Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum.

An UV-B-exclusion experiment was established in high arctic Zackenberg, Northeast Greenland, to investigate the possible effects of ambient UV-B on plant performance. During almost a whole growing season, canopy gas exchange and Chl fluorescence were measured on Vaccinium uliginosum (bog blueberry). Leaf area, biomass, carbon, nitrogen and UV-B-absorbing compounds were determined from a late season harvest. Compared with the reduced UV-B treatment, the plants in ambient UV-B were found to have a higher content of UV-B-absorbing compounds, and canopy net photosynthesis was as an average 23% lower during the season. By means of the JIP-test, it was found that the potential of processing light energy through the photosynthetic machinery was slightly reduced in ambient UV-B. This indicates that not only the UV-B effects on PSII may be responsible for some of the observed reduction of photosynthesis but also the effects on other parts of the photosynthetic machinery, e.g. the Calvin cycle, might be important. The 60% reduction of the UV-B irradiance used in this study implies a higher relative change in the UV-B load than many of the supplemental experiments do, but the substantial effect on photosynthesis clearly indicates that V. uliginosum is negatively affected by the current level of UV-B.

The influence of auxins on the biosynthesis of isoprene derivatives in callus cultures of Vaccinium corymbosum var. bluecrop.

Callus cultures of Vaccinium corymbosum var. bluecrop were optimized for their isoprene derivatives production by supplementing Schenk-Hildebrandt (SH) medium with constant concentration of kinetin (2.32 microM) and two different amounts of selected auxins. Every auxin, except for IBA, used in 10-time higher concentration (2,4D, NAA, IAA, NOA) stimulated biosynthesis of beta-sitosterol and inhibited triterpene synthesis. Quantitative analysis of isoprene derivatives in callus biomass collected on the 25th day of the experiment proved that the analyzed callus of Vaccinium corymbosum var. bluecrop synthesized the highest amount of isoprene derivatives after subculturing on SH medium modified with 22.6 microM of 2,4D and 2.32 microM of kinetin.

Anthocyanin production from Vaccinium pahalae: limitations of the physical microenvironment.

Physical microenvironmental parameters conducive to production of flavonoids in vitro from continuous Vaccinium pahalae suspension cultures were examined first in shake flask culture experiments, and results were used to guide adaptations of a bioreactor production environment. Anthocyanin pigments were primarily concentrated in smaller aggregates up to 519 microm diameter. Agitation at 150 rpm and routine use of a mechanical scraper to periodically retrieve cells thrown out of solution was sufficient to keep productive plant cell aggregates in bioreactor suspension. A set up for enhanced irradiance with mercury lamps providing an average of 240 micromol m(-2) s(-1) PPF at the inner surface of the bioreactor vessel was required to sustain anthocyanin productivity through a 10-day production cycle.

Anatomical study on Vaccinium arctostaphylos L.

Vaccinium arctostaphylos L. (Ericaceae), locally named Qaraqat, is widely used in Iranian folk medicine as antidiabetic and antihypertensive agents. The anatomical study on the different organs of the plant was performed to give a clear standard for identification of the drug. Various diagnostic elements such as particular cells, rubiaceous stomata, covering and glandular trichomes, Ca-oxalate crystals were found in different parts.