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GPC of soil humic and fulvic acids from Trojmezí area
Šestauberová, Martina ; Novák, František
Humic (HA) and fulvic acids (FA) were isolated from individual soil horizons from podzol of spruce forest in Trojmezí stand (Bohemian Forest, 48°46´25¨ N, 13°51´04¨ E). Their molecular weight M.sub.r./sub. and weight-average molecular weight M.sub.w./sub. were determined by the gel permeation chromatography(GPC). For the high-molecular HA fraction (HM-HA), it was found the range of M.sub.r./sub. 380 – 569 kDa, for the main fraction of HA and for FA 6.7 – 31.4 kDa and 1.8 – 3.3 kDa, respectively. The M.sub.r./sub. of humic substances and the proportion of HM–HA decreased with soil depth. HA isolated from horizon B.sub.h./sub. didn´t contain any high-molecular fraction and its molecular weight approached the values specified for FA.
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Vegetation carbon-stores and net primary in upper Stropnice river catchment
Stará, Lenka ; Bodlák, L. ; Pokorný, J. ; Macků, J. ; Janderková, J. ; Šefrna, L. ; Středa, T. ; Burešová, Renata ; Pechar, Libor ; Cudlín, Pavel
Vegetation carbon-stores were quantified and net primary production estimated in upper Stropnice river catchment.Subsequently carbon cycle in the studied territory was composed for to estimate the total carbon balance of the area.Based on the results studied territory appear to be a carbon sink,i.e.carbon storing area.
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The effect of elevated air CO2 concentration on water regime and transpiration of Norway spruce
Valouch, Ludvík ; Pokorný, Radek ; Tomášková, Ivana
Under the elevated CO2 air concentration, changes in physiological processes and morphology were evident in relatively short time. Direct measurement via heat pulse method proved reduction of specific sap flux throw the stem in the first year of cultivation in elevated CO2. SSF in both treatments was comparable in the next tree years. During the sixth year of fumigation, higher transpiration rate in trees growing under elevated CO2 was recorded. It was implication of larger bearing leaf area, larger conducting vessels area on the in crosscut stems section and larger root absorbed area. Continuously sap flow measuring of sun and shaded part of the crown was found that SSF of higher crown part was higher in both treatments. Average hydraulic conductance soil-leaf (GTsa) was 1,4 times higher in sunny part of the crown than estimated for the whole crown in ambient treatment A (ambient [CO2] concentration). Difference in hydraulic conductance between the upper and lower crown part of the E treatment (doubled [CO2] concentration of A treatment) was not so pronounced.
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