连作对丹参生长的障碍效应

通过对1～4年不同连作年限地块丹参生长发育情况进行的连续调查分析,结果表明,连作严重危害丹参生长,主要表现在6～9月,丹参生长期的枯苗率大幅度上升,地上、地下部生长量下降,根系数量、直径和长度减小,产世降低。同时由于有效成分含量降低,根系外观畸形,造成商品率下降,从而影响丹参质量。通过对土壤pH测定发现．丹参连作障碍可能与土壤酸性增加有关。     

有益微生物缓解花生连作障碍机理研究进展

花生是我国重要的油料作物,种植过程中会遇到连作障碍问题.有益微生物可以有效缓解花生连作障碍,其机理包括有益微生物分解化感物质、改变花生根际微生物区系、增加花生抗病能力、促进花生结瘤固氮、促进花生养分吸收五个方面.阐明该机理,对花生连作障碍缓解有指导意义,对其他作物连作障碍的缓解也有参考价值.     

间作植物和茬口对连作党参生长和品质产量的影响

选择两种茬口(轮作茬、连作茬)和6种植物材料(党参、大蒜、玉米、黄芪、苦参、向日葵),组成党参单作和间作6种种植模式,设置茬口和间作模式两因素田间随机区组试验,通过监测不同生长时期党参的生长指标(蔓长、主根长、主根直径、地下部分鲜干重)、根部产量及品质指标(根部多糖含量、炔苷含量、醇溶性浸出物含量和灰分含量)的变化衡量不同茬口和间作植物对党参连作障碍的缓解效应。结果表明：(1)轮作茬口下党参单作及各间作处理对党参生长、品质和产量的改善效果都较连作茬口下明显,且两茬口下各间作处理的改善效果都较党参单作明显。(2)与向日葵、大蒜和玉米间作处理对两茬口党参的主根长、主根直径、地下部分鲜干重的提升效果比党参单作和其余间作处理(与黄芪、苦参间作)更显著。(3)大蒜和向日葵间作处理能够显著提高两茬口党参根部产量,尤其大蒜表现最优,与其间作的轮作茬和连作茬党参分别较各自对照增产49.92%和22.55%。(4)与大蒜间作能有效提升两茬口党参根部多糖含量、炔苷含量和醇溶性浸出物的含量,党参单作和其余间作处理对两茬口连作党参的品质提升效果不及大蒜间作处理理想。研究发现,从党参长势及根部产量和品质综合分析,两茬口下党参与大蒜间作最有利于党参植株生长,能有效缓解党参连作障碍,并显著提高其药用部位的产量和品质,且轮作茬口下的提高效应更明显。     

连作对大豆根部土壤微生物的影响研究

研究了正茬与连作大豆根际及非根际土壤微生物区系的变化。结果表明,细菌总数占绝对优势,连作低于正茬。放线菌数量总体变化幅度不大,真菌数量有显著变化,连作明显高于正茬。连作使土壤pH、含水率和微生物主要生理类群数量明显下降,土壤肥力降低。无论细菌、放线菌和真菌,正茬及连作大豆根际微生物数量明显高于非根际。     

消毒、伴生和微生物菌对连作基质性质及黄瓜生长发育的影响

以连续种植2茬的连作基质为对象,采用室内盆栽试验,设置连作基质太阳能消毒、热水消毒、多菌灵消毒、大蒜伴生栽培和施入微生物菌处理以及新基质对照,在种植黄瓜后观测基质理化性质、养分含量、酚类物质含量、相关酶活性的变化以及黄瓜结果期生长发育、光合作用和果实产量的变化,探究不同处理对连作基质栽培黄瓜生长发育影响的机制,以期在生产上为废旧基质重复利用提供新的思路和方法。结果表明:在连作基质栽培黄瓜后,太阳能消毒和热水消毒处理均能显著提高连作基质的pH,同时降低电导率;施入微生物菌处理的基质EC值、速效氮、速效磷、速效钾和总酚含量均显著低于连作基质,而其基质磷酸酶活性和过氧化氢酶活性显著高于连作基质。热水消毒还显著降低连作基质的总酚含量和复合态酚含量。黄瓜生长至结果期,太阳能消毒、热水消毒、多菌灵消毒、大蒜伴生栽培和施入微生物菌均显著增强黄瓜的根系活力和株高;其中热水消毒和施入微生物菌处理的产量增加最为显著,分别比连作基质栽培提高了16.56%和18.40%。可见,连作基质进行热水消毒处理和施入微生物菌处理均能降低基质盐分积累,减少总酚含量,进而显著提高黄瓜的根系活力和光合作用,从而增加产量。     

连作西瓜抗逆系统及土壤微生态对大蒜伴生的响应

以大蒜-西瓜化感伴生栽培模式为研究对象,设置连作西瓜单作(对照)、大蒜苗期伴生连作西瓜、大蒜全生育期伴生连作西瓜3个处理,考察西瓜枯萎病发病率,西瓜叶片抗氧化酶活性和渗透调节物质含量,以及根际土壤酶活性和微生物数量,探索大蒜伴生对西瓜酶促抗氧化系统及土壤特性的影响.结果表明:(1)大蒜-西瓜伴生栽培体系中,西瓜枯萎病发...     

Soil Fungal Diversity and Community Composition in Response to Continuous Sweet Potato Cropping Practices

Soil fungi are extremely important for maintaining soil health and plant production in agricultural systems. Currently, the effect of continuous cropping of sweet potato on soil fungal communities and physiochemical parameters has not been well documented. In the present study, four sweet potato fields consecutively monocultured for 1, 2, 3, and 4 years were selected to investigate the effect of monoculture on soil fungal communities through Illumina MiSeq sequencing. Continuous cropping of sweet potatoes dramatically altered the fungal community composition, whereas fungal diversity was almost unchanged. Ascomycota and Basidiomycota were the most abundant phyla in all soil samples, accounting for 32.59% and 21.14% of the average relative abundance, respectively. The abundance of some potential pathogens, such as Ascobolus spp, specifically Ascobolus stercorarius, and some unknown fungi increased significantly as the sweet potato monoculture period increased, and their presence were highly positively correlated with disease incidence. In contrast, Basidiomycota, Bullera, Fusarium and Trichocladium most likely play roles as antagonists of sweet potato disease development, as their relative abundance decreased significantly over time and were negatively correlated with disease incidence. Redundancy and correlation analyses revealed that soil pH and organic carbon content were the most important factors driving these changes. Our findings provided a dynamic overview of the fungal community and presented a clear scope for screening beneficial fungi and pathogens of sweet potato.     

Effects of Continuous Cropping of Rye on Soil Biota and Biochemistry

Long-term studies on the ecological effects of continuous rye cultivations carried out in Poland are summarized. It was shown that in continuous cropping of rye, despite the decrease of crop yields, no significant difference was observed in annual primary production rates compared with estimates found for rye fields cultivated in diversified crop rotation patterns. In continuous cultivation of rye fauna impoverishment was observed, while at the same time the number of crop pests increased. The animal groups reduced by continuous cropping of rye belong to Protozoa, Lumbricidae, Acarina, and winged insects. The cultivation of rye in continuous cropping influenced the increase of fungi with bacteria and actinomycetes becoming less abundant. In soils under continuous rye the average concentration of phenolic acids was 400% higher than under rye in diversified rotation. Five different phenolic acids were identified. The mean content of bound amino acids in soils under diversified rotation was 417?mg×kg^?1and in soils under continuous rye cropping was 371?mg×kg^?1. The energetic cost of total soil animal community maintenance calculated per unit of biomass under continuous cropping of rye was almost twice as high as under the diversified rotation. The accumulation of toxic metabolites caused negative effects among biota under continuous cropping of rye.     

重茬种植西洋参对其根区土壤微生物与土壤理化性质影响

以北京产区西洋参根际土为研究对象,通过对不同重萑年限西洋参根际土与对照新土进行比较,研究重茬对西洋参根际土壤微生物及其土壤理化特性的影响。结果显示：西洋参种植第1a微生物及土壤各项理化性质指标与对照相比都戍较低水平,随着重茬年限的增加土壤理化性质与微生物都变化较大,其中重萑2a土的全钾含量较高,为对照新土的1．38倍。重茬3a土的细菌、真菌均达到高峰,分别为对照的11．26、5．94倍。放线菌含量在重茬4a土中达到高峰为对照的8．41倍。     

套作玉米对草莓生长生理特性及其产量和品质的影响

该研究采用草莓玉米套作和草莓连作方式,对草莓的生长、生理及其产量和品质进行比较分析,为生产中克服草莓连作障碍提供理论依据。结果表明：（1）套作条件下草莓的株高、根长、茎粗和整株重量等营养生长指标均显著高于相应的连作模式。（2）与连作相比,套作可提高草莓植株的总超氧化物歧化酶（SOD）、乙醇脱氢酶（ADH）和过氧化物酶（POD）活性,同时可提高草莓植株根系和叶片的可溶性糖含量,使根系丙二醛含量维持在较低水平,保证草莓植株良好生长。（3）与草莓连作相比,套作玉米使秋季草莓苗的定植入田死苗率降低28.8%,加快缓苗速度,且单株保持良好长势和后期正常坐果。（4）套作玉米能够显著提高草莓果实的硬度、单果重及单株产量,但对果实可溶性固形物无显著影响。研究认为,草莓套作玉米能够克服草莓连作障碍,促进草莓植株的营养生长,增强草莓植株抵御逆境胁迫的能力,提高产量和品质。     

连作改变土壤性状对甜叶菊产量和品质的影响

为了解连作障碍的产生机理,对甜叶菊(Stevia rebaudiana)连作后的土壤性状变化进行了研究,并探讨土壤性状与叶片干质量和甜菊糖苷之间的相关性。结果表明,连作2 a和3 a的土壤pH值、有机质、速效磷、脲酶、过氧化氢酶、蔗糖酶、磷酸酶和甜叶菊叶片干质量及甜菊糖苷组分含量均无显著差异。连作4 a后,土壤pH值、全氮和速效钾含量显著下降,分别比对照降低了10.07%、14.38%和24.79%,土壤电导率(EC)和速效磷含量显著增加,是对照的2.57和1.70倍;土壤脲酶、蔗糖酶、磷酸酶活性、微生物量碳和微生物量氮在连作4 a降到最低,比对照分别降低了63.68%、72.03%、47.43%、78.35%和41.07;多酚氧化酶则在连作4a达到最高,是对照的4.22倍;与对照相比,连作4a的叶片干质量和甜菊苷含量降低了29.51%和16.00%,莱鲍迪苷A含量则增加了22.19%。叶片干质量及甜菊糖苷含量与土壤性状间存在着相关性。因此,连作通过改变土壤性状影响甜叶菊产量和品质,生产中最大连作年限不宜超过3 a。     

附子连作障碍效应初步研究

通过大田试验,调查了连作附子的生长发育、产量及病虫害的变化,分析附子的连作障碍原因;并通过实验室常规分析,测定连作土壤的理化性状,探讨附子连作障碍的形成机理。结果显示：随着连作年限的增加,连作附子株高、茎粗、母根直径、最大子根直径均出现了不同程度的下降,其中连作对附子株高和茎粗的影响极显著;连作使病、虫害逐年加重,产量显著下降;附子连作使土壤pH下降,有机质含量升高,全N、有效P、速效K过剩。结果表明,连作加重了附子根腐病的发生,影响了附子母根的正常发育,从而导致附子产量下降;连作导致土壤pH降低是影响附子正常生长的限制因子。因此通过采用科学的配方施肥措施,调节土壤pH值,改善土壤环境,是缓解附子连作障碍的重要途径。     

湿垃圾来源的蚯蚓粪肥对连作障碍土壤质量和黄瓜产量的影响

随着城市化的发展,湿垃圾产量与日俱增,湿垃圾资源化利用迫在眉睫。利用蚯蚓处理湿垃圾制作蚯蚓粪肥用于农田土壤改良,是一项有效的湿垃圾资源化利用途径以及有利于缓解蔬菜连作障碍方面问题。该文以常规有机肥为参照,选取以湿垃圾及其厌氧沼渣为原料制作的蚯蚓粪肥为研究对象,研究连续3年施加蚯蚓粪肥对黄瓜(Cucumis sativus)土壤综合质量和作物产量的影响。结果表明,经过3年的改良后,施加60.0 t/hm²蚯蚓粪肥的黄瓜产量提高了5.60%,土壤有机质含量提高了50.0%,且蚯蚓粪肥的效果要高于常规有机肥;土壤全氮含量达到最高,高于背景值33.0%;土壤的养分含量(硝态氮、速效磷、速效钾)也得到了提高,其中速效钾含量升高了94.0%。经过3年的改良,土壤中的细菌数量在施加了有机肥后明显增加,其中以添加30.0t/hm²蚯蚓粪肥的细菌数量最多;土壤细菌/真菌的比值有所提高,土壤生物性状得到改善。土壤的呼吸强度随着有机肥的施入而升高,以施加60.0t/hm²蚯蚓粪肥的最大;土壤pH略有降低,盐度无明显变化。因此,湿垃圾来源的蚯蚓...     

断根对冬小麦荧光特性和产量的影响

用荧光淬灭分析技术研究了断根对冬小麦荧光特性的影响以及不同水分条件下断根对产量的影响.结果表明,在不同生育期中小麦断根与未断根处理相比其最大量子产量(Fv/Fo)和PSⅡ潜在活性(Fv/Fm)无显著差异.通过对不同生育期荧光特性研究表明,断根初期小麦电子传递速率和有效光量子产量降低,而PSⅡ光合电子传递活性增加,孕穗期随着更多的能量向地上部的运转,此时根系补偿作用使ETR、ΦPSⅡ和qP增加,而且断根并显著降低光系统Ⅱ光化学效率.混播处理ΦPSⅡ和ETR值高于单播处理,认为断根降低了小麦的竞争能力,使总体光合活性增强,促进了能量向地上部运转,与混播处理产量增加相一致.小麦单播湿润处理下,断根降低了小麦穗重和地上部生物量,且籽粒产量降低了19.2%.在干旱处理下,断根降低了根冠比,提高了小麦穗重和籽粒产量.     

模拟酸雨对大豆、花生生长和产量的影响

大豆(Glycine max)、花生(Arachis hy-pogaea)是我国主要油料作物,国内外均曾用大豆作为模拟酸雨的试验材料。本文对大豆作了较详细的观察。在大田中进行了花生试验,研究酸雨对其产量的影响。     

作物连作障碍的成因与机制及其消减策略

在论述作物连作障碍危害的基础上,从植物营养学、土壤学、微生物学角度分析产生作物连作障碍的原因与形成机理,认为作物连作障碍形成是复杂的根际生物学过程,它是由连作作物根系分泌物介导引起根际土壤微生物结构失衡,导致病原微生物增多,土壤酸化和营养封存综合作用的结果。据此,进一步就连作障碍防治措施及修复技术进行归纳总结,为有效克服作物连作障碍提供技术借鉴。     

茉莉酸甲酯和脱落酸对花生幼苗根和下胚轴生长的影响

高浓度 (10 -6～ 10 -4mol/L)的脱落酸 (ABA)和茉莉酸甲酯 (methyljasmonate ,MeJA)均抑制花生根和下胚轴的生长 ;低浓度 (10 -7mol/L)的ABA作用不明显 ,MeJA在低浓度下对生长表现出明显的促进效应。MeJA与ABA抑制花生幼苗根和下胚轴的生长时提高IAA氧化酶与过氧化物酶的活性 ,尤其对胞壁结合型(离子型和共价型 )的过氧化物酶活性的影响较明显。     

连作对麦冬根际土壤细菌群落的影响

以中草药麦冬为研究对象,采用变性梯度凝胶电泳(DGGE)方法,考察连作对麦冬根际土壤细菌群落的影响。结果表明,重茬麦冬根际细菌群落的Shannon-Wiener指数从苗期至快速生长期、再到块根膨大期分别为3.36-3.40-3.69,丰富度指数为55.0-61.5-63.5,均匀度指数为0.84-0.82-0.89;而同期正茬根际细菌群落的上述指数值分别为3.66-3.33-3.72、67.5-53.5-63.5和0.87-0.84-0.90。通过对土壤细菌群落的DGGE图谱进行主成分分析,结果显示,上述各个时期重茬与正茬样本均发生显著分离,表明连作改变了麦冬根际细菌群落的多样性变化趋势和结构组成。进一步比较麦冬块根膨大期根际主要功能菌群的数量变化,发现连作后氨化细菌和好气性纤维素分解菌数量增加,而硝化细菌和固氮菌的数量减少。对比发现重茬麦冬的产量仅为正茬的70.6%,表明麦冬连作减产与其根际土壤细菌群落的变化相关。     

Ultrastructure and Lipase Activity of Cotyledon cell During Pod Development in Peanut

A series of significant changes of the ultrastructure and lipase activity of cotyledon cell were found in peanut (Arachis hypogaea) during pod development. In he initial stage of cotyledon development there were many plastids which kept producing starch grain and there were low lipase activity and very few lipid and protein bodies in the cell. In the middle stage of cotyledon development, a great number of larger lipid bodies were seen in the cell and a lot of protein bodies formed in the vacuoles and continued to increase in size. Lipase activity increased in the cytoplasm, endoplasmic reticulum, protein bodies, plasmalemma and intercellular space. In the later stage of cotyledon development, the lipid bodies did not increase in number but became slightly larger. The protein bodies continued to increase both in number and in size. Lipase acttvity was even hegher in the cytoplasm. In the final stage the protein bodies became irregular in shape and some of them tended to disintegrate with their content entered into the space around the lipid bodies. The lipase activity in the cell declined. The results indicated that the lipid body originated in the cytoplasm and the protein body originated in the vacuole; that the accumulation of oil and protein in peanut cotyledon resulted from the formation and development of lipid and protein bodies in the cell, and that the changes of plasmid and lipase activity in the cell played a role in the development of lipid body during the development of cotyledon.     

不同作物轮作对连作高粱生长及其根际土壤环境的影响

以高粱连作5年为对照(CK),研究了高粱连作3年轮作苜蓿(T₁)和葱(T₂),对下茬高粱生长、根际土壤微生物及土壤酶活性的影响.结果表明:与CK相比,轮作改善了高粱地上部的生长;T₁增产16.5%,效果明显.轮作也促进了高粱根系的生长,T₁和T₂处理的高粱总根长是CK的1.3和1.4倍,根总表面积是CK的1.6和1.5倍,根体积是CK的2.2和1.6倍,根系生物量是CK的2.0和1.3倍,T₁促进了根系在10 cm以下土层中的分布.借助Biolog法对穗花期根际土壤微生物群落功能多样性分析表明,T₁和T₂处理根际土壤微生物活性显著高于CK,且Shannon多样性指数分别是CK的1.2和1.1倍;轮作提高了根际土壤蔗糖酶活性.综上,轮作苜蓿比轮作葱更能改善高粱根际土壤环境,提高土壤微生物活性和酶活性,控制高粱连作障碍,提高高粱产量.