玫瑰花不同部位清除DPPH·能力的比较研究     

曾佑炜  刘肖珍  彭永宏 《中国农学通报》2008,24(6):417-420

通过不同取材,研究了红色、金黄色、白色和粉红色玫瑰花花瓣、花蕊、花萼和叶片清除DPPH能力,结果表明,红色和金黄色玫瑰花瓣对DPPH清除能力比白色和粉红色强;四种玫瑰花花蕊都有较强的DPPH清除能力,且无显著差异;粉红色和金黄色玫瑰花花萼具有较强的DPPH清除能力;在较高的浓度下四种玫瑰花的叶片同样有较强的DPPH清除能力.在实验条件下,红色、金黄色花瓣以及不同花蕊50%DPPH清除率(rs50)都小于芦丁的rs50.  相似文献   

生物质糖化和乙醇发酵菌种资源的研究进展     

张立  熊兴耀  苏小军  周红丽  李美群  曾璐 《农产品加工．学刊》2009,(7):4-6,9

世界能源安全正面临着挑战。发展清洁可再生的生物质燃料乙醇越来越被重视。菌种资源在燃料乙醇生产中起到至关重要的作用。概述了生物质糖化和乙醇发酵菌种资源的研究进展,并展望了今后的研究方向。  相似文献   

水稻细菌性条斑病及其抗性研究进展   总被引：13，自引：0，他引：13  

曾建敏  林文雄 《分子植物育种》2003,1(2):257-263

本文简要综述了近年来国内外对水稻抗细菌性条斑病在病原菌鉴定、水稻抗源筛选、抗性生理遗传以及抗性的分子生物学等方面的研究进展，以期为水稻细条病的深入研究提供参考。  相似文献   

“云南小麦”(Triticum aestivum ssp.yun-nanense King)的考察与研究   总被引：4，自引：0，他引：4  

董玉琛  郑殿升  乔丹杨  曾学琦  恩在诚  陈勋儒 《作物学报》1981,7(3):145-152

1979年和1980年我们对金善宝教授命名的“云南小麦”亚种进行了考察和研究。查明“云南小麦”分布在云南省澜沧江和怒江下游十二个县,约在北纬22°54′—25°03′和东经95°36°—100°85′左右。“云南小麦”生长在海拔1500米至2500米之间的高山区,而以1900米至2300米地带种植较多。原产地年均温15℃、年雨量1480mm 左右。小  相似文献   

Effects of fruit bagging on coloring and related physiology,and qualities of red Chinese sand pears during fruit maturation   总被引：1，自引：0，他引：1  

Chunhui Huang  Bo Yu  Yuanwen Teng  Jun Su  Qun Shu  Zaiquan Cheng  Liqiong Zeng 《Scientia Horticulturae》2009

Red Chinese sand pears (Pyrus pyrifolia Nakai) are particular to China. In order to determine the effects of fruit bagging treatments (including bag types, bag removal patterns and dates) on fruit qualities and to understand the mechanism of coloring of red Chinese sand pears, two experiments were carried out. In the first experiment, fruit of ‘Meirensu’ were firstly covered by light-impermeable paper bags with different levels of light permeable liners during their early development stage, then, the whole bag were/not removed or only the outer layer of bags were removed 3, 2 or 1 weeks before harvest. Thus, the fruit were/not totally re-exposed or were under different levels of sunlight transmission (80.31% or 34.71%). Non-bagged fruit were used as the control. Bagging treatments significantly affected the concentration of anthocyanin and the visual qualities of pear fruit. Compared to control, fruit re-exposed totally for 2 or 3 weeks accumulated the largest amount of anthocyanin and fruit receiving 80.31% and 34.71% of sunlight for 1–3 weeks could synthesize a little anthocyanin, indicating that high light intensity is imperative for coloring in red Chinese sand pears. Bagging treatments did not affect contents of total soluble sugars, but decreased organic acids contents in fruit. In the second experiment, fruit of ‘Meirensu’ and ‘Yunhongli No. 1’ were covered with only one type of light-impermeable bag during the early development stage and totally re-exposed after the bag removal 15 days before harvest. Fruit were then collected at different intervals to trace the time-course of coloring, and related physiology and inner qualities. With increasing time after the bag removal, the concentration of chlorophyll, carotenoid, flavonoid and total phenols changed little, but the concentration of anthocyanin accumulated extremely fast within 10 days after the bag removal in both cultivars and thereafter kept constant. ‘Yunhongli No. 1’ had higher anthocyanin contents and lower hue angle than ‘Meirensu’, indicating a higher potential of anthocyanin synthesis. After the bag removal, the sucrose contents and PAL activities increased gradually and correlation analysis revealed that they were highly correlated with anthocyanin accumulation in two cultivars. This study suggests that anthocyanin biosynthesis in red Chinese sand pears is a highly light dependent process and modified by genotypes. Based on the current results, in order to obtain red Chinese sand pear fruit with attractive appearance and good inner qualities, fruit must be covered with light-impermeable bags at the early stage of fruit development and the bag should be removed totally at least 10 days before harvest.  相似文献   

数控螺旋锥齿轮磨齿机机床加工误差补偿   总被引：1，自引：0，他引：1  

王志永  于水琴  曾韬 《农业机械学报》2009,40(1)

根据螺旋锥齿轮齿面的数学模型,对轮齿曲面进行了离散化处理.运用矢量运算的方法,给出了齿面离散点径矢及其法矢的计算方法.基于螺旋锥齿轮切齿计算得到的比例修正参数以及砂轮可任意修形的特点,建立了一种基于比例修正参数和砂轮参数,对机床加工误差进行补偿的方法,运用最优化算法可得到各种比例修正参数的修正倍数以及砂轮参数的改变量.通过实际的磨齿加工、齿形误差的测量以及机床调整参数的补偿,验证了机床加工误差补偿方法的正确性.  相似文献   

机床误差对螺旋锥齿轮齿形的影响规   总被引：1，自引：0，他引：1  

王志永  于水琴  曾韬 《农业机械学报》2009,40(6):199-202

基于螺旋锥齿轮齿面分析的数学模型,采用最优化算法和一种新的计算齿形误差的方法,计算了误差齿面与理论齿面在理论齿面法线方向的齿形误差.通过引入机床调整误差和刀具参数误差,分析了各种误差对螺旋锥齿轮齿形的影响规律,以图形的方式表示了误差齿面相对于理论齿面的偏离方向以及误差值的大小,为机床的精度设计、齿形误差的修正以及指导实际加工提供了理论依据.通过实际的磨齿加工和检测对算法以及分析结果进行了验证.  相似文献   

牧场土壤含水率与坚实度空间变异与相关性分   总被引：3，自引：2，他引：1  

程强  孙宇瑞  林剑辉  曾庆猛  Schulze Lammers P  Schellberg J 《农业机械学报》2009,40(3):103-107

利用土壤水分/圆锥指数复合测量装置,应用精细农作技术体系网格定点测量与GPS定位,在一块面积约1.27 hm2的草地上获取了土壤含水率与坚实度空间分布基础数据,并针对采样过程中出现的数据缺失,用偏最小二乘法对数据进行修补.然后运用克里格插值法进行数字化成图,并在此基础上分别对含水率与坚实度的空间变异性及两者的相关性做了分析.  相似文献   

胡萝卜微粉物理特性和营养成分的影响因   总被引：1，自引：0，他引：1  

宫元娟  曾程  王强  秦军伟 《农业机械学报》2009,40(11):124-128

胡萝卜微粉制备中,影响微粉物理特性及营养成分的试验分析表明:热风和微波干燥获得的胡萝卜微粉容积密度大,冷冻干燥的胡萝卜微粉容积密度小.微波干燥获得的胡萝卜微粉溶水性好,其次是冷冻干燥;胡萝卜生粉比熟粉溶水性好.胡萝卜生粉的氨基酸质量比高于熟粉和冻融粉;真空冷冻干燥生胡萝卜,粉碎粒径小于240目时,氨基酸质量比高.经过冻融处理的胡萝卜微粉V_c质量比高于其生粉和熟粉;冷冻干燥的胡萝卜微粉V_c质量比高.类胡萝卜素质量比随着粒径减小而减小;冷冻干燥冻融处理的胡萝卜,在粉碎粒径为80～120目时,类胡萝卜素和V_c质量比高.  相似文献   

基于计算机视觉的葡萄茎直径高精度测量方法   总被引：1，自引：0，他引：1  

曾庆兵  刘成良  苗玉彬  王世平  黄丹枫 《农业机械学报》2009,40(12):182-185

提出了基于计算机视觉的葡萄茎直径测量方法,采用双边滤波降低图像噪声,通过Otsu阈值分割和BloB分析实现葡萄茎与背景的分离,应用基于特征点的定位方法得到茎直径测量位置,由茎直径所包含像素数和尺寸当量计算出茎直径值,从而实现茎直径连续测量.实验和现场应用表明,系统测量重复精度可达±0.5μm.  相似文献