The incidence of mistletoe (<Emphasis Type="Italic">Viscum album</Emphasis> ssp. <Emphasis Type="Italic">abietis</Emphasis>) on silver fir (<Emphasis Type="Italic">Abies alba</Emphasis>) in Croatia

The research on incidence of mistletoe (Viscum album ssp. abietis) on silver fir (Abies alba) was carried out in natural fir stands in Croatia. In the area of Gorski Kotar 32.8 % of the examined dominant fir trees were infected with mistletoe. The mistletoe incidence was presented according to the damage degrees of silver fir from 0 (healthy trees) to 4 (dead trees), rated by the crown defoliation and needle discoloration. With the increase of incidence, mistletoe spreads more onto more vital, i.e. less damaged trees. In the Dinaric Alps 28.6% of the examined fir trees were infected, this percentage amounting to 27.1% for the mountainous regions between the Sava and Drava rivers. The site and stand parameters (exposure, elevation, site quality, forest community and crown closure) were analysed in order to establish whether there was a correlation between these parameters and mistletoe incidence. There was a negative correlation between the elevation and mistletoe incidence. Among the compartments with a closed stands there were considerably less compartments with higher mistletoe incidence than among compartments with a sparsely closed and understocked stands. The other analysed site and stand parameters individually had no significant influence on mistletoe incidence. The correlation of silver fir mortality in 2004 and mistletoe incidence in 2002/03 was analysed, and their strong correlation was established. Mistletoe could be considered as a bioindicator of silver fir decline, and probably a significant contributor to that decline. In the areas where mistletoe incidence is great it can be presumed that silver fir is significantly damaged.     

Some features of somatic embryo maturation of algerian fir

Summary Maturation of Abies numidica De Lann. somatic embryos was tested on media with abseisic acid and various maltose and polyethylene glycol-4000 concentrations. The effect of basal medium and subculture period on maturation was also examined. The maturation of somatic embryos was promoted by polyethylene glycol-4000, at 7.5–10%. Three to 6% maltose significantly enhanced the yield of mature embryos. The most effective somatic embryo maturation occurred when embryogenictissue was transferred to maturation medium after 14–21 d cultivation on proliferation medium. The ability for A. numidica cultures to form cotyledonary somatic embryos was assessed over a period of 3 yr. Plantlets germinated on half-strength SH (Schenk and Hildebrandt) medium with charcoal and survived transfer to the soil.     

The contact zone between two migration routes of silver fir,Abies alba (Pinaceae), revealed by allozyme studies

Enzyme data from 35 populations or regional samples ofAbies alba were obtained from different regions of Austria and Bavaria. The genetic analysis revealed a clear differentiation between the western and the north/eastern populations. A rather narrow transition zone (the river valleys of Salzach and Traun) with genetically intermediate populations connects these two regions. This west-east differentiation can be interpreted as the result of distinct migration routes from a glacial refuge in Central Italy. The transition zone is assumed to be the contact area of two routes north of the Alps. Each migration route of silver fir parallels the distribution range ofCardamine trifolia (east) andAposeris foetida (west) respectively. It is supposed that these two species were already associated with silver fir during colonization.Dedicated to emer. Univ.-Prof. DrFriedrich Ehrendorfer on the occasion of his 70th birthday     

Photoacoustic spectra of needles as an indicator of the activity of the photosynthetic apparatus of healthy and damaged conifers

Photoacoustic spectra were measured at chopping frequencies of the excitation light at 22 and 515 Hz in order to detect differences between needles from healthy and damaged conifers ( Abies alba Mill, and Picea abies Karst.) with respect to pigment distribution and possibly also to photosynthetic activity. Fully green needles of healthy trees exhibit photoacoustic spectra at 22 Hz with a maximum in the red absorption region of the chlorophyll. This maximum is lost with increasing damage to needles and chlorophyll breakdown. The photoacoustic spectra at 22 Hz of the damaged needles therefore are characterized by a higher signal in the blue-light region as compared to that in the red-light region. This can be quantified by forming the ratio of the photoacoustic signals at 675 and 475 nm (ratio PA 675/475). The needles of the damaged trees possess a lower photosynthetic activity, as seen from the CO₂ fixation rate and the variable fluorescence (Rfd-values). It is assumed that the changes in the PA-spectra of the needles from damaged trees are the result of this decline of the photosynthetic apparatus and its function. In contrast to the PA-spectrum at 22 Hz the PA-spectra at 515 Hz, where the PA-signals primarily emanate from the epidermal layer, exhibit a different shape with a maximum near 550 nm. In the needles from the damaged trees the PA-signals are higher, particularly in this maximum range of the spectrum, than those of fully green needles from healthy trees.     

Species delimitation and phylogeography of Abies delavayi complex: Inferred from morphological,molecular, and climatic data

The species delimitation within Abies delavayi complex, consisting of A. delavayi Franch., A. fabri (Mast.) Craib, A. nukiangensis W. C. Cheng & L. K. Fu, and A. delavayi subsp. fansipanensis (Q. P. Xiang, L. K. Fu & Nan Li) Rushforth, has been a subject of long‐term dispute. We combined different lines of evidence, including morphological characters, population‐based mitochondrial DNA and chloroplast DNA sequences, and plastome data to assess its species delimitation. These four independent datasets revealed a consistent result that the four taxa of A. delavayi complex were hardly separated and could be regarded as one species. Our results further suggested that these four taxa might have experienced rapid morphological diversification, following a common expansion triggered by climate oscillations during the Pleistocene. In addition, we surveyed the phylogeographical history of A. delavayi complex as a whole based on ecological niche models and molecular data. These results consistently revealed that this high‐mountain fir complex had experienced glacial expansion and interglacial contraction. Therefore, we propose that A. delavayi complex probably has undergone the phalanx expansion model in response to climate change during the Quaternary. Such expansion patterns demand consideration when establishing conservation strategies for threatened fir species.     

Geographic variability of monoterpenes from cortex of Abies concolor

Cortical oleoresin from 351 Abies concolor trees collected in 43 localities was analyzed for composition of its monoterpenoid fraction. The populations could be segregated into three geographic groups: (1) Northern and Central California (equivalent to var. Iowiana), producing camphene and 3-carene in trace to small amounts; (2) Southern California (the Cuyamaca race), producing camphene in trace to small and 3-carene in larger amounts; and (3) states to the east of California (equivalent to var. concolor) producing camphene and 3-carene in larger amounts. California populations from the southernmost Sierra Nevada and Northern Transversal Ranges were found to be chemically intermediate between var. Iowiana and var. concolor. Statistical analysis indicated the presence of additional second-order segregations in each of the four population groups, The results are explained on the basis of existing paleobotanical records.     

A new record ofMycena picta from Japan

Mycena picta, a rare species of Agaricales, is reported for the first time from Japan, based on specimens collected in Hokkaido.     

Effect of nitrogen fertilization on leaf phenolic production of grand fir seedlings

Summary A significant decrease in production of total phenolics was apparent with nitrogen fertilization in three of five seed sources of grand fir [Abies grandis (Dougl.) Lindl.]. Subsequent extraction and identification of phenolics indicated that two compounds increased with fertilization, and when grouped by biosynthetic origin into cinnamic acids, benzoic acids, and flavonoids, no differences were apparent with fertilization. Total biomass increased with fertilization, and the relation between growth and total phenolics was similar for all seed sources. The increase in growth and decrease in total phenolics suggest that, in the carbon allocation hierarchy, as available soil nitrogen increases, phenolics represent a lower priority.