Breaking the crossability barriers between disomic tetraploid Solanum acaule and tetrasomic tetraploid S. tuberosum

Summary A combination of compatible second pollinations and embryo rescue was applied for systematic production of true tetraploid hybrids from crosses between disomic tetraploid Solanum acaule and tetrasomic tetraploid potato, S. tuberosum. Several genotypes of tetraploid potatoes were pollinated with S. acaule, and the compatible second pollinations were made on the following day, with a genotype of S. phureja, IvP 35 to promote fruit development. Embryo rescue was carried out in 21 families, 14 to 27 days after the first pollination. A total of eight plants were obtained from the embryo rescue and their chromosome numbers were counted in the root tips. Three of the eight plants were identified as tetraploid, and five others as diploid. Morphology, isozyme banding patterns, and pollen stainability, as well as potato spindle tuber viroid (PSTVd) resistance, indicated the hybrid nature of the three plants. This is the first report of successful tetraploid hybrid production between disomic tetraploid S. acaule (4x) and tetrasomic tetraploid potatoes. Seed set from the crosses between one of hybrids and diploid potatoes indicated workable levels of both male and female fertility for introgression of valuable genes from S. acaule into the cultivated potato gene pool. The methodology used may be applied to other disomic tetraploid tuber-bearing Solanum species and with some modifications also to distantly related solanaceous species and genera.     

Identification and quantification of short oligomeric proanthocyanidins and other polyphenols in boysenberry seeds and juice

Proanthocyanidins and other polyphenols in the seeds and juice of boysenberry were quantitatively analyzed. Polyphenolic extracts were prepared from the waste seeds and commercial juice by chromatographic fractionation. Compositional analysis revealed that both extracts contained six polyphenolic classes: flavanol monomers, proanthocyanidins, anthocyanins, ellagic acid, ellagitannins, and flavonol glycosides. Ellagitannins were the most abundant polyphenols in both extracts. Proanthocyanidins were present as short oligomers consisting of dimeric and trimeric procyanidins and propelargonidins, with the most abundant component being procyanidin B4 in both extracts. Quantification by high-performance liquid chromatography-mass spectrometry (HPLC-MS) revealed that the seeds contained a 72-fold higher amount of proanthocyanidins than the juice. These results indicate that boysenberry fruits contain short oligomeric proanthocyanidins along with flavanol monomers and the seeds represent a good source of short oligomeric proanthocyanidins.     

Near-isogenic lines of durum wheat: their development and plant characteristics

Summary The effect of specific plant characteristics on the grain and biomass yield of durum wheat can be accurately determined by using isogenic lines, which, however, were not usually available. This study reported the effects of long glume, glaucousness, glume pubescence, black glume and purple culm on the yield and its associated characteristics in near-isogenic lines of durum wheat cv. LD222, which were developed by continuous backcrossing. The long glume trait which resulted in a large photosynthetic area did not enhance yield. Increased glume size associated with the P gene tended to increase the main culm dominance, characterized such as vigorous main culm and weak tillers, and plant height, but to reduce tillering and spike number. Consequently, grain yield and harvest index declined. Under the adequate water supplying condition of the present study, the glaucous trait was beneficial for grain yield. The trait of glume pubescence did not excert any significant effect on the yield related characteristics in the LD222 background. The traits of black glume and purple culm reduced the number of spikes per unit area and the number of kernels per unit area.     

Classification of Azolla spp., section Azolla

Summary Azolla accessions (section Azolla) from the germplasm collections of the International Rice Research Institute and Washington State University were fingerprinted and classified by enzyme electrophoresis and leaf trichome morphology. A. filiculoides was enzymatically distinctive and also reliably identified by its prominent one-celled trichomes. Neotropical accessions labelled as A. filiculoides proved to be members of other species. Two groups of isolates were designated A. rubra, but those from Japan were identified as A. filiculoides. The A. rubra of Australia-New Zealand was biochemically unique and possessed less protuberant trichomes than A. filiculoides. A. microphylla, A. mexicana, and A. caroliniana were phenetically similar, but a. microphylla was identifiable from the others in the banding patterns of certain enzymes. A. mexicana and A. caroliniana were closely related enzymatically. The two-celled leaf trichomes of these three species were similar in size and shape.     

Artificial neural network modeling for predicting final moisture content of individual Sugi (Cryptomeria japonica) samples during air-drying

Sugi (Cryptomeria japonica D. Don) lumber is known to have a large variability in final moisture content (MC_f) and is difficult to dry. This study assessed the capability of artificial neural networks (ANNs) to predict the MC_f of individual wood samples. An ANN model was developed based on initial moisture content, basic density, annual ring orientation, annual ring width, heartwood ratio and lightness (L ^* in the CIE L ^* a ^* b ^* system). The performance of the ANN model was compared with a principal component regression (PCR) model. The ANN model showed good agreement with the experimentally measured MC_f with a higher correlation coefficient (r) and a lower root mean square error (RMSE) than the PCR model, demonstrating the importance of nonlinearity of the variables and the higher capability of the ANN model than the PCR model. By adding redness (a ^* ) and yellowness (b ^* ) and drying time to the input variables of ANNs, r and RMSE values were improved to 0.98 and 1.2 % for the training data set, and 0.85 and 2.2 % for the testing data set, respectively. Although the developed ANNs are available under the limited conditions of this study, our results suggest that the ANNs proposed offer reliable models and powerful prediction capability for the MC_f, even though wood properties vary considerably and their complex interrelations are not fully elucidated.     

Early response of stand structure and species diversity to strip-clearcut in a subtropical evergreen broad-leaved forest in Okinawa Island, Japan

Natural regeneration by strip-clearcut has rarely been used for restocking of evergreen broad-leaved forests in the East Asia. To contribute to a better understanding of the likely reasons for either the successful recovery of these forests or failure, the early response of stand structure and tree species diversity to strip-clearcut were studied in Okinawa Island, southwest Japan. The 4,000 m² study area was divided into 10 adjacent sections of equal area with a 10 m × 10 m sampling plot in the center, of which five sections were strip-clearcut while the remaining five sections uncut. Eight-year secondary succession following strip-clearcut showed that the density of woody stems, tree species diversity increased significantly not only in the regenerating stands but also in the residual stands compared to the primary stands. The primary dominant target species, Castanopsis sieboldii, continued to dominate both the regenerating and residual stands although colonizing species invaded abundantly in the stands, occupying approximately one-third of total tree species in each treatment. The community similarity analyses showed that the species composition were similar between the primary stands and the regenerating stands or residual stands reflected the high similarity amongst the primary stands and the regenerating stands or the residual stands. The similar stand structure, high tree species diversity and greater community similarity after strip-clearcut provided no evidence of forest degeneration, suggesting that the regenerating stand might gradually develop into stand similar to that prior to strip-clearcut.     

Factors affecting forest growth and possible effects of climate change in the Taihang Mountains, northern China

To estimate the possible effects of site factors and climatechange on forest growth in the Taihang Mountains, northern China,we assessed the factors influencing forest growth by using forestinventory data from 712 forest sample plots. Meteorologicaldata from 77 meteorological stations in the region were usedto estimate temperature and precipitation at each site fromelevation and longitude. Analyses showed that temperature, aspect,precipitation and soil thickness all significantly influencedforest growing stock (FGS), i.e. stem volume. When temperaturerose, FGS was reduced, possibly because increasing temperatureincreased evapotranspiration. Precipitation had a positive effecton FGS. The effect of aspect on FGS was perfectly expressedas a cosine function, with south-west- and south-facing slopeshaving the lowest FGS and north-facing slopes having the highest.We developed multifactorial regression models to predict changesin FGS in the Taihang Mountains. Temperature, forest age, forestcover, soil thickness, precipitation and aspect were well relatedto FGS. The effects of a temperature decrease and a precipitationincrease on FGS would be 2.5–8 per cent per degree centigradeand 10 per cent per 100 mm, respectively. The combination oftemperature increase and precipitation changes under futureclimate change is likely to result in a decrease of FGS, thoughthis does not take account the effect of increasing CO₂. Wealso used multifactorial regression models to analyse the effectsof site factors on FGS of Pinus tabulaeformis Carr. and Robiniapseudoacacia L., two major species used in afforestation inthe Taihang Mountains. Although site factors had similar effectson FGS, diameter at breast height and tree height of both species,prediction accuracy (regression coefficient) was improved greatlywhen we treated the species separately.     

Distribution of boron in wood treated with aqueous and methanolic boric acid solutions

The distributions of boron in Japanese cedar (Cryptomeria japonica D. Don) sapwood blocks treated with aqueous or methanolic boric acid [B(OH)₃] solutions were explored through Raman spectroscopy and prompt gamma-ray analysis (PGA). B(OH)₃ was the sole boron species observed in Raman spectra of the wood blocks treated with either solution. Plots of weight gain of the treated wood blocks versus boron concentration in treatment solutions were found to be linear. The results indicated that the methanolic solution makes it possible to impregnate wood with much larger amounts of boron than the aqueous solution. PGA confirmed that B(OH)₃ was highly enriched near the end grains of the treated wood blocks. Raman measurements suggested that boron content in the bulk of the wood block is not as large as expected from the weight gain of the treated wood blocks when an ordinary air-drying method is used. It was concluded that the aqueous solution impregnates the cell walls of wood with boron more easily than the methanolic solution. Part of this report was presented at the 55th (Kyoto, March 2005) and 56th (Akita, August 2006) Annual Meetings of the Japan Wood Research Society. This article follows the previous rapid communication “Analysis of boron in wood treated with boric acid solutions using Doppler broadening method of prompt gamma-rays.” J Wood Sci (2006) 52:279–281     

Lignin-degrading activity of edible mushroom <Emphasis Type="Italic">Strobilurus ohshimae</Emphasis> that forms fruiting bodies on buried sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) twigs

Strobilurus ohshimae is an edible mushroom, and it specifically forms its fruiting bodies on buried sugi (Cryptomeria japonica) twigs. In this research, we studied lignindegrading activity of S. ohshimae. We isolated 18 strains of S. ohshimae from various regions of Japan, and determined their lignin degradation rates on sugi wood meal medium. All the strains of S. ohshimae degraded approximately 6%–12% of sugi lignin in 30 days, and these lignin degradation rates were 1.5–3 times higher than those of Trametes versicolor, which is a typical lignin-degrading fungus. Among the three main lignin-degrading enzymes, activity of lignin peroxidase and manganese peroxidase was not observed, while 4340U/g of laccase was produced in 30 days. To investigate the effect of wood species on lignin degradation by S. ohshimae, the lignin degradation rate and laccase productivity on sugi wood meal medium were compared with those on beech (Fagus crenata). In T. versicolor, both lignin degradation rate and laccase productivity were higher on beech than on sugi. Conversely, in S. ohshimae, lignin degradation rate and laccase productivity were higher on sugi than on beech. Therefore, it was suggested that coniferous lignin is not always difficult to degrade for the fungi that inhabit softwood. Part of this article presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004     

Numerical experiments of watershed-scale soil water movement and bedrock infiltration using a physical three-dimensional simulation model

Numerical experiments of soil water movement and bedrock infiltration based on a simplified simulation method were conducted to analyze watershed-scale rainfall-runoff processes. To verify the model accuracy, it was applied to a Minamitani watershed (0.45 ha). The simulation was performed with 2.5-m space grids horizontally and five cells vertically. Results of long-term calculation of this model proved that this simulation model is robust and demonstrated good computational water mass conservation. Calculation results showed the best agreement with observed hydrographs and the number of groundwater levels simultaneously when laboratory-tested soil hydraulic characteristics for topsoil were used and infiltration into bedrock was included in numerical calculations. Numerical experiments show that bedrock infiltration generated a stable base flow and suppressed the secondary discharge peak. The reproducibility achieved by observed soil hydraulic characteristics with the assumption of bedrock flow demonstrates the effectiveness of the simulation model used in this article for analyses of watershed-scale soil water movements.