适期早栽和追肥前移对烤烟产质量的影响

为研究移栽时期和追肥时期对烤烟产质量的影响,以移栽时期、追肥时期二因素进行裂区试验,研究了不同处理对烤烟生长发育、烤后烟叶内在化学成分协调性、烤后烟叶物理特性和经济性状等方面的影响。结果表明:随着移栽期的推迟,大田生育期逐渐缩短。随着追肥时间的提前,各处理生育期相应缩短;适期早栽和追肥前移对烤烟品质的提高有积极影响,烟叶的物理性状以提前10 d膜下井窖式深栽+移栽之后30 d内完成氮素追肥和提前10 d膜下井窖式深栽+移栽之后25 d内完成氮素追肥最适宜;各处理产量差异不大,产值、均价、上等烟和中上等烟比例均随着移栽时期和追肥时期的提前而增大,提前10 d膜下井窖式深栽+移栽之后30 d内完成氮素追肥的栽培组合最适宜当地的烤烟生产。     

罗平县植烟土壤主要养分分析及施肥建议

为了提高罗平烟区土壤养分管理水平,对其烟植烟土土壤主要养分现状进行了调查,采集210个土壤样本进行主要养分含量分析测试,结果表明土壤全氮平均为2.03 g/kg,碱解氮161.89 mg/kg,全磷1.64 g/kg,速效磷40.6 mg/kg,全钾13.7 g/kg,速效钾263.19 mg/kg。全氮和碱解氮含量偏高,全磷和速效磷含量较丰富,全钾含量偏低,速效钾含量丰富。针对罗平烟区土壤养分状况,建议适当控制氮肥用量,稳定磷肥和钾肥用量。     

有机物料对烤烟农艺性状、产量及叶绿素降解的影响

以烤烟品种G80为材料,在土壤中添加6种不同有机物料,研究其对烤烟农艺性状、产量及叶绿素含量的影响。结果表明:(1)添加有机物料对烤烟生长农艺性状影响较小;(2)常规施肥基础上增加有机物料施用不利于烟叶成熟落黄,同一氮素水平下增加有机物料比例可降低成熟期叶绿素含量,减缓成熟前期叶绿素降解速率,加快后期降解速率;(3)增施有机物料可提高烟叶经济效益;(4)基肥减施9 g/株,同时添加生物碳(100 g/株)和饼肥(20 g/株)处理表现最好,成熟期叶绿素含量最低,6月23日前降解速率最慢(18.59%),6月23日之后降解速度最快(14.17%和28.08%),产量、产值、上等烟比例和均价分别比对照高11.10%、38.20%、143.29%和19.53%,说明该处理有利于烟株成熟落黄及经济效益提升。     

二次打顶对烤烟经济性状及化学成分的影响

以秦烟96为试验材料,研究了二次打顶措施对烤烟经济性状及化学成分的影响。结果表明,烤烟二次打顶后,产量略有降低,平均减少5.55%,但产值、均价和中上等烟比例都大幅提升,平均分别增加了7.02%、13.33%、8.35%。这表明二次打顶可不同程度上影响各部位烟叶化学成分含量,改善化学成分协调性。     

钾肥不同基追比对烤烟K326烟叶品质的影响

在钾肥用量不变的前提下,为明确钾肥的最佳基追比例,通过梯度对比试验,比较了钾肥不同基肥与追肥配比对K326烟叶的外观质量、内在化学成分及感官评吸的影响。结果表明:在钾肥的基肥与追肥配比为4︰6时,烤后烟叶的成熟度、颜色、叶片结构、油分及色度均有改善,烟叶的外观质量达到最优;烟叶的总糖和还原糖含量增加,总氮和烟碱含量有所增加但均处于合理范围,同时各项化学成分指标更趋于协调;增加了烟叶的香气质和香气量,减小了刺激性和杂气,改善烟叶吃味。综合考虑钾肥不同基追比对烟叶品质的影响,建议在生产中钾肥的基肥和追肥配比为4︰6,以提高烟叶工业可用性。     

嘉禾烟区云烟99适宜留叶数与上部叶采收方式研究

通过考察农艺性状、经济性状与烤后烟叶化学成分,初步研究了烤烟品种云烟99在郴州嘉禾的适宜留叶数与上部叶采收方式。结果表明:留叶17片和留叶15片处理的云烟99烟株农艺性状差异不明显,但留叶17片处理的上中等烟比例、均价和产值分别较留叶15片处理的高3.2个百分点、3.9%和4.8%,其中产值提高显著;留叶17片和留叶15片处理烤后烟叶化学成分含量有一定差异,留叶15片处理还原糖与钾含量更接近优质烟标准,而留叶17片处理烟碱含量更接近优质烟标准。上部叶采收方式对云烟99烟株农艺性状影响不明显,上部叶一次采收处理的产量与产值较常规分次采收处理略有下降,但有利于提高上部烟叶质量,主要表现为钾含量提高和烟碱含量降低。这表明云烟99在郴州嘉禾烟区种植的适宜留叶数为17片,同时上部叶一次采收是可行的。     

Histological Features of Parotid Gland of Albino Rats Exposed to Smokeless Tobacco

Smokeless tobacco is very common personal habit of people living in various areas of Asia which is an alarming sign for the development of different oral diseases in such people.The aim of present study was to investigate effects of smokeless tobacco on parotid glands of the Aalbano rats by using various percentages of the smokeless tobacco.The rats were divided into three different groups,control group(A) no smokeless tobacco,experimental group(B) 5%smokeless tobacco and experimental group(C) 10%of smokeless tobacco with different feeds required according parameters.Weekly weight gain and partid gland were analyzed through student P test and histological structures were recorded through HE stain and Retculin stain.The results showed that as compared to control group body,weight of the rats was decreased in groups B and C having smokeless tobacco percentage in the diet.Weight of parotid gland as compared to control group was decreased in groups B and C with diet of smokeless tobacco.Further,histological observation under HE stain showed that parotid gland of group B showed mild narrowing of ductal lumen,collapse of vessels and stromal was also increased,in group C parenchymal tissues with loss of acini found damaged and glandular dystrop and lymphatic infiltration were determined moderate to severe.Meanwhile,reticulin stain showed that vascular collapses were shown because of increasing in stromal glandular atrophy in group C as compared to control group.In conclusion,this study showed that smokeless tobacco caused serious injuries in the tissue level in parotid gland with high percentage of smokeless tobacco which highlight health hazards on its consumption.     

热应激环境下育成鸡肠道菌群多样性及黏膜结构的相关性分析

为分析热应激环境下育成鸡肠道菌群以及黏膜结构的变化,揭示热应激下家禽肠道中正常菌群定植与黏膜结构变化的相关性,选取健康状况相似的10周龄日照琅琊鸡96只,设适温对照组((24±1)℃,Ⅰ)和高温组((38±1)℃),随机分在2个人工环境气候舱中饲养,试验期为14d。采用16SrDNA PCR-DGGE技术,分析热应激处理后1d(Ⅱ)、7d(Ⅲ)和14d(Ⅳ)时十二指肠、空肠及回肠部位内容物细菌群落多样性以及组织黏膜形态变化、肠黏膜上皮内杯状细胞数量。结果表明:热应激持续时间越长,对回肠部位菌群影响越大,Ⅲ组十二指肠与回肠部位优势细菌菌群组成分离明显;Ⅳ组十二指肠、空肠与回肠部位优势细菌菌群组成具有明显差异。不同热应激时段在空肠部位可检测到罗伊氏乳杆菌(Lactobacillus reuteri)、螺旋链霉菌(Streptomyces spiralis)、Plebeius杆菌属细菌(Bacteroides plebeius strain)和嗜酸乳杆菌(L.acidophilus),而回肠部位可检测到拟杆菌属(Bacteroidetes)和不可培养的细菌等;Ⅲ组十二指肠、空肠和回肠的绒毛长度、宽度、隐窝深度及绒毛高度/隐窝深度(V/C)均发生了明显的变化,各肠段的绒毛长度均明显下降,其中回肠绒毛长度减少最为显著(P0.05);十二指肠、空肠隐窝深度及V/C均出现明显下降(P0.05),各肠段肠壁厚度均显著比对照组低(P0.05)。Ⅲ组空肠和回肠内杯状细胞的数量明显减少,其中回肠差异显著(P0.05)。结果显示,热应激对育成鸡各肠段细菌菌群组成的影响很大,并且黏膜组织结构发生了明显变化,从而破坏消化道菌群平衡,导致消化吸收功能严重受阻。     

外源一氧化氮对铝胁迫下烟草叶片光能利用和光保护系统及活性氧代谢的影响

以云烟100(耐铝)和云烟105(铝敏感)为材料,采用水培法研究外源一氧化氮(NO)对铝胁迫下烟草植株生长、叶片活性氧含量、光合特性、叶绿素荧光参数、光呼吸和抗氧化酶活性的影响。结果表明,铝胁迫显著降低了烟草叶片叶绿素含量、净光合速率(Pn)、最大光化学效率(Fv/Fm)、PSII光合电子传递量子效率(FPSII)和光化学猝灭系数(q P),提高了反应中心PSII过剩激发能,从而导致叶片超氧阴离子(O_2·)和过氧化氢(H_2O_2)含量升高,植株生物量下降。外源NO可显著提高铝胁迫下烟草叶片叶绿素含量、Pn、Fv/Fm、FPSII、q P和植株生物量,降低反应中心PSII过剩激发能和叶片O_2·、H_2O_2含量,且云烟105变化幅度高于云烟100。此外,外源NO还显著提高了铝胁迫下烟草叶片非光化学猝灭系数、光呼吸速率、超氧化物歧化酶和抗坏血酸过氧化物酶活性,说明NO可通过提高烟草叶片光化学反应能力、热耗散、光呼吸以及抗氧化酶活性来降低反应中心PSII过剩激发能,防止或清除叶绿体内产生的活性氧,缓解铝对烟草的毒害,这种缓解效应在敏感基因型云烟105中表现更明显。     

Development of a quantitative PCR assay for monitoring Streptococcus agalactiae colonization and tissue tropism in experimentally infected tilapia

Streptococcus agalactiae has become one of the most important emerging pathogens in the aquaculture industry and has resulted in large economic losses for tilapia farms in China. In this study, three pairs of specific primers were designed and tested for their specificities and sensitivities in quantitative real‐time polymerase chain reactions (qPCRs) after optimization of the annealing temperature. The primer pair IGS‐s/IGS‐a, which targets the 16S‐23S rRNA intergenic spacer region, was finally chosen, having a detection limit of 8.6 copies of S. agalactiae DNA in a 20 μL reaction mixture. Bacterial tissue tropism was demonstrated by qPCR in Oreochromis niloticus 5 days post‐injection with a virulent S. agalactiae strain. Bacterial loads were detected at the highest level in brain, followed by moderately high levels in kidney, heart, spleen, intestines, and eye. Significantly lower bacterial loads were observed in muscle, gill and liver. In addition, significantly lower bacterial loads were observed in the brain of convalescent O. niloticus 14 days post‐injection with several different S. agalactiae strains. The qPCR for the detection of S. agalactiae developed in this study provides a quantitative tool for investigating bacterial tissue tropism in infected fish, as well as for monitoring bacterial colonization in convalescent fish.