The accumulation of Se(IV) and its effects on the physiological and biochemical characteristics of duckweed (Lemna minor L.) have been studied. Concentrations of 2 and 5 mg Se L-1 mostly negatively affected photochemical efficiency, and in weeks 1–4 increased respiratory potential in comparison to the control, while beyond week 4 the respiratory potential decreased. The addition of Se had a minor effect on the amount of chlorophylls and carotenoids. The content of Se in duckweed increased with the increasing concentration of Se: plants growing in 0.5 mg Se L-1 contained 0.9 mg Se g-1 DM, and plants exposed to 5 mg Se L-1 contained 5.8 mg Se g-1 DM. The group of plants exposed to 10 mg Se L-1 for 21 days, contained 19.5 mg Se g-1 DM. Our study revealed that duckweed can accumulate high amount of Se. Duckweed could be suitable for the phytoremediation of lower (0.5, 1, 2, 5 mg Se(IV) L-1) concentrations of Se(IV)-contaminated water.
We determined differences in the leaf spectral signatures of plant species groups growing in habitats along the hydrological gradient of an intermittent wetland and to define leaf traits that explain their variability in order to contribute to the understanding of the causes for plant spectrum variability at leaf and community levels. The reflectance spectra of the different species groups differed most in the green, yellow and red spectral ranges. The reflectance spectra of submerged leaves of hydrophytes with simple structures were explained by their biochemical traits (carotenoids), while for more complex aerial leaves, morphological traits were more important. In submerged and natant leaves of amphiphytes, total mesophyll and spongy tissue thickness were the most important traits. The redundancy analysis biplots of helophytes and wet meadow species show clustering of graminoids and dicots into two distinct groups. Leaf encrustation (prickle hair properties and epidermis thickness) is important for graminoids, while leaf thickness and specific leaf area have more important roles in dicots. Our results show that knowledge of the species composition and leaf traits is necessary to interpret the reflectance spectra of plant communities.
The spatial variability of the mineral composition of grapevines in production vineyards along the east Adriatic coast was determined and compared between conventional and sustainable vineyard management. Cluster analysis shows a high level of spatial variability even within the individual locations. Factor analysis reveals three factors with strong loading for the macronutrients K and P and the micronutrient Mn, which explain 67% of the total variance in the mineral composition. Here, 26% to 34% of the variance of these three elements can be explained by abiotic and biotic soil parameters, with soil concentrations of K, Fe and Cu, organic matter content, and vesicular colonisation showing the strongest effects on the mineral composition of the grapevines. In addition, analysis of the mineral composition data shows significant differences between differently managed vineyards, with increased bioaccumulation of P and K in sustainable vineyards, while Zn bioaccumulation was increased in conventional vineyards. Our data confirm the importance of soil and vineyard management in the concept of terroir, and demonstrate the effects of sustainable management practices on the mineral nutrition of grapevines that result from modified nutrient availability related to changes in the abiotic and biotic characteristics of the soil.
The hypothesis of this study is that the variable hydrological regime of intermittent lakes and wetlands affects the primary productivity, decomposition and root fungal colonisation of Phragmites australis, with effects on the whole ecosystem metabolism. The above-ground biomass of reed stands was monitored in littoral and riparian stands of Lake Cerknica, under different water levels. Leaf and culm litter decomposition was also studied at three locations, from predominantly dry to permanently submerged. Root colonisation by fungi was monitored across two seasons in the littoral reed stand. The primary productivity of the littoral stands was related to a variable degree with water levels and air temperature in July in the current year. In the riparian reeds, only monthly temperatures in October of the previous year were important. The submersion duration of the litter enhanced the decomposition rates. The frequency of fungal colonisation of reed roots was decreasing with the submersion time length. The main outcomes of this study deals with the role of intermittent hydrological conditions in determining the structure and functioning of reed-dominated lacustrine wetlands, which are exposed to climate threats.
The occurance and germination of seed of Fallopia japonica, F.xbohemica and F. sachalinensis in Slovenia were determined. The amounts of nuclear DNA were measured and potential pollen donors were determined. Sexual reproduction was confirmed, highet level of seeds developed on F. japonica plants. Genome size corresponded to 3 ploidy levels. F.x bohemica was the most frequent pollen donor.