Effect of electric impulse on sporocarp formation of ectomycorrhizal fungusLaccaria laccata in Japanese red pine plantation
We examined the effect of electric impulses on sporocarp formations of ectomycorrhizal fungus in a Japanese red pine (Pinus densiflora) plantation.Laccaria laccata was the dominant species in this study plantation. Spatial distribution concentrated in the electric impulse treatment zone, and recorded a markedly larger number of sporocarps compared with untreated control plots. The effect of electric impulses was also recognized onL. laccata fruiting with a mycorrhizal sapling in a pot. Sporocarp production ofL. laccata was strongly promoted by the electric impulse in experiments bothin vivo natural plantation stands andin vitro pot saplings. Our work indicates the possibility of enhancement of sporocarp production of the mycorrhizal fungi with electric impulses in the nursery and plantation.
Genetic engineering of an ectomycorrhizal fungus Laccaria bicolor for use as a biological control agent
We are developing genetically engineered ectomycorrhizal fungi for use as biological control agents. Using the gold particle bombardment tech- nique, we transformed Laccaria bicolor, an ectomy- corrhizal fungus capable of forming ectomycorrhizae on a wide range of plant hosts. Structural gene se- quences of the hygromycin B phosphotransferase (hph) gene (hygromycin resistance for selection of transformants), r3-glucuronidase (GUS) gene (re- porter gene for tracking transformants) and Bacillus thuringiensis 8-endotoxin (BtCryIIIA) gene (Coleop- teran specific insecticidal gene from Bacillus thurin- giensis var tenebrionis) were introduced into L. bicolor simultaneously. Southern and western blot analyses showed that the introduced sequences were inserted into the fungal genome and transcribed and trans- lated. One of the transformants produced the insec- ticidal toxin; however, the levels were not sufficient to perform toxicity assays. The technique developed can be employed to generate superior strains of L. bicolor suitable for use as biological control agents in various soil and plant conditions.
Frequency distributions of the mixing height over an urban area from SODAR data
The height of the mixing-layer (MLH) is an important parameter in the assessment of the dilution of primarily emitted or secondarily formed air pollutants in the atmospheric boundary-layer. A continuous measurement of MLH is possible only by remote sensing. Here, 17 months of SODAR data have been analysed automatically to derive the MLH over the city of Hannover in Northern Germany. In contrast to earlier studies the MLH has been determined from vertical profiles of the acoustic backscatter intensity and from the variance of the vertical velocity component. The results are presented in form of monthly frequency distributions and mean daily courses of MLH. These statistical evaluations of MLH show a clear annual course and interannual variability. The study shows the possibility to derive meaningful climatological information from long-term SODAR measurements for air quality issues.