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21.
Genetic parameters for chronic progressive lymphedema (CPL)‐associated traits in Belgian Draught Horses were estimated, using a multitrait animal model. Clinical scores of CPL in the four limbs/horse (CPLclin), skinfold thickness and hair samples (hair diameter) were studied. Due to CPLclin uncertainty in younger horses (progressive CPL character), a restricted data set (D_3+) was formed, excluding records from horses under 3 years from the complete data set (D_full). Age, gender, coat colour and limb hair pigmentation were included as fixed, permanent environment and date of recording as random effects. Higher CPLclin certainty (D_3+) increased heritability coefficients of, and genetic correlations between traits, with CPLclin heritabilities (SE) for the respective data sets: 0.11 (0.06) and 0.26 (0.05). A large proportion of the CPLclin variance was attributed to the permanent environmental effect in D_full, but less in D_3+. Date of recording explained a proportion of variance from 0.09 ± 0.03 to 0.61 ± 0.08. Additive genetic correlations between CPLclin and both skinfold thickness and hair diameter showed the latter two traits cannot be used as a direct diagnostic aid for CPL. Due to the relatively low heritability of CPLclin, selection should focus on estimated breeding values (from repeated clinical examinations) to reduce CPL occurrence in the Belgian Draught Horse.  相似文献   
22.
A 4‐year‐old intact male ferret was presented to the Ophthalmology Service of the Department of Clinical Sciences of Companion Animals of Utrecht University with chronic blepharospasm, epiphora, and conjunctivitis of the right eye. Examination of the eye revealed mild conjunctivitis and three hairs protruding from the openings of meibomian glands in the upper eyelid, providing the clinical diagnosis of distichiasis. The distichia were removed by transconjunctival unipolar electrocautery. Recovery was uneventful, but the original signs recurred 10 weeks after surgery. Ophthalmic examination revealed another distichia at a different location in the same eyelid and it was removed by full‐thickness wedge excision. Histopathological examination failed to reveal the exact origin of the distichia. To our knowledge, this is the first reported case of distichiasis in a ferret.  相似文献   
23.
大麦小孢子再生植株气孔保卫细胞长度与倍性的相关性   总被引:2,自引:0,他引:2  
为了建立一种快速鉴定大麦小孢子来源植株倍性的方法,对大麦品种"花30"不同倍性(种子来源二倍体,小孢子来源单倍体和单倍体加倍系)早期植株的不同叶位、不同叶片部位的气孔保卫细胞长度进行了测定,考察了不同取材部位气孔保卫细胞长度的差异,对种子来源二倍体、小孢子来源单倍体和单倍体加倍材料的气孔保卫细胞长度的分布进行了区分。结果表明,"花30"单倍体材料的气孔保卫细胞长度在不同叶位以及不同叶片部位差异较小,而单倍体加倍材料和种子来源二倍体材料受叶片部位影响较大,单倍体和二倍体材料间气孔保卫细胞的长度差异显著,而单倍体加倍材料和种子来源二倍体材料间气孔保卫细胞长度未观察到明显差异。单倍体和单倍体加倍材料气孔保卫细胞的长度值范围分别为26.9~37.7μm和36.7~62.1μm;利用37μm临界值可对大麦小孢子来源的DH群体中的单倍体进行快速区分。  相似文献   
24.
内蒙古绒山羊Hoxa7基因在毛囊中的表达   总被引:1,自引:0,他引:1  
利用原位杂交技术检测Hoxa7基因在毛囊不同生长时期的表达模式,结果表明,Hoxa7基因分别在胚胎期的95 d初级毛囊的内根鞘表达、在115 d次级毛囊的内根鞘和绒干表达、在125 d初级毛囊内根鞘和毛干皮质表达、在兴盛期10月的初级毛囊毛干皮质和次级毛囊的绒干中表达。揭示在毛囊发育中,Hoxa7基因对于毛囊细胞的增殖可能起一定的作用。  相似文献   
25.
Abstract

Signal molecules are among the major factors required for the legume–bacteria symbiosis. The excretion of signal molecules by plants stimulates the bacterial Nod genes resulting in the production of lipochitooligosacharides (LCOs). LCOs cause root hair deformation (RHD) and induction of nodule cells division, leading to the formation of nodules. The chemical structure of LCOs determines their biochemical activities; for example, removal of the sulfate group can significantly reduce the morphogenic activities of LCOs. Stressful conditions interrupt the excretion of signal molecules by the legumes' roots and consequently the inhibition of LCO production by the bacteria. This research has studied the effect of different concentrations of LCOs on RHD of two soybean [Glycine max (L.) Merr] cultivars, AC Bravour and Maple Glen, under acidity stress. In the first experiment, two different concentrations of LCO (10?7 and 10?6M) and in the second experiment, three different concentrations of LCO (10?7, 10?6, and 10?5M) were added to the soybean roots subjected to the pH levels of 4, 5, 6, and 7 for 24 h. By microscopy observation, the ratios of RHD were determined. Addition of LCOs resulted in RHD in both cultivars. Maple Glen roots responded similarly to different concentrations of LCO, whereas roots of AC Bravour responded differently. The concentration of 10?5M LCO could inhibit the stressful effect of pH 4 on RHD compared with pH 7 in both cultivars. The significant interaction between LCO and pH suggests that the effect of LCO on RHD may be more significant under higher levels of acidity.  相似文献   
26.
Red clover cultivars, including diploid and tetraploid, are commonly used in legume‐based pasture mixtures. However, information on nodulation under different starter N regimens is limited. We hypothesized that there is genetic variability among different red clover cultivars for nodulation. A root hair deformation assay was conducted using three diploid (AC Christie, Tapani and CRS15) and three tetraploid (Tempus, CRS18 and CRS39) red clover cultivars by inoculating them with Rhizobium leguminosarum biovar trifolii. Nodulation and morphological characteristics of two selected red clover cultivars, AC Christie and Tempus, were determined under five starter N concentrations (0, 0.2, 0.4, 0.8 and 1.6 mg per plant). Inoculation with rhizobia increased root hair deformation with significant interaction across cultivars. Nodulation was delayed under high starter N concentrations, and genotypic differences were evident for days‐to‐nodule initiation. There was a positive quadratic response to starter N for AC Christie and a negative quadratic response for Tempus for nodulation. Tempus had more active nodules (92 %) than AC Christie (73 %). The genetic variability of red clover cultivars should be considered in N fixation studies and their response to availability of initial N.  相似文献   
27.
本文对当前众多养猪户在猪品种毛色与性能、仔猪早期断奶、育肥猪的合圈饲养与配合饲料的使用方面存在的认识偏差产生原因和克服方法从技术上进行了讨论 ,这些偏差已在一定程度上制约了养猪生产的发展。建议通过加大宣传、教育、引导和科学技术普及力度 ,提高认识 ,以提高养猪生产水平的经济效益  相似文献   
28.
从近几年网络犯罪的手段来看,计算机网络系统已成为一些罪犯侵犯的对象和渠道.本文根据网络安全的现状及问题由来以及几种主要网络安全技术,提出了实现网络安全的几条措施.  相似文献   
29.
采用计算机仿真的手段,运用有限元仿真软件LS-DYNA建立了圆柱形立柱形式的波形梁护栏的有限元模型,护栏的材料采用的是钢材,护栏板与立柱之间通过螺栓连接,基于这个模型,本文对轿车与护栏碰撞过程中影响护栏防护性能的摩擦系数以及护栏板与立柱之间的连接性能进行了研究,结果发现,通过减小摩擦力以及改变护栏板与立柱之间螺栓连接的临界失效载荷,可以提高事故中护栏对乘员的保护能力。  相似文献   
30.
Anatomical and physiological characters of the leaf surface and its physico‐chemical environment substantially influence the density and diversity of phyllosphere‐inhabiting microorganisms, which may include natural antagonists of important pathogens. The objective of this investigation was to quantify the phyllosphere (i.e. leaf surface) microbial population in a range of rice varieties grown in Sri Lanka and to identify the leaf anatomical and physiological characters that determine the density and diversity of phyllosphere microbes. Fifteen rice varieties including both traditional and new high‐yielding varieties were used in a planthouse experiment and a field experiment in two consecutive seasons to quantify the phyllosphere microbial population and measure leaf characters that may influence it. There were highly significant intervarietal variations in the density and diversity of epiphytic bacterial, fungal and total microbial populations under both planthouse and field conditions. However, there was no difference between traditional and new, high‐yielding varieties in their capacity to harbour epiphytic microbes in the phyllosphere. Total microbial density (TMD) under both conditions showed positive correlations with leaf hair density, stomatal density and transpiration rate. Under planthouse conditions, TMD was also positively correlated with leaf hair length and negatively correlated with leaf temperature. These correlations can be explained in terms of providing favourable microsites on the phylloplane for epiphytic microbial growth.  相似文献   
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