逆境胁迫下的农业管理中土壤-植物-微生物相互作用研究进展   总被引：2，自引：0，他引：2  

Shobhit Raj VIMAL  Jay Shankar SINGH  Naveen Kumar ARORA  Surendra SINGH 《土壤圈》2017,27(2):177-192

The expected rise in temperature and decreased precipitation owing to climate change and unabated anthropogenic activities add complexity and uncertainty to agro-industry.The impact of soil nutrient imbalance,mismanaged use of chemicals,high temperature,flood or drought,soil salinity,and heavy metal pollutions,with regard to food security,is increasingly being explored worldwide.This review describes the role of soil-plant-microbe interactions along with organic manure in solving stressed agriculture problems.Beneficial microbes associated with plants are known to stimulate plant growth and enhance plant resistance to biotic (diseases) and abiotic (salinity,drought,pollutions,etc.) stresses.The plant growth-promoting rhizobacteria (PGPR) and mycorrhizae,a key component of soil microbiota,could play vital roles in the maintenance of plant fitness and soil health under stressed environments.The application of organic manure as a soil conditioner to stressed soils along with suitable microbial strains could further enhance the plant-microbe associations and increase the crop yield.A combination of plant,stress-tolerant microbe,and organic amendment represents the tripartite association to offer a favourable environment to the proliferation of beneficial rhizosphere microbes that in turn enhance the plant growth performance in disturbed agro-ecosystem.Agriculture land use patterns with the proper exploitation of plant-microbe associations,with compatible beneficial microbial agents,could be one of the most effective strategies in the management of the concerned agriculture lands owing to climate change resilience.However,the association of such microbes with plants for stressed agriculture management still needs to be explored in greater depth.  相似文献   

Effect of nucleotide on growth, immune responses and resistance of Macrobrachium rosenbergii (De Man) to Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV) and Aeromonas hydrophila infection     

R. Shankar  H. Shivananda Murthy  H. R. Sujatha  E. G. Jayaraj  C. S. Tejpal  V. S. Chinthamani 《Aquaculture International》2012,20(1):1-12

A 60-day feeding trial was conducted to evaluate the effect of dietary nucleotide on growth, survival, immunity and resistance to white muscle disease and Aeromonas hydrophila infection in freshwater prawn (Macrobrachium rosenbergii). The nucleotide was supplemented at 0, 1.5, 2.25 and 3.0 g/kg diet. The test diets were fed for 60 days in triplicate groups of prawns, which had initial weight of 0.27 g. At the end of the feeding trial, growth was recorded and non-specific immune parameters, such as, prophenol oxidase activity, superoxide anion production, total haemocyte count and total serum protein, were studied in haemolymph samples. Phenol oxidase activity and superoxide anion production were significantly (P < 0.05) higher in prawns fed nucleotide-based diets. Total haemocyte count and haemolymph were higher (P < 0.05) in prawns fed nucleotide-based diets. The relative per cent survival of prawn after the challenge test against white muscle disease was significantly (P < 0.05) higher in prawn fed nucleotide-incorporated diets. However, there was no effect of nucleotide supplementation on growth and survival of prawn.  相似文献   

A Model For Prediction Of Survival In Critically III Dogs     

Lesley G. King MVB  MRCVS  Martha T. Stevens BSc    Ernest N. So. Ostro  Deborah Diserens M. Phil  Ravi Shankar J. MS 《Journal of Veterinary Emergency and Critical Care》1994,4(2):85-99

A system was developed for objective prediction of survival, which could be applied to all critically ill patients, regardless of disease, at an early stage of hospitaluation. Such a system would allow risk assessment of groups for experimental studies according to probability of survival and it might allow us to avoid expenditure of scarce clinical resources on animals with little chance of survival. The prospective study included 200 critically ill dogs: 93 females and 107 males, representing 62 breeds. With survival defined as alive 30 days after admisssion to ICU the overall mortality rate was 40.5% (81 of 200 dogs). Data collected included signalment and parameters that reflected vital organ function, the severity of physiologic derangement and the extent of physiologic reserve. We recorded the most abnormal value for each parameter within 24 hours of admission to ICU and logistic regression analysis was used to analyze four different weighting systems. The best model had a concordance 0f 86.5% with outcome, and it was then re-evaluated to determine whether individual variables could be eliminated without losing predictive accuracy. Fourvariables were eliminated, resulting in a final model with 18 variables which had 86.3% concordance with outcome. At a 0.5 cut-off for predicted risk, the model had sensitivity Of 69%, specificity ficity of 86% and positive predictive value of 77%. A Receiver Operating Curve was constructed using serial cut-offs for predicted outcome from 0.1 to 0.9, and the area under the curve was 0.89. Thus, an equation was generated that gives an estimate of the probability of survival.  相似文献   

Genetic Variability for Net Photosynthesis in Finger Millet (Eleusine coracana Gaertn) Genotypes An Approach to Identify High CER Types     

A. G. Shankar    M. Udaya Kumar  T. G. Prasad 《Journal of Agronomy and Crop Science》1990,165(4):240-252

Germplasm lines of finger millet (400 lines) with diverse genetic background were screened to identify high CER and CGR genotypes. Considerable variation was noticed in LA, biomass and all the growth and yield attributes but range in stomatal frequency was relatively less. The difference in plant stomatal number was more due to variation in LA but not the frequency. Since high TDM is a primary criteria for achieving higher grain yield, from amongst the high biomass types, genotypes differing in LA/DM ratios but with similar DM and HI were selected. In six genotypes each from low and high LA/DM group which showed stability across the environment, gas exchange characteristics were studied. The CER in low LA/DM types was 45 per cent higher. A significant negative relationship (r = -0.87) exists between CER and LA/DM ratios. Higher net assimilation rate in these genotypes therefore could be attributed mainly due to CER rather than the dark respiration.
An approach to identify high CER types with high CGR and low plant conductances from the germplasm lines has been proposed. These conceptual types will have high CGR but with low functional LA, thus low transpiration leaf surface. These conceptual types will have specific advantage under rainfed water limited conditions.  相似文献   

ROC analysis of prepartum feeding time can accurately predict postpartum metritis development in HF crossbred cows     

Tapas Kumar Patbandha  Tushar Kumar Mohanty  Siddhartha Shankar Layek  Arumugam Kumaresan  Suresh C. Kantwa  R. Malhotra  A.P. Ruhil  Shiv Prasad 《Journal of Veterinary Behavior: Clinical Applications and Research》2013,8(5):362-366

Receiver operating characteristic (ROC) analysis is a useful statistical tool to visualize, organize, and select diagnostic variables. Accuracy of the test is represented by the area under the ROC curve (AUC), sensitivity (Se), and specificity (Sp). In the present study, ROC analysis of prepartum feeding time (day ?11 to day ?2) of 20 pluriparous Holstein-Friesian crossbred cows were recorded, and the cows were followed up for detecting postpartum metritis development if any. Prepartum daily feeding time data during whole study was grouped into 2 periods (P1 [day ?11 to day ?7] and P2 [day ?6 to day ?2]). The AUC of feeding time for the P1 and P2 periods was 0.64 (P = 0.29) and 0.86 (P = 0.006), respectively. Cows with daily feeding times below the optimum threshold value of 284.5 min/d during P2 (Se = 75% and Sp = 91.67%) had more chance of developing postpartum metritis compared with those with daily feeding time above the threshold value (positive likelihood ratio = 9.0). Furthermore, relative risk (RR) analysis revealed that the risk of development of postpartum metritis increased as feeding time decreased below the optimum threshold value during P2 (RR = 5.571, P = 0.004). Thus, the optimum threshold value of feeding time during P2 may be used to predict risk of postpartum metritis, allowing for preventive measures to be implemented in the early postpartum period to reduce the likelihood of postpartum complications.  相似文献   

Carbon nanotube flow sensors     

Ghosh S  Sood AK  Kumar N 《Science (New York, N.Y.)》2003,299(5609):1042-1044

We report that the flow of a liquid on single-walled carbon nanotube bundles induces a voltage in the sample along the direction of the flow. The voltage that was produced fit a logarithmic velocity dependence over nearly six decades of velocity. The magnitude of the voltage depended sensitively on the ionic conductivity and on the polar nature of the liquid. Our measurements suggest that the dominant mechanism responsible for this highly nonlinear response involves a direct forcing of the free charge carriers in the nanotubes by the fluctuating Coulombic field of the liquid flowing past the nanotubes. We propose an explanation based on pulsating asymmetric ratchets. Our work highlights the device potential for nanotubes as sensitive flow sensors and for energy conversion.  相似文献   

Effects of paddy straw and sugarcane bagasse on water quality, bacterial biofilm production and growth and survival of rohu, Labeo rohita (Hamilton)     

Ramanath M Mridula  Joseph K Manissery  Perar Keshavanath  Kalkuli M Shankar  Mudnakudu C Nandeesha  & Kothanahally M Rajesh 《Aquaculture Research》2005,36(7):635-642

Sugarcane bagasse (T₁), paddy straw (T₂) and their mixture (T₃) were added to mud‐bottomed, manured cement tanks in triplicate to study the effect on bacterial biofilm production and growth and survival of rohu, Labeo rohita. All tanks were stocked with fingerling rohu at 10 000 ha^?1. The total plate count (TPC) of bacteria in water and on substrate did not differ significantly between treatments. The mean phytoplankton and zooplankton density in water was the highest in T₂, followed by T₃ and T₁. The growth of fish was significantly (P<0.05) higher in T₂ and T₃ compared with T₁. Significantly higher RNA values were recorded in T₂ and T₃ compared with T₁. Similarly, T₂ and T₃ registered higher DNA values than T₁. RNA:DNA ratio was higher in T₂ compared with T₁. However, T₃ did not differ significantly from T₁ and T₂. Both intestinal and hepatopancreatic protease and lipase activity was higher in T₁ and T₂ compared with T₃ and both differ significantly from T₁. Intestinal amylase activity was higher in T₂ and T₃ compared with T₁, whereas hepatopancreatic amylase activity was higher in T₂ compared with T₁ and T₃. The results demonstrated that production of L. rohita can be significantly increased by the introduction of biodegradable substrates into culture systems where fertilization is employed.  相似文献   

Incidence of white muscle disease, a viral like disease associated with mortalities in hatchery-reared postlarvae of the giant freshwater prawn Macrobrachium rosenbergii (De Man) from the south-east coast of India     

K K Vijayan  V Stalin Raj  S V Alavandi  V Thillai Sekhar  & T C Santiago 《Aquaculture Research》2005,36(3):311-316

Incidence of post‐larval mortalities of 30–100% was reported from commercial freshwater prawn, Macrobrachium rosenbergii (De Man) hatcheries in Andhra Pradesh and Tamil Nadu (south‐eastern states of India) since 2001. Infected postlarvae (PL) exhibited clinical symptoms with lethargy, anorexia and whitening of abdominal muscles and the disease was identified as white muscle disease (WMD). The waterborne infection of WMD was induced in the laboratory by exposing uninfected and healthy M. rosenbergii PL to the filtered muscle homogenates of the naturally infected PL, resulting in mortality that reached 99% within 10 days post infection. Histopathological examination of the infected animals revealed highly necrotic musculature. Degenerated muscle areas showed aggregations of melanized nuclei, many of which looked like inclusion bodies. Bacteriological examination of affected PL showed the presence of Staphylococcus spp. as a predominant organism, while laboratory challenge of healthy PL with this bacterial isolate did not reproduce WMD.  相似文献   

Effect of dietary vitamin C on the inflammatory response of mrigal, Cirrhinus mrigala (Hamilton), to Freund's complete adjuvant     

K S Sobhana  C V Mohan  & K M Shankar 《Journal of fish diseases》2002,25(3):179-184

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Cardiac myxosporiosis of pearl-spot, Etroplus suratensis (Bloch), due to Myxobolus etropli sp. nov     

Rajendran KV  Vijayan KK  Alavandi SV 《Journal of fish diseases》1998,21(3):169-176

A new myxosporean, Myxobolus etropli sp. nov., was found to infect the bulbus arteriosus of Etroplus suratensis (Bloch) from brackishwater lagoons of Muttukkadu, Chennai coast, India. A survey from May 1993 to October 1994 revealed a prevalence rate of 33.7% of this parasite. Macroscopic discoloured foci/cysts were seen in the bulbus arteriosus of the fish. The parasite showed strict host and site specificity. Histopathology showed that the infection was restricted to the bulbus. This is the first report of a myxosporean from E. suratensis.  相似文献