J. Vítámvás

Quantitative analysis of proteome extracted from barley crowns grown under different drought conditions

Barley cultivar Amulet was used to study the quantitative proteome changes through different drought conditions utilizing two-dimensional difference gel electrophoresis (2D-DIGE). Plants were cultivated for 10 days under different drought conditions. To obtain control and differentially drought-treated plants, the soil water content was kept at 65, 35, and 30% of soil water capacity (SWC), respectively. Osmotic potential, water saturation deficit, 13C discrimination, and dehydrin accumulation were monitored during sampling of the crowns for proteome analysis. Analysis of the 2D-DIGE gels revealed 105 differentially abundant spots; most were differentially abundant between the controls and drought-treated plants, and 25 spots displayed changes between both drought conditions. Seventy-six protein spots were successfully identified by tandem mass spectrometry. The most frequent functional categories of the identified proteins can be put into the groups of: stress-associated proteins, amino acid metabolism, carbohydrate metabolism, as well as DNA and RNA regulation and processing. Their possible role in the response of barley to drought stress is discussed. Our study has shown that under drought conditions barley cv. Amulet decreased its growth and developmental rates, displayed a shift from aerobic to anaerobic metabolism, and exhibited increased levels of several protective proteins. Comparison of the two drought treatments revealed plant acclimation to milder drought (35% SWC); but plant damage under more severe drought treatment (30% SWC). The results obtained revealed that cv. Amulet is sensitive to drought stress. Additionally, four spots revealing a continuous and significant increase with decreasing SWC (UDP-glucose 6-dehydrogenase, glutathione peroxidase, and two non-identified) could be good candidates for testing of their protein phenotyping capacity together with proteins that were significantly distinguished in both drought treatments.

In vitro Conservation of Smallanthus sonchifolius under Slow-Growth Conditions

Abstract The aim of this work was to optimize in vitro storage of yacon (Smallanthus sonchifolius) under slow-growth conditions. Mediumterm conservation was tested on ½ MS supplemented with mannitol and sorbitol (1-3%), BAP (5 mg l-1), or MS and ½ MS medium free of plant growth regulators. Within 60 days, height of plants, number of nodes, number of roots and their length were measured in all of these treatments. The results revealed that there was a decline in plant growth along with the increase in the concentrations of mannitol (1.88, 1.49 and 1.07 cm for 10, 20 and 30 g l-1 mannitol) and sorbitol (3.66, 3.19 and 1.74 cm for 10, 20 and 30 g l-1 sorbitol), and along with the decrease of nutrient concentration in the cultivation medium (4.74 and 2.24 cm for MS and ½ MS medium). The survival of explants was found to be minimal at the highest concentrations of osmotic regulators (70% in mannitol and 50% in sorbitol) and on the medium supplemented with BAP (60%), while maximal on MS medium, ½ MS medium and on ½ MS medium with addition of 10 g l-1 mannitol (in all cases 100%). On full-strength MS medium and medium with addition of BAP plant growth was rapid, suggesting that these media could be rather used for multiplication of yacon. On the basis of our results it can be concluded, that for medium-term conservation of yacon can be satisfactory used ½ MS medium and media supplemented by 10 or 20 g l-1 mannitol or sorbitol.

Birds girdling activity on exotic tree species as a form of adaptive behavior

Four tree species in the Kostelec n. Č. l. arboretum (Czech Republic) have been repeatedly damaged by Dendrocopos medius. The unique aspect of this otherwise common behavior called girdling consists in regularly visiting the same trees every spring, although there are more than 1.200 tree species within the arboretum. We monitored transpiration, leaf phenology and the chemical composition of the xylem sap of girdled and nongirdled trees. Spectral analysis revealed slightly higher amounts of sugars, especially saccharose, in Cladrastis Raf. as the most regularly girdled tree among other conditions, comparing girdled to non-girdled trees. Higher transpiration rates were not confirmed in connection with girdling—quite the opposite—Cladrastis Raf. as the most highly favored tree for girdling showed the lowest transpiration rates (in average 6 kg water per day within spring months) compared to other non-girdled trees. We presume that the birds do not choose a particular tree on the basis of any visible or chemical traits but they examine many trees within their territory. Afterwards they probably remember the position of trees whose xylem sap starts to flow early in the spring compared to other trees, as their transpiration stream is enriched with sweet organic substances that represent an advantage for the forthcoming nesting period.