The colonisation and diversity of arbuscular mycorrhizal fungi (AMF) on roots of grapevines were investigated in production vineyards located along a 500 km long stretch of karst along the coast of the Adriatic Sea. AMF communities on roots of grapevines were analysed using temporal temperature gel electrophoresis and sequencing of the 18S and internal transcribed spacer segments of the rDNA operon. The AMF colonisation of these grapevines roots was consistent along the whole of this east Adriatic karst region, at 64 to 82% of fine roots. The comparison of the AMF communities on the roots of these grapevines showed that the fungal community associated with grapevine roots seems to be relatively stable, with inter-vineyard variability comparable to intra-vineyard variability. Some of the changes in the fungal communities were attributed to environmental factors (plant-available P) and location of the vineyard, although the latter could also have been influenced by an unmeasured environmental factor. A total of 27 taxa of fungi were identified, including taxa from Glomus group B, based on the sequencing of 18SrDNA. Sequencing of the internal transcribed spacer rDNA yielded 30 different fungal taxa, which comprised eight different Glomeromycota taxa, including Glomus sinuosum and Glomus indicum. To our knowledge, this is the first report of grapevine colonisation by G. indicum.
The uptake of Se(IV) by Myriophyllum spicatum, Ceratophyllum demersum and Potamogeton perfoliatus, and its effects on their physiological and biochemical characteristics were studied. Plants were cultivated outdoors under semi-controlled conditions in water solution containing Na selenite (20 µg Se L-1 and 10 mg Se L-1). The higher dose of Se lowered the photochemical efficiency of PSII in all species studied, while the lower dose had no effect on any species. The concentration of Se in plants cultured in 10 mg Se(IV) L-1 ranged from 436 to 839 µg Se g-1 DM in M. spicatum, 319 to 988 µg Se g-1 DM in C. demersum and 310 to 661 µg Se g-1 DM in P. perfoliatus. The amount of soluble Se compounds in enzyme extracts of high Se treatment was 27 % in M. spicatum, 41 % in C. demersum and 35 % in P. perfoliatus. Se compounds were determined using HPLC-ICP-MS. It was observed that the applied Se(IV) was mainly transformed to insoluble Se.
The amphibious plant species Sagittaria sagittifolia and Ranunculus lingua here serve as model systems to study differences in leaf optical properties of different leaf types that develop in aquatic and terrestrial environments. Comparisons of leaves of the same form revealed marked differences in their structures and particularly in the content of total UV-absorbing compounds. Submerged leaves transmit radiation over the whole range measured, but emerged leaves transmit only at wave-lengths from 500 to 650 nm, and above 690 nm. The analysis shows that biochemical leaf traits, together with the specific leaf area (SLA), significantly affect the reflectance spectra, explaining 60% of the spectra variability. Physical traits like thickness of the palisade mesophyll, SLA, and thickness of the lower and upper epidermis, along with anthocyanin content, explain 62% of the transmittance spectra variability. This study provides new insight into the understanding of data collected for aquatic and semi-aquatic plants based on spectral analyses.
Dark septate endophyte (DSE) fungi are the most frequent colonists on the roots of Salix caprea in highly metal-contaminated soils. The present study was performed to obtain insights into the physiology and potential role(s) of DSE fungi for Salix caprea growing in metal-enriched sites. Fungal isolates from S. caprea roots were identified using molecular methods, and tested for their tolerance and metal accumulation in axenic cultures. In addition, an inoculation experiment was performed to monitor the effects of the fungi on the metal uptake by the plant host. Fitness of S. caprea cuttings was assessed by photosynthetic pigment quantification and measurements of transpiration. Fungal isolates were identified as members of the Phialophora/Cadophora complex. They showed different levels of metal tolerance and maintained growth on metal-enriched media. In comparison to non-inoculated cuttings, the DSE-inoculated cuttings had lower leaf Cd content, and for isolates DB146 and DB148, also lower Zn concentrations. All DSE isolates increased the chlorophyll levels of the cuttings, with isolate DB146 also positively affecting the transpiration rate of S. caprea.
To investigate the impact of Se on Tartary buckwheat (Fagopyrum tataricum Gaertn.) plants, the plant foliage was sprayed with 10 mg Se(VI) L−1 at the beginning of flowering. The Se was effectively assimilated by the plants and taken into the seeds, where its concentration was more than double that in untreated plants. The seeds were collected and sown to obtain the progeny of these Se-treated plants. Three weeks after germination, the Se-treated progeny plants showed higher ETS activity compared to the controls. Through weeks 4 and 5, this high ETS activity approximately halved, and the difference in ETS activity seen at 3 weeks was lost. On the other hand, at week 4, the potential photochemical efficiency was higher in the Se-treated progeny plants than the controls. In adult plants, the leaves dry mass was significantly greater in the Se-treated progeny plants than the controls. This study demonstrates an impact of Se in Tartary buckwheat on the progeny plants of Se sprayed plants, as shown previously in pea plants.