发育时期对紫茎泽兰化感作用的影响

为探讨紫茎泽兰化感作用与其入侵性的关系,利用生物检测法研究了不同发育时期紫茎泽兰叶片水提液对4种本地草本植物种子萌发和幼苗生长的影响。结果表明,高浓度时紫茎泽兰叶片水提液能显著抑制4种本地植物种子发芽率、发芽速度,但低浓度时有时抑制作用不显著,甚至有促进作用;除狗肝菜胚轴生长外,不同浓度下紫茎泽兰叶水提液均能抑制4种本地植物胚轴和胚根生长,但有时对胚轴生长的抑制作用不显著,甚至有促进作用。不同植物和同种植物的不同参数对紫茎泽兰化感作用的敏感程度不同,拔毒散和狗肝菜的种子萌发参数较敏感,莎草砖子苗的生长参数较敏感,种子发芽速度和胚根生长较敏感。总的看,随发育时间的增加,紫茎泽兰抑制本地植物种子萌发和幼苗生长的最低叶片提取液浓度减小,相同浓度下叶片水提液对本地植物的抑制作用增强,表明紫茎泽兰化感作用增强。化感作用在紫茎泽兰入侵的不同阶段所起的作用可能不同。     

紫茎泽兰光合特性对生长环境光强的适应

测定了不同光强下生长的紫茎泽兰叶片最大净光合速率(Pmax)、叶绿素荧光参数、光合色素含量和比叶重(SLW),探讨了其光适应能力及生理生态学机制．强光下(100％相对光强)紫茎泽兰发生了轻度光抑制,Pmax、SLW、类胡萝卜素含量和日间热耗散升高,但热耗散能力没有提高．强光下紫茎泽兰通过：1)加强日间热耗散和活性氧清除能力以及光系统Ⅱ反应中心可逆失活来耗散过剩光能;2)增大P～以增加光能利用;3)提高SLW,降低单位干重叶绿素含量以减少光能吸收3个途径避免了光合机构光破坏．弱光下(36％、12．5％和4．5％相对光强)紫茎泽兰日间热耗散很小,SLW降低,但P～较高,这有利于其增加光能吸收和利用效率．紫茎泽兰能在很大的光强范围内有效地维持光合系统正常运转,这可能是其表现较强入侵性的原因之一．     

紫茎泽兰粗提物对草地贪夜蛾生长发育及繁殖的影响

为明确紫茎泽兰粗提物对草地贪夜蛾生长发育及繁殖的影响,在实验室条件下分别利用4个不同稀释浓度（20、15、10、5倍）的紫茎泽兰粗提物处理玉米叶片后喂养草地贪夜蛾初孵幼虫,记录各虫态的发育历期、存活率、重量、成虫寿命以及后代性比、F2代卵孵化率、F2代卵的发育历期。结果表明,随着紫茎泽兰粗提物浓度的升高,草地贪夜蛾各虫态的发育历期延长,5倍稀释液处理下蛹的发育历期最长,达20.27 d,10倍稀释液处理下幼虫的发育历期最长,为21.46 d;随着处理浓度的增加,各虫态的重量逐渐降低,且存活率呈下降趋势,其中粗提物对蛹存活率的影响最大,对1~3龄幼虫存活率的影响较小;随着处理浓度的升高成虫的寿命均缩短,且雌成虫寿命长于雄成虫;随着处理浓度的升高,草地贪夜蛾的产卵前期和F2代卵发育历期延长,产卵期缩短;单雌产卵量、后代性比和卵的孵化率降低。总的来说,紫茎泽兰粗提物对草地贪夜蛾的生长发育及繁殖均造成消极影响。5倍稀释液对草地贪夜蛾的生长发育及繁殖的影响最显著,可作为草地贪夜蛾防治研究中的重要植物源杀虫剂材料。     

紫茎泽兰种子种群动态及萌发特性

在紫茎泽兰的入侵地四川省德昌县, 选择撂荒地、农田和马尾松林3个不同的生境, 从种子雨、种子库角度研究了紫茎泽兰种子种群动态规律,及其种子在不同光照和土壤基质条件下的萌发特性. 结果表明,3个生境下紫茎泽兰种子种群仅存在于当年3～6月,于4月底达到年高峰值. 其年降种子雨量在撂荒地中高达2.4×10⁵粒·m^-2,并均分布于2 cm土层以上, 且在撂荒地生境下紫茎泽兰种子的千粒重和活力均显著高于另外两个生境. 到7月上旬, 3个生境下土壤中均未发现有活力的种子. 在实验的光照条件下, 全光照对紫茎泽兰的种子萌发有抑制作用,而在28%光照条件下萌发率最高;砂壤土较适宜紫茎泽兰种子的萌发,生红土中其萌发速度及萌发率均最低.     

紫茎泽兰9-羰基-10,11-去氢泽兰酮分布积累动态

9-羰基-10,11-去氢泽兰酮为紫茎泽兰（Eupatorium adenophorum）的主要致肝脏毒性成分及杀虫的生物活性成分。从紫茎泽兰叶片中分离提纯得到9-羰基-10,11-去氢泽兰酮（Euptox A）标准品,建立了高效液相色谱法测定紫茎泽兰中Euptox A含量的分析方法。采用C18反相色谱柱,柱温30°C,以甲醇-水（60：40,v/v）为流动相、流速为0.8 mL.min–1、检测波长为255 nm进行测定。Euptox A在紫茎泽兰中的添加回收率为97.3%–103.7%,检测限为0.4μg.g–1。利用建立的方法测定Euptox A在紫茎泽兰体内分布与积累的动态变化规律。结果表明,Euptox A主要分布在紫茎泽兰的叶片中,且在营养生长期积累量高,生殖生长期积累量低。该方法快速、简捷,可用于紫茎泽兰原料及其产品中Euptox A成分的测定。     

紫茎泽兰生长发育过程中糖、激素、单宁、黄酮的变化

采用高效液相和分光光度法对紫茎泽兰不同发育阶段（种子,芽,幼苗和成株）糖、激素、单宁及总黄酮含量差异进行了研究。结果表明：不同糖类的变化。紫茎泽兰的葡萄糖含量以芽最高,为6.93%;而种子（0.16%）、幼苗（1.27%）、成株(1.07%)均明显低于芽阶段;同样,紫茎泽兰中蔗糖含量芽较高,为2.68%,而种子（0.32%）、幼苗（0.52%）、成株(0.09%)均明显低于芽阶段。果糖含量的变化,最大值也是在芽阶段（3.28%）,其次为种子阶段（2.56%）,而种子和成株阶段均很低（0.14%和0.55%）。测定中,海藻糖、棉子糖、甘露糖的含量差别很大,仅种子阶段测定出3种糖的含量,结果表明差别不大,依次为0.04%、0.04%、0.03%。激素类的变化。在不同发育阶段,紫茎泽兰芽阶段吲哚乙酸（IAA）含量较高,达到14.20μg·g^-1 Dw ,比种子阶段高1.25μg·g^-1 Dw,是幼苗的1.63倍,成株阶段的5.55倍。紫茎泽兰赤霉素（GA）含量在不同发育阶段存在着明显的差异,而且种子的GA含量（901.11μg·g^-1 Dw）明显高于芽、幼苗和成株阶段,而以芽和幼苗阶段含量最低,分别为97.35和84.29μg·g^-1 Dw,成株阶段略高于芽和幼苗阶段,为280.50μg·g^-1 Dw。单宁类的变化：紫茎泽兰单宁变化差异明显,紫茎泽兰种子中单宁含量为1.98%,明显高于芽、幼苗和成株阶段（<0.30%）;总黄酮类的变化：紫茎泽兰总黄酮含量在发育过程中呈不断上升趋势。紫茎泽兰种子中总黄酮含量很微弱,为0.04%,而芽、幼苗和成株阶段的紫茎泽兰总黄酮含量均明显高于种子阶段,并且这3个阶段之间含量差别不大,分别为（0.60%、0.64%、0.62%）。这些结果说明,糖、激素、单宁及总黄酮含量与植物生长发育的基本规律和代谢过程的调控密切相关。     

A congeneric comparison shows that experimental warming enhances the growth of invasive Eupatorium adenophorum

Rising air temperatures may change the risks of invasive plants; however, little is known about how different warming timings affect the growth and stress-tolerance of invasive plants. We conducted an experiment with an invasive plant Eupatorium adenophorum and a native congener Eupatorium chinense, and contrasted their mortality, plant height, total biomass, and biomass allocation in ambient, day-, night-, and daily-warming treatments. The mortality of plants was significantly higher in E. chinense than E. adenophorum in four temperature regimes. Eupatorium adenophorum grew larger than E. chinense in the ambient climate, and this difference was amplified with warming. On the basis of the net effects of warming, daily-warming exhibited the strongest influence on E. adenophorum, followed by day-warming and night-warming. There was a positive correlation between total biomass and root weight ratio in E. adenophorum, but not in E. chinense. These findings suggest that climate warming may enhance E. adenophorum invasions through increasing its growth and stress-tolerance, and that day-, night- and daily-warming may play different roles in this facilitation.     

紫茎泽兰叶片化感作用对10种草本植物种子萌发和幼苗生长的影响

化感作用在生物入侵过程中具有重要的意义,紫茎泽兰具有化感物质,它能抑制豌豆等一些对化感物质敏感的植物种子萌发,但它对入侵早期直接与之竞争的植物的影响以及化感作用与其入侵性的关系还知之甚少。以紫茎泽兰入侵早期直接与之竞争的草本植物和为替代控制紫茎泽兰引进的牧草为材料,利用培养皿滤纸法研究紫茎泽兰叶片提取液对种子萌发和幼苗生长的影响,探讨化感作用与其入侵性的关系,并为其替代控制提供依据。紫茎泽兰叶片提取液对10种受体植物种子萌发和幼苗生长均有化感作用,不同浓度的提取液对植物的化感作用强度不同,低浓度时较弱,高浓度时较强。高浓度的提取液能降低种子发芽率、发芽速率、胚轴和胚根长度,增加幼苗丙二醛含量,其中发芽速率更敏感,可能是衡量化感作用的最敏感指标。不同植物对紫茎泽兰化感作用的敏感程度不同,无芒虎尾草、白三叶、细叶苦荬和莎草砖子苗对紫茎泽兰化感作用较敏感,紫花苜蓿最不敏感。     

High propagule production and reproductive fitness homeostasis contribute to the invasiveness of Lespedeza cuneata (Fabaceae)

Comparative studies of congeneric native and exotic species have proved fruitful in understanding plant traits that foster invasion. Using this approach, we investigate the complex reproductive system of the invasive Lespedeza cuneata (Dum.-Cours.) G. Don in relation to three native congeners in the variable environment of the North American tallgrass prairie. Lespedeza species produce both chasmogamous (CH) and cleistogamous (CL) flowers, and propagate clonally via vegetative buds. Utilizing multiple natural populations over 2 years, we investigated reproductive modes of individuals from bagged and unbagged treatments of each species. We found that L. cuneata produced a mean of five times as many seeds and a significantly greater number of vegetative buds than any native studied, and over twenty times as many CH flowers. Insect visitation significantly affected seed set in CH flowers, though some autonomous CH selfing occurred in all species. The invasive relied relatively less on selfing than the natives and exhibited less variation in reproductive output from both modes of reproduction. We conclude that the diverse reproductive biology and wide regeneration niche of L. cuneata in relation to its native congeners confer a fitness homeostasis that facilitates the successful spread of this invasive under a wide range of conditions.     

用超微细胞化学定位技术揭示ATP酶在紫茎泽兰高温适应性中的作用

【背景】外来人侵植物紫茎泽兰自然演化出耐高温种群,其适应机制与各种生理代谢有关。【方法】本文从超微细胞化学水平,对紫茎泽兰抗高温种群、敏感种群ATP酶活性定位,明确其在高温适应性中的作用,试图阐明该草的生态适应机制。【结果】正常情况下,紫茎泽兰ATP酶主要定位于细胞壁及细胞间隙周围的细胞壁表面;经40℃高温处理后,在不同的处理时间下,抗性、敏感种群之间ATP酶的活性表现出明显差异,其中以处理12h时差异最大,具体表现为抗高温种群的ATP酶活性明显高于敏感种群,ATP酶的定位点除细胞壁外,在细胞膜上也呈现大量的分布,而敏感种群在处理12h时的酶活性明显降低,只在细胞壁上有零星的分布。处理24h时,敏感种群叶片已完全萎蔫,细胞结构毁坏,细胞膜破损;而抗高温种群叶片仍然完好,细胞膜上仍有ATP酶分布。【结论与意义】经40℃高温处理后,紫茎泽兰抗高温种群ATP酶活性明显高于敏感种群,初步认为紫茎泽兰对高温的适应性与ATP酶活性相关。本研究为进一步阐明与紫茎泽兰适应性相关的入侵机理提供了资料。     

Microbial enhancement of crop resource use efficiency

Naturally occurring soil microbes may be used as inoculants to maintain crop yields despite decreased resource (water and nutrient) inputs. Plant symbiotic relationships with mycorrhizal fungi alter root aquaporin gene expression and greatly increase the surface area over which plant root systems take up water and nutrients. Soil bacteria on the root surface alter root phytohormone status thereby increasing growth, and can make nutrients more available to the plant. Combining different classes of soil organism within one inoculant can potentially take advantage of multiple plant growth-promoting mechanisms, but biological interactions between inoculant constituents and the plant are difficult to predict. Whether the yield benefits of such inocula allow modified nutrient and water management continues to challenge crop biotechnologists.     

紫茎泽兰花蕾发育过程中类Beclin1基因的克隆表达分析

以紫茎泽兰不同发育时期花蕾为实验材料,通过光学显微观察、DNA ladder检测表明紫茎泽兰花蕾发育过程中绒毡层有PCD现象发生,自紫茎泽兰花蕾中克隆长为679 bp的Beclin1 cDNA基因部分片段,同烟草叶片的Beclin1基因序列（AY701316）同源性为98%,通过Northern blotting分析,在紫茎泽兰花蕾发育过程中细胞程序性死亡（PCD）相关Beclin1基因表达在花蕾发育第Ⅱ期和Ⅲ期较为旺盛,且在花蕾发育第Ⅱ期最强烈。本研究首次克隆并证实紫茎泽兰花蕾Beclin1基因与PCD有一定的相关性,为分析紫茎泽兰入侵机理提供新的思路和手段。     

紫茎泽兰提取物对番茄青枯菌的抑菌作用及其机理

用紫茎泽兰70%的乙醇提取物及其氯仿萃取物,对番茄青枯菌生理、生化、细胞形态等方面进行抑菌试验。乙酸乙酯、正丁醇、乙醚、氯仿萃取物具有较好的热稳定性,在pH9时抑菌圈最大;通过透射电镜观察,菌体经紫茎泽兰提取物作用后,鞭毛消失,中央出现空腔。SDS-PAGE显示紫茎泽兰氯仿萃取物处理番茄青枯菌后,菌体内蛋白质减少,随着作用时间的延长,完全抑制或破坏了小分子蛋白质的合成,对大分子蛋白质也有一定的抑制作用。POD、CAT、SDH酶活测定显示,随着加入的紫茎泽兰氯仿萃取液浓度的增大,酶活显著降低。以上试验结果表明,紫茎泽兰氯仿萃取液对番茄青枯菌有明显的抑制作用,对于番茄青枯病防治的应用有一定的指导意义。     

稻麦两熟系统适期晚播对周年产量和资源利用效率的影响

受气候变化影响,江淮地区稻麦两熟种植模式周年资源配置不合理、资源利用效率低,限制了该区域作物周年高产高效协同发展。通过播期调整优化两季资源配置是提高资源利用效率,挖掘周年产量潜力的重要途径。本研究于2013—2015年进行大田试验,设置不同稻麦播期组合,对其周年产量和资源配置与利用特征进行了比较。结果表明:与常规种植模式(T₂)相比,稻麦双季适期晚播模式(T₃)通过播期调整协调了两季间资源配置,将小麦季冗余的温光水资源转移给高贡献率作物水稻,水稻季积温、辐射、降雨资源分别占60.5%、46.5%和56.7%,小麦季分别占36.3%、50.0%和40.9%,两季间比值为1.67、0.94和1.39;水稻产量显著提高,并提高了水稻在周年产量中的占比;小麦产量显著降低,但变幅小于水稻;周年总产量提高了336.3 kg·hm^-2。水稻季温度生产效率、光能生产效率和降雨生产效率分别提高了9.8%、5.6%和8.3%,小麦季资源利用效率无显著差异,T3模式周年温、光、水生产效率分别提高了4.8%、3.1%和6.0%。稻麦双季早播模式...     

From introduction to nuisance growth: a review of traits of alien aquatic plants which contribute to their invasiveness

Invasive alien aquatic plant species (IAAPs) cause serious ecological and economic impact and are a major driver of changes in aquatic plant communities. Their invasive success is influenced by both abiotic and biotic factors. Here, we summarize the existing knowledge on the biology of 21 IAAPs (four free-floating species, eight sediment-rooted, emerged or floating-leaved species, and nine sediment-rooted, submerged species) to highlight traits that are linked to their invasive success. We focus on those traits which were documented as closely linked to plant invasions, including dispersal and growth patterns, allelopathy and herbivore defence. The traits are generally specific to the different growth forms of IAAPs. In general, the species show effective dispersal and spread mechanisms, even though sexual and vegetative spread differs strongly between species. Moreover, IAAPs show varying strategies to cope with the environment. The presented overview of traits of IAAPs will help to identify potential invasive alien aquatic plants. Further, the information provided is of interest for developing species-specific management strategies and effective prevention measures.

     

Comparisons of plastic responses to irradiance and physiological traits by invasive Eupatorium adenophorum and its native congeners

To explore the traits contributing to invasiveness of Eupatorium adenophorum and to test the relationship between plasticity of these traits and invasiveness, we compared E. adenophorum with its two native congeners at four irradiances (10%, 23%, 40%, and 100%). The invader showed constantly higher performance (relative growth rate and total biomass) across irradiances than its native congeners. Higher light-saturated photosynthetic rate (P(max)), respiration efficiency (RE), and nitrogen (PNUE) and water (WUE, at 40% and 100% irradiances only) use efficiencies contributed directly to the higher performance of the invader. Higher nitrogen allocation to, stomatal conductance, and the higher contents of leaf nitrogen and pigments contributed to the higher performance of the invader indirectly through increasing P(max), RE, PNUE and WUE. The invader had consistently higher plasticity only in carotenoid content than its native congeners in ranges of low (10-40%), high (40-100%) and total (10-100%) irradiances, contributing to invasion success in high irradiance by photo protection. In the range of low irradiances, the invader had higher plasticity in some physiological traits (leaf nitrogen content, nitrogen contents in bioenergetics, carboxylation and in light-harvesting components, and contents of leaf chlorophylls and carotenoids) but not in performance, while in the ranges of high or total irradiances, the invader did not show higher plasticity in any variable (except Car). The results indicated that the relationship between invasiveness and plasticity of a specific trait was complex, and that a universal generalization about the relationship might be too simplistic.     

紫茎泽兰与黑麦草苗期相对竞争力和生长特征的研究

为探究替代物种黑麦草（Lolium perenne）抑制外来人侵杂草紫茎泽兰（Eupatorium adenophorum）的潜力,采用de Wit取代系列设计,在野外小区内设置3水平多年生黑麦草栽植时间、4水平种植密度以及3水平混种比例等不同种植处理,于12周后收获,分别测量黑麦草与紫茎泽兰的地上生物量和地下生物量,用单株相对产量分析其竞争力。结果表明,种植密度、混种比例和黑麦草栽植时间显著影响紫茎泽兰的地上生物量,紫茎泽兰的竞争力在低种植比例情况下,随黑麦草栽植时间的推迟而明显增强,随种植密度的降低而增强。种植密度、混种比例、黑麦草栽植时间以及这些因素的互作等对黑麦草的地上生物量与地下生物量均具有显著影响;栽植时间越晚、密度越大,黑麦草的竞争力就越弱（尽管不存在直线关系）。在大多数种植处理条件下,紫茎泽兰经历的种间竞争明显大于种内竞争,表现出较弱的竞争力;而黑麦草在与紫茎泽兰同时栽植的情况下,经历的种内竞争大于种间竞争,表现出较强的竞争力。     

入侵植物紫茎泽兰化感作用及其途径研究

紫茎泽兰广泛入侵中国西南地区,研究结果表明化感作用是其入侵的重要武器,但其化感作用的途径并不十分清楚。本研究中,我们发现紫茎泽兰可以通过多种途径对两种栽培植物大麦和玉米的生长产生化感作用,这些途径包括了叶挥发物、叶淋溶物以及根分泌物。并且在紫茎泽兰幼苗早期就可以检测到这些化感作用。然而,没有实验证据表明紫茎泽兰落叶的微生物降解物对两种测试植物具有化感作用。     

Micropropagation of Eclipta alba and Eupatorium adenophorum using a single-step nodal cutting technique

Protocols for the micropropagation of two traditional medicinal plants Eclipta alba (L.) and Eupatorium adenophorum (L.) from nodal segments were developed. Proliferated microshoots of Eclipta alba and Eupatorium adenophorum were obtained through axillary branching by culturing nodal segments in modified MS medium and half strength of MS, respectively, with minimal strength of nutritional support. Simultaneous rooting could also be induced in the same medium. Regenerated rooted plantlets were successfully acclimatized in soil where they grew normally without showing any morphological variation. This revised version was published online in June 2006 with corrections to the Cover Date.