Effects of intercropping with persimmon on the rhizosphere environment of tea

The rhizosphere environment of tea (Camellia sinensis Kuntze) intercropped with persimmon (Diospyros kaki) differs from monocultures of tea. A trial was conducted to determine the effects of intercropping with persimmon on root exudates and soil nutrient condition of tea. Amino acid exuded in intercropping was three times higher than that in monoculture. Phenol, phenol/amino acid ration, dissolved sugar, and total organic acid were also lower in intercropping. The value of pH in soil was higher, and soil nutrient condition of rhizosphere, especially available nutrient, was not as well in intercropping as that in tea grown alone. While soil nutrient of non-rhizosphere was better than that in monoculture, tea quality and soil nutrient condition were better in intercropping ecosystem. __________ Translated from Journal of Southwest China Normal University (Natural Science), 2005, 30(4): 715–718 [译自: 西南师范大学学报 (自然科学版), 2005, 30(4): 715–718]     

Biological hardening of tissue culture raised tea plants through rhizosphere bacteria

Four antagonistic bacterial isolates, Bacillus subtilis, Bacillus sp., Pseudomonas corrugata 1 and P.-corrugata 2, isolated from the rhizosphere of tea plants growing in different geographical locations in India, were tested as microbial inoculants for hardening of tissue-cultured tea plants raised in the laboratory prior to the transfer to open land. Bacterial inoculations resulted in enhanced survival (up to 100, 96, and 88%), as against 50, 52, and 36% survival observed in the corresponding control plants, in rainy, winter and summer seasons, respectively. Rhizoplane and rhizosphere soil analyses showed that the major biotic factor responsible for mortality following the transfer of tissue culture raised plants to soil was fungal attack (Fusarium oxysporum). Bacterial inoculations also resulted in plant growth promotion of tissue culture as well as seed raised plants of tea.     

间作作物种间相互作用对马铃薯根际土壤丛枝菌根真菌的影响

为揭示间作作物种间相互作用对土壤丛枝菌根(AM)真菌的影响,以马铃薯单作(T0)为对照,基于高通量测序平台的方法,研究了连续3年马铃薯‖玉米(T1)、马铃薯‖蚕豆(T2)下马铃薯根际土壤AM真菌群落组成、多样性与土壤环境因子间的相互关系.结果表明:共获得2893个AM真菌操作分类单元(OTUs),分属1门、3纲、4目、...     

Studies on the improvement in iron nutrition of peanut by intercropping with maize on a calcareous soil

Both rhizobox and field experiments were conducted to investigate nutritional interactions between peanut and maize in intercropping systems for Fe acquistion. Field observations indicated that Fe deficiency chlorosis symptoms in peanut grown in monoculture were more severe and widespread compared to those of peanuts intercropped with maize. This indicated a marked improvement in the iron nutrition of peanut intercropped with maize in the field and was further studied. In experiments with rhizoboxes, roots of maize and peanut were either allowed to interact with each other or prevented from making contact by inserting a solid plate between the root systems of the two species. A field experiment for four cropping treatments were examined: peanut grown separately in monoculture, normal peanut/maize intercropping, peanut/maize intercropping with solid plates between the root systems of the two crop species and peanut/maize intercropping with 30 μm nylon nets between the root systems. The results show that the chlorophyll and HCl-extractable Fe concentrations in young leaves of peanut in the intercropping system with unrestricted interactions of the roots of both plant species were much higher than those of peanut in monoculture. In the nylon mesh treatment, the beneficial effects of the maize extended to row 3. The improvement of Fe nutrition in the intercropping system got reduced but not diminished completely in the treatment with nylon net. It is suggested that the improvement in the Fe nutrition of peanut intercropped with maize was mainly caused by rhizosphere interactions between peanut and maize. This revised version was published online in June 2006 with corrections to the Cover Date.     

Dominant fungi in the rhizosphere of established tea bushes and their interaction with the dominant bacteria under in situ conditions.

Species of Penicillium and Trichoderma were found to dominate the rhizosphere of established tea bushes in a detailed study conducted from various tea growing locations in India. Penicillium erythromellis, P. janthinellum, P. raistrickii, Trichoderma pseudokoningii and T. koningii were found to be closely associated with tea roots. While seasonal fluctuation was observed in the case of Penicillium spp., the population of Trichoderma spp. showed less variation during the year. Both species were sensitive to low temperatures. In general, fungi associated with the tea rhizosphere were found to prefer a mesophillic temperature range (15 °C to 35 °C). The dominant species of Penicillium and Trichoderma also exhibited tolerance to lower temperatures, i.e., 5 to 10 °C on agar plates. Most fungi were able to grow in a wide range of pH (4 to 12). Lowering of soil pH in the rhizosphere of tea bushes was positively correlated with the age of the bush and may have affected the development of a specific microbial community in the rhizosphere.

The populations of Penicillium and Trichoderma species were inversely correlated with the populations of two most dominant rhizosphere bacteria, Bacillus subtilis and B. mycoides. Both Bacillus species have been shown to have antagonistic activity against these two fungi under in vitro conditions. The present study demonstrates the existence of a similar antagonism under in situ conditions in the rhizosphere of established tea bushes.     

Influence of intercropping and intercropping plus rhizobial inoculation on microbial activity and community composition in rhizosphere of alfalfa (Medicago sativa L.) and Siberian wild rye (Elymus sibiricus L.)

Alfalfa–Siberian wild rye intercropping is the predominant cropping system used to produce forage in China. In this study, the effects of intercropping and intercropping-rhizobial inoculation on soil enzyme activities, microbial biomass and bacterial community composition in the rhizosphere were examined. In both treatments, the yield of alfalfa, microbial biomass and activities of soil urease, invertase and alkaline phosphatase in the alfalfa rhizosphere were markedly increased, whereas there was a slight increase in the yield of Siberian wild rye, few impacts on soil microbial biomass, and decreased enzyme activities (except for urease) in the Siberian wild rye rhizosphere. Terminal restriction fragment length polymorphism (T-RFLP) of 16S rRNA genes indicated that Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Firmicutes, Actinobacteria and Bacteroidetes were the major bacterial groups in the rhizosphere of both plants. However, intercropping and rhizobial inoculation induced some shifts in the relative abundance of them. Nitrosomonas and Nitrosospira groups were detected in all treatments by the T-RFLP patterns of ammonia monooxygenase subunit A ( amoA ) gene, but the relative abundance of Nitrosomonas increased and that of Nitrosospira decreased in the intercropping-rhizobial inoculation treatment. Both treatments tended to increase the diversity of amoA . Conclusively, the two treatments clearly affected soil microbial composition and soil enzyme activities, which might be reflected in changes in yield.     

大蒜-小白菜间作套种对菜田节肢动物功能团的影响

2004年9-11月于福建省琅岐岛针对大蒜与小白菜间作(CG1)套种(CG2)对节肢动物群落功能团影响进行调查和分析。结果显示:CG1提高了植食性昆虫、寄生性和捕食性天敌丰盛度,CG2可在降低植食性昆虫数量的同时提高寄生性天敌的数量;多作田寄生性天敌物种丰富度、丰盛度和多样性指数均高于单作田;优势类群动态表现为菜蚜茧蜂与蚜虫种群在CG1出现"天敌跟随现象",多作田在整个生长期都有利于提高捕食者球腹蛛的控制效能;中性昆虫在生长前期和中期是菜蚜虫茧蜂和球腹蛛的替代寄主或猎物。因此合理的间作或套种,有利于提高菜田生境的多样化,强化自然天敌对害虫的生态控制作用。     

Dominant fungi in the rhizosphere of established tea bushes and their interaction with the dominant bacteria under in situ conditions

Species of Penicillium and Trichoderma were found to dominate the rhizosphere of established tea bushes in a detailed study conducted from various tea growing locations in India. Penicillium erythromellis, P. janthinellum, P. raistrickii, Trichoderma pseudokoningii and T. koningii were found to be closely associated with tea roots. While seasonal fluctuation was observed in the case of Penicillium spp., the population of Trichoderma spp. showed less variation during the year. Both species were sensitive to low temperatures. In general, fungi associated with the tea rhizosphere were found to prefer a mesophillic temperature range (15 °C to 35 °C). The dominant species of Penicillium and Trichoderma also exhibited tolerance to lower temperatures, i.e., 5 to 10 °C on agar plates. Most fungi were able to grow in a wide range of pH (4 to 12). Lowering of soil pH in the rhizosphere of tea bushes was positively correlated with the age of the bush and may have affected the development of a specific microbial community in the rhizosphere.The populations of Penicillium and Trichoderma species were inversely correlated with the populations of two most dominant rhizosphere bacteria, Bacillus subtilis and B. mycoides. Both Bacillus species have been shown to have antagonistic activity against these two fungi under in vitro conditions. The present study demonstrates the existence of a similar antagonism under in situ conditions in the rhizosphere of established tea bushes.     

甘蔗—大豆间作对大豆鲜荚产量和农艺性状的影响

为探讨甘蔗-大豆间作模式对大豆鲜荚产量和农艺性状的影响,于2009—2011年连续3年在广州市华南农业大学农场进行大田试验,试验设置2种施氮水平(常规施氮(525kg·hm-2)和减量施氮(300kg·hm-2))和3种种植模式(甘蔗-大豆(1∶1)、甘蔗-大豆(1∶2)、单作大豆)。结果表明:甘蔗-大豆间作(1∶2)模式下,2009年减量施氮水平的大豆鲜荚产量较常规施氮水平提高了33%,2010和2011年不同施氮水平间均无显著差异;甘蔗-大豆间作模式对大豆的单株鲜荚重、多粒荚数和百粒鲜重无显著影响;大豆单株鲜荚重与多粒荚数在不同种植模式下均呈显著相关(P<0.05),在常规施氮间作模式下与大豆单株荚数呈显著相关(P<0.05)。甘蔗-大豆间作没有降低大豆的单株鲜荚产量,也没有对大豆的农艺性状产生负面影响,从增产增收、提高土地生产力来考虑,减量施氮模式下甘蔗-大豆间作具有一定的可行性。     

茶园间作不同绿肥对节肢动物群落结构和多样性的影响

【目的】研究在茶园中合理间作绿肥对茶园节肢动物群落结构和多样性的影响。【方法】本文在茶园中分别设间作铺地木兰+罗顿豆、圆叶决明+白三叶、白三叶+平托花生3种不同绿肥组合处理,并设不间作绿肥、常规除草的茶园为对照。【结果】间作不同绿肥均能提高茶园节肢动物群落的物种丰富度和群落多样性,提高茶园捕食性天敌昆虫、蜘蛛和寄生性天敌在茶园冠层群落的比率;不同处理茶园冠层节肢动物Shannon-wiener多样性指数(H)、Simpson指数(D)和均匀度指数变化趋势基本一致;茶冠层的节肢动物群落多样性指数在4类不同处理茶园间差异显著;间作绿肥增加了茶园的生物多样性,4类不同处理茶园茶冠层群落相似性系数在0.741~0.892之间,表明4类不同处理茶园冠层群落在物种组成上有较高的相似性。4类不同处理茶园害虫与天敌两类群功能团的丰盛度之间成显著的正相关,表明天敌对害虫的空间数量跟随效应强,主要表现为二者数量间的相互作用。灰色关联度分析表明在4类不同处理茶园中的群落节肢动物物种数/个体数、天敌物种数/害虫物种数、害虫丰富度与多样性指数和均匀度指数的关联系数较高,反应了群落的多样性和稳定性。【结论】间作增强了茶园群落的生物多样性,提高害虫天敌的种类和个体数,有利有效发挥天敌对有害生物的生态控制。     

Effects of mutual intercropping on cadmium accumulation by the accumulator plants Conyza canadensis,Cardamine hirsuta,and Cerastium glomeratum

In this study, three cadmium (Cd) accumulator species (Conyza canadensis, Cardamine hirsuta, and Cerastium glomeratum) were co-cultured in Cd-contaminated soil in pots to study the effects of intercropping on co-remediation. Only C. canadensis intercropped with C. glomeratum, C. hirsuta intercropped with C. glomeratum, and three-species intercropping increased plant biomass compared with their respective monocultures. The treatments of C. canadensis intercropped with C. glomeratum and three-species intercropping increased the Cd contents in roots and shoots of C. canadensis, whereas the other intercropping treatments decreased or had no significant impact on Cd contents. As for Cd accumulation, the treatments of C. canadensis intercropped with C. glomeratum, C. hirsuta intercropped with C. glomeratum, and three-species intercropping increased Cd accumulation in a single plant compared with that of their respective monocultures, whereas other intercropping treatments decreased Cd accumulation in individual plants. Only the treatments of C. canadensis intercropped with C. glomeratum and C. hirsuta intercropped with C. glomeratum increased Cd accumulation in shoots of a single pot compared with that of their respective monocultures. Therefore, C. canadensis intercropped with C. glomeratum and C. hirsuta intercropped with C. glomeratum may improve the phytoremediation efficiency for Cd-contaminated soil.     

套作不同化感潜力分蘖洋葱对黄瓜生长及土壤微环境的影响

盆栽试验以黄瓜为主栽作物,分蘖洋葱为套作作物,研究了套作不同化感潜力分蘖洋葱对黄瓜生长及土壤微环境的影响.结果表明:与化感潜力强的分蘖洋葱套作,黄瓜根际土壤电导率降低、pH值提高;根际土壤过氧化氢酶和转化酶活性提高,过氧化物酶活性降低;根际土壤细菌丰富度增加.DGGE条带测序显示,黄瓜根际土壤细菌大多与不可培养的细菌种属具有较高的同源性,共有条带的测序比对推测为放线菌纲和变形菌纲,差异条带的测序比对推测为变形菌纲和酸杆菌纲,红螺旋菌目、酸杆菌属只出现在与化感潜力弱的分蘖洋葱套作的黄瓜根际土壤中.相关分析表明,土壤脲酶与黄瓜幼苗株高、全株干质量、叶面积、DGGE条带数呈显著正相关.综上,与化感潜力强的分蘖洋葱套作,可为黄瓜生长创造良好的根际微环境,显著促进黄瓜幼苗生长.     

Effects of transgenic potatoes with an altered starch composition on the diversity of soil and rhizosphere bacteria and fungi

The aim of this study was to investigate potential effects on the composition of the bacterial and fungal diversity in rhizosphere and soil of a transgenic potato line (SIBU S1) which was modified in its starch composition by RNA anisensing, compared to the non-transgenic parental cultivar (SIBU) at the flowering stage in 2000. Furthermore a second non-transgenic cultivar (SOLANA) was included in the study. To avoid artefacts derived from cultivation depending approaches, molecular techniques based on 16S-(bacteria) and 18S-(fungi) rDNA respectively were used to describe the microbial community structure. Comparing 16S- and 18S-rDNA DGGE fingerprints from the different bulk soil samples, it could be shown that no significant differences between the two cultivars and the transgenic line were found. Similar results were obtained for the rhizosphere samples using the eubacterial, α-and β-proteobacterial and fungal specific primers with the exception of, the eubacterial DGGE patterns obtained for the rhizosphere of SOLANA. These patterns revealed that the relative abundance of one band was enhanced compared with the patterns of SIBU and SIBU S1 and the sequence of the differentiating band showed the highest similarity with Enterobacter amnigenus. When Pseudomonas specific primers were used, relevant differences were found between the rhizosphere patterns of the transgenic potato line (SIBU S1) and the parental cultivar (SIBU). However, clear effects of the cultivar SOLANA on the structure of the Pseudomonas community compared to SIBU were also detected.     

Influence of root-induced pH on the solubility of soil aluminium in the rhizosphere

Increase in solubility of soil aluminium (Al) as a result of root-induced decrease of soil pH was studied. Soil samples of known distances from the roots of NH₄-N fertilized Ryegrass were analyzed for pH and aluminium extractable with 0.01 M CaCl₂. Results showed that though no Al was found in bulk soil (pH 6.8), its concentration in the vicinity of roots increased to 0.023 mM with a concomitant decrease of soil pH from 6.8 to 4.4.     

超声辅助从柿叶中提取熊果酸的工艺研究

通过单因素实验,以熊果酸的提取率为指标,考察了柿叶中熊果酸超声提取过程的几个影响因素;并通过正交实验,对过程参数进行了优化。结果表明,各因素对熊果酸提取效果的影响程度从高到低分别是：乙醇体积分数→提取次数→提取时间→液固比;确定的最适提取条件为：体积分数95％乙醇溶液超声提取2次,每次40min,液固比为10：1。     

Models of the rhizosphere

A mathematical model has been developed which is capable of simulating the population dynamics of microbial biomass surrounding a root which is releasing soluble and insoluble carbon compounds into the soil. The model simulates the interconversions of C between different pools within the soil as well as the diffusion and mass flow of soluble carbon. Two main aspects of carbon release were examined: (i) a strategy where exudate was released uniformly over the root surface was compared to the case where exudation was confined to a small region behind the root tip; (ii) the situation in which all the C released was in soluble form was compared to the case of an approximately equal partition between soluble and insoluble forms. Substantial differences between the different simulations were found. It was shown that the maximum concentration and penetration of soluble exudates differed markedly between different simulations and the implications of this for micronutrient acquisition by phytosiderophores and for colonisation of the rhizosphere by root pathogens were discussed. The different simulations also predicted very different biomass distributions in the rhizosphere in both space and time.     

The influence of intercropping with Allium on some insect populations in potato (Solatium tuberosum)

Two field experiments were conducted in West Java, Indonesia to investigate the effects on insect populations in a potato crop of intercropping with Allium cepa or A. sativum. Intercropping reduced populations of Myzus persicae, Aphis gossypii and Empoasca spp. when less than 0.75 m separated the potato plants and Allium spp. Leaf damage to potato by Henosepilachna sparsa was also reduced at this spacing; but populations of Thrips palmi or T. parvispinus were increased. The implications of these trends are noted.     

Effects of intercropping white cabbage with clovers on pest infestation and yield

During two consecutive years the effects of intercropping fresh market white cabbage with two species of clover on pest populations and yield were studied. White cabbage cv. Minicole was intercropped withTrifolium repens (white clover) andTrifolium subterraneum (subterranean clover) as compared to the monocrop. During the season observations were made on pest population developments, especially ofMamestra brassicae L. (cabbage moth),Brevicoryne brassicae L. (cabbage aphid),Delia brassicae L. (cabbage root fly), and evaluation of caterpillar feeding injury. At harvest the yield in quantity and quality was determined to be able to assess the gross financial result. Intercropping effects in terms of suppression of oviposition and larval populations of various pests were found. Although no pesticides were used and competition reduced the weight, the quality of the intercropped cabbages lead to a better financial result compared to the monocropped cabbage crop. The results are discussed in the perspective of the practical implications in the context of IPM.     

间作对桑树和谷子生长和光合日变化的影响

以桑树和谷子为研究材料,探讨了大田条件下,桑树-谷子间作对桑树和谷子的干物质生产、土地利用率和光合日变化的影响.结果表明:桑树-谷子间作条件下,间作桑树的株高、地茎、根长和枝条数分别比单作桑树增加了6.0％、13.7％、6.8％和14.8％,且间作桑树的产叶量比单作桑树增加了31.3％;间作谷子与单作比较,其株高和根长的变化不大.桑树-谷子间作增加了土地当量比,提高了土地利用率.单作、间作桑树和谷子叶片在12:00时均表现出明显的光合午休现象,且单作桑树的光合午休现象比间作桑树严重.桑树-谷子间作提高了中午时桑树叶片气孔导度和水分利用率,增加了桑树光合碳同化能力,抑制了桑树叶片实际光化学效率、电子传递速率和最大光化学效率的下降,从而减缓了桑树的“光合午休”现象.桑树-谷子间作能明显提高桑树叶片的光合生产能力.