Prematurity and Dysmaturity Are Associated With Reduced Height and Shorter Distal Limb Length in Horses

The long-term effects of gestational immaturity in the premature (defined as < 320 days gestation) and dysmature (normal term but showing some signs of prematurity) foal have not been thoroughly investigated. Studies have reported that a high percentage of gestationally immature foals with related orthopedic issues such as incomplete ossification may fail to fulfill their intended athletic purpose, particularly in Thoroughbred racing. In humans, premature birth is associated with shorter stature at maturity and variations in anatomical ratios, linked to alterations in metabolism and timing of physeal closure in the long bones. We hypothesized that gestational immaturity in horses might similarly be associated with reduced height and different anatomical ratios at maturity. In this preliminary study, the skeletal ratios of horses with a history of gestational immaturity, identified through veterinary and breeder records, were compared with those of unaffected, closely related horses (i.e., sire, dam, sibling). External measurements were taken from conformation photographs of cases (n = 19) and related horses (n = 28), and these were then combined into indices to evaluate and compare metric properties of conformation. A principal component analysis showed that the first two principal components account for 43.8% of the total conformational variation of the horses’ external features, separating horses with a rectangular conformation (body length > height at the withers), from those that are more square (body length = height at the withers). Varimax rotation of PC1 and analysis of different gestational groups showed a significant effect of gestational immaturity (P = .001), with the premature group being more affected than the dysmature group (P = .009, P = .012). Mean values for the four dominant indices showed that these groups have significantly lower distal limb to body length relationships than controls. The observed differences suggest that gestational immaturity may affect anatomical ratios at maturity, which, in combination with orthopedic issues arising from incomplete ossification, may have a further impact on long-term athletic potential.     

Sap flow in ‘Hass’ avocado trees on two clonal rootstocks in relation to xylem anatomy

The rates of sap flow and xylem vessel features were studied in two-year-old nongrafted and grafted avocado (Persea americana Mill.) trees. Daily sap flow rates were measured with heat and balance stem gauges in clonal Duke 7 (D7) and Toro Canyon (TC) trees and ‘Hass’ clonal scions grafted onto clonal D7 (H/D7) and TC (H/TC) rootstocks. Vessel features as size, number and total vessel area were determined histologically in the stem of the scion and rootstock and the roots of the grafted trees. Significant differences in the sap flow rate were found among the rootstocks, where D7 had a 29% higher sap flow rate than did TC (grafted and nongrafted trees). There were no differences among xylem vessel features in the stems of any of the varieties. However in the roots, D7 had wider and fewer vessels then TC do. Also, D7 had a 19% higher total vessel area than TC. These results suggest that the differences in water consumption of ‘Hass’ on different rootstocks may be associated with differences in the efficiency of the roots to absorb water across conductive tissue which may be linked to differences in the area of xylem vessels in the root.     

独立学院植物生产类专业植物形态解剖实验实践教改研究

对独立学院植物生产类专业的专业基础课植物形态解剖实验实践的教学目标、教学内容、教学方法、考核手段等方面进行了较深入的分析,从培养独立学院学生理论结合实践的能力、解决实际问题的能力等方面提出了教改的内容与实施措施,并在学生中初步实验验证,效果良好。     

同工酶与动物发生遗传学

本文对同工酶与动物发生遗传学各自的形成、发展以及二者的结合等问题作了概括的阐述。     

梨幼果表皮果点形成的组织解剖观察

梨幼果期皮层细胞组织具有荧光物质,采用活组织切片和荧光显微观察的方法,研究了梨幼果表皮气孔转变为果点过程中,外部形态和内部细胞结构的变化,并根据皮孔细胞组织生长发育的特点,提出了栽培中减小果点形成的有效措施。     

山西省农村体育现状及发展趋势的研究

本文通过对山西省１１个地市８２５８名２０岁以上的农民进行了６７项问卷调查，内容涉及农民的体育意识、体育兴趣、体育价值取向、人均收入、体育投入、体育活动内容和形式等方面，探讨了山西省农民体育的现状。依据社会学的基本理论，运用逻辑分析法，对影响农民体育活动的因素进行了全面分析，阐述了山西省农村体育的发展趋势。文中反映的问题，对实施全民健身计划，体育宏观决策，具有重要的意义。     

Studies on the Developmental Genetics of Tiller Number in Three-line Indica Hybrid Rice

Following NC Ⅱ design, the developmental genetic behavior of tiller number (TN) in three-line indica hybrid rice was studied using additive-dominance developmental genetic models and the corresponding statistical methods. The results showed that dominance effects were predominant for TN. The expression of those additive effects were affected by environment and genotype interaction, but the expression of dominance effects were not affected. Heterosis was the strongest in the middle developmental periods of TN. Additive effects and dominance effects were selectively expressed throughout in the entire tillering developmental stage.Analysis of genetic correlation between TN at different stages and the productive panicles indicated that a close correlation appeared earlier in the populations with higher heterosis than in those with less heterosis. Utilization of heterosis at the middle tillering stage might enhance the final biomass but reduce the percentage of productive panicles.     

转矩传感器发展现状

介绍了国内外振弦式，应变式，磁致伸缩式，电容式，光电式，磁电式以及磁敏式转矩传感器等的发展现状。这些传感器有些曾经在汽车上得到过应用，但因应变式，电容式，光电式以及磁电式转矩传感器等或者测量精度低，或者抗干扰能力差等问题。目前都未能在汽车上大量使用。     

Path-Coefficient Analysis of Leaf-Anatomical Characters Affecting Frost Injury in Potato

Correlation and path-coefficient analysis for leaf-anatomical characters affecting frost injury was carried out in twenty eight varieties and accessions belonging to several wild and cultivated tuber-bearing species of Solanum in order to identify selection criteria in breeding for frost resistance in potato Palisade thickness and palisade proportion showed a significant negative correlation with frost injury Path-coefficient analysis revealed that palisade thickness had the highest direct negative effect on frost injury whereas leaf thickness, not conforming to its behaviour as found in simple correlation analysis, emerged ax the next highest factor to have direct positive effect on frost injury. Direct and indirect effects of these factors on frost injury vis a vis their interdependence were found to be in support ot the ‘palisade thickness method’ for screening frost resistant genotypes in potato breeding programmes.     

比克氏棉和司笃克氏棉色素腺体形态建成的组织结构观察

对具有子叶色素腺体延缓形成性状的比克氏棉和种子有色素腺体但低酚的司笃克氏棉的休眠种子、幼胚发育过程和种子萌发过程中的子叶进行连续切片观察。结果表明,比克氏棉的种仁中虽无肉眼可见的色素腺体,但具有色素腺体原,其色素腺体形态建成从开花后子叶形态建成后开始到种子萌发后12h才完成。司笃克氏棉在幼胚发育过程中,也出现色素腺体原的结构,但保持的时间较短,到种子成熟时,其种仁中的色素腺体原大多已发育成正常的色素腺体,且色素腺体空腔中含有某些有色物质,腔壁明显不同于比克氏棉或一般有色素腺体棉。司笃克氏棉的色素腺体性状为介于一般有色素腺体棉和具有子叶色素腺体延缓形成性状棉种的中间过渡类型,这种性状在低酚棉育种研究中具有重要的实践意义。