【作者】 杨成超；

【导师】 苏晓华；

【作者基本信息】 中国林业科学研究院 ， 林木遗传育种， 2010， 博士

【摘要】 杨树(Populus)是具有重要经济学和生态学价值的双子叶木本植物。黑杨派树种,尤其是美洲黑杨(P. deltoides Marshall)和欧美杨(P. euramericana),高生长速度较快,是研究高生长的代表性树种。一年生苗的高生长在杨树高生长形态建成研究中占据重要地位。为探讨黑杨高生长形态建成的分子基础,确定杂种优势分子机理的试验材料和采样策略,本文从形态学、组织学、内源激素、分子生物学角度研究了一年生苗高生长形态建成与杂种优势,试验结果如下:通过对凌丰1号杨、347杨和荷兰3930杨的定位观测,总结出黑杨在苗期具有如下特征:(1)在生长季的某一时间点上,不是所有节间都在伸长。伸长节间的数量是有一定范围的,不同月份伸长节间的数量不同,一般在6个节间之内。在全生长季,在较大的欧美杨及美洲黑杨群体中,群体的伸长节间数的出现频数表现为右偏分布,而伸长节间数为1～6节的出现频数近似于正态分布。伸长节间数为3～4节的出现频数最高,最多的伸长节间数达到8个。(2)在苗木生长的不同阶段,节间长和节间数2个要素对高生长的贡献不同。节间数是高生长构成中最重要的要素,对高生长起主导作用,其次是节间长。节间发生率越高则高生长越快。各节间的伸长是独立的,节间之间是无影响的。(3)在全生长季,欧美杨和美洲黑杨的高生长符合慢～快～慢“S”型曲线规律。总体来看,茎尖的第二节间和第四节间细胞联系比较致密,韧皮部、形成层、木质部之间联系也紧密,细胞长度较短,细胞较小。从第六节间开始,表皮、皮层、韧皮部、木质部等各组织部位间联系松散,节间伸长趋于停止。从茎尖的横切和纵切图可以看出,原生分生组织不断分化出叶,形成茎,是分生区。分生区与伸长区的边界大概在第一节间。而从表皮、皮层等各个组织部位之间联系的紧密程度和细胞尺寸来看,第六节间是分生区和成熟区的界限,这与节间定位观测结果一致。从内源IAA的测定结果来看,顶芽,顶节和幼叶三个组织部位的内源IAA含量都是7月的含量高于5月的含量,而7月的节间数月增加量也高于5月节间数月增加量,从表面上看二者成正相关关系。对凌丰1号杨来说,它在7月的节间数月增量比5月的高,苗高也是7月的高,内源ABA含量也如此。不同发育时期的节间数量增加量不同,这可能与IAA及ABA含量有关。然而不同无性系的高生长量不同,不能通过内源IAA或ABA含量来进行早期预测。采用RACE技术,从欧洲黑杨中克隆出生长素诱导基因IAA9,大小为1786bp。通过计算杂种优势,在50号×荷兰3930和中驻6号×巨霸杨之间选择具有超亲杂种优势中驻6号×巨霸杨为准备做基因表达谱试验的试验材料。同时,从苗高、地径、叶片长和叶片宽四个性状中确定苗高为目标性状。根据定位观测的结果和组织结构切片实验结果确定与高生长密切相关的是顶芽和第一节间,采集茎尖即可代表目标性状。在采样时间上,根据高生长形态建成的“S”型生长曲线图确定采样的最佳时间是7月中旬。本论文为杨树高生长形态建成和杂种优势分子机理研究打造了一个平台。下一步拟定研究内源激素含量配比与苗高生长、IAA9基因功能验证和杂种优势分子机理。更多还原

【Abstract】 Poplar is an important economic and ecological value woody plants of dicotyledonous. Black poplar, especially P. deltoides Marshall and P. euramericana, grows fast and is the representation to study height growth. Height growth of one years old seedings occupy an important position in height growth studying of morphogenesis. To investigate the molecular basis of morphogenesis of height growth, and to deternine the materials and sampling strategy of molecular mechanism of heterosis, tests of height growth morphogenesis and heterosis were conducted from the morphology, histology, biochemistry and molecular biology. The results show as follow:By location observation to Lingfeng poplar 1, poplar 347 and N3930, summarized with the following characteristics in the seedling stage: (1) Not all internodes are elongating at certain time during growth season. The number of elongating internode is limited, generally within six internodes. There are different numbers of elongating internode in different seasons. The frequence distribution of elongating internode number follows right-skewness in deltoides and euramericana population, while it approximately follows normal distribution from one to six internodes. The frequence of three to four internodes is the highest. The most numbers of elongating internode are eight. (2) The contribution of internode number and internode length to tree height growth is different in different growth stages. The more internode frequency happens higher, the more height growths faster. Internode number is the most important factor contrast to internode length, and internode number is the most significant morphologic marker close to height. (3) During the whole growing season, height growth of deltoides and euramericana follows‘S’shape curve law. There are few reports about the first and the second law. The guiding significance of the first law to sample of tree growth is important. After the second law was discovered, internode number should be regarded as a key factor of poplar conventional breeding, molecular marker-assisted breeding and gene cloning. Application scope and mechanism of the two laws were discussed. Overall, linkages between the cells of tip of the II and IV are relatively compact, the same as to between phloem, cambium, xylem. The cell length is shorter, cells are also smaller. Starting from the inter-section VI, the contact between the epidermis, cortex, phloem, xylem and other tissues are loose, elongation growth tends to stop.The transverse and longitudinal map of the stem tip show that the meristem differentiate leaf and stem. Stem tip is meristematic zone. The boundary of between meristematic zone and elongation zone exist in the first internode. Section VI is divided between the elongation zone and the mature zone, which is the same as observation results.Seen from the results of determination of endogenous IAA, the content of endogenous IAA of apical bud, apical internode and young leaf are all july’s content higher than May’s content. The increment of July’s internodes is higher than May’s also. On the surface a positive correlation is conducted between the two. To Lingfeng 1 poplar, its internode number of July is higher than May, the same as height. The content of ABA is like IAA. The internode number increments are different in different developmental stages, which may be related to IAA and ABA content. However, different clones’height are different, which can not be predicted early by content of endogenous IAA or ABA.Gene IAA9 was cloned from Populus nigra by RACE technology, it is 1786bp.By calculating heterosis, (P.×deltoides‘zhongzhu 6’)×(P.×deltoides‘juba’) was regarded as the heterosis experimental material to do gene expression profiling test. Meanwhile, height was identified as target trait from the height, diameter, leaf length and leaf width. According to the results of location observation and biospy, it was determined that height growth was closely related to the apical bud and the first internode. Stem tip can be representative of the target traits. It was determined that the best time to sample was middle ten days of July according to the‘s’curve of height growth morphogenesis.The paper has created a platform for poplar height growth morphogenesis and molecular mechanism of heterosis. Next step will study the endogenous hormone content ratio and height growth, IAA9 gene function and molecular mechanism of heterosis.更多还原