直播。结果表明,PI312777和化感1号植株产生和释放的化感物质(多酚、黄酮和羟基肟酸)显著高于非化感品种华粳籼1号,而且在6叶期植株中的化感物质含量达最大值。这种不同水稻材料植株在不同生育期产生并释放化感物质量的差异是导致它们在田间抑草效应强弱的重要原因之一。进一步研究发现,PI312777植株由地上部分合成化感物质后经根部分泌到环境中,根组织并不产生化感物质,且稗草能诱导 相似文献
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含氧萜类化合物对稗草的化感抑制作用 总被引:2,自引:1,他引:1
以5种含氧萜类物质(-)香芹醇、(+)香芹酮、(-)薄荷酮、(-)香芹基乙酸酯和(+)雪松醇为化感物质替代物,以稗草为受体,运用正交旋转回归组合实验,分析物质间的互作效应.各单因子的主效应分析结果表明:(-)香芹醇、(+)香芹酮、(-)薄荷酮和(-)香芹基乙酸酯的主效应曲线均为开口向下的抛物线,而(+)雪松醇为开口向上的抛物线.各单因子的边际效应分析表明:当浓度低于-2水平时各因子对稗草根长的抑制作用大小为(-)薄荷酮>(-)香芹醇>(+)香芹酮>(-)香芹基乙酸酯>(+)雪松醇,当各因子浓度高于+2水平时,则为(+)雪松醇>(+)香芹酮>(-)香芹基乙酸酯>(-)香芹醇>(-)薄荷酮.综合分析显示,当各物质浓度水平分别为(-)香芹醇0.033mmol·L-1、(+)香芹酮0.030 mmol·L-1、(-)薄荷酮0.080 mmol·L-1、(-)香芹基乙酸酯0.020 mmol˙-1和(+)雪松醇0.001 mmol·L-1时,方程有最优解,即在理论上其混合物对稗草根长的抑制率达到最大,为93.69%. 相似文献
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Most natural algicides including macrophytic allelochemicals are known to selectively inhibit algal growth. The investigations on the modes of action about the species-specific algicides are little. In this study, the effects of allelochemical ethyl 2-methyl acetoacetate (EMA) identified from reed (Phragmites communis) on the growth, physiological, and biochemical processes of green alga Selenastrum capricornutum were investigated. The results showed that EMA had multiple effects on the growth of S. capricornutum under different initial algal densities (IADs). The algal growth was inhibited by EMA at low IADs, but stimulated at high IADs. Further, the potential modes of action of EMA on S. capricornutum were explored from ultrastructure, metabolic activity, reactive oxygen species level, and lipid peroxidation to trace the microenvironment changes in the algal cells. Damage in cell structure occurred at low IAD, but cells were well developed with increased metabolic activity at high IAD. The reactive oxygen species (ROS) levels were increased under both conditions. The increase of ROS level was acute at low IAD but slow at high IAD. EMA caused significant lipid peroxidation, i.e. oxidative damage on membrane lipids at low IAD but not at high IAD. Based on these results, the initial algal density is considered an important factor to influence algal growth and physiological and biochemical responses to EMA, the effects of EMA on S. capricornutum may be “hormesis-like”, and different ROS increase ratio may be directly related with different responses of S. capricornutum to EMA. 相似文献
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采用丙酮、乙酸乙酯、蒸馏水(2:2:1)混合提取腐解3个月后的杉木根化感物质,并用杉木种子发芽试验进行生物检测。结果表明:杉木根腐解3个月后.添加氨态N、硝态N素及不加N素处理的杉木根化感物质对种子发芽具有不同的效应。就弱杉性化感物质200 mg·kg~(-1)处理而言,NH_4Cl 100 g、NH_4Cl 50 g、NaNO_3 50 g处理的对杉木种子绝对发芽势抑制作用强于不加N素处理;NH_4Cl 50 g、NaNO_3100 g处理的对胚根长和胚轴长抑制作用强于不加N素处理。就极性化感物质200 mg·kg~(-1)处理而言,NH_4Cl 100 g和NaNO_3100 g处理的对绝对发芽率抑制作用强于不加N素处理,NH_1Cl 100 g、NaNO_3 100 g和NaNO_3 50 g处理的对绝对发芽势抑制作用强于不加N素处理,添加氨态N和硝态N素处理的根极性化感物质对胚根长抑制作用强于不加N素处理。 相似文献
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