【作者】 李亚蒙；

【导师】 沈向；

【作者基本信息】 山东农业大学 ， 果树学， 2006， 硕士

【摘要】 枝条下垂生长现象是植物中的一种常见变异,但对其生理及遗传规律研究较少,本试验选择垂枝桃(Prunus. persica var. Pendula)性状分离后代为试材,通过对其进行生物学形态、生理特性及分子标记研究,对垂枝性状发育特性和基因标记进行了初步探讨。本研究首次采用SSR微卫星标记技术对桃的垂枝基因进行分子标记,并对下垂枝条进行了木质素和赤霉素分布与含量的综合分析,主要结果如下:(1)在对枝条下垂性状的描述上,枝条延伸角是定义枝条类型的一个重要参数。枝条延伸角在对树形的评价上具有重要意义。根据对两种类型桃枝条分枝角度的调查,直枝类型基角和延伸角极为接近,分枝角度平均值分别为52.5°和52.0°;而垂枝类型基角和延伸角则分别为51.7°和92.9°。说明垂枝类型在生长过程中发生向下弯曲。根的基角与枝条的延伸角有相关性,直枝类型和垂枝类型根的基角平均值分别为78.3°和42.5°,垂枝桃的根也有明显的向下生长的趋势。倒置生长的垂枝桃枝条仍然表现为向重力生长,说明枝条下垂是受重力诱导的。(2)木质素作为机械组织的重要组成成份对枝条的支撑能力起重要作用。通过对木质素染色的切片发现,在新梢中,直枝类型木质部的厚度高于垂枝类型133%,垂枝桃类型中水平面上下两侧维管束发育不均衡。对枝条中木质素的定量检测发现,直枝类型中木质素含量高于垂枝类型,垂枝桃枝条下侧木质素含量则显著低于上侧。木质素的分布不均导致枝条机械组织的支撑能力降低,枝条下侧机械组织支撑能力不足使得垂枝桃枝条在生长过程中发生下垂。(3)赤霉素在枝条发育、木质素合成方面起重要的调控作用。通过对赤霉素等激素含量的酶联免疫法测定发现,赤霉素在枝条中的含量由基部至梢部递增,在垂枝桃枝条上侧赤霉素含量高于下侧,与木质素分布状况一致,赤霉素分布的不均衡是导致次生木质部发育不均衡的重要原因。而且垂枝桃梢端赤霉素含量较直枝桃中更高,将导致枝条先端生长快于次生木质部发育,使枝条无法支撑自身重量而下垂。外源GA3处理的垂枝桃枝条中IAA/GA3比例与CTK/GA3比例均显著增高,促进了垂枝桃枝条中部细胞分裂与木质部分化,使其表现直立生长。生长延缓剂PP333处理均更多还原

【Abstract】 Weeping characteristic is a very usual variation in plants, but with very little physiological or genetic studies. Character segregated progenies of weeping peach (Prunus persica var. Pendula) were studied by using morphological, physiological and molecular marker methods, and the developmental characteristics of weeping branches and gene marker technique were disscussed. In this study we used SSR technology in the identification of weeping gene in peach and did integrative analysis in the distribution and content of lignin and gibberellin, the main results were submited as follows:1. Branch angle measured as the virtual angle was found a more reliable parameter in characterizing the tree shape in peach than the actual crotch angle measured at the base of the branch since the shape of the crown is more closely related to the former branch angle measurement. As the investigate on the standard and weeping tree form, the mean crotch angle is 52.5°and 52.0°, respectively; but in weeping form, the mean basal crotch angle and extended angle is 51.7°and 92.9°, respectively. That means the weeping trees grew downward when growing longer. Moreover, the angle of the root is related to the extended angle of the branch, the crotch angle of standard and weeping form is 78.3°and 42.5°, respectively, the roots of weeping peach also grow“downward”. When the trees were grown upside down, the braches also grown down to the earth, suggesting that the growth direction is induced by gravity.2. Lignin is an important component of mechanical tissue and contributes to the supportive function of branches. Cross sections stained for lignin using phloroglycinol-HCl reagent suggests that the width of xylem in young shoot of standard form is 133% higher than that of weeping form, and the development of vascular bundles between upper and lower sides in weeping peach is not proportional. The lignin content in standard form was a little higher than in weeping form, and lignin content in lower side of weeping form is much lower than in upper side. The distribution of lignin results in the lower support ability of mechanical tissue in branches, and the deficiency of support ability results in the weeping of weeping peach’s branches.更多还原