Effects of symbiosis with Rhizobium fredii on transport of fixed nitrogen in the xylem of soybean plants

An experiment was conducted to identify the main nitrogenous compound transported in the xylem sap of soybean plants nodulated with Rhizobium fredii. Soybean (Glycine max L. Merr.) cultivars, wild type Bragg (nod⁺, fix⁺) and its nitrate tolerant, hypernodulating mutant ntsll16 (nod⁺⁺, fix⁺) were used for this experiment. These soybean plants were inoculated with a slowgrowing rhizobium, Bradyrhizobium japonicum USDAllO or fast-growing rhizobia consisting of a mixture of R. fredii USDA191, USDA193, and USDA-194 and grown in a phytotron under natural light and controlled temperature conditions. Xylem sap was collected from Bragg and ntsll16 plants at the flowering and pod elongation stages. Acetylene reduction activity per plant or per nodule weight was not different between soybean lines and inoculums. The composition of the nitrogenous compounds in the xylem sap was compared between the symbionts, with B. japonicum and R. fredii. At the flowering stage, ureide-N and amide-N accounted for 53 to 70% and 20 to 27% respectively of the total N in the sap collected from the plants inoculated either with B. japonicum or R. fredii. At the pod elongation stage, ureide-N and amide-N accounted for 74 to 85%, and 7 to 19% of total sap N. With the growth of the soybean plants, the ratio of ureide-N in the xylem sap increased. These results suggest that in the case of wild soybean and the hypernodulating mutant line nodulated by R. fredii, ureide is transported as the main nitrogenous compound of fixed nitrogen in the xylem sap in the same way as in plants nodulated with B. japonicum.     

乳苣叶绿体基因组特征及其系统发育分析

乳苣（Mulgedium tataricum）为菊科（Compositae）乳苣属（Mulgedium）植物,该物种含有天然黄酮类化合物,具有清热解毒、抗肿瘤、抗氧化等作用。叶绿体基因组中含有大量功能基因,在物种鉴定及系统发育中具有重要作用。采用高通量测序技术获得乳苣全长叶绿体基因组序列,并与NCBI已公布的32个菊科物种及拟南芥（Arabidopsis thaliana）的叶绿体基因组进行了系统发育分析。结果显示,乳苣叶绿体基因组大小为152 401 bp,呈现出典型的环状四分体结构,其包含有一对反向重复序列区（IRa和IRb）、大单拷贝区（LSC）和小单拷贝区（SSC）,它们的长度分别为25 010、83 833和18 548 bp。共注释得到132个基因,其中包含8个rRNA基因、37个tRNA基因和87个mRNA基因;SSR位点分析发现,基因组序列中含有21个散在重复序列和197个串联重复序列。边界分析表明,乳苣与其他5个菊苣族物种在边界基因上存在一定差异,且6个菊苣族物种在IR/SC区出现明显扩张和收缩。系统进化分析将菊科14个属的33个物种被聚为两个分支：第一分支包括乳苣属（Mulgedium）、莴苣属(Lactuca)、蒲公英属(Taraxacum)、苦苣菜属(Sonchus)、香青属(Anaphalis)、火绒草属(Leontopodium)、茼蒿属(Chrysanthemum)、蒿属(Artemisia)、紫菀属(Aster)和向日葵属(Helianthus),其中乳苣属和莴苣属的亲缘关系最近;第二分支包括蓟属（Cirsium）、红花属（Carthamus）、风毛菊属（Saussurea）和苍术属（Atractylodes）。研究结果为乳苣属植物的物种鉴定、系统进化及资源开发利用等奠定新的证据和材料基础。     

新疆棉花胞质不育系主要农艺性状的配合力分析

为进一步利用棉花杂种优势,促进三系杂交棉的选育,以哈克尼西棉、三裂棉（D8）和海岛棉（05 53A）3种不同来源细胞质雄性不育系为母本,以新疆早熟陆地棉新陆早33号、新陆早36号、系9为回交亲本,连续回交4代,获得9个新不育系（A1~A9）;用3个恢复系（R1~R3）与之进行杂交,获得27个杂交组合,并对8个主要性状的一般配合力（GCA）和特殊配合力（SCA）进行分析。结果表明,不育系衣分、籽棉产量、纤维长、整齐度、马克隆值、伸长率和比强GCA的差异均达到显著水平;恢复系纤维长、伸长率、比强和籽棉产量GCA差异均达到极显著水平;杂交组合铃质量、衣分、马克隆值、伸长率、比强和籽棉产量SCA的差异均达到显著水平;纤维长和整齐度主要受加性效应的影响,铃质量主要受非加性效应的影响,马克隆值、伸长率、比强和籽棉产量同时受加性和非加性效应的影响。从GCA来看,产量性状中铃质量和籽棉产量的GCA效应值是正值的比例较高（均为58.33%）; 3个恢复系中,R3的7个性状的GCA效应值均为正值;9个不育系中,A1、A4的GCA效应值综合较高,A6籽棉产量的GCA效应值最高,A9纤维长的GCA效应值最高。从SCA来看,产量性状中铃质量和衣分的SCA效应值是正值的比例较高（均为55.56%）;杂交组合A2×R1、A6×R2、A5×R3、A7×R3、A8×R3产量性状的SCA效应值综合较高;A5×R1、A3×R2品质性状的SCA效应值综合较高;A9×R1、A7×R2、A4×R3产量和品质性状的SCA效应值综合较高。     

Application of the wood properties of large-diameter Sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) logs to sorting logs and sawing patterns

The purposes of this study were to accumulate fundamental data on wood properties within large Sugi logs and to take applicable variations in wood properties into consideration for sorting logs and sawing patterns. The characteristics of basic density, moisture content, growth ring width, and microfibril angle (MFA) were measured and the relationship with log and lumber quality was examined. It was considered reasonable to estimate the lumber moisture content based on the moisture content of heartwood rather than that of whole logs, especially when producing large-sized lumber. The MFA reached a constant value before the 15th ring, and within a distance of 10 cm or less from the pith. Since the E _fr of lumber correlated with that of the log affected by MFA, it would be possible to produce lumber with a higher E _fr from the outer position of the log, based on selecting a log above the E _fr . Since the MFA would also affect the lumber warp, a sawing pattern avoiding the area around the pith or enlarging the rough sawn size when a large warp was expected could be effective in improving the lumber quality. To improve the lumber quality, not only one but also multiple wood properties must be applied to the sawing pattern.     

仔猪消化道胃泌素和五羟色胺分泌细胞时空分布的观察

为探讨仔猪消化道内分泌细胞的发育规律。本实验取0日龄、7日龄、28日龄、35日龄、两个月、四个月仔猪消化道各部分,并利用免疫组织化学方法显示其消化道的胃泌素和五羟色胺分泌细胞,观察仔猪胃泌素和五羟色胺分泌细胞分布及数量变化规律。实验结果显示胃泌素阳性细胞主要分布在胃幽门处,其他组织偶尔可见零星散布的胃泌素阳性细胞;五羟色胺阳性细胞在肠道中空肠处最多,胃部分泌多于肠道。结论：胃肠道五羟色胺与胃泌素分泌细胞在胃肠道的分布具有一定的规律性,且其时空分布应和母乳、应激等因素有关.     

垄作免耕对土壤团聚体中微生物生物量N和脲酶活性的影响

笔者分选出垄作免耕、常规耕作、冬水田每种耕作方式下的7个粒径的土壤团聚体,测定了3种耕作方式下土壤微生物生物量N及土壤团聚体中脲酶的活性,以试图找到土壤团聚体中脲酶的活性与土壤耕作方式的关系,以及土壤团聚体中脲酶的活性和土壤微生物生物量N的相关性。结果表明：土壤微生物生物量的分布主要受土壤结构体的制约,受耕作方式的影响不显著;不同的耕作方式对土壤团聚体中脲酶活性的影响比较明显;脲酶活性与微生物生物量N无显著相关性,说明紫色水稻土中脲酶的主要来源可能不是微生物。     

Termite resistance and color of heartwood of hinoki (Chamaecyparis obtusa) trees in 5 half-sib families in a progeny test stand in Kyushu, Japan

Hinoki (Chamaecyparis obtusa) wood has been used as a structural material in Japan because of its superior mechanical properties, its excellent durability and the beautiful color of its heartwood. Variations of termite resistance and compositions of extractives among hinoki trees have been reported. However, genetic variation of termite resistance and the effect of heartwood color on termite resistance remain unknown. In this study, we report the characteristics of termite resistance and color indexes (L*, a* and b*) of heartwood of hinoki half-sib families in a progeny test stand. The survival days of termites and the mass loss of samples of hinoki heartwood differed significantly among hinoki families. Families with red-color heartwood had larger termite resistance than families with yellow-color heartwood. The termite resistances of individual samples from two families with yellow-color heartwood were as small as that of Pinus densiflora. Larger a* and smaller b* induced larger termite resistance of heartwood. The effect of DBH (diameter at breast height) of hinoki trees on termite resistance of hinoki families was small.     

Texture analysis of stereograms of diffuse-porous hardwood: identification of wood species used in Tripitaka Koreana

Tripitaka Koreana is a collection of over 80,000 Buddhist texts carved on wooden blocks. In this study, we investigated whether six hardwood species used as blocks could be recognized by image recognition. An image data set comprising stereograms in transverse section was acquired at 10×?magnification. After auto-rotation, cropping, and filtering processes, the data set was analyzed by an image recognition system, which comprised a gray-level co-occurrence matrix method for feature extraction and a weighted neighbor distance algorithm for classification. The estimated accuracy obtained by leave-one-out cross-validation was up to 100% after optimizing the pretreatments and parameters, thereby indicating that the proposed system may be useful for the non-destructive analysis of all wooden carvings. We also examined the specific anatomical features represented by textures in the images. Many of the texture features were apparently related to the density of vessels, and others were associated with the ray intervals. However, some anatomical features that are helpful for visual inspection were ignored by the proposed system despite its perfect accuracy. In addition to the high analytical accuracy of this system, a deeper understanding of the relationships between the calculated and actual features is essential for the further development of automated recognition.     

Natural durability of the culturally and historically important timber: <Emphasis Type="Italic">Erythrophleum fordii</Emphasis> wood against white-rot fungi

The natural resistance of Erythrophleum fordii Oliver wood to degradation by Phanerochaete sordida and Phanerochaete chrysosporium white-rot fungi was investigated. In this study, Fagus crenata Blume (Japanese beech) was selected as reference species. The results showed that both fungi caused less than 2% mass loss in E. fordii wood, while the degradation of beech wood produced by P. chrysosporium and P. sordida was approximately 12 and 14%, respectively. Microscopic observations revealed high structural rigidity of E. fordii timber. Hyphae were only observed in the lumen of vessels and parenchymal cells, while the fibers were not affected. The E. fordii wood fiber consisted of highly lignified thick-walled fibers with the fiber lumina almost completely closed. Two-dimensional heteronuclear single-quantum coherence nuclear magnetic resonance evaluation revealed the E. fordii wood to have a highly condensed-lignin structure that reflected by the durability classes. These unique parameters are likely to be critical for the high natural resistance of E. fordii.     

Somaclonal variation in Tricyrtis hirta plants regenerated from 1-year-old embryogenic callus cultures

The Liliaceous perennial Tricyrtis hirta, sometimes called ‘Japanese toad lily’, has recently become popular as an ornamental for pot and garden uses. Highly embryogenic callus cultures of this plant predominately consisted of diploid cells but also contained tetraploid cells after 1 year of establishment. In the present study, plans regenerated from the 1-year-old embryogenic callus cultures were subjected to ploidy level analysis and morphological characterization following 3 years of cultivation. Among 37 plants examined, 28 kept the diploid level (2n = 2x = 26) but nine were tetraploid (2n = 4x = 52) as indicated by FCM analysis and chromosome observation. Although no morphological alterations were detected in 26 out of 28 diploid regenerants, the remaining two showed noticeable variations: both were severely dwarf and had crimped leaves and many malformed flowers. The tetraploid regenerants had several horticulturally attractive characteristics compared with the diploid controls, such as longer shoots, thicker stems, and larger flowers. Thus regeneration of tetraploid plants from 1-year-old embryogenic callus cultures offers a possibility to improve the horticultural value of T. hirta, although regeneration of trueness-to-type plants is essential for utilizing the cultures for micropropagation and genetic transformation.