【作者】 肖华山；

【导师】 吕柳新；

【作者基本信息】 福建农林大学 ， 果树学， 2002， 博士

【摘要】 本研究以亚热带果树荔枝为试材，研究荔枝花性分化、发育过程中的生理生化基础。主要实验结果有如下几个方面： 1．应用透射电镜对荔枝茎尖生长锥由营养生长转变为生殖生长过程的细胞超微结构进行观察，结果表明，荔枝圆锥花序发育前期细胞排列紧密，细胞质浓，液泡小，细胞核大并占据着细胞大部分位置；细胞质内有丰富的线粒体和膜状系统，整个膜状系统内连细胞核，外接胞间连丝；细胞内囊泡大量形成、融合与迁移。这些均显示出细胞内结构物质在此期经历着活跃的周转和合成代谢，为发育过程质的转变积累足够的信息和物质。生长锥由尖长变为宽平的花序原基时，其组织细胞结构也发生了相应的变化，最显著的特征是在此过程中，有一些细胞发生了程序性死亡。正在凋亡的细胞核染色质固缩、趋边、核膜破裂或皱缩、细胞质囊泡化并将降解的物质运到周围细胞，从而保证了其它细胞正常发育以及生长的细胞对物质和能量的需求。 2．荔枝花雌雄蕊发育过程的细胞组织化学动态变化的研究结果表明：早期雌雄蕊花原基均有淀粉、蛋白质的积累，减数分裂后，可育的雌雄蕊一直到成熟都保持较强的PAS反应和蛋白质代谢；败育的雌雄蕊则 福建农林大学博士学位论文 中文摘要 较少积累淀粉和蛋白质；败育的雄蕊减数分裂后花药绒毡层不解体，导致 花粉不育。应用透射电镜和 DAPI荧光染色方法观察的结果也表明，败育 的花药或雌蕊在减数分裂后，药壁组织或雌蕊组织亦存在细胞程序性死亡 现象，导致对营养物质竞争力的减弱，从而引起花药或雌蕊逐渐败育。 3．荔枝花性决定中碳氮化合物的动态变化的研究结果发现：C／N 较大有利于雄蕊分化，反之则有利于雌蕊分化：氨基酸含量较高有利于雌 蕊分化，雄蕊的氨基酸含量仅为雌蕊的一半：脯氨酸与花粉育性存在着密 切相关关系。 4．荔枝花＄J’分化过程中多胺和核酸及蛋白质的动态变化研究结果表 明：从叶芽期到圆锥花序发育初期多胺含量持续上升并达到高峰的过程先 于核酸和蛋白质的大量合成，因而多胺可能通过调控生物大分子的合成影 响花芽发育；成熟秋稍叶片的即d和Spin及可溶性蛋白的含量随顶芽或 花（序）芽的增加而增加，表明了叶片含氮化合物的代谢对荔枝茎尖由营 养生长转变为生殖生长极为重耍。 荔枝雄蕊的发育与P［Jt 的合成密切相关联，雌蕊的发育则与高 Spd＋Spin含量相关联。荔枝雌雄蕊发育过程中多胺积极参与了调节核酸、 蛋白质代谢，表明多胺具有调节性器官发育的功能；可育的雄蕊和雌蕊其 多胺的总量都比败育的高，RNA／DNA和蛋白质／RNA的比值在可育的雌雄 蕊中绝大部分比相应的败育雌雄蕊高，也表明了多胺具有提高DNA转录活 性和蛋白质翻译的功能。 5．在荔枝花芽分化临界期O 月至翌年 1月），3类促进植物生长 发育的内源激素含量都较高，而且其相应的叶片也具有同样的变化趋势， 表现为相互增益的效应；与此同时，ABA的含量也升高，抑制茎尖的营养 5福建农林大学博士学位论文 中文摘要生长，使其免发“冬梢”。可见，在这个由量变到质变过程中，除了基因的表达具有时空顺序性外，激素的信号传导和相互增益、相互桔抗的作用是非常重要的。花器官分化期，3类促进植物生长发育的内源激素再度升高，而ABA则消火。它们再次起到相互协调，相互增益的效应。 从荔枝花性决定中雄蕊和雌蕊内源激素含量的动态变化研究结果发现：较高浓度的【＊A和s与雌蕊的发育相关联：口A和＊＊s的含量在较低浓度时有利下花性器宫发育，而较高浓度则抑制了花性器官的发育：在败育的雄蕊或雌蕊中都含有较高浓度的ABA，但从檄素平衡的角度分析，促进生长物质与抑制生长物质的比值相对高时，雄蕊发育正常；当该比值相对较低时，雌蕊发育正常。提出调节荔枝雌、雄花的发育不是某一种激素单独作用的结果，而是各种激素在时间、空间上的相互作用产生的综合效果。 6．通过对荔枝雌雄花不同发育时期的可溶性蛋白组分进行比较分析，大部分蛋白质在雌雄花发育过程中保持不变，其中尤为突出的、可能与荔枝花发育有关的13个特异蛋白质，不仅稳定地出现在各个时期中，而且其分子量及等电点都非常接近，这对它们发挥特有的生理功能应是有利的。 在减数分裂期前和减数分裂期荔枝的雌雄花的发育都有一个相似的历程，即该时期都有两性花原基，都能正常减数分裂，因而这2个时期都有出现和消失同样的特异蛋白，同时，雌雄花?更多还原

【Abstract】 Cytological, physiological and biochemical basis of sex differentiation and development of litchi were investigated. The main results are summarized as follows:1. Cell ultrastructure of litchi meristem of stem apex during the stage of transformation from vegetative growth to reproductive growth was observed using transmission electron microscope. Cells before paniculiform development were arranged tightly without cell gap. The cytoplasm was thick, vacuole was small, and most space of cell was occupied by big and round nucleus. There were abundant mitochondria and many membranaceous structures in the cytoplasm. The whole membranceous system connected nucleus inside to plasmodesmata outside. A lot of vesicles formed, fused and migrated. The results show that structure substances of cells were experiencing active synthetic metabolism and changing to accumulate enough information and substances for radical changes in the process of development. When the growth cone changed from sharp and long to thin and flat during paniculiform development, changes taken place in cellular structure to fit for the differentiation of floral primodia. The most obvious characteristics was that programmed cell death (PCD) occurred in some cells. During the PCD, condensation of nucleus, marginalization of chromatin, nuclear membrane shrinkage and destruction apparently occurred, and many vesicles appeared in the cytoplasm, which may be related to the degradation of cell substances. The degradation products were transfered to nearby cells in the form of vesicles through plasmodesmata. Therefore, the normaldevelopment of other cells and the need of other normal cell development for substances and energy were assured.2 Comparing and analyzing the dynamic changes of cellular histochemistry on litchi pistil and stamen development indicate that the accumulation of starch and protein happened in the early stage both pistil and stamen floral primordium . After meiosis, fertile pistil and stamen always keep strong PAS reaction and protein metabolism until maturity. However, abortive pistil and stamen accumulate less starch and protein. Tapetum of abortive anther does not degrade after meiosis and resulted in pollen sterility. Ultra-structure changes of anther abortion and pistil abortion during development of litchi flower indicate that the programmed cell death (PCD) also occurred in the abortive anther or pistil tissue after meiosis, which leads to weak competition ability for nutrient and gradually causes abortion of the anther or pistil.3 By comparing and analyzing the dynamic changes of carbonitride in the floral sex determination of litchi we found that: higher C/N and lower amino acid content are beneficial to androecium differentiation; in contrast, lower C/N and higher amino acid content are adequate for gynoecium differentiation; the amino acid content in androecium is only half of that in gynoecium. Proline is associated with pollen developmental capacity.4 Results obtained by analyzing the dynamic changes of polyamine, nucleic acid and proteins in differentiation process of litchi floral bud indicate that in the process from the leaf bud to the primary panicle development, the content of polyamine continually rises and reaches the peak value before the mass-synthesis of nucleic acid and proteins. So polyamine may affect floral development by regulating the synthesis of biological macromolecule. The content of Spm, Spd and soluble proteins in the mature autumn top leaf increase along with the increase of terminal buds or floral buds. It showed that the metabolism of nitrogenous compound in the leaf is vital for stern apex shiftingfrom nutritive growth to reproductive growth.Development of litchi stamen is related closely to the synthesize of Put, and development of pistil is related to high content of Spd+Spm. During development of litchi pistil and stamen, polyamine help to regulate nuclear acid and protein metabolism, which implied that polyamine has a role in regulating sex更多还原