4种药用芦荟叶的形态解剖学研究

通过植物形态解剖学方法研究４种药用芦蔡的叶的结构,结果表明：它们都具有早生多浆植物中的结构特征。表皮及角质层厚,气孔下陷,气孔下陷,孔下室大。叶肉分为二部分,由同化薄壁组织和储水组织组成。同化薄组织由多层细胞组成,细胞形态相似,不分化为栅栏组织和海绵组织。储水组织占据叶的体积一半以上,细胞大、不规则、壁薄、富含粘液。维管束具鞘,呈环状分布。紧靠同化组织的维管束赶忙皮薄壁组织发达,具有合成和储存芦荟     

First report of leaf spot disease caused by Phoma eupyrena Sacc. on Aloe vera from Madhya Pradesh,India

A leaf spot disease caused by Phoma eupyrena Sacc. on Aloe vera was reported from Madhya Pradesh, India. Disease symptoms were observed as irregular to elongated, sunken lesion on both leaf surfaces which later turns creamish brown with maroon margin. The fungal colonies were whitish or light pale to dark grey colour. The pycnidia were glabrous and solitary, papillate, and indistinctly uniostiolate averages 100–260 μm in diameter. Conidia were ellipsoidal, 4.5–7.5 × 2.5–3.75 μm in size, with two large guttules. To the best of our knowledge, this is the first report of P. eupyrena causing leaf spot disease on A. vera in India.     

Effect of Aloe vera preparations on the human bioavailability of vitamins C and E

There are no literature references describing the effect of consumption of Aloe vera liquid preparations on the absorption of water- or fat-soluble vitamins. There is a very large population worldwide which consume vitamins and many people also consume Aloe. Thus we report the effect of Aloe on the human absorption of vitamins C and E, the most popular vitamin supplements. The plasma bioavailability of vitamins C and E were determined in normal fasting subjects, with eight subjects for vitamin C and ten subjects for vitamin E. In a random crossover design, the subjects consumed either 500 mg of ascorbic acid or 420 mg of vitamin E acetate alone (control), or combined with 2 oz of two different Aloe preparations (a whole leaf extract, or an inner fillet gel). Blood was collected periodically up to 24 h after consumption. Plasma was analyzed for ascorbate and tocopherol by HPLC with UV detection. There was no significant difference in the areas under the plasma ascorbate–time curves among the groups sincerely due to large differences within the groups. For comparative purposes the control area was 100%. The Aloe Gel area was 304%, and Aloe Whole Leaf 80%. Only Aloe Gel caused a significant increase in plasma ascorbate after 8 and 24 h. For vitamin E, the results for the relative areas were control 100%, Gel 369%, and Leaf (198%). Only the Aloes produced a significant increase in plasma tocopherol after 6 and 8 h. Both Aloes were significantly different from the control after 8 h. Aloe Gel was significantly different from the baseline after 24 h. The Aloes slowed down the absorption of both vitamins with maximum concentrations 2–4 h later than the control. There was no difference between the two types of Aloe. The results indicate that the Aloes improve the absorption of both vitamins C and E. The absorption is slower and the vitamins last longer in the plasma with the Aloes. Aloe is the only known supplement to increase the absorption of both of these vitamins and should be considered as a complement to them.     

芦荟维管束的结构与芦荟素积累的相关性

应用半薄切片、组织化学、荧光显微镜观察和薄层层析 (TLC)相结合的方法研究了中华芦荟 (Aloeve-ra L.var.chinensis)、木立芦荟 (Aloe arborescens)叶和茎内维管束的结构及其与芦荟素积累的关系。结果表明 ,木立芦荟叶内维管束和中华芦荟叶内外轮的维管束中有大型韧皮薄壁细胞 ,而木立芦荟茎和中华芦荟叶中内轮维管束无大型韧皮薄壁细胞。组织化学结果表明 ,用醋酸铅处理过的上述材料 ,大型韧皮薄壁细胞内出现沉淀物 ;在荧光显微镜下经蓝光激发 ,大型韧皮薄壁细胞发出桔黄色荧光 ,都显示出芦荟素反应。薄层层析(TLC)结果证明 ,木立芦荟和中华芦荟叶含有大型韧皮薄壁细胞的维管束都含芦荟素 ,而木立芦荟茎及中华芦荟叶中内轮维管束都不含芦荟素。为此 ,维管束中的大型韧皮薄壁细胞与芦荟素的积累密切相关 ,维管束中是否有大型韧皮薄壁细胞可作为判断是否含有芦荟素的解剖学指标。     

遮荫对库拉索芦荟细胞超微结构和芦荟素含量的影响

分别用透射电子显微镜技术、高效液相色谱法研究了生长在遮荫和自然光照条件下库拉索芦荟叶片的超微结构和芦荟素含量.电镜观察结果表明,遮荫处理6个月后,库拉索芦荟叶片细胞中叶绿体基粒数量减少,类囊体片层数目减少且排列疏松,质体中原来积累的淀粉粒逐渐减少直至消失;内质网、高尔基体等内膜系统不发达.高效液相色谱分析结果显示,生长在遮荫条件下的库拉索芦荟叶片,芦荟素含量明显低于生长在自然光照下的含量.其中,遮荫下幼叶芦荟素的含量是自然光照下的63.33%,而成熟叶芦荟素含量仅有自然光照下的23.77%.无论自然光下还是遮荫条件下生长的芦荟,芦荟素的含量与叶龄有显著的负相关性,遮荫对成熟叶的影响更大.综合两方面的实验结果认为,遮荫首先影响芦荟叶片细胞内膜系统的发育,进而限制了芦荟素的合成和运输,使芦荟叶片中芦荟素含量降低.     

芦荟凝集素的分离、纯化和部分性质的研究

新鲜芦荟叶（Ａｌｏｅ ｖｅｒａ Ｌ．ｖａｒ．ｃｈｉｎｅｎｓｉｓ（Ｈａｗ．）Ｂｅｒｇｅｒ）于室温用低浓度ＮａＣｌ溶液提取。离心和透析后,经Ｎ－乙酰氨基葡萄糖０Ｓｅｐｈａｒｏｓｅ ４Ｂ亲和层析,分离纯化出芦荟凝集素（ＡＣＬ）。用ＳｅｐｈａｄｅｘＧ－１００测表观分子量为３５ＫＤ,ＳＤＳ－ＰＡＧＥ出现两条色带;染色 ;宽带和较浅的罕带。亚基分子量分别为１５ＫＤ和２０ＫＤ。能专一性凝集兔血细胞和人血红细胞     

木立芦荟组织培养pH分化特性及快速繁殖的研究

以木立芦荟的叶片、叶鞘、带腋芽的茎段为外植体进行试管培养 ,结果叶鞘和茎段可诱导形成愈伤组织 ,腋芽直接萌生。经试验筛选出各培养阶段最适宜的培养基为 :( 1 )愈伤组织诱导 ,MS BA 2 .5mg/L NAA0 .1 5mg/L ;( 2 )腋芽萌生 ,MS BA 2 .0mg/L NAA 0 .1 5mg/L ;( 3 )丛生芽分化及继代 ,MS BA 2 .0mg/L NAA0 .1 0mg/L ;( 4)生根 ,MS BA 0 .3～ 0 .5mg/L IBA 0 .2mg/L 活性碳 0 .5%。研究还发现 ,培养基酸碱度对木立芦荟组织培养分化效果的影响非常显著。     

六种芦荟叶的解剖结构及其与芦荟素含量的相关性

应用半薄切片法、高效液相色谱法(HPLC)和荧光显微镜研究了6种芦荟叶的结构、芦荟素的含量和储藏芦荟素的组织.结果表明,6种芦荟叶均由表皮、光合组织、储水组织和维管束组成,都表现出明显的旱生植物肉质叶的结构特征,表皮由一层扁平的细胞组成,其外壁加厚,并覆盖着厚的角质膜,气孔器凹陷,储水组织发达.6 种芦荟叶的结构存在显著差异.木立芦荟(Aloe arborescens Mill.)和易变芦荟(A. mutabilis Pillans)的光合组织细胞呈长柱状,类似栅栏薄壁组织.中华芦荟(A. vera L. var. chinensis Berg.)、库拉索芦荟(A. vera L.)、皂叶芦荟(A. saponaria Hawer)和绿芦荟(A. greenii Bak.)则为等直径薄壁细胞.木立芦荟、中华芦荟、易变芦荟和库拉索芦荟的维管束中有大型薄壁细胞,皂叶芦荟和绿芦荟的维管束中无大型薄壁细胞.木立芦荟、易变芦荟和库拉索芦荟在光合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.中华芦荟、皂叶芦荟和绿芦荟则没有储水组织鞘.HPLC测量结果表明,木立芦荟叶芦荟素含量最高,库拉索芦荟和易变芦荟次之,中华芦荟、皂叶芦荟和绿芦荟含量最低.荧光显微镜观察结果表明,在紫外光和蓝光下,黄色和黄绿色小球体仅存在于维管束的大型薄壁细胞、维管束鞘和储水组织鞘中,而光合组织和储水组织中没有黄色和黄绿色小球体.因此,维管束中大型薄壁细胞、维管束鞘和储水组织鞘是芦荟素等蒽醌类物质的储藏场所.综上所述,芦荟素含量与维管束的大型薄壁细胞、维管束鞘和储水组织鞘的情况密切相关.     

不同生境中国芦荟凝胶活性成分的分析

中国芦荟产于云南元江地区,是一种极具发展潜力的芦荟品种,在全国均有引种,特别在东北地区的温室中已开始大面积种植。本项研究对不同生境的中国芦荟凝胶中活性成分的含量进行了分析。生境不同的中国芦荟凝胶中活性成分含量有明显差异。从测定结果上看,云南元江产的中国芦荟凝胶中所含的活性成分要高于黑龙江温室内产的中国芦荟;积温高、土壤呈弱酸性的条件下,中国芦荟凝胶中的蛋白质、有机酸含量较高。     

Of feathers and fur: Differential pollinator roles of birds and small mammals in the grassland succulent Aloe peglerae

The pollination syndrome of the genus Aloe, with gaudy inflorescences and orange–red flowers, suggests bird pollination. However, the diversity of flowering phenologies and structures suggests that generalizations within the group are currently uninformative because few studies have addressed the role of multiple pollinator guilds, especially mammals. Aloe peglerae, endemic to montane grassland of the Magaliesberg Mountains, South Africa, is primarily bird pollinated, although small mammals are recorded nocturnal visitors. We compared the independent contributions of diurnal and nocturnal visitors, i.e. birds and small mammals respectively, to reproductive success by assigning 12 flowering A. peglerae plants to each of four pollinator selective exclusion treatments: (i) no‐visitors; (ii) nocturnal‐visitors; (iii) diurnal‐visitors; and (iv) all‐visitors (control). Birds alone contributed more to fruit set (1.2–2.6 times), average seed/fruit (1.0–1.8 times) and total seed production (1.1–2.8 times) than both the all visitors (birds and small mammals combined) and the small mammal visitors respectively. The exclusion of all visitors resulted in no fruit set, suggesting that A. peglerae requires pollinators to set seed. Germination trials over six weeks and viability testing with tetrazolium staining identified no significant differences among the three treatments that produced fruit and seed. Germination success was 90–97%, indicating that seed quality of small‐mammal and bird‐pollinated plants are similar. Aloe peglerae inflorescences were visited continuously throughout the day and night, with the Cape rock‐thrush (Monticola rupestris) and dark‐capped bulbul (Pycnonotus tricolor) being the most abundant pollinators, accounting for 68.2% and 13.7% of all visits respectively in the control treatment. Small mammals, i.e. Namaqua rock mouse (Micaelamys namaquensis) and eastern rock sengi (Elephantulus myurus), while not increasing reproductive success in the absence of birds, are suitable alternative pollinators. The presence of diurnal bird and nocturnal small mammal visitors provides a diversity of pollinators in this resilient pollination syndrome.