冬小麦苗期氮素吸收利用生理指标的综合评价

为了快速筛选冬小麦耐低氮品种,本研究通过对两种氮素水平下15个冬小麦品种苗期的株高、根长、干物质、植株氮积累量等多项生理指标的测定,以各项指标的耐低氮指数作为衡量耐低氮性的指标,利用主成分分析和聚类分析对其耐低氮性进行综合评价。结果将9个单项生理指标综合成为4个相互独立的综合指标,并通过聚类分析将15个基因型划分为3类:新冬18号、新冬15号、石4185属耐低氮类型;石家庄8号、新冬7号、偃展4110、河农9901、邯5316、新冬28号属中间类型;新冬3号、新乡9408、新冬23号、石审6185、豫麦34号、郑9023属低氮敏感类型,三个类群之间植株干重和植株氮积累量的耐低氮指数在0.05水平上差异显著。     

Assessment of Brown Planthopper, (Nilaparvata lugens) [Stål], damage in rice using hyperspectral remote sensing

Hyperspectral remote sensing was used to detect stress on potted rice plants caused by the Brown Planthopper (BPH), Nilaparvata lugens (Stål). BPH damage influenced reflectance of rice plants compared to uninfested plants in the visible and near-infrared regions of the electromagnetic spectrum. Correlations between plant reflectance and BPH damage, when plotted against wavelengths, enabled us to identify four sensitive wavelengths, at 1986, 665, 1792 and 500 nm, in relation to BPH stress on rice plants. Based on rice plant reflectance corresponding to the sensitive wavelengths, three hyperspectral indices were developed. The BPH damage showed a positive association with normalized pigment chlorophyll index, and a negative relationship with normalized difference vegetation index and soil adjusted vegetation index. Using rice plant reflectance corresponding to the sensitive wavelengths, a multiple-linear regression model was developed and validated, which would facilitate assessment of BPH damage based on rice plant reflectance, thereby ensuring prompt forewarning to stakeholders.     

三种气象干旱指标在内蒙古地区的适用性分析

用近五年(2006～2010)内蒙古地区的气象观测资料,对降水距平百分率(pa)、相对湿润度干旱指数(M)和标准化降水指数(SPI)三种气象干旱等级指标的适用性进行了对比分析。发现在作物生长季,pa指标和SPI指数对旱情的评判结果高度一致,而冬春季节则是pa指标和M指数的评判结果比较一致。在多雨季节,可能蒸散量通常比同期降水量小,因此M指数对内蒙古夏季旱情评判等级偏低,不宜使用。同时指出应该将不同时间段干旱影响上的差异,以及干旱灾害的累积效应问题,加入到干旱等级指标的改进中。     

青藏高原地区冷季补饲对牦牛生产性能和血液生化指标的影响

本试验旨在探究冷季放牧牦牛补饲对生长性能和血液生化指标的影响。试验选取健康牦牛120头,分为对照组（放牧）和补饲组（放牧+补饲）共8组,每组15头牦牛,试验期为120天,其中预饲期7天。结果表明,与放牧组相比,补饲组牦牛日增重均显著提高(P<0.05),并且,随着补饲量的升高,增重呈线性增加;补饲对放牧牦牛血液生化指标均无显著影响(P>0.05);补饲能量料每头牦牛每天净收入为4.93元,显著高于放牧组的1.69元,全期可比放牧组多收入388.80元。随着补饲料添加量增加,每头牦牛毛收入也显著增加(P<0.05),补饲0.4%混合料的净收入最高,较放牧组可多收入247.20元。综上所述,冷季对放牧牦牛进行补饲,不仅可以缓解由于饲料短缺带来的体重下降,并且对牦牛健康不会带来负面影响,同时可以提高牦牛养殖的经济效益。     

应用型本科食品专业“生化分离工程”教学改革探索与实践

专业选修课开设的目的是为了扩展学生知识面,启发学生创新思维,拓宽学生的就业领域。"生化分离工程"是食品科学与工程专业的一门重要的专业选修课。随着生物技术的快速发展和生物技术产业崛起,生化分离技术日益受到重视,生物技术人才也备受企业青睐。地方性应用型本科院校为培养具有创新能力、符合企业需求的高素质人才,对"生化分离工程"的教学改革必不可少。通过革新教学内容和教学方法、改革课程考试方式等方式进行课程教学改革,激发学生兴趣,提高教学成效,为食品专业毕业开拓更宽的就业领域奠定基础。     

二次杀菌方式对红肠在冷藏过程中微生物及理化性质影响的研究

为研究常压杀菌方式对红肠在冷藏过程中理化及微生物指标变化的影响,将加工好的红肠真空包装后分为3组,分别为对照组(CK)、一次杀菌组和二次杀菌组。将3组红肠置于0~4℃条件下冷藏9周,分别在0、3、5、7、9周取样分析各组的理化指标(pH、硫代巴比妥酸反应物(TBARs)值、水分迁移变化、亚硝酸盐残留量)和微生物指标(细菌总数、肠杆菌科菌、假单胞菌、乳酸菌)的变化。结果表明:随着冷藏时间的延长,各组红肠样品中微生物数量、TBARs值和pH均有不同程度的升高趋势,亚硝酸盐残留量呈降低趋势;与CK组相比,各冷藏时间点的一次杀菌组和二次杀菌组红肠中的细菌总数、肠杆菌科菌、假单胞菌、乳酸菌数量和TBARs值、亚硝酸盐残留量均显著低于CK组(P<0.05),且二次杀菌组显著低于一次杀菌组(P<0.05);从水分迁移的变化来看,二次杀菌的红肠,初始横向驰豫时间T₂₂由CK组的37.649 ms升至41.408 ms,说明不易流动水向右发生了微弱的迁移现象,肌肉蛋白对水分约束力略有下降。由此说明,常压杀菌尤其是经过二次杀菌的红肠,其微生物指标、脂肪氧化程度、亚硝酸盐残留量显著降低,呈现出显著的优势,提高了红肠的食用安全性。     

Insecticide-induced resurgence of the whitebacked planthopper Sogatella furcifera (Horvath) (Hemiptera: Delphacidae) on rice varieties with different levels of resistance

The influences of the insecticides quinalphos, chlorpyriphos, methyl parathion, endosulfan, imidacloprid and deltamethrin applied three times at 10 days intervals at half of their recommended field concentrations to potted plants of a planthopper-susceptible and a planthopper-resistant rice variety, on reproduction and survival of whitebacked planthopper, Sogatella furcifera (Horvath), and on the chemistry of its host plant, were investigated. Methyl parathion, deltamethrin and quinalphos enhanced the fecundity of the hopper (164-211 vs. 131 for the control) and consequently the resurgence ratio (increased up to 1.75 fold). Methyl parathion and deltamethrin significantly increased nymphal survival (59.3 vs. 52.2% for the control) and the growth index (4.8 vs. 4.2 for the control) of the hopper. The sex ratios of adults emerging on methyl parathion- and deltamethrin-treated rice plants increased in favour of females (1.51 vs. 1.15 for the control) on the susceptible variety but was not altered on the resistant variety. Biochemical analyses of the rice leaves revealed significantly higher quantities of reducing sugars, proteins and amino acids, but lower amounts of total phenols in leaf sheaths and blades of methyl parathion-, deltamethrin- and quinalphos-treated plants of the two varieties. The leaf sheaths and blades of the resistant variety contained more than twice the total phenols present in those of the susceptible variety. The results showed a positive correlation between increased levels of reducing sugars, amino acids and proteins in the rice plants and the fecundity of S. furcifera and a negative correlation between phenol contents of the rice plants and fecundity.     

低温胁迫对烟草幼苗生化指标的影响及相关性分析

研究了不同胁迫温度对不同类型烟草幼苗(ZY08-4、野生种、栖霞晒烟、K326)生化指标的影响,测定了MDA、游离脯氨酸、可溶性糖、可溶性蛋白等生化指标并对各指标间的相关性进行了分析。结果表明:除对照K326外,3个品种(系)幼苗的游离脯氨酸、可溶性糖含量均随处理温度的降低与胁迫时间的延长呈增加的趋势;MDA、可溶性蛋白则表现出相反的变化,各生化指标间的相关性也达到了极显著性差异。     

Competition effects in an afrotemperate forest

Background： Information about competition responses is mainly available for monospecific stands or mixed stands with a small number of species. Studies on complex multi-species and highly structured forest ecosystems are scarce. Accordingly, the objective of this study was to quantify competition effects and analyse competition responses in a species-diverse afrotemperate forest in South Africa, based on an observational study with mapped tree positions and long-term diameter increment records. Methods： The sensitivity to competition was analysed for individual species and involved the calculation of the slope of the linear relation between the value of a competition index （CI） and diameter growth as a measure of sensitivity. In a next step different competition indices were combined and tree diameters were grouped in three classes as surrogates for canopy status and ontogenetic stage. Results： Five competition indices were found to be effective in showing sensitivity to competition for a number of canopy and sub-canopy species. Significant linear regressions were fitted for 18 of a total of 25 species. Species reactions varied significantly in their sensitivity to the different CIs. The indices were classified as belonging to two groups, those that responded more to local crowding and those that are more sensitive to overtopping, which revealed species-specific sensitivities to both factors. The analysis based on diameter classes revealed that species clearly changed their sensitivity to crowding or overtopping depending on diameter. Canopy and sub-canopy species showed distinct differences in their reactions. Conclusions： The application of multiple CIs brought novel insights relating to the dynamics of afrotemperate forests. The response patterns to different competition indices that focus on crowding and overtopping are varied and tree diameter dependent, indicating that oversimplified assumptions are not warranted in the interpretation of Cl- growth relations.     

烤烟湿润育苗不同营养供应模式对烟苗生长及生理指标的影响

[目的]研究烤烟湿润育苗不同营养供应模式和不同营养供应时期对烟苗生长及生理指标的影响.[方法]3种营养供应模式分别为“全浇式”（整个育苗过程中把专用营养液配成一定浓度的营养液浇施盘面并淋清水）、“全灌式”（整个育苗过程把专用营养液配成一定浓度的营养液灌施到营养池中）、“分段式”（在烟苗封盘前把专用营养液配成一定浓度的营养液灌施到营养池中,封盘后把专用营养液配成一定浓度的营养液浇施盘面并淋清水）,3种营养供应时期分别为播种后出苗前、出苗后、小十字期,各处理N供应量分别为100 mg/kg.[结果]烤烟湿润育苗“分段式”营养供应模式和播种后出苗前开始供应营养出苗率更高,出叶速度更快,根系更发达,根系活力更高,束缚水含量更高,烟苗综合素质更高.[结论]播种后出苗前开始供应营养不会抑制种子萌发出苗,可为烟叶生产上应用湿润育苗培育出高素质的烟苗提供依据.