叶绿素铜钠的抑菌活性及稳定性研究

采用菌丝生长速率法测定叶绿素铜钠对5种植物病原真菌在光照和黑暗条件下的抑菌作用，测定菌丝生物量，并进行比较分析。筛选抑菌效果最佳的菌种进行温度、pH、紫外照射时间、氧化还原性稳定性试验。抑菌试验结果表明，叶绿素铜钠对5种植物病原菌均有不同程度的抑制作用，且抑菌作用随着浓度的增加而增加。在药液浓度为20 mg·mL^-1时，苹果腐烂菌在光照和黑暗条件下抑菌率均高达100%，光照条件下叶绿素铜钠供试药液EC₅₀为7.405 mg·mL^-1，黑暗条件下其EC₅₀为6.959 mg·mL^-1；菌丝干重随着药物浓度的增加而减少；在药液浓度为10 mg·mL^-1时，抑菌率高达100%；菌丝干重仅为5 mg。稳定性试验结果表明，温度对抑菌率的影响表现为先升高后降低，在50℃~70℃，抑菌率差异不显著（P>0.05）；在酸性条件下抑菌率随酸度的增加而降低，碱性条件下抑菌率差异不显著（P>0.05）；紫外照射和氧化还原剂对抑菌率的影响差异不显著（P>0.05）。研究叶绿素铜钠的抑菌效果和稳定性，为叶绿素铜钠作为新型农药的研制提供理论依据。     

Variation of intra‐aggregate organic carbon affects aggregate formation and stability during organic manure fertilization in a fluvo‐aquic soil

The aggregate formation and stability are controlled by the dynamics of soil organic matters (SOM), but how it is related to SOM chemical composition within different‐sized aggregates is largely unknown during manure fertilization. In this study, the variations of intra‐aggregate organic carbon (OC), including intra‐particulate organic matter (iPOM) and mineral‐associated organic matter, were quantitatively and qualitatively analysed, and then, their effects on aggregate formation and stability were assessed under four treatments: control (CK), mineral fertilizer (NPK), reduced manure (30%M) and manure fertilizers (M). Manure application (M) significantly increased macroaggregate proportion, mean weight diameter (MWD), and OC contents within different‐sized aggregates compared to CK, NPK, and 30%M. The OC accumulation of macroaggregate in M was attributed to OC content increase in silt plus clay subfraction rather than iPOM with more labile organic groups; oppositely, in microaggregate it was located in the relatively stable fine iPOM. The macroaggregate formation and stability were controlled by the fine iPOM within macroaggregates, whose abundant polysaccharide‐C and aliphatic‐C after manure fertilization advanced the microbial growth except for Gram‐positive bacteria, which further promoted macroaggregate formation and stability. The free silt plus clay fraction also affected macroaggregate formation and stability, and its polysaccharide‐C derived from microorganisms or decomposing SOM was positively associated with MWD and macroaggregate proportion. Because polysaccharide‐C can be easily associated with mineral particles, further improving micro‐ or macroaggregation. We conclude that continuous manure fertilization could increase labile SOM accumulation within aggregates and then facilitate microbial growth, which collectively are responsible for aggregate formation and stabilization.     

安福县杉木人工林二元立木材积动态模型的研究

杉木人工林为安福县重要的森林资源，本研究根据1526株样木数据，在分析其干形变化特点的基础上，建立了符合安福县实际的杉木人工林二元立木材积动态模型。经适用性检验，该模型精度高，其参数稳定可靠，能对样木客观规律作出解释。模型适合在安福县使用。     

Potassium influence on soil aggregate stability

Improving soil aggregate stability (SAS) is important for crop production and environmental protection. Here we aim to quantify the effects of potassium (K) on SAS and to examine SAS as a function of potassium adsorption ratio (PAR) and cation ratio of soil structural stability (CROSS). The soils were treated with the incremental K and analyzed for their aggregate stability, clay dispersion, PAR, and CROSS. The influence of K on SAS, therefore, was tested statistically and fitted functionally. The results showed that K decreased clay dispersion and improved SAS. Also, SAS as a function of PAR fit an inverse exponential regression. Based on the coefficients of determination (R²) of the obtained functions, SAS can be explained by PAR with the accuracy above 94%. Increasing CROSS according to K also caused higher SAS, implying that K is considered as a flocculating inducer for kaolinitic tropical soils.     

Phenotypic Yield Stability Depending on Plant Density and on Mean Yield per Plant of Winter Rapeseed Varieties and of Their F1 and F2-Generations

Among the common agricultural crops winter-rapeseed ( Brassica napus L.) is considered to be especially susceptible to varying environmental conditions. The commonly used stability statistics, which measure these fluctuations, are based on the yields of genotypes in different environments. An improvement of stability analysis may be obtained by an additional estimation of stability using yield components rather than absolute yield values. Relationships between stability of seed yield (SY) and stabilities of plant densities (PD) and of single plant yield (SPY) were examined for four winter-rapeseed varieties, their six F₁'s and their six F₂'s. Environmental variance was applied to estimate phenotypic stabilities. Furthermore, generations were compared for their stability in SY, PD and SPY. Regarding all genotypes and generations the correlation coefficients did not show any relation between stability of SY and stabilities of PD and of SPY (r = -0.04 and r = -0.17). Comparing generations the F₂ showed a higher stability of SY than varieties and F₁, But no consistent results were obtained regarding PD and SPY. The pattern of the heterotic effects of stability of yield components PD and SPY were different from the respective pattern of SY. Eg although possessing desired heterotic effects in stability of PD and SPY some crosses showed undesired heterotic effects in stability of SY. Therefore, a theory of multiplicative heterosis of stability should be developed in analogy to the corresponding theory for yield.     

优质油菜新品种丰产稳产适应性及产量性状的遗传效应

于1987～1988年和1989～1990年,各用9个品种,选取9个有代表性的试验点进行试验,研究了单、双低油菜品种的适应性和丰产稳产性,产量和构成因素的遗传变异及遗传相关。结果表明:①一些单、双低油菜品种的产量已达到了大面积推广应用的常规品种的水平,且适应性和稳产性也有了较大的改善;②优质油菜要获得高产和稳产,对产量构成因素的要求是:在具有单位面积内较高果数的基础上,每果粒数要稳定,尤其是千粒重要较高而稳定,这就要求品种的生育期较为适中且抗逆性较强;③进一步的产量育种目标可以是在单位面积内具有一定果数的基础上提高粒数,稳定粒重;山可以是在单位面积内有一定果数的基础上保持中等果粒数,增加粒重同时提高生长后期的抗病抗倒性。     

无穷时滞泛函微分方程解的完全全局稳定性

建立了无穷时滞泛函微分方程完全有界性与完全全局渐近稳定性的概念及基本定理。     

实用光温敏核不育水稻育性稳定性鉴定方法的探讨

在对水稻光温敏核不育系的育性光温反应研究的基础上，提出了实用不育系育性稳定性鉴定的原则，并据此建立和完善了实用不育系育性稳定性鉴定的４级８组处理法，摸索建成了适用于实用不育系筛选、鉴定和提纯的人工气候实验室，借助上述条件和方法，成功地对安湘Ｓ等５个实用不育系的育性稳定性实施了鉴定。     

TMAOase, trimethylamine-N-oxide demethylase, isa thermostable and active enzyme at 80°C

ABSTRACT:   Purified trimethylamine- N -oxide demethylase (TMAOase)from walleye pollack muscle is a thermostable protein that was notinactivated after heating at 80°C for 30 min.The heated enzyme was electrophoresed in the same manner as fornative enzyme. Circular dichroism (CD) spectra for purified enzymechanged reversibly in the temperature range of 10–80°C.As the enzyme was still active at 80°C, the CD spectralchange did not directly relate to enzyme activity. TMAOase activity inthe myofibrillar fraction decreased sharply above 30°C,but was extracted and recovered from the heated myofibrillar fraction,suggesting that the activity seemed to be interrupted and apparently inactivateddue to the thermal alteration of myofibrillar proteins or some unknownfactors. The complicated profile found in dimethylamine (DMA) formationfrom trimethylamine- N -oxide (TMAO) in walleye pollack muscleduring heating consisted of both enzymic and non-enzymic processes.Most DMA was produced enzymatically below 40°C and interruptedabove 40°C. Therefore, DMA and trimethylamine was formednon-enzymatically at high temperatures regardless of the presenceof native enzyme. A new, simple and easy purification method wasproposed based on the thermostable nature of the enzyme.     

Yield Stability of Winter Oil-Seed Rape (Brassica napus L.) as Affected by Stand Establishment and Nitrogen Fertilization

The effects of stand establishment and nitrogen fertilizer on yield and yield stability of winter oil-seed rape ( Brassica napus L.) were investigated in two field experiments in north eastern Germany (Mecklenburg-Vorpommern). During six years of testing from 1984/85 to 1989/90 three sowing dates (10 Aug, 20 Aug, 5 Sept) as combined with three plant densities (60, 100, 140 plants/m² in autumn) were compared. Although seed yield did not respond to the main effects of these treatments, the two-way classification resulted in significant differences from the average yield. August sowing combined with lower plant densities caused comparably high yields, while delayed sowing was somewhat effective only with higher plant density. Highest yield stability was achieved at early sowing when combined with lower plant densities. From 1986/87 to 1988/89 nitrogen top-dressings were applied during early March, at start of stem extension and shortly before start of flowering at five locations. 200 kg N/ha in one dose resulted in lowest yield performance and enhanced instability. Contrastingly, the 240 kg N/ha treatment advanced yield stability regardless of split regimes. Nevertheless, split application to 100 kg N/ha + 50 kg N/ha + 50 kg N/ha also guaranteed that high yield performance and optimum yield stability were reached simultaneously and, that the total nitrogen input could be limited to 200 kg N/ha.