芦荟属植物叶内蒽醌类物质的分布与其化学防御的关系

芦荟属植物是一类生长在干旱或半干旱沙漠环境的肉质植物,木立芦荟和海藻芦荟的肉质叶的植物研究结果表明,叶内含高浓度的芦荟素,高那特芦荟素,芦荟苦素和芦荟宁等蒽醌类物质,其中,海莱芦荟整叶的蒽醌类物质总含量占其泌出物干重的44．89％。两种芦荟叶内蒽醌类物质的分布有共同的规律,即幼叶的含量高于老叶;叶上部的含量高于中,基部,叶缘则高于叶的中央。但由于木立芦荟和海莱芦荟的个体形态不同,蒽醌类物质的分布在种间还存在各自的特点,根据实验结果推测,蒽醌类物质在芦荟属植物体内的累积和分布与其化学防御机制有关。     

芦荟属植物叶内蒽醌类物质的组织化学定位研究

蒽醌类物质是芦荟属（Aloe)植物叶内贮存的重要次生代谢物质,主要是芦荟素,高那特芦荟素,芦荟苦素和芦荟宁等。根据蒽醌类物质的理化性质,用2％－5％NaOH和5％Pb(CH3COO)2溶液对材料进行处理,再辅以荧光和超薄切片观察等多种方法,对芦荟叶内的4种主要蒽醌类物质进行了组织化学定位研究。结果表明,蒽醌类物质在芦荟叶内的贮藏是多位点的。芦荟素和高那特芦荟素主要位于韧皮部的大型薄壁组织细胞之中;而芦荟苦素和芦荟宁主要位于维管束鞘细胞以及贮水组织与同化薄壁组织之间的1圈薄壁组织细胞之中,贮水组织细胞中不贮存蒽醌类物质。     

增强UV-B辐射对3种芦荟蒽醌类物质含量的影响

以中华芦荟、库拉索芦荟和木立芦荟为试验材料,采用HPLC技术,研究了增强UV-B辐射对3种芦荟叶片中主要药用成分总蒽醌、芦荟素和芦荟大黄素含量的影响。结果显示:增强UV-B辐射20 d,每天处理6 h,库拉索芦荟和木立芦荟叶中总蒽醌、芦荟素、芦荟大黄素的含量增加,叶提取物中出峰数量增多,总峰面积增大;而中华芦荟中蒽醌类物质含量显著降低,叶提取物中出峰数量减少,总峰面积减少。研究表明,增强UV-B辐射能刺激库拉索芦荟和木立芦荟叶片中蒽醌类物质的积累和新物质的合成,而不利于中华芦荟蒽醌类物质的积累。     

中华芦荟叶的解剖学、组织化学和植物化学研究

用解剖学,组织化学和植物化学方法研究了中华芦荟（Aloe vera L.var.chinensis(Haw.)Berg.)叶的结构,芦荟素的含量及其可能的储藏和合成场所,解剖学研究结果表明,中华芦荟叶的结构由表皮,同化薄壁组织,维管束和储水组织组成,其旱生结构特征比较明显,表皮具厚的角质层,外切向壁次生加厚,气孔下陷,中央储水组织发达,绿色组织没有明显的分化,其中,5个细胞环绕的气孔器和叶基出现的第二轮维管束在芦荟属中首次报道,具有种的特征,中华芦荟叶中所含的蒽醌类次生代谢物主要是芦荟素（barbaloin or aloin),其含量和叶位及同一叶的不同部位有关,植株上剖嫩叶及每一叶的上部含量高于下部老叶和叶的中部,叶基部含量最低,比较被测的解剖学指标和植物化学分析的结果发现,叶中维管束的密度和芦荟素的含量呈明显的正相关,用5％Pb(CH3COOH)2沉淀处理及5％NaOHR颜色反应检测芦荟素的储藏物合成部位,初步结果表明,位于韧皮部端的数个发达大型薄壁细胞是芦荟素的储藏场所,而绿色组织和维管束鞘是可能的合成场所。     

粗柄独尾草不同器官蒽醌类成分的消长规律

采用高效液相色谱法对沙生类短命植物粗柄独尾草苗期、营养生长期、初花期、盛花期、果期各器官中大黄素、大黄酚、大黄酸、芦荟大黄素含量的消长规律进行了研究。结果表明:叶中,芦荟大黄素的含量在苗期和初花期都较高,在盛花期时最低;大黄酸的含量在苗期最高,盛花期时最低;大黄素的含量在苗期达到最高,初花期和盛花期最低;大黄酚的含量也以苗期最高,盛花期和果期最低。且在初花期时,4种蒽醌类物质含量均呈现明显的叶先端>叶中部>叶基部的空间差异性。根中,芦荟大黄素的含量在苗期和营养生长期较高,而以盛花期和果期较低;大黄酸的含量在果期最高,其余时期差异不显著;大黄素的含量以苗期和初花期较高;大黄酚的含量在果期达最高,而盛花期时最低。同时期的根叶蒽醌含量相比,叶中的芦荟大黄素要高于根,而根中大黄酚含量要高于叶。同时期各器官蒽醌总量相比:叶>根>花>花葶。故若选取粗柄独尾草作为蒽醌类药材利用,建议最佳采集方式为采集初花期的叶先端部分。     

3种芦荟属植物叶的表皮扫描电镜观察及芦荟素含量的测定

以库拉索芦荟、木立芦荟和皂质芦荟为材料,用扫描电镜观察其叶表皮气孔和角质膜的结构,用高效液相色谱法(HPLC)测定了3种芦荟属植物叶中芦荟素的含量。扫描电镜观察结果表明,3种芦荟叶表皮都覆盖有厚的角质膜,气孔下陷,表现出典型的旱生植物特征。但角质膜的纹饰和厚度在不同芦荟间有显着差异。木立芦荟角质膜表面呈瘤状突起,角质膜厚度为5～6μm,库拉索芦荟和皂质芦荟的角质膜表面较平,库拉索芦荟的角质膜厚度为3～4μm,皂质芦荟的角质膜厚度为8～10μm。高效液相色谱法(HPLC)测定结果表明,木立芦荟叶含芦荟素最高,库拉索芦荟叶含量较低,而皂质芦荟叶含量最低。此外,本文还初步探讨了芦荟属植物叶表皮结构与芦荟素含量的关系。     

木立芦荟不同叶龄叶的解剖学和组织化学及其植物化学研究

应用植物解剖学、组织化学、荧光显微观察与植物化学技术相结合,研究了木立芦荟不同叶龄叶的解剖结构、叶绿素和类胡萝卜的含量、芦荟素的含量及其合成和贮藏结构的特点。结果表明:芦荟素由同化薄壁组织产生,叶绿体的基质为其合成场所。芦荟素细胞可能是芦荟素早期贮存的场所,随着芦荟素细胞的逐渐萎缩老化,维管束鞘细胞成为贮藏芦荟素的代替场所。同一植株的叶随着叶龄的增长,维管束的密度降低,芦荟素细胞占维管束横切面的百分比减小,同化薄壁组织细胞中的叶绿体逐步衰老、解体,芦荟素含量逐渐降低,但不同叶龄叶中叶绿体色素的含量与芦荟素含量间没有明显的相关性。     

遮荫对库拉索芦荟蒽醌类物质的影响

采用高效液相色谱技术,研究了遮荫65%处理6个月对库拉索芦荟叶片中主要有效成分蒽醌类物质的影响,以探讨遮荫导致芦荟有效成分变化的原因.结果显示:(1)遮荫使芦荟叶中总蒽醌、芦荟素和芦荟大黄素含量分别比自然光下显著减少了39.22%、18.65%和40.96%.(2)遮荫处理下芦荟叶片中大部分物质含量较对照减少,且化学成分种类也明显减少,但在24、46 min两个时间遮荫处理出现的物质含量明显高于对照.(3)遮荫使芦荟叶中可溶性蛋白和可溶性糖含量较自然光下分别显著减少33.33%和73.05%,MDA含量显著减少48.78%.研究表明,遮荫使芦荟叶片中可溶性糖和可溶性蛋白含量下降,致使同化产物合成效率降低,次生代谢物合成前体减少,最终影响总蒽醌、芦荟素和芦荟大黄素的合成和积累.     

芦荟蒽醌类物质对灌浆期冬小麦光合作用及产量的影响

UV—B辐射伤害是导致小麦光合效率降低的环境因素之一。于2007年5月2日-6月5日，在河南新乡地区，研究了叶面喷施芦荟蒽醌类物质对冬小麦灌浆期旗叶光合速率、光呼吸速率、叶绿素含量、丙二醛含量和产量等的影响，旨在探索预防UV辐射伤害的新途径。结果表明：在灌浆期用浓度为1和5mg·L^-1的芦荟蒽醌类物质喷施小麦，光合作用速率分别提高了38．03％和39．73％；叶绿素含量分别提高了3．53％和3．83％，丙二醛含量分别降低了11％和23％；蒽醌类物质能够吸收太阳中的紫外线，并将紫外线转换成能促进光合作用的蓝光或黄光；芦荟蒽醌类物质能促进小麦光合作用效率，减轻紫外线对小麦的损伤；喷施合适浓度的芦荟蒽醌类物质能够提高小麦产量。     

9种芦荟属植物叶的结构和芦荟素含量的比较研究

9种芦荟属植物叶的比较解剖研究结果表明,它们都具有明显的旱生叶的结构特征,其维管束的韧皮部内都有大型薄壁细胞,但其表皮角质膜的厚度,表面纹饰,气孔上,下腔的形状和大小,同化组织 导 ,细胞分化情况,维管束的大小,分布密度和其大型薄壁细胞占维管束的比例,中央贮水组织占叶横切面的比例等特征,在各种间存在差异,且性状稳定,可以作为该属内种间分类的解剖学指标,植物化学分析结果表明,9种植物叶内蒽醌类物质的主要种类和含量不同,其含量高,低与叶内维管束密度,大型薄壁细胞占维管束的比例以及同化组织的厚度密度切相关,从而为芦荟属植物选育商业用良种提供了植物解剖学依据。     

The distribution of the phenolic metabolites barbaloin, aloeresin and aloenin as a peripheral defense strategy in the succulent leaf parts of Aloe arborescens

Aloe arborescens is a large, multi-stemmed shrub. It is used as hedge plants to protect agricultural fields or stock and as horticultural plants in gardens. In natural habitats it is one of the very common Aloe species along the Indian Ocean coast of southern Africa, from the Cape, in the south, to Zimbabwe and Malawi in the north. Secondary phenolic metabolites such as barbaloin (Rf 0.31-0.35), aloeresin (Rf 0.25-0.3) and aloenin (Rf 0.51-0.55) have been found to be distributed in the succulent leaves of Aloe arborescens in a peripheral defense strategy. The youngest leaves have the highest content. The terminal third of each leaf has the highest content and the basal third, the lowest. Along the leaf margins, on the top third and adaxial side, the content is the highest and in the base third, the lowest along the leaf center on the abaxial side. Similar relative amounts of these three secondary phenolic metabolites were found in the different leaf locations. The leaf orientation may affect the total content of these three phenols but not their relative amounts in the different parts of the leaves. It is possible that the more often the plant parts are damaged by consumption by animals such as elephants, kudu or insects, the greater the increase of their phenolic metabolites. This increase may reduce or prevent further consumption when the content of the metabolites reaches a certain level. The plants then have a chance to renew themselves.     

Anatomical structure and distribution of secondary metabolites as a peripheral defence strategy in Aloe hereroensis leaves

Eight leaves from four different plants of Aloe hereroensis and 18 leaf parts of each leaf were tested by anatomic, fluorescence microscopy and TLC methods. Four phenolic secondary metabolites, homonataloin and three isomers of aloeresin, were found in the leaves. The highest content of these metabolites was found in the top third of a leaf and along the leaf margins. In the margins, the content of the four secondary metabolites in the adaxial was higher than in the abaxial direction. In the centre parts of the leaves, the metabolic content of the abaxial parts was higher than in the adaxial parts. The results indicate that homonataloin mainly accumulates in the inner bundle sheath cells (IBSC). The three isomers of aloeresin appear in the outer bundle sheath and in the boundary cells between the chlorenchyma and water-storage tissues. The density of the vascular bundles, the area ratio of the chlorenchyma to the tested counterpart, and the area ratio of the IBSC to a whole bundle are important structural factors to determine the differences in the content of these four secondary metabolites in all the leaf parts. The distribution according to the rosette leaf arrangement and the existence of the 'cocktail' of four phenolic secondary metabolites indicate a peripheral defence strategy of this plant. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 138 , 107–116.     

不同栽培龄期光果甘草不同部位总黄酮含量的分析

光果甘草(Glycyrrhiza glabra L.)为甘草属(Glycyrrhiza L.)多年生草本植物,是药用甘草的原植物之一[1].甘草属植物所含的黄酮类成分具有抗血栓、抗氧化、抗肿瘤、抗衰老、增加白细胞、抗动脉硬化、抗心律失常和抑制HIV等作用[2-5];光果甘草中的黄酮类成分光甘草定具有良好的抗氧化、抗炎及抗菌作用,应用前景广阔[6].目前关于光果甘草总黄酮含量已有一些报道[7-8],但有关生长年限对栽培光果甘草总黄酮含量的影响却很少报道[9-10],尤其是对不同栽培龄期光果甘草在不同采集时间各部位总黄酮含量的变化规律缺乏较全面的研究,致使光果甘草药材生产缺乏有力的理论指导依据.     

Peripheral defence strategy: variation of barbaloin content in the succulent leaf parts of Aloe arborescens Miller (Liliaceae)

Ah arborescens is a large, multi-stemmed shrub and is one of the very common Aloe species along the Indian Ocean coast of southern Africa, from the Cape, in the south, to Zimbabwe and Malawi in the north. It is used as a hedge plant to protect agricultural fields or stock and as a horticultural plant in gardens. Barbaloin, a secondary phenolic metabolite, is distributed in the plants as part of a peripheral defence strategy. Barbaloin content was found to be highest in the youngest leaves. Within these, concentration varied at its highest in the terminal third of the leaf, at its lowest in the basal third; higher in the terminal, adaxial, leaf margin and lower in the basal, abaxial, leaf centre. The more times a leaf is cut, the higher the barbaloin content of the new growth from the leaf base that remains on the plant. This may deter animals such as elephants and kudu from eating the new growths. They may prefer to eat other plants that have not been damaged by consumption for longer periods. This phenomenon may give damaged plants the chance to renew themselves before their leaves are consumed again.     

Polarity of the stem and ontogenetic changes in sunflow (Helianthus annuus L.) leaves in relation to endogenou cytokinins and ethylene

The content of endogenous cytokinin-like substances and the release of ethylene were determined in leaves of different insertion of sunflower plants during their ontogeny. The content of cytokinin-like substances was highest in the leaves on the middle part of the stem (that is in leaves just before full expansion), with a decrease occurring both towards the base and the apex of the stem, when followed at four growth phases (vegetative plants, plants with inflorescence diameter up to 0.5 cm, plants with inflorescence diameter up to 3 cm, and plants in flower). Changes in the content of cytokinin-like substances during the ontogeny of the leaf also corresponded to this pattern. Data obtained with the leaf at the third node from the basis of the stem showed that the level of cytokinin-like substances first sharply increased, and then after reaching maximal value (at the time when leaf blade area reached approximately 70 % of the final value) slowly and continuously decreased. The highest amount of ethylene released from the leaves was recorded in basal leaves and then also in apical leaves, whereas the leaves with the largest blade area situated at the central part of the stem released the lowest amount of ethylene. This pattern was repeatedly found at all four selected growth phases of sunflower plants.     

Chemical and mechanical changes during leaf expansion of four woody species of dry Restinga woodland

Young leaves are preferential targets for herbivores, and plants have developed different strategies to protect them. This study aimed to evaluate different leaf attributes of presumed relevance in protection against herbivory in four woody species (Erythroxylum argentinum, Lithrea brasiliensis, Myrciaria cuspidata, and Myrsine umbellata), growing in a dry restinga woodland in southern Brazil. Evaluation of leaf parameters was made through single-point sampling of leaves (leaf mass per area and leaf contents of nitrogen, carbon, and pigments) at three developmental stages and through time-course sampling of expanding leaves (area and strength). Leaves of M. umbellata showed the highest leaf mass per area (LMA), the largest area, and the longest expansion period. On the other extreme, Myrc. cuspidata had the smallest LMA and leaf size, and the shortest expansion period. Similarly to L. brasiliensis, it displayed red young leaves. None of the species showed delayed-greening, which might be related to the high-irradiance growth conditions. Nitrogen contents reduced with leaf maturity and reached the highest values in the young leaves of E. argentinum and Myrc. cuspidata and the lowest in M. umbellata. Each species seems to present a different set of protective attributes during leaf expansion. Myrciaria cuspidata appears to rely mostly on chemical defences to protect its soft leaves, and anthocyanins might play this role at leaf youth, while M. umbellata seems to invest more on mechanical defences, even at early stages of leaf growth, as well as on a low allocation of nitrogen to the leaves. The other species display intermediate characteristics.     

农林复合系统滇龙胆茎叶化学计量特征研究

以农林复合系统种植的滇龙胆(Gentiana rigescens Franch.ex Hemsl.)为材料,采用高效液相色谱法建立不同栽培系统滇龙胆茎、叶的色谱指纹图谱,并测定其主要活性成分马钱苷酸、獐牙菜苦苷、龙胆苦苷和当药苷含量,研究不同栽培系统滇龙胆茎、叶化学计量特征。采用相关性分析、指纹图谱相似度分析、偏最小二乘判别分析(PLS-DA)、变量投影重要性准则(VIP)等方法进行化学数据分析。结果显示,滇龙胆主要活性成分马钱苷酸含量为(1.85±0.92)mg/g~(7.43±7.64)mg/g,獐牙菜苦苷含量为(1.03±0.17)mg/g~(1.58±0.50)mg/g,龙胆苦苷含量为(15.28±11.34)mg/g~(24.59±7.84)mg/g,当药苷含量为(4.10±1.64)mg/g~(31.67±22.70)mg/g,且叶片中4种活性成分的总含量高于茎;不同栽培系统中,与尼泊尔桤木间作的滇龙胆茎、叶活性成分总含量最高,而与核桃间作的滇龙胆茎、叶活性成分总含量最低。相关性分析显示,植株相同部位和不同部位间的环烯醚萜和裂环烯醚萜含量呈显著(P0.05)或极显著(P0.01)正相关。指纹图谱相似度分析表明,不同栽培系统滇龙胆茎指纹图谱相似度介于0.989~0.992之间、叶指纹图谱相似度为0.988~0.996,相同部位样品化学成分种类相似。PLS-DA分析结果表明,茎和叶片整体化学计量特征具有明显差异;单作及林药间作的样品被区分为不同类群,不同间作模式下滇龙胆茎、叶化学成分具显著差异,叶片高效液相色谱指纹图谱可用于区分不同栽培系统滇龙胆样品。本研究结果可为农林复合系统滇龙胆有效成分含量研究及滇龙胆资源的合理开发利用提供科学依据。     

Utilization of Photosynthetically Fixed 14CO2 into Alkaloids in Relation to Primary Metabolites in Developing Leaves of Catharanthus roseus

Partitioning of current photosynthates towards primary metabolites and its simultaneous incorporation in leaf alkaloids was investigated in developing leaves of medicinally important Catharanthus roseus. Of the total ¹⁴CO₂ assimilated, the leaves at positions 1–6 fixed 8, 22, 25, 19, 13, and 8 %, respectively, and stem 3 %. Leaf fresh mass, chlorophyll content, and CO₂ exchange rate increased up to the third leaf. The total alkaloid content was highest in young actively growing leaves, which declined with age. Total ¹⁴C fixed and its content in ethanol soluble fraction increased up to the third leaf and then declined. The ¹⁴C content in primary metabolites such as sugars and organic acids was also highest in the 3^rd leaf. The utilization of ¹⁴C assimilates into alkaloids was maximum in youngest leaf which declined with leaf age. Hence the capacity to synthesize alkaloids was highest in young growing leaves and metabolites from photosynthetic pathway were most efficiently utilized and incorporated into alkaloid biosynthetic pathway by young growing leaves.