Development of microsatellite markers and their effectiveness in Lolium temulentum

Screening a genomic library of Lolium temulentum (darnel) with synthetic (GT)₁₅ and (GA)₁₅ oligonucleotides, we identified microsatellite‐containing clones. Based on the sequence data of the clones, specific primer pairs were synthesized and their effectiveness examined using 10 L. temulentum and two L. persicum accessions from Asia, Africa and Europe. Fifteen primer pairs amplified single fragments, and five of them showed polymorphism in polyacrylamide gel electrophoresis in the L. temulentum and L. persicum accessions. Fifteen primer pairs reported in L. perenne (perennial ryegrass) were also applied in this study. Nine of them amplified the microsatellite alleles, and two of the nine showed polymorphic alleles in L. temulentum and L. persicum. For the polymorphic markers, polymorphic information content values ranged from 0.60 to 0.86 with an average of 0.76 among 10 L. temulentum accessions. The microsatellite markers developed for L. temulentum and L. perenne should be informative and powerful in analysing the intraspecific genetic diversity and the phylogenetic relationships of L. temulentum and L. persicum.     

Effect ofl-phenylalanine on rooting of shoots from axillary buds of adultLarix leptolepis

Rooting of shoots derived from axillary buds was examined to establish an efficient shoot culture system of clonal micropropagation in adult tree ofLarix leptolepis Gord. (Japanese larch). Nine out of ten shoots induced calli (90%) on their shoot bases, and the two of them formed root primordia with a red pigment (20%) on the calli surface within 5 weeks after culturing on modified Murashige and Skoog (MS) medium supplemented with 1.5 μM of indolebutyric acid (IBA) and 1.5 μM of naphthaleneacetic acid (NAA). However, the primordia did not elongate actively. The addition of 10 mMl-phenylalanine in the MS medium with the auxins resulted in the formation of roots at high frequency, about 80%, and they elongated actively. Although callus was formed in all the shoots cultured on the medium withl-phenylalanine, it appeared that the callus development was less as compared to the medium withoutl-phenylalanine. Consequently, the rooting might be associated with the suppression of the induced callus.     

Somatic embryogenesis from immature and mature zygotic embryos ofCryptomeria japonica I: Embryogenic cell induction and its morphological characteristics

Embryogenic cells (ECs) of sugi (Cryptomeria japonica D. Don) were induced from immature and mature zygotic embryos cultured on different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D)-containing modified Campbell and Durzan medium. The rate of induction of ECs varied depending on the stage of embryos collected. The highest percentage of induction (35%) was obtained with immature zygotic embryos collected July 18 and July 30, 1997, when 1 M of 2,4-D was added to the induction medium. The ECs easily proliferated when subcultured in a medium of the same composition as the induction medium within 3 weeks. Morphological characteristics of nonembryogenic cells and embryogenic cells of different developmental stages were studied under an inverted fluorescence microscope.Part of this work was presented at the 109th annual Japanese Forestry Society meeting at Tochigi, April 1998     

Changes in levels of endogenous plant hormones in cambial regions of stems ofLarix kaempferi at the onset of cambial activity in springtime

The total amounts of endogenous indole-3-acetic acid (IAA), cytokinins, and abscisic acid (ABA) were quantified by gas chromatography-selected ion monitoring-mass spectrometry (GC-SIM-MS) in cambial regions of the main stems ofLarix kaempferi during the spring season. During the sampling period, cambium in the dormant state entered the active meristematic state. The total amount of IAA did not change at the onset of cambial reactivation but increased when the active division of cambial cells became apparent. Four cytokinins —trans- andcis-ribosylzeatin (RZ),N ⁶-isopentenyladenine (iP),N ⁶-isopentenyladenosine (iPA) — were quantified, but no zeatin (Z) was detected. The total amount of the four cytokinins together and the total amount of isopentenyl-type cytokinins (iP and iPA) varied during the sampling period but did not appear to be specifically associated with cambial activity. The total amounts oftrans- andcis-RZ remained relatively constant during the sampling period, as did the total amount of ABA. The results suggest that there is little correlation between total amounts of endogenous plant hormones in the cambial region and reactivation of the cambium during the spring.     

Preparation of activated carbon moldings from the mixture of waste newspaper and isolated lignins: mechanical strength of thin sheet and adsorption property

To expand the utilization of waste newspapers and lignin, activated carbon (AC) sheets, as an example of AC moldings, were prepared from those mixtures. The isolated lignins used were softwood and hardwood acetic acid lignins (SAL and HAL), softwood kraft lignin (KL), and wheat-straw lignin (WSL). The mixtures were molded into precursory sheets by thermal compression and then converted to AC sheets by carbonization and steam activation. The flexural strength of the precursory sheets was dramatically improved by additing the lignins compared to that of sheets without lignin. The strength of several sheets was more than 25 MPa. This suggested that lignins act as adhesives. SAL and HAL sheets with 40% newspaper were strengthened by the carbonization, whereas the strength of other lignin sheets was depressed. Finally, the AL-based AC sheets showed higher flexural strength (>6MPa) than others. Most of the AC sheets had adsorption ability comparable to that of commercially available AC powder and granules. The capacities were almost independent of paper content. Among the AC moldings tested, the AL-based AC sheets showed the fastest adsorption top-chlorophenol. Thus, viable AC moldings can be prepared from lignin-wastepaper mixtures, particularly SAL and HAL.     

Effect of estradiol‐17β during in vitro growth culture on the growth,maturation, cumulus expansion and development of porcine oocytes from early antral follicles

Growing porcine oocytes from early antral follicles can acquire meiotic and developmental competence under suitable culture conditions, but at lower rates compared to full‐grown oocytes. We postulated that estradiol‐17β (E₂) supported the acquisition of meiotic and developmental competence as well as cumulus‐expansion ability during growth culture. Growing oocytes from early antral follicles (1.2 to 1.5 mm in diameter) were grown in vitro for 5 days in a medium containing 0, 10^?7, 10^?6, 10^?5 or 10^?4 mol/L E₂; after in vitro maturation, 35, 58, 47, 74 and 49% of oocytes matured to metaphase II, 25, 79, 77, 90 and 97% acquired cumulus‐expansion ability, and 23, 54, 63, 89 and 64% were fully surrounded by cumulus cells, respectively. Following maturation, electro‐stimulation was applied to the oocytes grown with 10^?5 mol/L E₂. After 6 days of culture, in vitro‐grown oocytes developed to the blastocyst stage at a rate similar to that for full‐grown oocytes (31% and 40%, respectively). Therefore, we suggest that the use of E₂ during growth culture improves the meiotic and developmental competence of oocytes, cumulus‐expansion ability, and cumulus cell attachment to the oocytes.     

Seasonal variations in major components of Crassostrea gigas from Seto Inland Sea

Fisheries Science - The proximate composition and nutritional content of oysters define their quality and commercial value. Cultivation site and harvest date may impact these characteristics. We...     

Morphological changes in the cytoskeleton, nuclei, and vacuoles during cell death of short-lived ray tracheids in the conifer Pinus densiflora

Morphological changes in the cytoskeleton, nuclei, and vacuoles were monitored during the cell death of short-lived ray tracheids in the conifer Pinus densiflora. After formation of the dentate thickenings that occurred at the final stage of formation of cell walls, organelles started to disappear in differentiating ray tracheids. First, the microtubules and vacuoles disappeared. Then actin filaments disappeared in the differentiating ray tracheids adjacent to ray tracheids that lacked nuclei, and, finally, the nuclei disappeared. These features indicate that cell death in ray tracheids might differ from the programmed cell death of tracheary elements that has been studied in vitro in the Zinnia culture system. This study was presented at the 57th Annual Meeting of the Japan Wood Research Society, August 8–10, 2007, Hiroshima, Japan     

Maturation and plant recovery from embryogenic cells of Japanese larch: Effect of abscisic acid in relation to their morphology

Two embryogenic cell lines characterized by different morphology and color, white and red, were obtained from an immature zygotic embryo of Japanese larch (Larix leptolepis Gord.). Mature somatic embryos with cotyledons and regenerated plants were obtained from both cell lines. However optimal concentration of abscisic acid (ABA) for maturation varied depending on morphology of ECs. From the white ECs which intermingled with somatic embryos of very early stage, mature somatic embryos were induced on maturation medium containing 50 μM of ABA. On the other hand, mature somatic embryos with cotyledons were observed from the red ECs which consisted of somatic embryos of more developed stage on hormone-free medium or 0.1 μM ABA containing-medium.     

Ring dike system to harness floodwater from the Mekong River for paddy rice cultivation in the Tonle Sap Lake floodplain in Cambodia

Located in the floodplain of the Mekong River and the Tonle Sap River, Batheay irrigation system and its reservoir directly receive floodwater from the Mekong. The Batheay reservoir formed by a ring dike functions as both a reservoir and a paddy field. In the wet season, the ring dike prevents floodwater from entering the reservoir and rainy season rice is grown inside the dike. After harvesting, the gates on the ring dike are opened to receive floodwater. The water is stored inside the dike for cultivating dry season rice outside the dike. In this paper, the irrigation system is studied as a model site for future development of the floodplain of the Tonle Sap Lake of Cambodia. Specifically, this paper is concerned with the study of water balance and analysis of the hydrologic components of the Batheay irrigation system, and the effectiveness of the ring dike system. The study found that floodwater of the Mekong River contributed about 74% to the total inflow to the Batheay reservoir. Contributions to the total water supply of reservoir water, floodwater remaining in the fields, and precipitation were 73, 12, and 15%, respectively. The efficiency of the system was found to be 92%. The dike system is expected to be a paradigm for the floodplain of the Tonle Sap Lake.