漆树产漆组织的结构、发育及其与生漆关系的研究

【作者】 赵猛；

【导师】 胡正海；

【作者基本信息】 西北大学 ， 植物学， 2013， 博士

【摘要】 漆树为我国重要的特产经济树种,所产生漆是从其树干次生韧皮部采割而来。本文应用植物解剖学、植物化学以及透射电子显微镜技术,对陕西产大红袍、高八尺以及宁陕等漆树品种的茎干树皮的结构、发育及其超微结构变化进行了研究,并对漆树各器官中乳汁道的发生、发育以及乳汁道拟侵填体的结构与发育进行了研究,在此基础上研究探讨了漆树韧皮部组成分子的结构与生漆产量及漆酚同系物含量之间的关系。结果表明陕西产三个漆树品种(大红袍、高八尺以及宁陕漆树)茎干树皮的基本结构相似,均由维管形成层、次生韧皮部和周皮组成,维管形成层由纺锤状原始细胞和射线原始细胞组成。次生韧皮部由垂直系统的筛管、伴胞、韧皮薄壁细胞、石细胞、乳汁道以及水平(径向)系统的韧皮射线组成。周皮由栓内层、木栓形成层、木栓层及其木栓层外颓废的组织构成。漆树茎干维管形成层的活动有明显的季节性,冬季休眠,春、夏季细胞分裂活动。在当年产生的具功能韧皮部中的筛管发育成熟,具输导功能,而韧皮薄壁组织和射线尚处于幼嫩期,乳汁道也在分化发育中。其外侧为往年产生的无功能韧皮部,其筛管萎缩,失去输导功能；而且无功能韧皮部中的乳汁道发育成熟,大量分泌生漆,韧皮薄壁体积增大,韧皮射线可增至3-5列细胞。此外,在无功能韧皮部中由部分薄壁细胞分化形成石细胞群,并有部分乳汁道腔内形成拟侵填体堵塞乳汁道。在上述次生韧皮部结构发育过程中,其组成分子的超微结构发生相应的变化。漆树乳汁道是由上皮细胞围绕着腔道构成,其外侧又由鞘细胞环绕。漆树各器官中除雄蕊和种子外均有乳汁道的分布,乳汁道主要分布在各器官维管束的韧皮部内,以裂生方式形成,茎的髓部薄壁组织也有少量乳汁道,但其直径较小。其中茎初生韧皮部中乳汁道存在二次发育的现象,雌蕊的柱头中乳汁道还存在裂溶生现象,漆树果实的果皮内的乳汁道结构特殊,其乳汁道鞘细胞发达,而分泌细胞萎缩。漆树茎干次生韧皮部的部分乳汁道腔中拟侵填体,由乳汁道上皮细胞增殖形成,其上皮细胞通过平周分裂的方式形成拟侵填体细胞并堵塞乳汁道腔,后期拟侵填体细胞解体,醌类物质聚合成团块状堵塞乳汁道腔。漆树树皮中乳汁道的侵填还存在季节性变化,拟侵填体细胞一般发生在每年秋季,其醌类物质对乳汁道的堵塞发生在拟侵填体细胞解体后并持续到第二年春,第二年春季末期堵塞乳汁道的醌类物质自溶,多数乳汁道腔逐渐恢复畅通；夏季除靠近周皮处得乳汁道被醌类物质堵塞外大部分乳汁道均保持畅通。拟侵填体细胞都发生在漆树无功能韧皮部的乳汁道中,在有功能韧皮部中未见分布,在不同漆树品种的树皮中乳汁道的拟侵填体细胞的形成过程相似,但在形成时间上存在差异。分泌道中产生拟侵填体在裸子植物中已有报道,但在被子植物的分泌道中产生拟侵填体是首次发现。不同漆树品种的树皮结构的研究结果表明,其基本结构相同,但在组成分子的大小、数量等方面存在品种间差异；不同漆树品种的生漆产量及生漆中漆酚同系物相对含量也存在差异。对构成漆树次生韧皮部的主要组成分子筛管直径,乳汁道数量、乳汁道平均直径、石细胞群数量、射线数量、树皮平均厚度等指标与生漆产量和漆酚同系物含量进行相关性分析发现,乳汁道数量、乳汁道平均直径和树皮平均厚度与生漆产量和漆酚同系物中的三烯漆酚均呈显著正相关,与二烯漆酚和单烯漆酚相关性不显著,与尚未鉴定的漆酚成分呈负相关,其中,生漆产量与三烯漆酚间呈正相关,而与其它同系物间呈负相关。从而表明,漆树树皮的结构特征、生漆产量和漆酚同系物含量可以作为区分漆树品种的指标之一,并表明漆树的树皮结构与其生漆产量及漆酚成分、三烯漆酚含量具有相关性。漆树是我国特有的经济树种,生漆的采割和应用在我国有着悠久的历史。前人对漆树的分布、种质资源、栽培管理、内部结构以及生漆化学等方面已有许多研究,为我国生漆的生产、加工和漆树品种的选育奠定了基础,本项研究是在前人研究基础上,系统研究漆树各器官中乳汁道的结构和发育、茎干韧皮部的结构和发育以及其乳汁道的发生、发育和拟侵填体的发生、分布规律,不同漆树品种主干树皮的结构特点与其生漆产量和漆酚组成的关系,研究结果可为提高生漆产量和质量提供科学依据。并为探讨植物的结构、发育与其次生代谢产物的关系提供新的资料。更多还原

【Abstract】 Toxicodendron vernicifluum (Stokes) F. A. Barkley is a kind of special economic tree in China, raw lacquer (also known as oriental lacquer) is the sap obtained by tapping lacquer trees. In this study, the bark structure and seasonal development and its ultrastructural changesof different lacquer trees varieties were characterized with the anatomical technique. Laticiferous canals development in different organs and tylosoids dynamic were also researched in this study. At the basis of those study, comparative studies of bark structure, lacquer yield and urushiel content were carried out with different cultivated T. vernicifluum varieties.The results showed that, the3varieties (Dahongpao, Gaobachi and Ningshan) had roughly similar bark structures, the bark was composed by vascular cambium, secondary phloem and periderm. The vertical system of secondary phloem consists of sieve tubes, companion cells, parenchyma cells, stone cells and secretory ducts, and radial system were composed with the phloem rays. Cambium activity has obvious seasonal variations, vascular cambium dormant in the winter and active in spring and summer. In the newly formed secondary phloem, sieve tube has been developed and mature with transporting function, parenchyma and phloem rays were still in the tender period, the secretion ducts were also in the differentiation period, this part of phloem known as the functional phloem. Outside of the functional phloem secondary phloem is the formation of in previous years, sieve tubes becomes atrophic and loss of transporting function, this part of phloem known as the non-functional phloem and occupied most of the area of bark; in non-functional phloem, the size of parenchyma cells gradually increased and squeezed sieve tubes, Secretory ducts development of mature and secreted a large number of lacquer in the canals, phloem rays can be increased to3-5rows. Moreover, part of the parenchyma cells formed into stone cells cluster in non-functional phloem. Corresponding changes of phloem were also found at ultrastructure level. The mature lumina were surrounded by a layer of secretory cells, which also had two to three layers of surrounding sheath cells. The T. vernicifluum laticiferous canals were mainly distributed in the vascular bundle and produced by the vascular cambium in the functional phloem through schizogenesis. Laticiferous canals distributed in almost all of the organs except the stamens and seeds. Laticiferous canals distributed in pith parenchyma, but it has smaller diameter. Secondary development of laticiferous canals were observed in primary phloem, Schizo-lysigenous of laticiferous canalswere also observed in the stigma of the pistil. Laticiferous canals which distributed in the lacquer tree fructification has special structure, the sheath cells of those laticiferous canals were evolutive but the secretory cells were shrinking.Tylosoids in the lumina oflaticiferous canals originated from epithelia through periclinal division. In the later dovelopment stages, the tylosoid cells disaggregated and the laticiferous canals were blocked by quinone conglomerations. Laticiferous canal invasions varied seasonally, at the beginning of traditional raw lacquer-tapping season, the quinone conglomerations dissolved, laticiferous canal function was renewed and epithelia secreted raw lacquer; at the end of the traditional raw lacquer-tapping season, tylosoids formed and blocked the laticiferous canals by quinone conglomerations until the next raw lacquer-tapping season. The irreversible invasion was mainly distributed in the nonfunctional phloem region near the periderm. These results suggest that the seasonal changes of tylosoids might provide insights into the defense mechanism of laticiferous canals against the invasion of other substances when cavity pressure decreases at the end of the tapping season.The bark structure and major chemical composition of raw lacquer in four cultivated varieties of the lacquer tree, T. vernicifluum, were characterized using the paraffin section technique and high-performance liquid chromatography, respectively. The four varieties had roughly similar bark structures; however, they differed in bark thickness, raw lacquer yields and urushiol homologue content. Laticiferous canal diameter and bark thickness were positively correlated with raw lacquer yields and triene-urushiol content. Our data suggest that bark structure, raw lacquer yield and urushiol homologue content are useful indicators for distinguishing among these four varieties.Raw (oriental) lacquer is the sap obtained by tapping lacquer trees, it has long been used as a coating and painting material because of its excellent waterproofing and antioxidative abilities and corrosion resistance. During past decades, most studies on T. vernicifluum have focused on the morpho-genesis and development of laticiferous canals and the chemical composition of raw lacquer, laid the foundation of lacquer production, processing and lacquer tree varieties bred. This study was carried out on the basis of previous studies, the bark structure and seasonal development and its ultrastructural changes and laticiferous canals development in different organs and tylosoids dynamic were systematicresearched in this study. At the basis of those study, comparative studies of bark structure, lacquer yield and urushiol content were carried out with different cultivated T. vernicifluum varieties. The results can provide a scientific basis to improve the yield and quality of raw lacquer, also can provide new datafor the relationship among the plant structure and development and secondary metabolites production.更多还原