The Japanese Forestry Society Congress Database

On the MRI images of healthy trees, water conducting tissues were shown white. On the cross section of Quercus crispula, small vessels were recognized as whitish area. After the inoculation with Raffaelea quercivora, above and below of the inoculated sites became darker. Eight weeks after the inoculation, darker area reached about 2cm above and below of the infection site. In the darker area, water conduction had stopped. Dysfunctioned area for the infection was shown as whitish area on the T1 weighed images.

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We examined the factors affecting the number of pinewood nematodes (Bursaphelenchus xylophilus) carried by Monochamus alternatus and Acanthocinus griseus which emerged from pine wilt-killed trees in Ibaraki in 2002. M. alternatus carried a great number of nematodes, while A. giseus carried few nematodes. The number of nematodes carried by M. alternatus ranged from 0 to 60,500. We discuss the effects of i) secondary metabolites of the beetles and ii) blue-stain fungi around their pupal chambers.

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Population dynamics of the pine wood nematode were investigated throughinoculation tests to pine logs. The pine wood nematode was inoculated to pine logs prepared from pine trees just after felling. Other treatments were established as follows; inoculations were made to pine logs from pine trees felled 1month before, 2 months before, 3months before, respectively. The nematode population increased in log wood after inoculation. Nematode reproduction was rapid and a large population developed in the wood. Populations reached a maximum level on 1 month after inoculation and then decreased gradually. Although a trend of population dynamics was almost similar among treatments, populations in log wood of treatments other than the treatment in which nematode inoculation was made just after tree felling were fewer than those of the latter treatment. In log wood from pine trees felled 3 months before, no population growth was observed. These results suggested that the pine wood nematode might feed on living wood tissues, such as parenchyma sells, and reproduce vigolously in wood. After deterioration in the quality of wood tissues, nematode reproductiondeclines. Inoculation of oyster mushroom and shiitake mushroom to pine logs were made 1 month after inoculation of the pine wood nematode. In pine logs inoculated with oyster mushroom, nematode population was significantly controlled. This result might indicate that microorganisms might affect on population dunamics of the pine wood nematode in pine wood.

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The aim of this study is to estimate the ability of acclimation to high irradiance of four fruit tree species planted at open site by using chlorophyll fluorescence methods. We discussed the differences in the acclimation capacity to high irradiance among species in terms of photoprotective mechanisms associated with electron transport rate (ETR) and thermal energy dissipation (NPQ) between shade-grown seedlings and open-planted seedlings. In addition, to evaluate the susceptibility to photoinhibition of the shade-leaves of each species, the extent of photoinhibition of PSII after exposure to full sunlight and subsequent recovery was followed by means of chlorophyll fluorescence recording. The ability of acclimation to strong irradiance differed among four fruit tree species. Bouea oppositifolia showed high susceptibility to photoinhibition by strong irradiance and low survival rate of open planted seedlings. Bouea oppositifolia was considered to have low ability to acclimation to full sunlight. Ficus enhanced light-saturated electron transport rate and decreased thermal energy dissipation in open leaves compared with shade leaves. It was suggested that Ficus had the highest capacity of acclimation to strong irradiance among four fruit tree species. Though Parkia speciosa increased thermal energy dissipation in open leaves compared with shade leaves, light-saturated ETR was the lowest both in shade leaves and in open leaves among measured species. These results mean that Parkia speciosa is not suitable for planting at open site. Pometia pinnata showed higher thermal energy dissipation in open leaves compared with shade leaves, while electron transport rate decreased markedly and the susceptibility of photoinhibition (indicated by declining of qP) increased in open leaves. However Pometia pinnata demonstrated comparative high survival rate in open planted seedlings. From these results, it was considered that Pometia pinnata might have another mechanisms for acclimation to strong irradiance, such as production of new leaves under high irradiance.

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