盐碱胁迫对"丰花2号"花瓣多酚类物质的影响     

卫乐  姚爱兵  孙福华  弓泽涛  张嘉新  李锦馨 《北方园艺》2021,(17):81-89

以"丰花2号"玫瑰为试材,设置不同浓度(0.2％、0.4％和0.6％)的NaCl、Na2CO3、NaCl和Na2CO3(1∶1)9个胁迫处理,以清水为对照,研究了不同处理下"丰花2号"花瓣多酚、黄酮及花青素的含量,及在不同胁迫处理下的时间响应规律,以期为北方盐碱地区玫瑰产业的科学田间管理,提高花瓣保健性物质水平提供参考依据.结果 表明:随着处理的进行,"丰花2号"花瓣多酚、黄酮及花青素含量变化呈先增加后降低的趋势,NaCl、Na2CO3胁迫与"丰花2号"花瓣多酚、黄酮及花青素含量存在相关性.多酚分别在0.6％NaCl胁迫第2周增加最多,增加了12.1％;0.4％Na2CO3胁迫在第1周增加最多,增加了8.2％;0.4％NaCl和Na2CO3混合胁迫第1周增加最多,增加了9.1％;在胁迫第4周以后会明显抑制多酚的合成.黄酮分别在0.4％ NaCl胁迫第1周增加最多,增加了23.1％;0.6％Na2CO3在第3周增加最多,增加了19.9％;0.2％NaCl和Na2CO3混合胁迫第1周增加最多;胁迫第4周以后会明显抑制黄酮的合成.花青素分别在0.6％ NaCl胁迫第3周上升最多,上升了16.1％;0.2％Na2CO3胁迫在第2周增加最多,增加了9.6％;0.6％NaCl和Na2CO3在胁迫第2周上升最多,上升了17.8％;在胁迫第5周以后会明显抑制花青素的合成.  相似文献   

Visualization of the Anticaging Effect of Ronozyme WX Xylanase on Wheat Substrates     

Duy Michael Le  Peter Fojan  Elisabeth Azem  Dan Pettersson  Ninfa Rangel Pedersen 《Cereal Chemistry》2013,90(5):439-444

A fluorescence microscope was used for visualization of the anticaging effect of a commercial xylanase on milled wheat, microtome cuts of wheat grains, and digesta samples obtained from piglets 1 or 4 h after feeding a wheat‐based diet (wheat 490 g/kg of diet, barley 100 g/kg of diet, and oats 100 g/kg of diet). Both starchy endosperm and aleurone cell walls were shown to be broken down by Ronozyme WX commercial xylanase. Data obtained by fluorescence microscopy was supplemented with measurements of starch and xylose released as a result of degradation of nonstarch polysaccharides by the xylanase. The results visualize and provide evidence that Ronozyme WX commercial xylanase can overcome the so‐called cage effect. This release of nutrients from their encapsulation in cereal cell wall structures has positive impact on nutrient digestibility and partially explains the positive effect of xylanase supplementation on livestock performance.  相似文献   

眼斑双锯鱼形态性状与体质量的相关性及通径分析          下载免费PDF全文

王海山  叶乐  胡清雨  符美好  肖子鸿 《南方农业学报》2021,52(1):221-227

【目的】评估人工养殖条件下影响眼斑双锯鱼（Amphiprion ocellaris）体质量的形态性状,并建立体质量与主要形态性状的多元回归方程,为眼斑双锯鱼快速生长品系选择育种工作的开展提供参考依据。【方法】以人工养殖的2月龄眼斑双锯鱼为研究对象,准确测定其体质量（W）及全长（L₁）、体长（L₂）、体高（L₃）、头长（L₄）、头高（L₅）、吻长（L₆）、尾柄长（L₇）、尾柄高（L₈）、背鳍前距（L₉）、胸鳍前距（L₁₀）、腹鳍前距（L₁₁）和臀鳍前距（L₁₂）等12个形态性状,运用相关分析计算各表型性状间的相关系数,应用通径分析筛选显著影响体质量的形态性状,并通过多元回归分析构建形态性状与体质量的多元回归方程,分析眼斑双锯鱼形态性状对体质量的影响。【结果】13个表型性状间均存在极显著相关性（P< 0.01）,与体质量相关系数最大的是体高（0.965）,其次是尾柄高（0.944）,与体质量相关系数较小的是吻长（0.730）和尾柄长（0.601）;剔除共线性影响后,通径分析筛选出对体质量影响显著的5个形态性状分别是体高、尾柄高、体长、头长和吻长。其中,对体质量的直接作用（通径系数）排序为体高（0.574）>体长（0.404）>尾柄高（0.284）>吻长（0.108）>头长（-0.358）,间接作用（间接通径系数）排序为头长（1.256）>尾柄高（0.667）>吻长（0.621）>体长（0.540）>体高（0.391）;对体质量的单独决定系数排序为体高（0.330）>体长（0.163）>头长（0.128）>尾柄高（0.081）>吻长（0.012）。体质量与体高、尾柄高、体长、头长和吻长等5个形态性状的多元回归方程为W=-0.708+0.085L₃+0.084L₈+0.025L₂-0.090L₄+0.070L₆,R2=0.963。【结论】体高可作为以2月龄眼斑双锯鱼选育快速生长品系的首选目标性状,体长、头长、吻长和尾柄高等变量则可作为辅助选择性状。  相似文献   

中国罗非鱼产业的国际地位及对外贸易评价   总被引：3，自引：0，他引：3  

骆乐  何韬 《渔业经济研究》2006,(3):27-30

分析我国罗非鱼产业在国际上的比较优势和竞争优势,通过分析近年贸易数据特点及走势,总结我国罗非鱼外贸特征。在此基础上,提出如何稳定增加罗非鱼产品出口,规避贸易风险的建议。  相似文献   

草鱼淋巴器官中的肥大细胞   总被引：16，自引：0，他引：16       下载免费PDF全文

许乐仁 《水产学报》2003,27(3):233-237

通过组织化学与形态学研究首次在草鱼的胸腺和头肾等淋巴器官中证实了肥大细胞的存在。草鱼肥大细胞的染色性质在某些方面似乎类似于哺乳动物的粘膜肥大细胞。Carnoy氏液及阿尔新蓝分别是优良的固定剂及染料，而中性缓冲甲醛却完全阻断草鱼肥大细胞的着染。值得注意的是一些曾被用于鉴定硬骨鱼肥大细胞(或嗜酸性颗粒细胞)的组织化学技术在本研究中未能检出草鱼肥大细胞。电镜下证实，草鱼肥大细胞中含有大量特征性的胞浆颗粒，其中充满无定形颗粒状基质，基质电子密度有的较高，有的较低，但未见特殊的亚微结构。  相似文献   

The temporal trend of urban green coverage in major Chinese cities between 1990 and 2010     

Jun Yang  Conghong Huang  Zhiyong Zhang  Le Wang 《Urban Forestry & Urban Greening》2014,13(1):19-27

Information on changes in urban green spaces and the causes of these changes is important for urban planning. In this study the trends of urban green coverage (UGC) between 1990 and 2010 in 30 major Chinese cities were studied using classified Landsat satellite images. Associations between the trends and natural and socio-economic variables were analyzed using the maximum information-based nonparametric exploration method. The results showed that, overall, the studied cities have become greener over the past two decades. Greening in old city districts and expanded built-up areas (BUAs) led to the increase of urban green coverage at a mean annual rate of 1.51%. However rapid urbanization also caused a dramatic turn-over in vegetation covers. On a regional scale, around 46.89% of original vegetation cover was converted to other land cover types. The trends of UGC cannot be attributed to any one of natural or socio-economic variables alone. The combined influences of economic growth, climate change, and urban greening policies are the most likely causes behind the detected trend. One lesson from this study is that the preservation of existing vegetation cover must be a priority in urban greening programs.  相似文献   

Classical swine fever (CSF) marker vaccine. Trial I. Challenge studies in weaner pigs     

Uttenthal A  Le Potier MF  Romero L  De Mia GM  Floegel-Niesmann G 《Veterinary microbiology》2001,83(2):85-106

Two commercial marker vaccines against classical swine fever virus (CSFV) and companion diagnostic tests were examined in 160 conventional pigs. To test the vaccines in a "worst case scenario", group of 10 weaners were vaccinated using a single dose of an E2 (gp55) based vaccine at days -21, -14, -10 or -7, and subsequently challenged at day 0. The challenge virus was CSFV 277, originating from a recent outbreak of classical swine fever (CSF) in Germany. In all groups, only 5 out of 10 pigs were challenged; the remaining 5 pigs served as vaccinated contact controls. Also, three control groups, each consisting of 10 non-vaccinated pigs, were challenged in parallel to the vaccinated animals. CSFV could be isolated from all non-vaccinated pigs. Among these pigs 40% displayed a chronic course of the infection (virus positive for more than 10 days). Pigs vaccinated 21 or 14 days before challenge displayed no clinical signs of CSFV after challenge. However, they were still able to replicate CSFV when challenged, as measured by reisolation of CSFV from leukocytes of the directly challenged pigs. CSFV could be isolated from the leucocytes of 25% of the pigs vaccinated 21 days before challenge and 50% of the pigs vaccinated 14 days before challenge. Chronic infection was not observed, but transmission to one vaccinated contact pig occurred. From all pigs vaccinated 10 or 7 days before challenge, CSFV could be reisolated. We observed a chronic course of infection in 5% of pigs vaccinated 10 days before challenge and in 30% of pigs vaccinated 7 days before challenge. The mortality rate was 20% in the pigs vaccinated 10 days before challenge, and varied between 20 and 80% in pigs vaccinated 7 days prior to challenge. The contact animals had lower mortality (0-20%) than directly challenged pigs, probably mirroring the delayed time point of infection. There was thus some protection against clinical illness by both marker vaccines, but not a solid protection against infection and virus shedding. The efficacy of the vaccine was best if used 3 weeks before challenge and a clear correlation between time interval from vaccination to challenge and the level of virus shedding was observed. Each vaccine had its own accompanying discriminatory ELISA, but 18% of the virus positive pigs never seroconverted in these tests.  相似文献   

Comparison of selective and systematic treatments to control nematode infection of the digestive tract in dairy goats     

Hoste H  Le Frileux Y  Pommaret A 《Veterinary parasitology》2002,106(4):345-355

Resistance to anthelmintics in nematode parasite of the digestive tract is a major concern in small ruminants and particularly in goats. One possible solution to limit the development and spread of resistance is to give treatments on a selective basis, i.e. by targeting the most susceptible animals within a flock rather than treating all the animals. In dairy goats, epidemiological studies have shown that, within a flock, goats in first lactation and the multiparous ones with the highest level of milk production were highly receptive to parasite infection. The objective of the study was to assess whether selective treatments could achieve a level of control of nematodes similar to systematic drenching. A similar experimental design was applied for two successive years. An experimental flock of 120 dairy goats was divided into two groups. All the goats from group SYS (systematic treatment) were drenched at mid-grazing season (July). In contrast, anthelmintics in group SEL (selective treatment) were restricted to the goats in first lactation plus the high producers. Overall, these treated goats represented 48% of the flock in year 1 and 66% in year 2. After treatments, both groups grazed on separate pastures. Parasitological and pathophysiological measurements were performed monthly. The results indicate a similar level of egg excretion in the two groups. The pathophysiological parameters (pepsinogen and phosphate concentrations) were also similar in the two groups, as well as the milk production for the 2 years. These results suggest that a targeted use of anthelmintics may allow efficient control of gastrointestinal nematodes whilst resulting in a predicted reduction in the selection pressure for the development of anthelmintic resistance.  相似文献   

Experimental study of the mechanical behaviour of thin slices of maturating green poplar wood using cyclic tensile tests     

Guillaume Pot  Catherine Coutand  Jean-Benoît Le Cam  Evelyne Toussaint 《Wood Science and Technology》2013,47(1):7-25

In this study, longitudinal cyclic tensile tests were performed on green wood samples of Populus cv I4551. Complex mechanical behaviour, such as permanent set in terms of displacement and strain-dependent stiffness, was found. A linear relationship between stiffness and strain enabled each sample to be characterized. A large-scale experimental campaign led to the observation of the evolution of temporal and spatial intra-ring mechanical behaviour of intra-ring sliced specimens during wood maturation and tree gravitropic response. The results showed that tension wood lamellas exhibit strain hardening behaviour whereas normal wood lamellas exhibit strain softening behaviour. Temporal variations in the strain hardening behaviour of tension wood lamellas occurred once cell wall deposition was achieved. Moreover, no correlation was found between infradensity and mechanical behaviour of lamellas. These results show that cells undergo temporal variations in their properties due to a complex maturation process.  相似文献   

Drought effects on water use efficiency, freezing tolerance and survival of Eucalyptus globulus and Eucalyptus globulus × nitens cuttings     

Darío Navarrete-Campos  León A. Bravo  Rafael A. Rubilar  Verónica Emhart  Rebeca Sanhueza 《New Forests》2013,44(1):119-134

Genetic improvement of Eucalyptus genotypes for drought and frost resistance is essential for successful intensive management of commercial plantations. Understanding the physiological mechanisms that relate water use and frost resistance for highly deployed genotypes may allow for better prediction of their future performance, genetic selection and seedling management for site specific purposes. We studied whether instantaneous water use efficiency (WUE _i ) may serve as drought, freezing and photoinhibition tolerance predictor by studying its response on six E. globulus clones (Eg1–Eg6) and four E. globulus × E. nitens hybrid seedlings (Egn1–Egn4) under drought and irrigated (control) treatments. Net photosynthesis (A) and transpiration (E) were studied using a gas exchange system in order to calculate WUE _i (A/E). Simultaneous chlorophyll a fluorescence measurements were performed to assess the non photochemical quenching components. Frost tolerance of plants under control and drought treatments were evaluated by measuring temperatures that exert 50% photoinactivation of photosystem II. Finally, drought tolerance was evaluated by plant survival within each genotype after rehydration. Our results showed significant genotype variability in the rate of soil and xylem water potential decrease during drought. While most of the genotypes reached ?4.0 MPa in about 35 days of drought, genotypes Eg6 and Egn4 required 56 days of drought to reach this xylem water potential. WUE _i exhibited significant differences among genotypes and irrigation treatments. Genotypes Eg5 and Egn4 increased their WUE _i between 70 and 80% after drought. This was associated with a more conservative control of water loss at the stomatal level combined with maintenance of relatively higher rates of net photosynthesis than the other genotypes under drought conditions. Plants exposed to drought were more freezing tolerant than control plants, having in average 3°C lower LT₅₀ than well irrigated ones. There was no a clear correlation between WUE _i and drought tolerance or drought-induced photoinhibition, however WUE _i was inversely correlated with LT₅₀. Our results suggest that WUE _i is not suitable by itself to select drought tolerant genotypes, but may provide evidence for discarding drought sensitive genotypes. In addition, it could provide valuable information to select for freezing tolerance.  相似文献