百年柿树经济系数模型研建及应用

以百年柿树为对象,利用树干解析的生物量及采果记录,研究不同树龄、胸径因子与生物量、产果量及经济系数之间的关系,建立柿树单木生物量、产果量与经济系数的回归模型。结果表明：以年为单位的 EC1(年产果量与累计生物量之比)与树龄及胸径间分别呈双曲线关系;以一个生命周期为单位时,EC3(累计产果量与累计生物量之比)趋于稳定,其值为0.846,标准偏差为0.036。经济系数在经济林生物量估算及研究中有重要作用,应给于充分的重视。     

涂饰工艺对木质体育地板表面滑动摩擦系数的影响研究

采用正交试验法,研究涂饰工艺对木质体育地板表面滑动摩擦系数的影响,试验因素为面漆涂饰次数、涂料种类和面板砂光目数,试验测试指标为表面滑动摩擦系数。方差分析结果表明,涂料种类与测试指标呈极为显著的影响关系,水性面漆涂饰的试件表面滑动摩擦系数相对较高;其他2个因素与测试指标之间无显著影响关系。砂光目数极可能对表面滑动摩擦系数有一定影响,但这一影响关系被底漆涂饰工艺所覆盖,因此所有试件的表面滑动摩擦系数全部达到了国家标准的要求。     

木材高速螺旋式玉米铣刀的设计与优化

使用砂光机磨削木材存在功耗大、噪声大和粉尘多等问题,因此设计了一种木材高速螺旋式玉米铣刀,其采用“以切代磨”的方式使这一问题得到解决。该玉米铣刀形似“玉米”,刀尖处直径Ф160～240mm,可实现高线速度切削,刀身均布有2～6排螺旋式阶梯槽,各螺旋槽上均布有6～10个刀片槽,可实现刀片逐刃切削;刀具采用组合结构,刀片前角20°～26°、后角9°～13°,刀具下装有可调高的碟形弹簧,以实现刀片磨损后的补偿,提高刀具材料利用率。通过分析计算发现,初步设计的玉米铣刀质量达105kg,刀身和刀片安全系数在83～402之间,材料浪费严重,因此在优化设计时刀身内部采用了中空结构以减轻质量,装有配重拉杆以调整平衡,增加刀片数量,优化后玉米铣刀质量降至43.5kg,安全系数降到33～70之间,完全满足强度要求。     

邓恩桉组培中影响继代增殖条件的研究

探讨抗寒树种邓恩桉组培快繁中影响其继代培养的因素。实验表明,继代培养以改良MS为基本培养基,随继代次数的增加逐渐减少细胞分裂素BA和生长素NAA的浓度。最初几次继代,BA的浓度为0.5 mg/L,NAA的浓度为0.2 mg/L。然后BA的浓度逐渐降低到0.1~0.3 mg/L,NAA的浓度逐渐降至0.05~0.1 mg/L,继代5~6次后,BA的浓度保持在0.1~0.3 mg/L,NAA的浓度保持在0.05~0.1 mg/L。继代周期随季节而不同,夏季为15~25 d,春秋季为20~35 d,冬季为40~50 d,芽的月增殖系数为3~5倍,满足工厂化育苗的要求。组培苗的玻璃化和遗传变异等异常现象很少,节间长度适中,有利于生根。     

Dynamics of arsenic-containing compounds sorption on sediments

Background  River and lake sediments constitute complex and difficult analytical samples. On the other hand, sediments play a fundamental role in the distribution of toxic compounds in aquatic systems and in the evaluation of the current state and the course of changes taking place in the environment. Among elements present in the environment in trace concentrations, but having well-elaborated toxic properties, one of most dangerous is arsenic. The element occurs in the environment in several chemical forms, predominant are inorganic forms of As(V) and As(III), and methylated forms such as monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA). Objectives  Reported herein are experiments, which were undertaken with the aim of examining the dynamics of arsenic sorption in sediments and its dependence on speciation of the element and the pH in the environment. Simultaneously, influence of organic matter content and chemical composition of the sediments on As sorption, were investigated. Methods  Sediment samples (upper 10 cm layer) were collected from three sites located in the vicinity of Cracow:

大麦多数量性状相关分析

穗长、穗粒重两性对小区产量直接影响较大;每穗实粒数和每穗不实粒两性状数对小区产量直接影响很小,但通过其他性状对小区产量的间接负影响很大;每穗总粒数对小区产量直接负影响很大,株高通过其他性状对小区产量间接正影响很大。     

Factors influencing fruit size in the strawberry (Fragaria ananassa Duch.)

Summary Fruit size is one of the most important characteristics of highly productive strawberry cultivars. The aim of the experiments was to establish the factors responsible for the expression of this trait. The total yield of large fruits correlates closely with the total yield of all fruits and depends mainly on the mean fruit weight of all fruits. The position of fruits on the inflorescence influences the decline of fruit size to a larger extent in small-fruited clones than in the large-fruited ones. The size of the fruit is controlled by the dimension of the receptacle and number of achenes. The stimulating effects of achenes are quite different in various genotypes and the fruit weight per achene declines with the inferior blossom position. The large-fruited clones have bigger leaves, a larger photosynthetic area, and thicker petioles and flower stalks. Their cells are larger, which is common for the giant genotypes. The results suggest that there exists a possibility for indirect selection of fruit size on the basis of some additional parameters, which can be useful particularily in the years of unsuitable weather conditions.     

Optimising potato breeding. II. A model for optimising single-stage and single-trait selection

Summary A model for optimising single-stage and single-trait selection is presented. The model is based on the expected selection response model, extended with parameters describing the nature of the environment and with variables allowing a manipulation of selection schemes. As an example, the model is used to optimize tuber yield selection in potato breeding.Estimated parameter values have an uncertainty, which may bias the model outcome. Sensitivity analysis shows that the sensitivity to unrealistic parameter values for optimal allocation is less than the sensitivity for the selection response.     

Stability Analysis of Yield in Maize,Wheat and Sorghum and its Implications in Breeding Programs*

Six stability statistics: (b_i, s²_di, , , and ) were estimated for maize, wheat and sorghum in different environments by using three statistical models. The significant linear portion of genotype × environment interaction for maize indicates different hybrids responded differently to environments, whereas the non-significant genotype × environment interaction (linear) were found for wheat and sorghum suggest that all genotypes responded similarly as the environments change. However, the highly significant pooled deviations (deviation from regression) for all three crops make yield predictions from the model less reliable. When regression coefficients (b_i) were non-significant, s²_di, became an important statistic in estimating stability. It appears that the regression coefficient, b_i, was best used to estimate genotypic adaptability, whereas s²_di, for stability. Maize and sorghum had negative correlations between the mean yield and stability statistics, s²_di, , and , suggesting that high yield and stability are not mutually exclusive in the range of environments used in this study; however, such correlations did not occur in wheat. Thus, maize and sorghum hybrids with high yield potential and high stability could be identified and selected. Correlations between mean yield and b_i, or , were positive and significant for maize and sorghum but were non-significant for wheat, indicating that such relationships may be species specific. Under a given set of testing environments, the stability ranking associated with each maize hybrid is correlated to and depends on other hybrids included in the analysis.     

关联度分析在农业生态系统技术调控上的应用

农业生态系统是个“灰箱”.我们运用模糊数学的关联度分析,尝试对这类灰色系统的投入进行技术调控,并取得了良好的效果.通过对农田子系统投入的化肥(尤其是N化肥)、粪肥和还田秸秆进行技术调控的实例证明;它可以作为能、物流分析的辅助手段,互相取长补短.通过关联序分析和关联系数分析,来调整系统的投入结构和投入技艺(时、空、量级及方式的选择).本文提出了应用关联度分析的基本程序和要领以及“贡献曲线”、“潜力曲线”等概念.