پاسخ فسفومونواسترازها به پيشرفت مراحل تجزيه لاشبرگ در جنگل هاي بلوط منطقه مركزي ايران

چكيده انگليسي :

The Response of Phosphomonoesterases to Oak Litter Succession in Central Iran Fereshteh Valipoor Fereshte valipoor94@gmail com January 1 2018 Department of Soil Science Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor F Nourbakhsh farshid@cc iut ac irAbstractForest is a natural ecosystem consisting of all land wood resources bushes and grasses animals microorganisms and other components of the natural habitat along with the natural environment In aforest ecosystem litter is the accumulation of plant tissue material that is decomposed or degraded duringthe biological processes Physical and chemical conditions litter quality and composition of thedecomposing society are the three main factors controlling the decomposition of litters under theenvironmental conditions Litter decomposition plays an important role in the cycling and the balance ofnutritional elements which maintain soil fertility and provide nutrients for plant growth This researchwas carried out to investigate i the response of alkaline and acid phosphatase available P to successionalchanges in anoak leaf litter at different biodegradation stages and ii the degradability of litters withdifferent degrees of degradation in two soils with contrasting landuse For this purpose an oak forest inDalvara region was considered and the samples were collected from fresh oak leaves L0 litter with lowrates of decomposition L1 litter with medium rates of decomposition L2 and and litter with high ratesof decomposition L3 Some important biological and biochemical properties in leaf and litters includingorganic carbon total nitrogen available P lignin content and alkaline phosphatase and acid phosphataseactivities were measured Results showed that in litter samples the amount of organic carbon and alkalineand acid phosphatase activity decreased with increasing the degradation rateswhereas total nitrogen available P and lignin content decreased Negative correlations observed between soil organic carbon andindices such as total nitrogen r 0 87 available P r 0 71 and lignin cnontent r 0 84 However there were positive correlation between organic carbon and biological indices such as alkalinephosphatase r 0 8 and acid phosphatase r 0 87 The activity of alkaline and acid phosphatase aswell as soil microbial respiration were consistently greaterin litter treated soils Moreover natural forestsoil supported greater enzyme activities and microbial respiration regardless of plant litter treatment inAlso in one type of land use A decreasing trend was monitored in alkaline and acid phosphatase enzymeandmicrobial respiration as biodegradation stage was greater L3 L2 L1 L0 in contrast a decreasingtrend was observed for available P The main effect of the land use plant residues well as their interactionwere significant for alkaline phosphatase acid phosphatase basal respiration and available P Microbialrespiration was positively correlated with alkaline phosphatase r 0 75 and acid phosphatase r 0 8 activities Therefore progressing the decomposition process of litters resulted in declining either C orbiodegradability of the litters It also looks likely that the progress in the litter decomposition induce astress to soil microbial population as indicated by greater values measured for metabolic quotient Thestress was interpreted by the fact that as successional stages progress a shortage in C adequacy would beappeared Key words litter ecosystem decomposition succession available P alkalinephosphatase acid phosphatase

ولي پور، فرشته

پاسخ فسفومونواسترازها به پيشرفت مراحل تجزيه لاشبرگ در جنگل هاي بلوط منطقه مركزي ايران

اكوسيستم لاشبرگ , توالي تجزيه , فسفرقابل جذب , آلكالين فسفاتاز , اسيد فسفاتاز