Lesion-based analysis of leaf blast suppression in mixture of rice cultivar and a resistant near-isogenic line

Leaf blast suppression in multilines was evaluated based on the number of susceptible lesions observed in a pure stand of susceptible rice cultivar Sasanishiki, and in 1 : 1 and 1 : 3 mixtures of Sasanishiki and a resistant near-isogenic line, Sasanishiki BL4 or BL7, from 1998 to 2001. The number of lesions first observed in fields in the 1 : 1 and 1 : 3 mixtures were close to theoretical numbers calculated using the number of lesions observed in the pure stands and the ratios of the susceptible Sasanishiki in the mixtures. The ratio of the number of lesions in the 1 : 1 and 1 : 3 mixtures to the number in the pure stand was 0.29 and 0.09, respectively. The relationship between these ratios and the ratios of susceptible Sasanishiki in mixtures was defined in an equation to estimate the degree of leaf blast suppression. Validation studies for the ratios of the number of lesions in the 1 : 1 and 1 : 3 mixtures to the number in the pure stand were conducted in two different locations and showed that the ratios are almost acceptable. The calculated autoinfection to alloinfection ratio was 1.3 and 1.4 in the 1 : 1 and 1 : 3 mixtures, respectively, suggesting that the calculated ratio will affect the degree of leaf blast suppression. Thus, predictors were obtained to estimate leaf blast suppression for effective blast control in multilines.     

The shrinking profitability of small-scale forestry in Japan and some recent policy initiatives to reverse the trend

About 80% of annual wood fiber consumption in Japan is imported. Even though most of the land surface is covered by forests in Japan, the domestic forestry and forest industry are threatened by such imports flooding the local market. Fragmented land ownership, steep terrain, rapid growth of weeds, and high labor costs have all contributed to the decline of domestic forestry. Further, the purchasing power of the Japanese Yen has become very strong in recent years, and the decreasing prices of imported timber have depressed the prices of domestic timber, eroding profitability and discouraging small-scale forestry. In spite of these difficult circumstances, there are several interesting new developments in Japanese forestry. One is the revision of the Basic Forestry Law of 1964, through which the Japanese government is steering forest policy from timber production towards environmental services. Because of this change, new ways to assist rural forestry activities will become available in the near future. Another change is the certification movement, where recent examples of Japanese companies acquiring ISO 14001 and Forest Stewardship Council (FSC) forest certifications provide hope to depressed domestic forestry activities. In particular, FSC group certification is useful in motivating small-scale forest owners to implement and maintain sustainable forestry practices. This paper is based on the presentation at IUFRO Group 3.08.00 Symposium at Joensuu, Finland 2001. The original article, ‘The economic situation of small-scale forestry in Japan’, is in Niskanen and Vayrynen (2001).     

Interactive effects of leaf age and self-shading on leaf structure,photosynthetic capacity and chlorophyll fluorescence in the rain forest tree,Dryobalanops aromatica

In the tropical canopy tree, Dryobalanops aromatica Gaertn. f., upper-canopy leaves (UL) develop under sunlit conditions but are subjected to self-shading within the crown as they age. In contrast, lower-canopy leaves (LL) are exposed to uniform dim light conditions throughout their life span. By comparing leaf morphology and physiology of UL and LL, variations in leaf characteristics were related to leaf age and self-shading. Mass-based chlorophyll (chl) concentration and the chlorophyll/nitrogen (chl/N) ratio were lower and the chl a/b ratio was higher in UL than in LL. In UL, the chl/N ratio gradually increased and the chl a/b ratio gradually decreased with leaf aging, whereas these ratios remained unchanged with leaf age in LL. The effective quantum yield of photosystem II (PSII) (DeltaF/F(m)') at a given irradiance remained unchanged with leaf age in LL, whereas DeltaF/F(m)' changed with leaf age in UL. These data indicate N reallocation within the leaves from carbon fixation components to light harvesting components and a dynamic regulation of photochemical processes of PSII in response to increased self-shading of UL. Despite the difference in light environment with leaf age between UL and LL, maximum photosynthetic rates and nitrogen-use efficiency decreased with leaf aging in both UL and LL. Constancy in the chl/N ratio with leaf age in LL indicated that the decrease in photosynthetic capacity was caused by effects other than shading, such as leaf aging. We conclude that N reallocation and acclimation of PSII to self-shading occurred even in mature leaves, whereas the change in photosynthetic capacity with leaf age was more conservative.     

Potential use of a spatially constrained harvest scheduling model for biodiversity concerns: Exclusion periods to create heterogeneity in forest structure

The objective of this paper is to investigate potential use of a spatially constrained harvest scheduling model for biodiversity concerns. Change in the degree of biodiversity is represented only by spatial characteristics of harvesting patterns of forest stands with different exclusion periods applied to adjacent forest stands. A spatially constrained harvest scheduling model called SSMART (Scheduling System of Management Alternatives foR Timber-harvest) is used for the analysis. It is one of the heuristics to solve a spatially constrained harvest scheduling problem by using the partitioning heuristic. The algorithm incorporated into SSMART is designed to seek a solution for a multicriteria problem with present net value maximum, meeting spatial feasibility and minimizing period-to-period harvest flow fluctuation, approximating even-flow constraints within the 0–1 integer programming framework. Our experimental analysis shows that the longer exclusion period, the less the harvest flow level and the total present net value are derived and the more heterogeneous the forest structure becomes in terms of the forest stand age distribution. It is also shown that the three exclusion period results in a stable forest stand age distribution over the time horizon for our experimental forest. This research supported by the Grants-in-Aid for Scientific Research (No. 09041071) from the Ministry of Education, Science, Sports, and Culture of Japan.     

Synthesis of dihydroxyphenacyl glycosides for biological and medicinal study: β-oxoacteoside from Paulownia tomentosa

The protected structure of -oxoacteoside (tomentoside A), 2-oxo-2-(3,4-dihydroxyphenyl)ethyl 3-O-(2,3,4-tri-O-acetyl--l-rhamnopyranosyl)-4-O-caffeoyl--d-glucopyranoside 14 was synthesized in 14% overall yield in 11 steps, starting from d-glucose for biological and medicinal studies of phenylpropanoid glycosides. The first step was the preparation of a 3-O-rhamnopyranosyl disaccharide sugar core 2 from a suitably protected rhamnosyl trichloroacetimidate 10 and glucose derivative (diacetone-d-glucose 1) in 71% yield. To the glucose moiety of this sugar core, several protection/deprotection procedures were performed sequentially to obtain a fully acetylated sugar core 7 with a 4-OH group on the glucose moiety, in 57% yield in five steps. Thereafter, to the 4-OH group of the glucose moiety, selective 4-O-caffeoylation was achieved by proton-transfer esterification with 3,4-di-O-allylcaffeic acid 16 to give the caffeoyl disaccharide 11 in 97% yield. Then, it was converted to trichloroacetimidate 13 for a glycosylation donor in 90% in two steps. Finally, anomeric glycosylation was conducted with 2-oxo-2-(3,4-di-allyloxyphenyl)ethyl alcohol 19 with catalytic amounts of BF₃·Et₂O to give 2-oxo-2-(3,4-di-allyloxyphenyl)ethyl 2,6-di-O-acetyl-3-O-(2,3,4-tri-O-acetyl--l-rhamnopyranosyl)-4-O-(3,4-di-allyloxycaffeoyl)--d-glucopyranoside 14 in 60% yield. Deprotected intermediates of compounds 2, 11, 14, and 19 which were obtained in high yield would be useful for biological and medicinal studies of phenylpropanoid glycosides.Part of this study was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April, 2002     

Generation and alteration of norlignans in a transition zone during the drying of a Cryptomeria japonica log

Sugi (Cryptomeria japonica D. Don) produces secondary metabolite norlignans in xylem. Several norlignans are involved in the coloration of heartwood and defense of sapwood against microbial invasion. Their biosynthetic process should be well understood so that their properties can be exploited to improve the quality and utility of C. japonica wood. Unfortunately, information on the norlignan biosynthesis is limited because norlignans are mainly synthesized in a particular season in the transition zone (TZ) along with the heartwood formation, and is difficult to study. Although the generation of two norlignans of C. japonica, agatharesinol and (E)-hinokiresinol, has been reported, systems for producing other norlignans are not yet known. To establish a novel norlignan generating system, we examined the changes occurring in norlignans in a TZ during the process of drying a C. japonica log. On the day of felling, the TZ contained agatharesinol and (E)-hinokiresinol, which increased until they reached a maximum on day 40 after felling. Sequirin-C appeared on day 40 and increased to day 70. The generation of sequirin-C in the TZ can be used to investigate the biosynthetic process of heartwood norlignans. This study describes for the first time the changes that occur in the composition of norlignan during the drying of the TZ.     

Experiences of a Forest Owners’ Cooperative in using FSC forest certification as an environmental strategy

Yusuhara Forest Owners’ Cooperative (YFOC) in Kochi Prefecture in Japan received its forest management certification from the Forest Stewardship Council (FSC) in 2000. YFOC is recognised as the resource manager of its members’ forests, and they were the first organisation to gain such certification in Japan. With the continuous efforts of selling FSC certified wood in the domestic housing construction market, YFOC has substantially increased their timber sales in recent years. It is a noteworthy event in Japanese small-scale forestry, which has been struggling with declining economic performance for many years. This paper analyses the detail of forestry activities and changes which occurred in YFOC after certification by FSC. An interesting effect of increasing economic performance is found to have come from an unexpected direction. It is concluded that the FSC certification system is a possible tool to revitalise Japanese small-scale forestry as well as obtain favourable environmental outcomes.     

First report of trunk rot caused by <Emphasis Type="Italic">Fomitiporia torreyae</Emphasis> in Kyoto prefecture on cultivars of Japanese cedar with no relatedness to ‘Sanbu-sugi’

Trunk rot, caused by Fomitiporia torreyae, is one of the most economically important sap rot diseases on Cryptomeria japonica, especially on a cutting cultivar ‘Sanbu-sugi’. This disease had been reported only from Chiba and Ibaraki prefectures in Japan; however, a similar trunk rot on Japanese cedars was found recently in Kyoto prefecture. We identified the causal agent of the trunk rot on Japanese cedars in Kyoto prefecture, clarified the genotype of ‘Sanbu-sugi’ (sensu stricto) using microsatellite markers, and then investigated the relatedness of these infected cedars with ‘Sanbu-sugi’. The pathogen was identified as F. torreyae by its DNA sequences and morphological characteristics of the fruiting body. The 25 ramets of ‘Sanbu-sugi’ had only one genotype based on eight microsatellite loci. Infected Japanese cedars in Kyoto were comprised of different genotypes and showed no close relatedness to ‘Sanbu-sugi’. This is the first report of trunk rot caused by F. torreyae on cultivars of Japanese cedar with no relatedness to ‘Sanbu-sugi’ outside of Chiba and Ibaraki prefectures and showed the potential for expansion of this disease to Japanese cedar plantations in other areas.     

Preparation and Characterization of Phenolated Wood Using Sulfuric Acid as a Catalyst I: Liquefaction Behavior of Plantation Wood

Chinese fir (Cunninghamia lanceolata) and poplar (Populus spp.) wood meal were phenolated in the presence of sulfuric acid used as a catalyst. The effects of reaction time and reaction temperature on the wood liquefaction were investigated. The results showed that the reaction temperature had the greater influence on the residue content than reaction time. Additionally, the liquefaction curve for the Chinese fir and Poplar were similar in general.