Characteristics of the microbial community in rhizosphere of Camptotheca acuminata cultured with exotic invasive plant Eupatorium adenophorum

The traditional culture-dependent plate counting and culture-independent small-subunit-ribosomal RNA gene-targeted molecular techniques, Single-Strand Conformation Polymorphism (SSCP) and ter-minal Restriction Fragment Length Polymorphism (tRFLP) combined with 16S rDNA clone library were adopted to investigate the impacts of secretion from Camptotheca acuminata (abbreviated to Ca) roots on the quantities and structure of eukaryotic microbes and bacteria in the rhizosphere, and the possi-bility that Ca controls exotic invasive plant Eupatorium adenophorum (Ea). The counting results indi-cated that the number of bacteria increased in turn in rhizospheres of Ea, Ca-Ea mixed culture and Ca, while that of eukaryotic microbes decreased. PCR-SSCP profiles showed eukaryotic microbial bands (corresponding to biodiversity) in rhizosphere of Ea were more complex than those of Ca and CE. Meristolohmannia sp., Termitomyces sp. and Rhodophyllus sp. were the dominant populations in the rhizosphere of Ca. Bacterial terminal restriction fragments (TRFs) profiles showed no difference among three kinds of rhizospheres, and the sequences of the 16S rDNA clone library from Ca rhizospheres were distributed in 10 known phyla, in which phylum Proteobacteria were the absolute dominant group and accounted for 24.71% of the cloned sequences (δ-Proteobacteria accounted for up to 17.65%), and phyla Acidobacteria and Bacteroidetes accounted for 16.47% and 10.59% of the cloned sequences, respectively. In addition, high performance liquid chromatography detected a trace amount of camp-tothecin and hydroxycamptothecin in the rhizospheric soil of Ca and CE, but examined neither camp-tothecin nor hydroxycamptothecin in rhizospheric soil of Ea. Therefore, invasion and diffusion of Ea evidently depended on distinguishing the eukaryotic community structure, but not on that of the bac-terial pattern. Ca was able to alter the eukaryotic community structure of invasive Ea by secreting camptothecin and hydroxycamptothecin into rhizospheres, and may benefit the control of overspread of Ea. This study provided theoretical evidence for rhizospheric microbial aspects on substituting Ca for Ea.     

Studies on the cytotoxicity of miscellaneous compounds from Eupatorium betonicaeforme (D.C.) Baker (Asteraceae)

A detailed study on the cytotoxic effects of five known constituents isolated from the flowers and roots of Eupatorium betonicaeforme is reported, including 2,2-dimethyl-6-vinylchroman-4-one (1), 2-senecioyl-4-vinylphenol (2), 6-acetyl-2,2-dimethylchroman-4-one (3), (4E)-8beta-angeloyloxy-9beta,10beta-dihydroxy-1-oxogermacra-4,11(13)-dien-12,6alpha-olide (4), and 3beta-hydroxyicosan-1,5beta-olide (5). The sesquiterpene lactone 4 exhibited the highest cytotoxicity, with IC50 values ranging from 3.9 to 9.9 microM, showing some degree of cell selectivity. The antiproliferative activity of 4 was examined towards HL-60 cells, and found to diminish cell viability in a dose-dependent manner. Moreover, at all concentrations tested, there was a decrease in the number of cells capable of incorporating 5-bromo-2'-deoxyuridine (BrdU), indicating disruption of DNA synthesis. The morphological changes induced by 4 were compatible with apoptotic cell death. This work, thus, corroborates the anticancer potential of Eupatorium secondary metabolites.     

不同盐浓度的混合盐对羊草苗的胁迫效应

用５０～３５０ｍｍｏｌ／Ｌ含有不同比例的ＮａＣｌ、Ｎａ２ＳＯ４、ＮａＨＣＯ３和Ｎａ２ＣＯ３等４种盐成分的３０种混合盐对羊草（Ａｎｅｕｒｏｌｅｐｉｄｉｕｍｃｈｉｎｅｎｓｅ（Ｔｒｉｎ．）Ｋｉｔａｇ．）苗进行盐碱混合胁迫处理。结果表明：相对生长率、Ｋ和Ｎａ含量、脯氨酸积累量及叶片电解质外渗率等胁变反应均随盐浓度增大以及碱性盐比例增高而加剧。而且碱性盐所造成的高ｐＨ的致胁变效应与盐浓度关系极大,浓度低时作用较小,随浓度增大其作用加剧。在含有碱性盐的混合盐胁迫中,包含有盐胁迫和碱胁迫两种作用。以总盐浓度代表盐胁强,缓冲量代表碱胁强。在碱胁强较弱时胁变主要受盐浓度影响,随碱胁强增大缓冲量变为影响胁变的主导因素     

Production of a hepatoprotective cerebroside from suspension cultures of Lycium chinense

Suspension cultures derived from Lycium chinense Miller seedlings produced significant amounts of a hepatoprotective cerebroside. Callus was induced from the stem of aseptic seedlings of L. chinense and maintained on MS solid media supplemented with 1.0 ppm 2,4-D and 0.1 ppm kinetin. Suspension cultures were established, and the cells were grown in the same liquid media in the dark. Lyophilized cells were extracted with a combined reagent of chloroform and methanol (2:1, v/v). An aqueous suspension of the evaporated cell extract was partitioned with chloroform, and the chloroform layer was subjected to silicic acid column chromatography followed by semi-preparative reverse phase C8 high pressure liquid chromatography. The purified compound showed hepatoprotective activity comparable to that shown by silymarin, and the structure was identified as 1-O-(β-d-glucopyranosyl)-(2S,3R,4E,8Z)-2-N-2′-hydroxy-(palmitoyl)-4,8-sphingadiene on the basis of spectral data. The content of the compound in cultured cell was tenfold higher than that of the fruit of L. chinense. The biosynthesis of the compound in cultured cell systems appears to parallel cell growth. Received: 12 June 1998 / Revision received: 30 July 1998 / Accepted: 14 August 1998     

永瓣藤濒危因素探讨

水瓣藤（MonimopetalumchinenseRehd．）是卫矛科（Celastraceae）的一个单种属植物,被列为国家二级珍稀濒危保护树种。永瓣藤濒危的因素主要是：（1）种子萌发障碍;（2）传粉受精不良,胚珠通常败育,结实率偏低;（3）种子成熟后胚因休眠或失水而失活;（4）人类活动对自然生态环境的严重干扰和破坏。本文提出了消除威胁生物多样性的社会因素、加强亚热带阔叶林生态系统的保护、重视自然保护区以外的就地保护工作、深入研究迁地保护的有效方法等保护策略。     

紫茎泽兰的化学成分研究

为了解紫茎泽兰(Eupatorium adenophorum Spreng.)的化学成分,从其乙醇提取物中分离得到7 个化合物。通过波谱分析,分别鉴定为万寿菊苷(1)、7-O-(6-methoxykaempferol)-β-D-glucopranoside (2)、4'-甲基醚万寿菊苷(3)、3-O-(6-methoxykaempferol)-β-D-glucopranoside (4)、邻苯二甲酸二丁酯 (5)、邻苯二甲酸二(2-乙基)己酯 (6)、1,4-bis(2-benzoxazolyl)naphthalene (7)。其中化合物1~4 为首次从紫茎泽兰中分离得到。     

西南岩溶地区黄荆和檵木叶片结构对其生态环境的响应

应用常规石蜡切片法对生长于桂林毛村岩溶区和非岩溶区的黄荆(Vitex negundo)和檵木(Loropetalumchinense)的解剖特征进行了比较研究,并对两区的黄荆叶片表皮形态进行了扫描电镜观察.结果显示:(1)两地的黄荆叶片背面均有浓密的绒毛,但致密程度有差异,岩溶区黄荆叶片的气孔深藏于绒毛间隙,这种结构可减少水分蒸发,降低因岩溶干旱带来的水分缺失.(2)岩溶区黄荆和檵木的叶片厚度、上下表皮厚度、栅栏组织的厚度以及栅栏组织的致密程度均大于非岩溶区,这些特征有利于减少水分蒸腾.(3)岩溶区黄荆和檵木叶片的维管组织发达程度高于非岩溶区,有利于在蒸腾减小的情况下促进水分运输和营养元素的迁移,说明2种植物叶片结构特征在不同生境区的改变是其长期在岩溶区干旱环境条件下形成的适应性变化.     

施肥对苗期紫茎泽兰和黑麦草相对竞争力的影响

为种植黑麦草替代控制紫茎泽兰提供依据,运用取代实验法,研究了施肥(氮、磷)对苗期紫茎泽兰和黑麦草的相对竞争力以及生长表现的影响。结果表明:增施氮肥和磷肥均能够提高紫茎泽兰的相对竞争力,而仅磷肥对黑麦草的竞争力略有促进作用;但在各种施肥水平下,黑麦草的竞争力仍然明显强于紫茎泽兰。增施氮肥可以显著提高紫茎泽兰的株高、分枝数和干质量,而磷肥仅在较高时才显著提高其干质量;增施氮肥虽然可以提高黑麦草的分蘖数量,但对其干质量没有影响,而增施磷肥(2次)可以显著提高其干质量;在竞争中紫茎泽兰植株生长的能量分配(用根茎比表示)对磷肥不敏感。建议适当增施磷肥、不施或少施氮肥,以提高黑麦草的替代控制效果。     

芙蓉菊挥发油的成分分析

用水蒸气蒸馏法提取芙蓉菊全草中的挥发油,GC-MS分析其化学组成。共检测出232个成分,归一化法分析各成分的相对含量。联机检索鉴定了56个化合物,占挥发油总量的62.59%,主要成分异石竹烯(Isocaryophyllene)的含量高达14.94%。     

Evaluation of Eupatorium cannabinum Linn. oil in enhancement of shelf life of mango fruits from fungal rotting

Essential oils extracted from 17 higher plants belonging to different families were screened against Botryodiplodia theobromae and Colletotrichum gloeosporioides causing stem end rot disease and anthracnose disease in mango respectively. The essential oil of Eupatorium cannabinum was found to be fungitoxic in nature against both the mango-rotting fungi. Eupatorium oil was standardized through physico-chemical and fungitoxic properties. Gas Liquid Chromatography (GLC) analysis of the oil led to the identification of 16 components, which represented 77.97% of the oil. Germacrene D (16.11%) was found to be the major component. The oil showed a broad fungitoxic spectrum and was recorded to be more efficient than some synthetic fungicides. The oil also showed an inhibitory effect on pectinase and cellulase enzymes. The oil enhanced the shelf life of mango fruits by protecting from fungal rotting when tested as a fumigant. The LD₅₀ of Eupatorium oil was found to be 22.01 ml/kg body weight on mammalian mice.