Barley (Hordeum vulgare L.

Barley (Hordeum vulgare L.) seeds were soaked in aqueous 10 -4 M dihydroquercetin (DHQ) to examine its influence on seed germination and further growth of seedlings under optimal soil watering and flooding conditions. The adaptive potential of the plants was estimated by the content of thiobarbituric acid reactive substances (TBARs) and the activity of ascorbate peroxidase (AsP). High-grade seeds were germinated evenly under (-DHQ)-and (?DHQ)-treatments. Low-grade seeds soaked in DHQ, showed no mold and twofold germination rate in comparison with the same seeds soaked in water.The seedlings grown from the similarly germinated seeds did not differ from each other in the shoot growth, independent of the DHQ-pretreatment. The root growth was higher in DHQ-pretreated plants. Soil flooding suppressed the shoot and root growth rates in non-pretreated and DHQ-pretreated plants, however TBARs content was lower in the roots and leaves of (?DHQ)-seedlings as compared to the (-DHQ)-ones. The activity of AsP increased more significantly in the (?DHQ)-plants. The ratio between TBARs content and the AsP activity was lower in the leaves of (?DHQ)-plants both under optimal soil conditions and flooding. Thus, the treatment of low-grade barley seeds with DHQ protects the seeds against mold and increases adaptive potential of the seedlings.

No abstract

Methane (CH4) production and consumption and soil respiration in loess soils collected from summit (Top), back slope (Middle), and slope bottom (Bottom) positions were assessed in laboratory incubations. The CH4 production potential was determined under conditions which can occur in the field (relatively short-term flooding periods with initially ambient O2 concentrations), and the CH4 oxidation potential was estimated in wet soils enriched with CH4. None of the soils tested in this study emitted a significant amount of CH4. In fact, the Middle and Bottom soils, especially at the depth of 20–40 cm, were a consistent sink of methane. Soils collected at different slope positions significantly differed in their methanogenic, methanotrophic, and respiration activities. In comparison with the Top position (as reference soil), methane production and both CO2 production and O2 consumption under flooding were significantly stimulated in the soil from the Middle slope position (P < 0.001), while they were reduced in the Bottom soil (not significantly, by 6 to 57%). All upper soils (0–20 cm) completely oxidized the added methane (5 kPa) during 9–11 days of incubation. Soils collected from the 20–40 cm at the Middle and Bottom slope positions, however, consumed significantly more CH4 than the Top soil (P < 0.001).

No abstract