DUNDEK, P., HOLÍK, L., ROHLÍK, T., VRANOVÁ, V., REJŠEK, K., FORMÁNEK, P.: Methods of plant root exudates analysis: a review. Acta univ. agric. et silvic. Mendel. Brun., 2011, LIX, No. 3, pp. 241-246 The aim of this review is to summarise current knowledge on methods being used to determine individual compounds and properties of water-soluble plant root exudates. These compounds include amino acids, organic acids and simple sugars, as well as polysaccharides, proteins and organic substances. Qualitative composition of water-soluble root exudates and exudation rate are commonly measured with the aim of consequent synthetic preparation of plant root exudates to be supplied to soil to create artifi cial rhizosphere for diff erent experimental purposes. Root exudates collection usually requires consequent fi ltration or centrifugation to remove solids, root detritus and microbial cell debris, and consequent concentration using an evaporator, lyophilizator or ultrafi ltration. Methods used for analysis of total groups of compounds (total proteins and total carbohydrates) and total organic carbon are simple. On the other hand, HPLC or GS/MS are commonly used to analyse individual low molecular weight organic molecules (sugars, organic acids and amino acids) with separation using diff erent columns. Other properties such as pH, conductivity or activity of diff erent enzymes as well as gel electrophoresis of proteins are sometimes assessed. All of these methods are discussed in this work. amino acids, HPLC, GC/MS, organic acids, root exudates, sugars Substances released by healthy and intact roots into the environment are collectively designated as root exudates. These substances aff ect the composition of microbial community in immediate proximity of plant roots and processes taking place in rhizosphere. Many compounds are released by plant roots, including inorganic ions and substances,

Diurnal variations in streamflow are becoming acknowledged as a way of analysing how changing climatic conditions and land use affects watersheds but also as a way to understand watersheds as a whole. Yet not many studies from uplands below 900 mm mean annual precipitation zone are available from European countries. During the 2012 growing season, a sampling campaign took place in an upland forested micro‐watershed, Czech Republic (65 ha). Tree sap flow, rainfall and temperature were measured continuously, while streamflow at the discharge point and soil moisture were estimated from short‐term measurements. Short precipitation‐free periods lasting several days were identified for evaluation of trends in diurnal dynamics of both sap flow and streamflow. The results demonstrated that during these periods, the main factor altering streamflow was almost exclusively tree sap flow. A decrease in streamflow was observed during the day and an increase at night. The decline in sap flow after sunset was accompanied by a continuous increase in streamflow throughout the night up to its initial maximum in the morning. The amplitude in diurnal variations reached 18%. The observed time lag between the diurnal variations of sap flow and streamflow was approximately 2 h. Relatively low changes in diurnal dynamics of streamflow pointed out a strong regulatory role of the forest in buffering water discharge from the catchment. Copyright © 2015 John Wiley & Sons, Ltd.

Abstract:The exact data from the field of soil mechanics from specific forest stands exposed to forestry mechanization operation were obtained. Field surveys were performed on four study plots within the Křtiny Training Forest Enterprise, Masaryk Forest, followed by laboratory analyses of the collected soil samples aimed at evaluation of the impacts of Zetor 7245 Horal System, PONSSE ERGO 16 harvester and Gremo 950 forwarder on the compaction of upper soil horizons as well as on the dynamics of soil saturated hydraulic conductivity. A specific objective of the performed investigation was to assess the influence of the used hauling/skidding technology on measurable parameters of soil mechanics with the emphasis on a possibility to apply the Guelph permeameter for direct study of soil saturated hydraulic conductivity. In the measurement points affected by machinery operation, the impact of the changed soil structure on the values of saturated conductivity is very well noticeable -on study plots No. 3 and 4, the values decreased by one order of magnitude from 0.7 × 10 -5 m·s -1 to 0.09 × 10 -5 m·s -1 : specifically, (i) on study plot No. 3 and from 6.9 × 10 -5 m·s -1 to 0.7 × 10 -5 m·s -1 , and (ii) on study plot No. 4; on study plot No. 2 even by two orders, i.e. from 1.6 × 10 -5 m·s -1 up to 0.03 × 10 -5 m·s -1 .After the operation of a universal wheeled tractor at the Babice nad Svitavou locality, the situation partially improved by one order to 0.3 × 10 -5 m·s -1 , similarly like at the Rudice locality to 1.5 × 10 -5 m·s -1 . Significant changes were found in both surface and subsurface horizons. Field-saturated hydraulic conductivity indicates also a reduction of the pore volume after machinery traffic; however, tendencies towards restoration of the original state were detectable as soon as after six months.

This work was aimed to test the effect of selected amino acid enantiomers on activity of casein-protease and acid phosphomonoesterase in soil. Casein-protease was selected due to its key role in nitrogen mineralization and acid phosphomonoesterase due to its importance in soil organic P mineralization. The results showed that 5 mg of L- and D-glutamic acid added to fresh soil from Ah horizon of a moderately mown mountain meadow significantly (P < 0.05) decreased casein-protease activity, whereas alanine enantiomers slightly increased activity of this enzyme. Testing the effect of cystine on activity of acid phosphomonoesterase in soil showed slight increase of this activity after application of 3.2 mg L- or D-cystine to fresh soil (equivalent to 8 mg to dry soil).

This work presents a summary of literature dealing with the use of plant root exudates in bioremediations. Bioremediation using plants (phytoremediation or rhizoremediation) and associate rhizosphere to decontaminate polluted soil is a method based on the catabolic potential of root-associated microorganisms, which are supported by the organic substrates released from roots. These substrates are called “root exudates”. Root exudates support metabolism of pollutants-decomposing microorganisms in the rhizosphere, and affect sorption / desorption of pollutants. Awareness of exudation rates is necessary for testing soil decontamination. Commonly, water-soluble root exudates of different plants are studied for their qualitative composition which should be related to total carbon of exuded water-soluble compounds. This paper presents the determined rate of plant root exudation and the amount of root exudates carbon used to form artificial rhizosphere.