Photosynthetic response dynamics in the invasive species Tithonia diversifolia and two co-occurring native shrub species under fluctuating light conditions

To determine the invasiveness of invasive plants,many studies have compared photosynthetic traits or strategies between invasive and native species.However,few studies have compared the photosynthetic dynamics between invasive and native species during light fluctuations.We compared photosynthetic induction,relaxation dynamics and leaf traits between the invasive species,Tithonia diversifolia and two native species,Clerodendrum bungei and Blumea balsamifera,in full-sun and shady habitats.The photosynthetic dynamics and leaf traits differed among species.T.diversifolia showed a slower induction speed and stomatal opening response but had higher average intrinsic water-use efficiency than the two native species in full-sun habitats.Thus,the slow induction response may be attributed to the longer stomatal length in T.diversifolia.Habitat had a significant effect on photosynthetic dynamics in T.diversifolia and B.balsamifera but not in C.bungei.In shady habitat,T.diversifolia had a faster photosynthetic induction response than in full-sun habitat,leading to a higher average stomatal conductance during photosynthetic induction in T.diversifolia than in the two native species.In contrast,B.balsamifera had a larger stomatal length and slower photosynthetic induction and relaxation response in shady habitat than in full-sun habitat,resulting in higher carbon gain during photosynthetic relaxation.Nevertheless,in both habitats,T.diversifolia had an overall higher carbon gain during light fluctuations than the two native species.Our results indicated that T.diversifolia can adopt more effective response strategies under fluctuating light environments to maximize carbon gain,which may contribute to its successful invasion.

Phytochemical screening and antioxidant activity of ethanol extract of Tithonia diversifolia(Hemsl)A.Gray dry flowers

Objective:To evaluate the antioxidant activity of extracts of dried flowers of Tithonia diversifolia(Hemsl) A.Gray(T.diversifolia) dry flower-a slirubby plant belonging to the Asteraceac family and very common in Brazil,providing data to help prevent premature aging skin.Methods:The tests of phytochemical screening included total phenols,tannins,flavonoids,alkaloids and saponins.The active antioxidant was determined by 2,2-diphenyl-1-picrylhydrazyl method.Results:The phytoehemical screening of T.diversifolia dry flowers revealed the presence of phenolic compounds(tannins,flavonoids and total phenolsi,while alkaloids and saponins were not detected.The IC_(50) values showed a strong antioxidant activity of the plant extracts.Conclusions:Therefore,this study suggests the possibility of using dry flowers extracts of T.diversifolia for the prevention of cell aging,as was shown to have significant antioxidant activity.

Phytochemical bioprospecting, antioxidant, antimicrobial and cytotoxicity activities of saline extract from Tithonia diversifolia(Hemsl) A.Gray leaves

Objective:To evaluate antimicrobial and antioxidant properties of saline extract from Tithonia diversifolia leaves by phytochemical bioprospecting,and investigate its safety against animal cells.Methods:The saline extract was prepared,with NaCl(0.15 M),by constant stirring of the dried and pulverized leaves,followed by volume reduction by lyophilization.The extract was phytochemical characterized using ultra-performance liquid chromatography,and total phenol and flavonoid analysis also was performed.The antioxidant capacity was determined through DPPH*radical,the antimicrobial property was evaluated against standard bacteria and fungi,and the viability assays were performed against mice splenocytes.Results:Fifteen compounds were identified belonging to two main classes terpenoids and phenolics.The extract showed 22.185 mg GAE/g of total phenolic compounds and 3.220 mg QE/g of flavonoid.Moreover,extract showed higher antioxidant ability similar to butylated hydroxytoluene a standard molecule[(3.042±0.019)mg AAE/g and(4.12±0.10)mg AAE/g to saline extract and butylated hydroxytoluene,respectively].The antimicrobial assays demonstrated that the extract had a significant antifungal potential against Candida species and could be used with safety against mice splenocytes,in concentrations lower than 50μg/mL,promoting higher proliferation in these cells.Conclusions:Saline extract from Tithonia diversifolia leaves presents potential antioxidant,antifungal properties and induces immunostimulation in mice splenocytes.

外来植物肿柄菊(Tithonia diversifolia)的繁殖特性及其地理扩散

肿柄菊Tithonia diversifolia(Hemsl.)A.Gray原产墨西哥及中美洲,被作为观赏及绿肥植物引入我国各地栽培。引入云南栽培的肿柄菊于20世纪30年代在云南南部逃逸生长,现在云南的热带、南亚热带和中亚热带地区形成危害。为了查明肿柄菊的扩散特点和入侵潜能,对选取的5个不同地理气候条件下的肿柄菊居群的果序直径、每序结实量、结籽率、千粒重、种子大小(长和宽)等6个指标进行统计分析。结果表明,6个生物学指标在5个居群间都具有极显著差异(p<0.01),并随着居群间地理气候条件差异的增大,这6个指标值在居群间的差异也有增大趋势。对新鲜采集的不同居群种子在15、20、25、30、35℃下做萌发实验,结果显示在前4种温度条件下5个居群间的种子萌发率有极显著差异(p<0.01),在35℃下萌发率有显著差异(p<0.05),并且5个居群的种子最高萌发率不相同且差异极显著(p<0.01)。分析对比作者以往对肿柄菊群落特征和克隆繁殖特性的研究结果认为,虽然肿柄菊在不同的地理气候条件下有性繁殖特性有较大差异,但群落结构差异不大,危害程度表现相似;由于肿柄菊有性繁殖和克隆繁殖的协同作用,使其通过人为引种、道路交通、水流等传播到新的地域后,极易建立新种群,并形成单优种群落而不断侵占和统治新的领地。

生境类型对入侵植物肿柄菊(Tithonia diversifolia)种群和个体水平特征的影响

外来植物入侵过程是入侵生态学研究的一个核心问题,被入侵生境中的各种要素对这一过程具有重要影响。为探讨入侵植物肿柄菊(Tithonia diversifolia)在种群和个体水平对不同生境的反应,调查了肿柄菊单优群落、肿柄菊与飞机草(Chromolaena odorata)共优群落和肿柄菊与紫茎泽兰(Ageratina adenophora)共优群落中肿柄菊的相对盖度、相对密度和高度,并开展了一个3因素(小气候、土壤类型和竞争)两水平的控制实验。结果表明:单优群落中,肿柄菊的相对盖度和相对密度显著大于其它两种群落中肿柄菊的相对盖度和相对密度;单优群落中肿柄菊的高度显著大于肿柄菊与紫茎泽兰共优群落中肿柄菊的高度,而与肿柄菊与飞机草共优群落中肿柄菊的高度无显著差异;肿柄菊的相对盖度、相对密度和高度在两个共优群落间无显著差异。小气候、土壤类型和竞争单个因素对肿柄菊的株高和叶片数没有显著影响,但三者的交互作用却显著影响肿柄菊的株高生长。这些结果表明:3个因素的综合作用影响肿柄菊的株高生长。

Stimulatory Effect of Tithonya diversifolia-by Products on Plantain Banana Vivoplants in Nursery (A Review)

Plantain banana is an important cash crop that serves as stable food for millions of people around the world and contributes to income generation. Indeed, they provide a major staple food crop for millions of people and play an important role in the social fabric of many rural communities. Plantain banana cultivation encounters major problem of seedlings unavailability that are essential for the creation of new plantations, as well as parasitic constraints. Mycosphaerella fijiensis is the main pathogen attack constraints of banana plant responsible of black Sigatoka disease, and viruses, which can severely reduce the photosynthetic leaf area, leading to banana production losses of more than 80% in plantations with soil fertility problems. The repeated use of synthetic input is the origin of contamination to the environment, different pollution sources of plants and human health, as well as resistance to some strains of pathogens and plant fertilization problems over time. Recent works carried out in nursery have shown that vivoplants of plantains treated with biostimulants based on natural products notably Tithonia diversifolia biopromote good growth and less susceptibility to M. fijiensis. Indeed, an increase in agromorphological characteristics, good accumulation of growth and defense biomarkers was also observed. In this context, Tithonia diversifolia is shown to be involved in the stimulatory effect mechanism of growth promotion and defensive reaction of plantain vivoplants against various pathogens and it is suggested to be acting as a vital stimulator. This article reviews the current state of knowledge on plantain banana cultivation constraints and on the potential of Tithonia diversifolia in relation with its different stimulatory effects on plantain vivoplants.

Anti-nitric oxide production, anti-proliferation and antioxidant effects of the aqueous extract from Tithonia diversifolia

Objective: To determine the cytotoxicity, reduction in nitric oxide production and antioxidative activity of the aqueous leaf extract from Tithonia diversifolia(T. diversifolia) in an in vitro model.Methods: Leaves of T. diversifolia were collected from natural habitats and extracted with distilled water using the decoction method. The cytotoxic effect of the extract in terms of cell viability was determined using RAW264.7 cells and human peripheral blood mononuclear cells(PBMCs) via the mitochondrial respiration method using the MTT reagent. The effect of the extract on lipopolysaccharide(LPS)-induced nitric oxide production in RAW264.7 cells was measured using the Griess reagent. The chemical antioxidant was evaluated by ABTS- and DPPH-radical scavenging assays.Results: The half-maximal cytotoxic concentration values were 145.87 mg/m L and73.67 mg/m L for human PBMCs and RAW264.7 cells, respectively. In the presence of phytohemagglutinin-M, the IC_(50) on PBMCs proliferation was 4.42 mg/m L. The noncytotoxic range of the extracts inhibited LPS-induced nitrite production in RAW264.7 cells with an IC_(50) value of 11.63 mg/m L. To determine the anti-oxidative properties, the N-acetyl cysteine equivalent antioxidant capacity of the extract was(32.62 ± 1.87) and(20.99 ± 2.79)mg N-acetyl cysteine/g extract, respectively determined by the ABTS-radical and DPPHradical assay. However, the extract did not confer death protection in a hydrogen peroxideinduced RAW264.7 co-culturing model.Conclusions: Our study demonstrated the immunomodulation caused by the aqueous leaf extract of T. diversifolia, resulting from the inhibition of phytohemagglutinin-Minduced PBMCs proliferation and LPS-induced nitric oxide production in RAW264.7macrophages. Although the anti-oxidative activity was presented in the chemical-based anti-oxidant assay, the extract cannot protect cell death from stress conditions.

Plantain Bananas PIF Seedlings Treatment with Liquid Extracts of <i>Tithonia diversifolia</i>Induces Resistance to Black Sigatoka Disease

Plantain bananas culture encounters the problems of seedlings quantity and quality unavailability. Black Sigatoka Disease (BSD) is one of the main pathological constraints of banana that can severely reduce the photosynthetic leaf area, leading to the losses of production of about 50% in banana plantation. The use of liquid extracts of Tithonia diversifolia could potentially induced the resistance of the PIF seedlings to BSD during the vegetative stages in the nursery. The aim of this work was to evaluate the effect of Tithonia diversifolia liquid extracts against the development of BSD on the PIF plantain bananas seedlings. The explants in the greenhouse and the seedlings in the shade were watered with liquid extracts of T. diversifolia during the process of PIF seedling production in sterile and non-sterile conditions. The treated seedlings show a more effective enhancement of seedlings quality parameters and also induce resistance against BSD. The vegetative stages parameters (the number of shoots, the diameter and the height of shoots, the foliar area, the length and weight roots) were improved in treated seedlings compared to controls ones. The treated seedlings showed maximum protection against BSD of up to 87% compared to controls. They also exhibited an increase in the accumulation of total proteins and total phenolics, as well as the activity of defense-related enzymes (peroxidase, polyphenol oxidase and glucanase). The treatment seems to acts as a vital stimulator and could therefore be a useful tool for small holder farmers favouring an eco-friendly agriculture using fewer synthetic inputs.

Does Soil under Natural <i>Tithonia diversifolia </i>Vegetation Inhibit Seed Germination of Weed Species?

Pot experiment was carried out in the screen house, Ladoke Akintola University Technology Ogbomosho, Nigeria to determine the possible impact of Tithonia diversifolia on the growth of thirteen selected weed species weeds growing in its surroundings. The study consisted of two treatments (Tithonia diversifolia infested and Non-Tithonia diversifolia infested soils) and from the two media, the growth of A. hispidium, B. pilosa E. heterophylla, P. maximum and P. polystachion was significantly affected in soil infested by T. diversifolia. The number of weed seedling emergence afore mentioned was significantly lower than what was obtained in soil not infested with T. diversifolia and this accounted for about 38% of the tested weed species. Germination of four of these weeds species (23%) (A. spinosus, C. viscosa, T. procumbens and D. gayana) was enhanced by the presence of T. diversifolia. The study further revealed that weed counts in T. diversifolia infested soil is significantly lower than the ones in soil without T. diversifolia infestation. Likewise, the vegetative growth of some species (A. spinosus, C. viscosa, T. procumbens and D. gayana) was improved in this soil. This shows that T. diversifolia infested soil contains allelochemicals that performed both stimulatory and inhibitory functions.

<i>Tithonia diversifolia</i>Mulch Stimulates the Growth of Plantain PIF Seedlings and Induces a Less Susceptibility to <i>Mycosphaerella fijiensis</i>in the Nursery

Plantain is an important crop that serves as a staple food and contributes significantly to income generation for millions of people in tropical and sub-Saharan Africa. Its cultivation faces the main constraint of seedlings unavailability in quantity and quality, essential for the creation of new plantations. The advent and popularization of the plantlets from stem bits (PIF) in the 2000s raised hopes for solving this problem. However, after about ten years, the PIF has shown some problems limiting its adoption and should be improved for more efficiency. The amendment of PIF substrate production with Tithonia diversifolia could be an alternative to seedlings’ unavailability. This study aims to evaluate the potential stimulative effect of T. diversifolia mulch on plantain PIF seedlings growth and protection against black Sigatoka disease (BSD)caused by Mycosphaerella fijiensis. The parameters of vegetative growth stages and biomarkers accumulation were assessed in sterilized substrate and non-sterilized substrate conditions. T. diversifolia mulch treatment increases the germination rate, the number of shoots, the height and the diameter of shoots, the leaf area as well as the seedlings roots, but it also protects the seedlings against BSD up to about 81% compared to the control seedlings. It also enhances the accumulation of biomarkers such as proteins, polyphenols content and defense-related enzymes (peroxidase, polyphenol oxidase and glucanase). T. diversifolia mulch seems to act in PIF seedlings production as a vital stimulator. It can therefore be taken as a tool for a more sustainable and resilient agriculture, and for poverty alleviation of poor small holder farmers.

Comparative Evaluation of NPK Fertilizer and Tithonia diversifolia Biomass in Sweet Pepper （Capsicum annum） Production in Ado Ekiti, Nigeria

The efficacy of the flower, leaf, stem and root of Tithonia diversifolia as organic fertilizer was comparatively studied with NPK fertilizer in improving the performance of sweet pepper （Capsicum annum） in the green house of the Department of Plant Science of Ekiti State University, Ado Ekiti, Nigeria. The different parts of Tithonia diversifolia were harvested, separately air dried and pulverized. 100 g each of the Tithonia parts and 10 g of NPK were respectively buried into each pot containing the pepper seedlings at two weeks after transplanting using the side dressing method. The study results showed that the leaf biomass of T. diversifolia was not significantly different from NPK fertilizer in improving the growth and yield of Capsicum annum. The stem and root biomass gave comparative growth and yield figures but higher than those recorded from the flower biomass. The control pots resulted to the lowest performance of capsicum annum. It is indicative in this study that Tithonia diversifolia plants ploughed into the soil at the tender stage before flowering will be useful in soil improvement for pepper production. It also revealed that the leave biomass contains nutrients in the required quantity that compared favourably with NPK for pepper production in the study area.

<i>Tithonia diversifolia</i>Leaves and Stems Use as Substrate Amendment Promote the Growth of Plantain Vivoplants in the Nursery

Tithonia diversifolia is a year-round weed that decomposes rapidly after application as a soil amendment and it is more and more used in agriculture due to its numerous properties. The use of Tithonia diversifolia in the production of plantain vivoplants is a great opportunity for small holders’ farmers that cannot easily buy chemical inputs for yield improvement. All plant parts are used because of their richness in nutrients, mineral elements and phytochemicals without knowing which part is the most efficient. Tithonia diversifolia used as substrate amendment for plantain vivoplants production in nursery could promote their growth. This study aims to evaluate the effect of T. diversifolia leaves and stems as substrate amendment on plantain vivoplants growth promotion. The vivoplants were produced in substrates amended with T. diversifolia leaves, stems, combination of leaves and stems, and control without amendment. The vegetative growth parameters (number of shoots, height and diameter of shoots, area of shoots leaves) were assessed in sterilized substrate and unsterilized substrate conditions. T. diversifolia leaves and stems treatment increases the number of shoots, the height and the diameter of shoots as well as the area of shoots leaves compared to the control. T. diversifolia stems are the more efficient treatment, followed by the combination of T. diversifolia leaves and stems and finally the T. diversifolia leaves. They act as a biofertilizer promoting thus, the growth of plantain vivoplants in the nursery. All parts of Tithonia diversifolia can therefore be used by poor small holder farmers, as green manure for soil amendment in a green agriculture context.

Field Efficacy of a Biopesticide Based on <i>Tithonia diversifolia</i>against Black Sigatoka Disease of Plantain (<i>Musa</i>spp., AAB)

Black Sigatoka disease (BSD) is a foliar disease caused by Mycosphaerella fijiensis, responsible of reduction of the photosynthetic area of banana plant and yield at harvest since it has an influence on fruit physiology. The control of BSD relies on the use of chemicals which are not affordable for the small holder farmers and increase the cost of production. Moreover, this chemical control is ineffective, negatively impacting the environment and human health, and is at the origin of strain resistance. Tithonia diversifolia is known as rich in many compounds such as mineral elements, defense metabolites, some phytochemicals;and it is increasingly used in agriculture. Recently, the protective effect of Tithonia diversifolia liquid extract against BSD development on plantain vivoplants in the nursery was highlighted. The aim of our study was to evaluate the efficacy of a biopesticide base on Tithonia diversifolia on the BSD development in a plantain field under high disease pressure. The effect of Tithonia diversifolia biopesticide on Mycosphaerella fijiensis mycelial growth in vitro was evaluated. An experimental field at the flowering stage was selected and treated with the biopesticide base on Tithonia diversifolia at three different concentrations: undiluted (100%), diluted at 1/2 (50%) and diluted at 1/4 (25%) for 17 weeks. The disease severity, the number of functional leaves, the youngest spotted leaf (YSL) and the youngest necrotic leaf (YNL) were evaluated in course of time. The biopesticide treatments significantly (P < 0.001) reduce the BSD severity in course of time, but it is more effective for the most diluted concentration (25%). The number of leaves increases in course of time as well as the rank of the YSL and the YNL confirming the efficiency of BSD control. The efficacy of this biopesticide base on Tithonia diversifolia could be a hopeful ecoresponsible solution for the plantain sector in general and in particular for poor small farmers.

不同入侵程度肿柄菊生态化学计量特征

【目的】研究不同入侵程度下肿柄菊植株不同器官及根际土壤化学计量特征,剖析肿柄菊资源利用和分配策略,为肿柄菊入侵防控提供理论参考。【方法】在云南省普洱市思茅区郊区公路边选取有肿柄菊入侵至少4年的研究样地,设15个试验区,包括5个重度入侵区(肿柄菊盖度占70%以上)、5个中度入侵区(肿柄菊盖度占30%~70%)和5个轻度入侵区(肿柄菊盖度占30%以下),分别采集肿柄菊根、茎、叶样品及根际土壤样品,检测植株和土壤中全磷(TP)、全氮(TN)和有机碳(SOC)含量,并分析化学计量特征。【结果】随入侵程度的增加,肿柄菊生境土壤TN和SOC含量呈显著降低趋势(P<0.05,下同),而TP含量无显著变化(P>0.05,下同);从轻度入侵到重度入侵,TN含量下降54.2%,SOC含量下降53.1%,肿柄菊入侵地土壤SOC和TN贫乏。3种入侵程度的肿柄菊各器官TP和TN含量均为叶>根>茎,SOC含量为根>叶>茎。重度入侵有利于肿柄菊植株TP含量积累,轻度入侵有利于肿柄菊茎TN含量积累。从轻度入侵到重度入侵,肿柄菊根、茎C∶N显著升高,根、茎C∶P显著降低,茎N∶P显著降低;同一入侵程度的肿柄菊C∶N和C∶P均为茎>根>叶;N∶P在轻度入侵为叶>茎>根,在中度和重度入侵为叶>根>茎。入侵程度对肿柄菊TN和TP含量及C∶N、N∶P具有显著或极显著影响(P<0.01,下同),不同器官对肿柄菊SOC、TN和TP含量及C∶N、C∶P、N∶P均具有极显著影响;器官与入侵程度交互作用仅对N∶P有极显著影响,对其他指标无显著影响。肿柄菊根、茎与土壤的TP、TN和SOC含量及化学计量比之间部分存在显著或极显著相关性。【结论】肿柄菊入侵对研究样地的土壤产生一定影响,土壤的改变同时反馈于肿柄菊。肿柄菊将N、P元素更多分配给叶,C元素更多分配给根,生长受到N元素限制;肿柄菊的根和叶具有相对快速的生长能力,以扩张种群、增大入侵性。

外来植物肿柄菊对入侵生境的生态影响及其防控对策

入侵杂草肿柄菊对我国热带和亚热带地区的生物多样性和生态系统功能产生严重影响,且其入侵呈现快速扩张态势。为提高对肿柄菊入侵危害的认识水平,加强对肿柄菊的监测预警及防控,本文通过搜集、整理和分析相关文献资料,总结肿柄菊在世界各国不同地区的入侵情况及其影响,分析肿柄菊在我国入侵的历史、分布现状及其入侵对遗传多样性、物种多样性和生态系统多样性的影响。结合肿柄菊生态入侵防控研究与应用实践,指出肿柄菊入侵防控存在的主要问题和面临的挑战,并针对肿柄菊监测和高效防控技术体系提出高度重视肿柄菊入侵危害影响的分类风险评价、多元化开展肿柄菊入侵扩张的基础科学研究、建立早监测早预防的预警机制和构建针对肿柄菊入侵防控的综合技术体系等防控对策。

入侵植物肿柄菊对三叶鬼针草的化感作用

肿柄菊(Tithonia diversifolia A.Gray)和三叶鬼针草(Bidens pilosa L.)同属菊科外来入侵植物。采用培养皿培养法用前者不同含量(0.8%,1.6%,2.4%,3.2%)的叶片提取液胁迫处理后者的种子和幼苗,通过测定后者种子活力及幼苗生长量、抗氧化酶活性和细胞膜透性,探讨肿柄菊对三叶鬼针草的化感作用,进而为前者用于后者防控提供理论依据。结果表明,随着肿柄菊叶片提取液含量的提高,三叶鬼针草种子发芽指数和种子活力及幼苗生长量逐渐下降,化感效应指数小于0;相对电导率逐渐提高,幼苗细胞膜的完整性下降;而超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)的活性则随之提高,化感效应指数大于0。肿柄菊叶提取含量达3.2%时,鬼针草种子发芽指数、活力指数和幼苗生长量仅分别为对照的25.7%、2.1%和9.4%。对照的SOD、CAT和POD活性分别为68.3±2.3、0.6±0.0和0.5±0.1,而提取液含量3.2%时则分别为117.2±3.2、1.2±0.1和0.9±0.2。显然,肿柄菊对鬼针草产生强烈化感作用,且随浓度的增加而加强。

逃逸外来植物肿柄菊在云南的生长繁殖特性、地理分布现状及群落特征

调查表明 ,肿柄菊在云南省已逃逸生长于北纬 2 4°10′以南的 53个县区 ,面积达 184,2 12 km2。分布区为热带、南亚热带、中亚热带气候类型。逃逸生长的肿柄菊呈多年生灌木或亚灌木状 ,植株全年生长 ,5～ 10月份的雨季是其生长旺盛期 ,10月份开始献蕾 ,花期为 11月至翌年 1月份 ,果熟期 12月下旬至翌年 2月份。肿柄菊的结实量高达 80 0 0 0～ 160 0 0 0枚 / m2 ,种子 (瘦果 )千粒重 4.5782～ 6.52 92 g。成熟种子在风力摇曳下从果序中脱出 ,借助风力、流水或附着于交通工具、人畜等广泛散播 ,在适宜的生境下实现萌发生长和种群扩增。肿柄菊能依靠植株基部节处萌生的小芽体形成克隆分株 ,克隆分株迅速生长后成密集状丛生 ,在倒伏或贴地面生长的茎秆上萌生无数的不定根和不定芽 ,进一步实现植物体的克隆增殖。由于肿柄菊强大种子繁殖潜力、特殊的克隆增殖特性和植物体固有的化感作用 ,种群个体在适宜的环境条件下快速扩增 ,排挤本土植物 ,形成大面积的单一优势种群落 ,其伴生植物多为一些适应范围广的 1年、2年生或多年生杂草。

肿柄菊乙酸乙酯部位的化学成分

目的肿柄菊乙酸乙酯部位化学成分的提取、分离和结构鉴定。方法肿柄菊地上部分80%的乙醇渗漉提取,通过萃取、硅胶柱层析、凝胶柱层析、MCI柱层析等方法进行成分分离,应用质谱、核磁等方法进行结构鉴定。结果从乙酸乙酯部位得到10个化合物,鉴定为香草醛(1)、麦角甾醇(2)、过氧化麦角甾醇(3)、3-甲氧基-4-羟基肉桂醛(4)、对羟基苯甲醛(5)、异东莨菪内酯(6)、5-羟甲基糠醛(7)、尼泊尔黄酮(8)、二十二烷酸单甘油酯(9)和13-羟基泽兰烯(10)。结论香草醛、麦角甾醇、过氧化麦角甾醇、3-甲氧基-4-羟基肉桂醛、对羟基苯甲醛、异东莨菪内酯、5-羟甲基糠醛、二十二烷酸单甘油酯和13-羟基泽兰烯均为首次从肿柄菊中分离得到。

肿柄菊挥发油的化学成分分析及其化感作用

采用水蒸气蒸馏法提取肿柄菊地上部分的挥发油,利用GC-MS技术对肿柄菊地上部分的挥发油进行分析,以假臭草、巴西含羞草、含羞草、蝶豆和鬼针草5种肿柄菊伴生植物为供试植物,用半密闭容器法对肿柄菊挥发油的化感效应进行生物测定。GC-MS分析结果显示,从肿柄菊挥发油中鉴定出50个化合物,占总出峰面积的94.79%,肿柄菊挥发油中主要含有α-蒎烯(63.81%)、柠檬烯(7.07%)、β-石竹烯(4.85%)、双环大香烯(2.95%)、香桧烯(2.78%)、斯巴醇(2.70%)等萜类和醇类化合物,占挥发油总量的94.15%,其中萜类化合物含量占总挥发油的86.01%。生测结果显示,肿柄菊挥发油对5种受试植物的种子萌发和幼苗生长均产生抑制作用,其中对巴西含羞草的抑制作用最为显著,而对含羞草和蝶豆影响较小。说明肿柄菊挥发油在其入侵扩散中发挥一定的化感作用。

中国的外来入侵植物肿柄菊

简述了外来入侵植物肿柄菊的分布现状、个体生长发育特征、遗传特征和种群特征。论述肿柄菊对本地生物多样性和生态系统的危害以及对农业生产和天然林恢复带来的影响。从药物的利用与研究,杀虫剂和除草剂的研究,肥料和饲料的利用与研究三个面综述目前国内外对肿柄菊的开发利用与研究现状。最后指出对肿柄菊的防治对策主要是保护当地生物多样性,恢复本地植被,减少人类对生态系统的干扰和破坏。