氮肥对辣椒果实中辣椒素含量的影响

以田间试验和室内分析相结合的方法,采用景尖椒3号(高辣度),以3种不同的氮肥施用量处理,就生长期中氮肥对辣椒果实中辣椒素含量的影响进行研究.结果发现,在一定条件下,增加氮肥施用量会导致辣椒果实中辣椒素含量减少;果实中过氧化物酶活力与辣椒素含量呈一定负相关.     

宁夏春小麦磷素利用效率的基因型差异研究

在不同施磷土壤条件下,采用肥料田间试验和测试分析方法,研究了宁夏春小麦磷素利用效率及其有关性状的基因型差异。结果表明,不论施磷与否,小麦籽粒产量、生物学产量、磷肥增产率、地上部茎叶和籽粒中含磷量以及磷素吸收累积量、磷素利用效率等均存在明显基因型差异,且这种差异在低磷条件下更为明显。在低磷条件下,籽粒生产中的磷素利用效率变化在160.1～448.3kg/kg之间,平均为223.1kg/kg,变异系数为23.05％;干物质生产中的磷素利用效率变化在332.6～898.5kg/kg之间,平均为458.4kg/kg,变异系数为22.57％。从中筛选出低磷高产高效品种8个。在较高供磷条件下,籽粒生产中的磷素利用效率变化在150.9～350.9kg/kg之间,平均为229.8kg/kg,变异系数为20.63％;于物质生产中的成素利用效率变化在358.3～746.5 kg/kg之间,平均为482.Ikg地,变异系数为 18.76％。从中筛选出高磷高产高效品种7个。通过相关分析,研究了不同供成条件下磷素利用效率与其它营养性状之间的关系,提出了培育磷高效品种的有用性状指标。     

外源甜菜碱对作物的抗旱作用效果研究

通过小麦浸种、水培、大面积喷施和茄子盆栽试验,研究了不同浓度外源甜菜碱对作物的抗旱作用效果。结果表明:外源甜菜碱浓度为25～50mg/L时可促进小麦种子发芽,光合作用强度[达7.07～7.57μmol/(s·m~2)]及生物学产量增加;在外源甜菜碱浓度100 mg/L时小麦幼苗叶片硝酸还原酶活性最高,达到35.23μg/(g·h),同时小麦抗旱性增强。数学模式寻优结果表明:在外源甜菜碱浓度26.4～68.9mg/L,土壤水分含量12.6％～20.7％时,可获得最佳的茄子生物总量。     

高分子量麦谷蛋白亚基的品质效应研究进展

介绍了小麦高分子量谷蛋白亚基(HMW—GS)的遗传，不同基因位点及位点内各等位亚基对品质的效应等研究进展，提出了通过回交转育创建几套不同高分子量谷蛋白亚基的近等基因系群，然后在同一遗传背景和不同遗传背景条件下分析高分子量谷蛋白亚基及其组合的品质效应及与遗传基础的关系。     

充足底墒播后不灌水时肥料和播期组合对小麦生长和耗水的影响

在充足底墒播后不灌水条件下,进行了适当晚播(10月15日播)与超晚播条件下的小麦肥料试验。主要结果为:(1)播后不灌水条件下超晚播减产严重,主要是单位面积总粒数下降太多,通过适当提高穗密度难以补偿;(2)高施磷条件下(施磷二铵450kg/hm2),随施氮量的增加,开花前的耗水量没有增加,而灌浆期的耗水量则随氮肥用量增加而增加;(3)控制花前无效生长,降低花前耗水,优化开花后的群体结构,提高灌浆期的灌浆强度是降低总耗水、提高水分利用效率的基本途径。     

关中平原小麦产量对气候变化区域响应的评价模型研究

根据关中地区宝鸡、西安、渭南与咸阳 4地 (市 )的 1 949～ 1 999年的逐年小麦单产记录序列以及 4地 (市 )的气象观测站点自建站以来至 2 0 0 0年近 5 0年的气象记录序列 ,对关中地区小麦产量与年均温、年降水作相关分析 ;探讨了关中地区小麦单产对气候变化区域响应的评价模型。结果发现 :关中平原气候具有暖干化趋势 ;随着气温变暖 ,小麦产量增加幅度减小 ;小麦产量对降水波动的响应比对气温波动的响应显著。     

Effect of mutant β-catenin gene on the proliferation of hepatocytes

AIM:The β-catenin is a key molecule in the Wnt signal pathway, which plays a critical role in normal development and tumorigenesis. However, the mechanisms of the β-catenin on the cell growth control are still not completely defined. The aim of this study was to test the hypothesis that the mutant β-catenin may regulate the hepatocyte proliferation. METHODS: The immortalized murine hepatocyte cell line, AML12, was used for this study. A plasmid that contain mutant β-catenin S33Y was transfected into the AML12 cells and a stable cell line AML12S33Y was established. The cell growth property of this cell line and the parental cell were compared by flow cytometry analysis and direct cell count. The cells were also tested for the ability to form soft agar colonies, and the ability to form tumors in the severe immune deficient mice (SCID). RESULTS:1. The mutant β-catenin containing cell line AML12S33Y has higher proliferating index compared with the parental AML12 cells (P<0.01), suggesting that mutant β-catenin promotes cell growth. 2. The mutant β-catenin cells formed small colonies in soft agar after 4 weeks of culture, but did not generate tumor in SCID mice. CONCLUSION:The mutant β-catenin promotes liver cell growth.     

Effect of tea-polyphenols on the activation of NF-κB and the expression of TGF-β1 mRNA in THP-1 cells incubated with VLDL,LDL or ox-LDL

AIM:To investigate the effect of tea-polyphenols (TP) on the activation of NF-κB and the expression of TGF-β₁ mRNA in THP-1 cells (a human acute monocytic leukemia cell line). METHODS:THP-1 cells were incubated with the different concentrations of TP, VLDL, LDL or ox-LDL. In the THP-1 cellls, the nuclear malposition rate of NF-κB was detected with immunohistochemistry technique, the positive index of the TGF-β₁ mRNA expression was detected by hybridization in situ, and accumulation of total cholesterol (TC) in cells incubated with 0.4-40 μg/L TP was determined with oxidase assay. RESULTS:The nuclear malposition rate of NF-κB, the positive index of the TGF-β₁ mRNA expression and TC in THP-1 cells incubated with 0.4-40 μg/L of TP were lower than those with 0 μg/L of TP in TP-V group, TP-L group and TP-O (P＜0.05). The differences of these markers in THP-1 cells incubated with more than 40 μg/L TP in TP-V group, TP-L group and TP-O were not statistically significant, compared with TP-C group (P＞0.05). CONCLUSION:TP inhibited the activation of NF-κB, the expression of TGF-β₁ mRNA and the foam cell formation in the mono-macrophage.     

Predicting the spatial distribution of ground flora on large domains using a hierarchical Bayesian model

Accomodation of important sources of uncertainty in ecological models is essential to realistically predicting ecological processes. The purpose of this project is to develop a robust methodology for modeling natural processes on a landscape while accounting for the variability in a process by utilizing environmental and spatial random effects. A hierarchical Bayesian framework has allowed the simultaneous integration of these effects. This framework naturally assumes variables to be random and the posterior distribution of the model provides probabilistic information about the process. Two species in the genus Desmodium were used as examples to illustrate the utility of the model in Southeast Missouri, USA. In addition, two validation techniques were applied to evaluate the qualitative and quantitative characteristics of the predictions.This revised version was published online in May 2005 with corrections to the Cover Date.     

Toxigenic Fusarium species and Mycotoxins Associated with Head Blight in Small-Grain Cereals in Europe

The Fusarium species predominantly found associated with Fusarium head blight (FHB) in wheat and other small-grain cereals all over Europe are F. graminearum, F. avenaceum and F. culmorum. Among the less frequently encountered species are several others which are less pathogenic or opportunistic, but also toxigenic. These include F. poae, F. cerealis F. equiseti F. sporotrichioides F. tricinctum and, to a lesser extent, F. acuminatum F. subglutinans F. solani F. oxysporum F. verticillioides F. semitectum and F. proliferatum. The species profile of FHB is due to several factors, primarily climatic conditions, particularly rain and the temperature at flowering stage, but also agronomic factors, such as soil cultivation, nitrogen fertilization, fungicides, crop rotation, and host genotype. The most frequently encountered Fusarium mycotoxins in FHB in Europe has proved to be deoxynivalenol and zearalenone produced by F. graminearum and F. culmorum with the former more common in southern (warmer) and the latter in northern (colder) European areas. Nivalenol was usually found associated with deoxynivalenol and its derivatives (mono-acetyldeoxynivalenols), together with fusarenone-X, formed by F. graminearum F. cerealis F. culmorum and, in northern areas, by F. poae. Moreover, from central to northern European countries, moniliformin has been consistently reported, as a consequence of the widespread distribution of F. avenaceum whereas the occurrence of T-2 toxin derivatives, such as T-2 toxin and HT-2 toxin, and diacetoxyscirpenol have been recorded in conjunction with sporadic epidemics of F. sporotrichioides and F. poae. Finally, beauvericin and various enniatins have recently been found in Finnish wheat colonized by F.avenaceum and F. poae.