毕业论文word标准排版格式.doc

武汉轻工大学 本科毕业设计（论文） 白杨无性系茎尖培养及 体细胞胚胎发生技术研究 论文作者： ⅩⅩⅩ 指导教师： ⅩⅩⅩ 学科专业： 所在院系： 2013年6月 摘 要“摘要 “摘要”字样用三号黑体，1.25倍行距，居中；下空一行（“摘要”二字之间用二个字符空格分开） 本论文采用茎尖培养三步法，首次对引入我国表现优良的8个白杨无性系，进行了微体快繁，为今后系统的苗期测定及田间试验提供了材料。同时，选用了5个无性系，以水培苗或组培无菌苗为材料，进行愈伤组织诱导或对其发育状态调控及体细胞胚胎发生研究，为建立稳定的杨树体细胞胚胎发生体系奠定了基础。 试验结果表明，以水培苗带芽茎段为茎尖培养材料，银白杨与大齿杨杂种AG和美洲山杨与欧洲山杨杂种3#芽分化率显著低于其余6个无性系；垂直接种可显著提高水培苗腋芽分化率；玉米素浓度对芽分化率影响不明显，但影响材料的离体器官发生表现；8个无性系皆易诱导生根，其中银白杨与大齿杨杂种AG和灰杨Ca较其它无性系更易，选用根数作为评定生根效果指标更合适。 4-D高浓度悬浮培养下，成功的将美洲山杨与欧洲山杨杂种3#叶柄愈伤组织调节为胚性状态，通过细胞悬浮培养，获得了大量的球形胚，并首次观察到灰杨Ca茎尖白色愈伤组织内起源的子叶胚形成，得到了完整植株。基因型和4-D浓度对愈伤组织状态调节，至为关键。温度变化可影响茎尖形态发生。愈伤组织达到胚性状态时，表面特征不一致，但有产生胚性细胞能力强弱之分。正文用小四号宋体，1.25 正文用小四号宋体，1.25倍行距，两端对齐，每段首行缩进四个字符空格，标点符号用全角 关键词：白杨，茎尖培养，体细胞胚胎发生，悬浮培养，微体繁殖“关键词 “关键词”字样用小四号宋体、加粗，关键词用小四号宋体，每一关键词之间用逗号（全角）分开，最后一个关键词后不打标点符号；均为1.5倍行距，左对齐 ABSTRACT“ABSTRACT “ABSTRACT”字样用Times New Roman三号，1.25倍行距，居中；下空一行 In this paper, a three-step micropropagation was successfully employed for 8 selected genotypes of aspen. At the same time, through the induction of embryogenic callus, Somatic embryogenesis was studied. It would be beneficial to establish a stable system of embryogenesis in poplar. The results of study on aspen shoot culture using node as explant show that percent bud regeneration of AG and 3# was lower than that of the other clones. Percentage of bud regeneration could be improved at vertical cutting. With the increasing of zeatin concentration, in vitro organogenesis was different. All clones were easy to induce rooting, especially AG and Ca, and number of roots was fit to estimate the effect on rooting of plantlet. Supplemented with 10mg/L 4-D, suspension cultures initiated from callus derived from petiole of aspen hybrid 3# produced embryogenic callus and a highest number of globular-shaped embryos, and cotyledonary-stage embryos originated from white callus of grey aspen Ca shoot were first observed and embling were obtained. Genotypes and concentration of 4-D was critical to induce embryogenic and somatic embryogenesis. Morpho