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51.
不同向日葵品种对黄萎病的抗性*   总被引:3,自引:0,他引:3  
采用浸根接种法鉴定不同向日葵种质资源对黄萎病的抗性差异。结果表明:40份供试向日葵品种依据抗性划分标准共分为3类,其中中抗品种有5份如:‘118’、‘新葵杂5号’等;低抗品种有8份如‘767’、‘KJ003’等;其余27份供试材料均呈现感病;没有鉴定出免疫和高抗的向日葵品种。  相似文献   
52.
莴苣花叶病毒病的研究Ⅰ。病原鉴定   总被引:2,自引:0,他引:2  
 由山东济南和泰安两市郊区大面积受害的莴苣(Lactuca sativa L.var.asparagina L.)上分离到一株病毒。莴苣上症状为系统花叶,畸型和褐色斑点。人工接种,在昆诺阿藜和苋色藜上产生局部枯斑和系统症状,千日红上呈不规则斑块,不侵染普通烟、心叶烟、曼陀罗、豇豆、菜豆和黄瓜。传毒试验证明经汁液和蚜虫传播,种子带毒。病毒稀释限点5×10-1~5×10-2;失活温度55~60℃;体外保毒期(22~23℃)24小时,经有机溶剂澄清,聚乙二醇沉淀和差速离心可部分提纯。病毒粒子线状,长约750毫微米;病组织超薄切片可见风轮状内含体。试管沉淀法初步测定与马铃薯Y病毒血清呈阳性反应。  相似文献   
53.
Melatonin (MLT) is an endogenous hormone with roles in animal germ cell development. However, the effect of MLT on porcine oocyte maturation and its underlying mechanisms remain largely unknown. Here, we investigated the effects of exogenous MLT on oocyte maturation, histone acetylation, autophagy and subsequent embryonic development. We found that 1 nmol/L MLT supplemented in maturation medium was the optimal concentration to promote porcine oocyte maturation and subsequent developmental competence and quality of parthenogenetic embryos. Interestingly, the beneficial effects of 1 nmol/L MLT treatment on porcine oocyte maturation and embryo development were mainly attributed to the first half period of in vitro maturation. Simultaneously, MLT treatment could also improve maturation of small follicle‐derived oocytes, morphologically poor (cumulus cell layer ≤1) and even artificially denuded oocytes and their subsequent embryo development. Furthermore, MLT treatment not only could decrease the levels of H3K27ac and H4K16ac in metaphase II (MII) oocytes, but also could increase the expression abundances of genes associated with cumulus cell expansion, meiotic maturation, histone acetylation and autophagy in cumulus cells or MII oocytes. These results indicate that MLT treatment can facilitate porcine oocyte maturation and subsequent embryonic development probably, through improvements in histone acetylation and autophagy in oocytes.  相似文献   
54.
Seedlings of a Chinese wild grape (Vitis piasezkii Maxim var. pagnucii) native to loess plateau of Eastern Gansu province, China, were evaluated to screen cold-resistant rootstocks in Lanzhou area. After 14-year investigation two selections of LDP-191and LDP-294 were screened as rootstocks for two table grape cultivars, ‘Fujiminori’ and ‘Red Globe’, respectively. The two graft unions demonstrated very high cold-resistance as well as good graft compatibility. Furthermore, they could survive through low temperatures in winter without soil coverage together with good fruit quality of the cultivars grafted.  相似文献   
55.
曹衍龙  徐朋  金鹭  杨将新 《农业机械学报》2012,43(3):219-222, 229
针对三维表面粗糙度评定中表面测量数据量大且计算复杂度高,常用处理方法不能满足实时测量要求的问题,提出了一种基于图形处理器(GPU)的三维表面形貌测量数据快速评定方法,应用CUDA平台开发了基于GPU的并行处理算法,在此基础上实现了三维表面质量的快速评定。实验结果表明,该方法在保证计算精度的同时,运算效率提高了60倍以上,可满足三维表面质量在线评定的要求。  相似文献   
56.
温度对嫁接番茄幼苗生长及SOD、POD活性的影响   总被引:1,自引:1,他引:1  
为探明华南地区番茄嫁接后的适宜生长温度,试验研究了3个温度处理下番茄嫁接苗的生长状况及其叶片内保护酶(SOD、POD)活性的变化。试验结果表明:20/17℃处理下地上部和根系生长都受到抑制,根冠比失调;30/27℃时植株出现徒长迹象,且整株生物量下降;25/22℃环境条件下,嫁接苗根冠协调,茎秆健壮,光合能力较强。相比于25/22℃环境,20/17℃的相对低温处理和30/27℃的相对高温处理下,番茄嫁接苗的SPAD读数分别下降20%和13%,叶片的SOD酶活性为237.58 U/(g?FW)和254.39 U/(g?FW),分别比25/22℃处理下的SOD活性低114 U/(g?FW)和97.19 U/(g?FW)。30/27℃处理下的POD活性高于另外两个处理,但差异不显著。综上所述,嫁接后的白天温度应控制在25℃左右,夜间温度为22℃左右。  相似文献   
57.
Objective The physiologic mechanisms involving growth factors, including PDGF‐BB, EGF, and TGF‐β1, as potent mediators of fibroblasts and epithelial cells in corneal wound healing remain unknown. The goal of this study was to determine culture methods for equine epithelial cells and keratocytes and to investigate how exogenous growth factors influence proliferation of both cell types. Procedures Cell cultures were established from healthy corneas harvested from horses immediately following euthanasia and maintained using standard tissue culture protocols. To determine the effects of PDGF‐BB, EGF, TGF‐β1, keratocytes (1 × 105/well) and epithelial cells (2 × 105/well) were each cultured in 12 well plates and exposed separately to the growth factors. The cells were exposed to concentrations of EGF between 0 and 50 ng/mL; PDGF‐BB between 0 and 75 ng/mL; and TGF‐β1 between 0 and 10 ng/mL. Cell proliferation was measured using 3H‐thymidine assay and differences in growth determined using anova and Tukey's HSD test (P < 0.05). Results Epithelial cell and keratocyte cultures were successfully established. EGF maximally stimulated keratocyte and epithelial cells at 25 ng/mL and 5 ng/mL, respectively. PDGF‐BB maximally stimulated keratocytes and epithelial cells at 50 ng/mL and 5 ng/mL, respectively. TGF‐β1 inhibited keratocytes at 5 ng/mL and 10 ng/mL, and epithelial cells at 1 ng/mL and 2 ng/mL. Conclusions Methods were established to maintain epithelial cells and keratocytes in vitro. PDGF‐BB and EGF stimulate, while TGF‐β1 inhibits the proliferation of epithelial cells and keratocytes. These growth factors may play a role in maintenance and repair of the equine cornea.  相似文献   
58.
基于三维点云数据的花瓣形态及生长过程模拟   总被引:1,自引:0,他引:1  
目前对于虚拟植物的研究多是通过图形建模来模拟植物的生长变化,计算复杂且操作不灵活。随着三维扫描和点云重建技术的发展,为复杂植物形态可视化提供了新的手段。论文基于三维扫描的植物点云数据模型,研究了植物花瓣的形变和生长过程模拟。利用三维扫描仪获取植物花瓣的生长序列,采用MATLAB根据实测点云数据拟合植物生长函数曲线,最后将传统花卉生长模拟与点云模型的自由变形相融合,提出了依据实测点云数据通过点云模型变形算法模拟花卉植物动态生长的方法。该方法不仅能够保留花卉植物复杂的形态特征,而且使形变控制简单,模拟的花瓣形态及生长真实自然。此外,该方法还与基于物理的模拟方法进行比较,并利用拟合回归分析、实测花瓣数据与重建数据间误差对该方法的准确性进行了分析。结果显示花瓣生长期内决定系数达0.75以上及平均误差控制在2mm以内,研究结果为花卉植物的生长形变模拟提供了参考。  相似文献   
59.
An 8-week feeding trial was conducted to evaluate the effect of N-acetyl cysteine (NAC) and glycine supplementation on growth performance, glutathione (GSH) synthesis, and antioxidative ability of grass carp, Ctenopharyngodon idella. Four practical diets were formulated: control, control + 0.2% NAC, control + 0.5% glycine, and control + 0.2% NAC + 0.5% glycine. Each diet was randomly assigned to quadruplicate groups of 30 fish (approximately 8.8 g). Weight gain and specific growth rate were significantly increased with the supplementation of NAC. Supplementation of NAC plus glycine significantly increased the feed efficiency. Glutathione peroxidase (GPx) and γ-glutamine cysteine synthase (γ-GCS) in plasma were significantly increased with the supplementation of NAC plus glycine. GSH in plasma increased and malondialdehyde (MDA) decreased in fish fed diets supplemented with NAC. Respiratory burst, superoxide dismutase (SOD), and catalase (CAT) activity were not affected by NAC or glycine. These results clearly indicated that NAC improved the growth performance and restored GSH of grass carp, supplemented NAC together with glycine enhanced GSH synthesis, and improved the antioxidative ability of grass carp.  相似文献   
60.
针对水稻工厂化育秧播种完成的秧盘人工取盘和层叠堆放劳动强度大、效率低、后续运输不便等问题,该研究设计了一种水稻秧盘自动码垛机,可完成秧盘精确夹取、转移和码垛;阐述了码垛机的基本结构和工作原理,对关键部件进行设计,以可编程逻辑控制器(Programmable Logic Controller,PLC)作为控制核心,搭建了...  相似文献   
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