【作者】 李景原；

【导师】 胡正海；

【作者基本信息】 西北大学 ， 植物学， 2003， 博士

【摘要】 芦荟属(Aloe)植物隶属于百合科(Liliaceae)，是多年生、常绿、肉质草本植物。其泌出物已广泛用于医药和日用化工中，芦荟的主要有效药用成分是芦荟素等蒽醌类物质。应用植物解剖学、植物化学、组织化学和荧光显微镜观察相结合的方法研究了芦荟属植物茎、叶的发育和结构，测定了芦荟素在芦荟属植物体内的积累部位和含量，在此基础上探讨了芦荟属植物茎叶的发育和结构与芦荟素积累的动态关系。 研究结果表明：1，芦荟叶的发育包括原生分生组织、初生分生组织和初生结构三个阶段。在原生分生组织阶段，叶原基呈现出典型的分生组织特征，细胞核大，细胞质浓，细胞壁薄，无细胞间隙。不久，叶原基发育到初生分生组织阶段，其结构明显分化为原表皮，基本分生组织和原形成层束三部分。原表皮位于最外面，由一层排列紧密的细胞组成。原表皮之内是基本分生组织，原形成层束排列成一轮，分布于基本分生组织之中。位于原形成层束内外两侧的基本分生组织，其细胞大小和分化程度明显不同。原形成层束外侧的基本分生组织，细胞体积较小，细胞核较大，细胞质开始液泡化；而其内侧的基本分生组织，细胞的体积明显增大，细胞核小，液泡化明显，并出现细胞间隙。之后，叶发育到初生结构阶段。原表皮分化为表皮。原形成层束分化为维管束。维管束外侧的基本分生组织分化为同化组织，而其内侧的基本分生组织分化为储水组织。2，叶内维管束和大型韧皮薄壁细胞的发育过程如下：在原形成层束分化成维管束初期，包围在原形成层束外的一圈基本分生组织细胞发育成维管束鞘。原生韧皮部筛管产生时，其外侧尚保留1-2层原形成层束细胞，当后生韧皮部和木质部开始分化时，此层细胞分裂。在后生韧皮部和木质部发育成熟过程中，这些细胞体积逐渐增大，并液泡化，发育成为大型韧皮薄壁细胞，位于筛管外侧。因此，芦荟叶维管束内的大型韧皮薄壁细胞(也称“芦荟素细胞”)来源、发生发育时间和空间结构位置与韧皮部相同，属于特化的韧皮部薄壁组织细胞。3，用经醋酸铅处理过的材料切片观察发现，在大型韧皮薄壁细胞液泡化之前，细胞内并没有芦荟素等葱酿类物质沉淀物。在细胞体积增大并液泡化时，液泡内开始出现芦荟素等葱酮类物质沉淀物，在成熟细胞的大液泡中充满沉淀物。电子显微镜观察表明，大型韧皮薄壁细胞在发育早期含有丰富的细胞质和大量质体。质体具有完整的膜片层结构。随着大型韧皮薄壁细胞的液泡化，其细胞中质体的膜片层结构开始解体。当中央大液泡形成时，中央大液泡内积累了大量嗜饿的蕙醒类物质。荧光显微镜观察结果也证明，成熟大型韧皮部薄壁组织细胞发出桔黄色荧光。由此可见，此种大型韧皮部薄壁组织细胞是芦荟叶内芦荟素等葱醒类物质的主要储存场所。4，不同叶龄的木立芦荟叶都由表皮、同化组织、储水组织和维管束组成。幼叶与老叶的主要区别在于:幼叶维管束中大型韧皮薄壁细胞发育良好，而老叶维管束中大型韧皮薄壁细胞已衰败。高效液相色谱法测定结果表明，在同一株植物上，木立芦荟叶从上到下随着叶龄的增大芦荟素的含量逐渐降低。幼嫩的叶虽然芦荟素含量高，但叶小，总生物量少;相反，老叶总生物量多，但芦荟素含量低。因此，幼叶和老叶均不是木立芦荟叶的最佳采收时期。而位于中部的2年生的成熟叶芦荟素含量比较高且生物量多，最适宜采收。5，木立芦荟茎结构的发育过程包括初生分生组织、初生结构和次生生长三个发育阶段。初生分生组织由原表皮、基本分生组织和原形成层束组成。初生结构由表皮、薄壁组织和维管束组成，其中的初生维管束为外韧有限维管束，分散于薄壁组织内。次生加厚分生组织起源于正常的散生维管束中柱外侧的薄壁组织细胞。次生加厚分生组织切向分裂，向外侧产生的细胞分化成薄壁组织;向内产生的细胞，一部分细胞分化成为薄壁组织，称为结合组织，另一部分细胞则分化成为次生周木维管束，分散于结合组织中。此时，由表皮之内的一层薄壁组织细胞恢复细胞分裂能力，进行切向分裂，以后形成周皮。木立芦荟茎初生结构阶段的增粗主要是基本分生组织和薄壁组织细胞的分裂和体积增大的结果，而在老茎中，茎的增粗主要是由次生加厚分生组织进行细胞分裂及其衍生细胞体积增大的结果。在茎的初生和次生维管束中都没有大型韧皮部薄壁组织细胞。薄层层析(几C)结果证明茎内不含芦荟素。6，对木 2立芦荟、易变芦荟、中华芦荟、库拉索芦荟、皂叶芦荟和绿芦荟等6种芦荟属植物成熟叶的比较解剖学研究证明，木立芦荟、中华芦荟、易变芦荟和库拉索芦荟的维管束中大型韧皮薄壁细胞发达，绿芦荟的维管束中大型韧皮薄壁细胞不发达，而皂叶芦荟的维管束中没有大型韧皮薄壁细胞;木立芦荟、易变芦荟和库拉索芦荟，在同化组织和储水组织之间有一层不含叶绿体的小型薄壁细胞，包围着储水薄壁组织，称之为储水组织鞘。而中华芦荟、绿芦荟和皂叶芦荟则没有储水组织鞘。HPLC测量结果表明，木立芦荟、易变芦荟和库拉索芦荟叶芦荟素含量高，中华芦荟?更多还原

【Abstract】 The plants of Aloe belong to Liliaceae, they are multiperennial, evergreen and succulent plants. The exudates of Aloe plants have been used as drugs or cosmetics widespreadly. The mainly biological activity constituents of the aloe exudates were anthraquinones ,such as aloin. In this study, we investigated the developments and structures of stems and leaves, fixed the storing location of aloin in aloe plant, determined the content of aloin by using anatomical, phytochemistry, histochemistry and fluorescent microscope multiply. Finally, the developments and structures of stems and leaves and their relations with the accumulation of aloin were discussed.The development of leaves consisted of three stages: promeristem, primary meristem and primary structure stage. Promeristem possessed the typical cell characteristics of meristem, with big nucleus, abundant of cytoplasm and thin cell wall. There were no intercellular space. Then the promeristem developed into primary meristem stage, the leaf primordium different into protodern, ground meristem and procambial bundles. Protodern was the outermost cells, it consisted of cells that fit closely together, nearly or quite without intercellular spaces. Ground meristem located at the center of leaf and a ring of procambial bundles embedded in ground meristem. The ground meristem located outside or inside of the ring of procambial bundles were different in cell volume and degrees of cell differentation. The ground meristem cells outside the ring of procambial bundles possessed small volume, big nucleus and started to vacuolization. In creast of, the ground meristem cells inside the ring of procambial bundles possessed big volume, small nucleus, developed vacuole and intercellular spaces. Finally, the leaf developed into primary structure stage. Protoderndeveloped into epidermis. Ground meristem outside the ring of procambial bundles developed into chlorenchyma and ground meristem inside the ring of procambial bundles developed into water storing tissue. The procambial bundles developed into vascular bundles.The development of vascular bundle and big phloem parenchymatous cells as fellow. The cells rounded the procambium bundle differentiated into bundle sheath at the initial stage when the procambium bundle developed into vascular bundle. When the sieve tube member emerged in protophloem, there were one or two lay of procambium bundle cells between the sieve tube member and bundle sheath, and these procambium bundle cells began to devise when metaphloem and metaxylem first appeared in the bundle. With the increase of volume and vacuolization, the cells between the sieve tube member and bundle sheath developed into big phloem parenchymatous cells. Because the big phloem parenchymatous cells shared the same origin development with the other phloem cells, the big phloem parenchymatous cells were special phloem parenchyma cells.The investigation of histochemistry showed that there were precipitate in the central vacuole of big phloem parenchymatous cells when the material was soaked in the liquid of 1% lead acetate [ Pb (CH3COO)2]. The observation of TEM showed that there were abundent of osmiophilic materials in the central vacuole of big phloem parenchymatous cells. The yellow fluorescence was observed in big phloem parenchymatous cells when the section of life material was investigated by fluorescent microscope with blue light. So the big phloem parenchymatous cells of vascular bundles were the mainly storage location of anthraquinones, such as aloin.The anatomical structures were studied in Aloe arborescens leaves according to leaf age. All leaves were consisted of epidermis, chlorenchyma, water storing tissue and vascular bundles. The different between young leaf and old leaf was that the young leaf with developed big phloem parenchymatous cells, whereas the old leaf with decrepit ones. The aloin content determined by HPLC decreased accompanying the increase of leaves age in the same plant. The young leaves had high aloin content,but their yiel更多还原