Variations in chlorosis and potential usefulness of alloplasmic Brassica rapa with the cytoplasm of male sterile Brassica juncea

To select superior seed parents for vegetable hybrid seed production, we conducted interspecific crosses between male sterile Brassica juncea (2n = 36, AABB) and eight inbred lines of Brassica rapa (2n = 20, AA). Alloplasmic lines of B. rapa with the cytoplasm of B. juncea were developed from B. juncea × B. rapa hybrids by repeated backcrossing using B. rapa as the recurrent male parent until the BC₃ generation. Seed fertility, male sterility and chlorophyll content were investigated in these plants cultivated under four different temperature conditions (5, 10, 12 and 20°C). At 10°C, the alloplasmic lines of B. rapa with the cytoplasm of B. juncea were male sterile with partly chlorotic leaves. The alloplasmic B. rapa had lower chlorophyll a, chlorophyll b and carotenoid contents than those of the original B. rapa. The leaves recovered from chlorosis when the plants were cultivated at 20°C. An alloplasmic line of B. rapa (A6) is available as a seed parent for vegetable hybrid seed production and contributes seed fertility, slight chlorosis and stable male sterility.     

Non-destructive evaluation of surface longitudinal growth strain on Sugi (Cryptomeria japonica) green logs using near-infrared spectroscopy

A use of near-infrared (NIR) spectroscopy for rapidly predicting the longitudinal growth strain (LGS), as a detector of growth stress, was described. NIR spectra and LGS were measured from peripheral locations of three Sugi (Cryptomeria japonica) green logs. Partial least squares regression model for predicting LGS was developed using the spectral range spanning 770–1200?nm. The predicted LGS was correlated with that measured by the strain gauge method. The coefficient of determination and the root mean square error of prediction were 0.61 and 0.013%, respectively. The predicted peripheral LGS distribution moderately fitted with the measured one. Our results indicate that NIR spectroscopy has a potential to evaluate the magnitude of longitudinal growth stresses on green logs.     

Surface-check variation in boxed-heart square timber of sugi (Cryptomeria japonica) cultivars dried by the conventional kiln drying

To investigate the factors affecting the surface-check variation in boxed-heart square timber of sugi (Cryptomeria japonica), surface checks formed by the conventional kiln drying were compared for two stem heights of five cultivars with different wood properties. The total length and average length of the surface checks were greater at the upper part of the stems for all the cultivars. This might be caused by more sapwood at the upper part of the stem, and large drying stresses between the outer sapwood and the inner heartwood. The cultivars, in which tangential shrinkage was large owing to small microfibril angle, formed longer surface checks and smaller bow. There was a positive relationship between surface-check length and tangential shrinkage. The heartwood percentage and tangential shrinkage were thought to be important factors affecting the surface-check variation in sugi boxed-heart square timber.     

Internal-check variation in boxed-heart square timber of sugi (Cryptomeria japonica) cultivars dried by high-temperature kiln drying

To investigate the wood properties affecting the internal-check variation in boxed-heart square timber of sugi (Cryptomeria japonica), two cultivars, yabukuguri and kumotooshi were kiln-dried together by the high-temperature setting method and their internal checks were compared. There was a difference in the area of internal checks between the cultivars. Kumotooshi formed a larger area of internal checks, which was thought to be affected by the larger tangential shrinkage of kumotooshi. The number, total length, and total area of internal checks were significantly correlated with tangential shrinkage. The area of internal checks around the pith was also larger for kumotooshi, which might be affected by the larger tangential shrinkage in the core part of kumotooshi. The results supported that tangential shrinkage should be one of the important properties affecting the internal-check variation of sugi boxed-heart square timber.     

The Efficiency of Moldboard Plowing upon Deactivation and Rehabilitation of Radioactively Contaminated Pastures in the North of Japan

The nuclear disaster at the Fukushima-1 nuclear power plant resulted in the widespread contamination of agrocenoses with radiocesium (¹³⁴Cs and ¹³⁷Cs) on the Honshu Island. Our study was performed on four agricultural fields located on gentle slopes of southern aspect 150 km to the northwest from the nuclear power plant. Three plots were tilled in different periods (in 2012–2013), and one plot remained untilled. The density of soil contamination and the specific activity of radiocesium in plants (June 2014) on tilled plots appeared to be permissible. Thus, the density of soil contamination varied within the range of 1.3–6.5 kBq/m², and the specific radioactivity of plants did not exceed 100 Bq/kg in plants. Such areas may be used as pastures without restrictions. At the same time, an increased density of the soil contamination (13–32 kBq/m²) and the concentration of radiocesium in plants (up to 138 Bq/kg) were detected in some areas not subjected to reclamation works. Such fallow lands are suitable as pastures only for feeding cattle for meat and for milk with their obligatory subsequent processing. On all the plots, the concentration of radiocesium in soils decreased down the soil profile. In general, radiocesium was accumulated on the middle and lower parts of slopes, which is associated with the development of water erosion and initial distribution of radiocesium during the snowmelt season. The air dose rate on the studied plots did not exceed the permissible safety level (0.2 μSv/h) and varied within the range 0.05–0.10 μSv/h. The maximum level of γ-radiation was determined on the fallow (untilled) plot. On tilled plots, γ-radiation was 30–50% lower. Therefore, soil moldboard plowin tillage to the depth of 20 cm with or without shallow cultivation is an efficient measure to reclaim agricultural lands with the initially low level of radiocesium contamination (up to 32 kBq/m²).     

Antifungal activity of a novel compound purified from the culture filtrate of <Emphasis Type="Italic">Biscogniauxia</Emphasis> sp. O821 against the rice blast fungus <Emphasis Type="Italic">Magnaporthe oryzae</Emphasis>

Rice blast is a devastating fungal disease resulting in major losses to rice crops. Owing to continuous acquisition of resistance by the causal fungus, several fungicide chemicals are no longer effective. Therefore, there is a need to identify natural components and develop new agents to control fungal pathogens. We previously demonstrated that the culture filtrate of Biscogniauxia sp. O821 inhibited infection behavior of Magnaporthe oryzae and subsequent blast lesion formation. In the present study, we isolated a new compound, (3aS,4aR,8aS,9aR)-3a-hydroxy-8a-methyl-3,5-dimethylenedecahydronaphto[2,3-b]furan-2(3H)-one (HDFO), from the culture filtrate of Biscogniauxia sp. O821 and determined its molecular weight as 248. The HDFO structure was determined by electrospray ionization-mass spectrometry and nuclear magnetic resonance spectroscopy after purification with column chromatography and high-performance liquid chromatography. The structure of this antifungal compound was similar to that of alantolactone and isoalantolactone. The growth inhibition zone against M. oryzae in presence of HDFO was observed at Rf 0.5–0.6 on a thin layer chromatography plate. HDFO inhibited conidial germination of M. oryzae in a dose-dependent manner (1–200 ppm). Furthermore, blast lesion formation was significantly suppressed by HDFO at over 5 ppm. These results suggest that HDFO from the culture filtrate of Biscogniauxia sp. O821 can protect rice from rice blast disease caused by M. oryzae. This is the first report that HDFO produced by Biscogniauxia sp. can serve as an antifungal compound against M. oryzae.     

Analysis by numerical experiments of desalinization of a salt-affected paddy field using a rice husk underdrainage system

Paddy and Water Environment - In a monsoon climate, salt accumulates not only in drylands, but also in paddy fields during the dry season. Because natural desalinization by gravitational drainage...     

The developmental ability of vitrified oocytes from different mouse strains assessed by parthenogenetic activation and intracytoplasmic sperm injection

Assessment of the developmental ability of oocytes following freezing and thawing is an important step for optimizing oocyte cryopreservation techniques. However, the in vitro fertilization of frozen-thawed mouse oocytes is often inefficient because of incomplete capacitation of spermatozoa in the absence of surrounding cumulus cells. This study was undertaken to determine whether the oocyte cryopreservation efficiency of different strains of mice could be assessed from the development of oocytes following parthenogenetic activation and intracytoplasmic sperm injection (ICSI). Oocytes were collected from hybrid (C57BL/6 x DBA/2) F1 or inbred (C57BL/6J, C3H/HeN, DBA/2J and BALB/cA) strains and were vitrified in a solution containing ethylene glycol, DMSO, Ficoll and sucrose. In the first series of experiments, oocytes were activated parthenogenetically by Sr(2+) treatment after warming. The oocytes from the inbred strains, but not those of the F1 hybrid, were diploidized by cytochalasin treatment to obtain a sufficient number of blastocysts. In all strains tested, parthenogenetic embryos derived from vitrified oocytes developed into blastocysts at rates between 23 and 68%. In the second series of experiments, vitrified oocytes from each strain were injected with homologous spermatozoa after warming. Normal offspring were obtained from all strains at rates between 5 and 26% per embryo transferred. Thus, the feasibility of oocyte cryopreservation protocols can be assessed easily by in vitro development of parthenogenetic embryos or by in vivo development of ICSI embryos. Moreover, the oocytes of these four major inbred strains of mice can be cryopreserved safely for production of offspring.