樱桃番茄新品种京丹1号和京丹2号的选育

京丹1号、京丹2号是通过单株系统选择、组合试配及评比选育出的樱桃番茄新品种.其亲本品系分别是从日本商业品种和台湾品种四季红的分离后代中选出.京丹1号为无限生长类型,连续生长势强,结果习性好,单果质量8～12g,口感风味极佳,可溶性固形物7.5%以上；高抗ToMV,耐叶霉病.京丹2号是极早熟有限生长类型品种,播种后90d(天)开始收获,单果质量10～15g,可溶性固形物高于6. 0%,高抗ToMV.这两个品种已应用于北京、河北、山东和辽宁等地.     

梨授粉受精影响因素研究进展

梨树是异花授粉果树,授粉受精直接影响坐果率和收益.开展梨树授粉受精影响因素的研究,有助于选择与配置适宜的授粉树,也有助于梨树遗传育种的研究与品种改良.目前,已有许多关于梨树授粉受精影响因素的研究,现将这方面的研究进展综述如下.     

Mycobacterium szulgai infection in a captive population of African clawed frogs (Xenopus tropicalis).

A colony of captive Xenopus tropicalis became infected with Mycobacterium szulgai. Clinical signs, when observed, were lethargy, weight loss, and emaciation. Visceral granulomas were common findings at laparoscopy and necropsy. The diagnosis of mycobacteriosis was based on histologic appearance and Ziehl-Neelsen staining of tissues. The identification of M. szulgai organisms was based on comparison of the 16S rRNA gene sequence with several GenBank databases. There have been no reports of this mycobacterial species as the causative agent of naturally occurring disease in amphibians.     

Effects of dexamethasone on emesis in cats sedated with xylazine hydrochloride

OBJECTIVE: To determine antiemetic efficacy of prophylactic administration of dexamethasone and its influence on sedation in cats sedated with xylazine hydrochloride. ANIMALS: 6 healthy adult cats (3 males and 3 females). PROCEDURE: The prophylactic antiemetic effect of 4 doses of dexamethasone (1, 2, 4, and 8 mg/kg of body weight, IM) or saline (0.9% NaCl) solution (0.066 ml/kg, IM) administered 1 hour before administration of xylazine (0.66 mg/kg, IM) was evaluated. Cats initially were given saline treatment (day 0) and were given sequentially increasing doses of xylazine on days 7, 14, 21, and 28. After xylazine injection, all cats were observed for 30 minutes to allow assessment of frequency of emesis and time until onset of the first emetic episode.The influence of dexamethasone on xylazine-induced sedation in these cats also was evaluated. RESULTS: Prior treatment with 4 or 8 mg/kg of dexamethasone significantly reduced the frequency of emetic episodes and also significantly prolonged the time until onset of the first emetic episode after xylazine injection. Time until onset of the first emetic episode also was significantly prolonged for dexamethasone at a dose of 2 mg/kg. Time until onset of sedation after administration of xylazine was not altered by administration of dexamethasone. CONCLUSIONS AND CLINICAL RELEVANCE: Dexamethasone (4 or 8 mg/kg, IM) significantly decreased the frequency of emetic episodes induced by xylazine without compromising sedative effects in cats. Dexamethasone may be used prophylactically as an antiemetic in cats treated with xylazine.     

天水市蔬菜大棚土壤重金属污染特征及生态风险评价

[目的] 对甘肃省天水市蔬菜大棚土壤重金属污染程度和生态风险进行评价,为该地区设施农产品安全生产提供科学依据。[方法] 以天水市大棚蔬菜主产区21个乡镇的362个土壤样品为研究对象,用电感耦合等离子体质谱仪（ICP-MS）测定As,Ni,Cu,Zn,Cd,Pb,Hg含量,采用内梅罗综合污染指数和潜在生态风险指数对蔬菜大棚土壤重金属环境质量和潜在生态风险进行评价;利用相关分析和主成分分析对土壤重金属的可能来源进行探讨。[结果] ①7种元素平均含量均未超出《土壤环境质量农用地土壤污染风险管控标准（试行）》（GB15618-2018）的土壤风险筛选值;但与甘肃省土壤背景值相比,Cu,Zn,Cd,Pb和Hg积累普遍,分别是背景值的1.9,1.4,3.1,1.3,5.2倍;②内梅罗综合污染指数平均值为0.508,9.9%的点位出现了轻度和中度污染;多金属潜在生态风险指数的平均值为289,Hg对潜在生态风险指数的贡献率为61.3%;③7种元素被识别出3个主成分。[结论] 蔬菜大棚土壤重金属90%以上点位处于安全水平,潜在生态风险为轻微—中度等级,Hg是最大的潜在风险因子。重金属轻度、中度污染和潜在生态风险强、极强的点位较为集中的分布在耕作年限高、人口密集的城镇和交通沿线。     

施肥对糜子密度、 产量及农艺性状的影响

为了研究提高糜子产量的途径,采用随机区组试验设计,设施肥处理和不施肥处理两组试验,对施肥对糜子出苗密度、产量及农艺性状影响进行研究.结果表明:施肥处理10个糜子品种出苗密度和出苗分蘖后单株密度分别低于不施肥处理7777.5丛/hm2、23888.6株/hm2.在本研究情况下,施肥处理产量小于不施肥产量467.7 kg/hm2,密度对于提高单位面积产量具有至关重要的作用.不同糜子的穗长、株高、地上生物量、单穗粒重、千粒重、茎粗受施肥影响不同,有的增加,有的减小.施肥处理10个糜子品种的穗长、株高、地上生物量和不施肥处理之间差异均没有达到显著水平.部分品种施肥处理单穗粒重、千粒重、茎粗与不施肥处理之间达到了显著性差异,施肥处理茎粗均高于不施肥处理.糜子群体在一定的生存空间范围内,种群密度随时间的增长符合逻辑斯蒂模型,研究中施肥处理会造成糜子烧苗.     

多糖、寡糖、蛋白酶对凡纳滨对虾生长、消化酶活性及血清非特异性免疫的影响

在基础饲料(对照组)中分别添加0.2%β-葡聚糖、0.05%黄芪多糖、0.4%甘露寡糖、175 mg/kg蛋白酶PT,饲喂初始体重为(4.55±0.08)g的凡纳滨对虾(Litopnnaus vannamei)6周,考察对凡纳滨对虾生长性能、血清非特异性免疫及消化酶活性的影响。结果表明:与对照组相比,饲料中添加0.2%β-葡聚糖、0.4%甘露寡糖及175 mg/kg蛋白酶PT可分别提高凡纳滨对虾增重率16.19%、12.78%、11.25%(P<0.05),降低饲料系数0.10、0.09、0.09(P<0.05);各处理组在肌肉水分、灰分、粗脂肪和粗蛋白含量上无显著差异(P>0.05);在血清非特异性免疫方面,各多糖、寡糖和蛋白酶添加组均显著提高血清酚氧化酶活力(P<0.05),添加0.4%甘露寡糖可提高溶菌酶、碱性磷酸酶活力(P<0.05),添加0.2%β-葡聚糖、0.4%甘露寡糖可显著提高超氧化物歧化酶活力(P<0.05);在消化酶活性方面,添加175 mg/kg蛋白酶PT可显著提高肝胰脏蛋白酶、脂肪酶和肠蛋白酶活性(P<0.05),添加0.2%β-葡聚糖及0.4%甘露寡糖可显著提高胃蛋白酶和肝胰脏脂肪酶活性(P<0.05)。上述结果表明,饲料中添加0.2%β-葡聚糖、0.4%甘露寡糖、175 mg/kg蛋白酶PT可提高凡纳滨对虾生长性能、改善消化酶活性,葡聚糖和甘露寡糖还具有改善血清非特异性免疫的功能,而添加0.05%黄芪多糖对凡纳滨对虾增重率、血清非特异性免疫无显著影响。     

石榴筒状花和钟状花生化指标研究

本文对石榴筒状花和钟状花花蕾期花瓣、花药和子房中的过氧化物酶同工酶等生化指标进行了分析,结果表明:筒状花子房的过氧化物酶同工酶活性比钟状花的强;而花药则相反;筒状花子房中可溶性糖、可溶性蛋白质和核酸含量皆显著高于钟状花。作者推测,钟状花的形成与营养供给不足有着直接的关系。     

Barley yellow dwarf virus-infected wheat plant modulated selection behavior of vector aphids

Journal of Pest Science - Evolution of the spread strategies of plant pathogens may be described using the vector manipulation hypothesis (VMH), which posits that pathogens can enhance their...     

甘蔗的抗盐育种技术Ⅱ．盐分胁迫下甘蔗性状的遗传特点和配合力分析

甘蔗５×４不完全双列杂交后代的盆栽试验结果表明,甘蔗株高、茎径、有效茎数、节间长、单茎重、出汁率、锤度和盆产糖量８个性状的抗盐遗传主要是由基因加性效应决定的,而盆产蔗量、重力纯度、蔗汁蔗糖分和甘蔗蔗糖分４个性状的抗盐遗传则主要受基因非加性效应所控制．性状的父本ｇｃａ方差多数大于母本ｇｃａ方差,说明甘蔗抗盐育种中父本选择的重要性．品质性状的ｈ￣２Ｂ多在６０％以上,暗示它们在早期阶段选择效果较好．研究发现,ＣＰ７２—１２１０、崖７１─３７４和崖７３—５１２多数性状的ｇｃａ效应值高,可认为是较理想的抗盐亲本．根据性状的ｔｃａ,筛选出ＣＰ７２—１２１０×崖７１—３７４、ＣＰ７２—１２１０×崖７３—５１２、新台糖１号×崖７３—５１２、ＣＰ５７—６１４×崖７１─３７４和ＣＰ６７－４１２×崖７３—５１２等５个抗盐组合．