金钟藤研究述评

述评了近年来有关金钟藤的报道和研究成果,论证确认金钟藤是喜光的阳性藤本植物,而不是阴性植物,具有广幅生态适应性,并含有入侵物种入侵机制之一的化感物质.金钟藤在中国分布于云、桂、粤,福建的分布则没有确证.广州及其附近正在成为该种新的分布区域,尽管倾向是由于全球变暖而导致从海南北移入侵的结果,但金钟藤毕竟不是纯热带植物,而是热带亚热带成分,北回归线是其分布的北界,因而极可能是全球变暖而激活的潜在本地物种.金钟藤在越南这个模式标本产地和海南这个原分布中心的蔓延成灾,有别于入侵物种在原产地因有天敌而不能蔓延成灾的论点,或显示其在原产地尚无致命的天敌.金钟藤能够蔓延成灾的根源在于干扰破坏了原有的自然生态系统,导致生境恶化、破碎、异质化、群落生物多样性和物种功能组群多样性的贫乏,增强了群落的可入侵性,从而给予入侵物种入侵的机遇,因而金钟藤入侵无选择性的论点值得商榷.金钟藤危害的防治仍待突破,利用综合防治策略应是首选,而防止干扰破坏自然生态系统、改建、重建和优化被干扰破坏的生态系统应是必要的策略和措施.

Abstract：

Recent researches demonstrated that Merremia boisiana is a photophilous heliophyte liana rather than a sciophyte, which has a wide ecological adaptability and contains the allelo-chemicals, one of invasion mechanisms of invasive species. In China, M. boisiana had a distri-bution in Yunnan, Guangxi, and Guangdong Provinces, but its distribution in Fujian Province has not been confirmed. Guangzhou City and its vicinity are becoming a new distribution area of M. boisiana due to its northward invasion from Hainan under global warming. However, M. boi-siana is not really a kind of tropical plants, but one of the tropical and subtropical elements. The tropic of cancer is the north boundary of M. boisiana distribution, and thereby, there is a high possibility that M. boisiana is a latent local species activated by global warming. M. boisiana causes widespread disaster in its holotype locality (Vietnam) and its original distribution center (Hainan Province), which is not consistent with the existing viewpoint that the invasive species cannot spread to be a disaster owing to the natural enemies in origin, while suggests that there are no fatal natural enemies in the origin. The widely spreading to be a disaster is originated from the intrinsic ecosystem being destroyed by disturbances, which causes the worsened, broken, and heterogeneous habitat. The reduced community biodiversity and functional group diversity intensi-fy the invasive possibility of exotic communities and provide chance for invasive species. There-fore, the viewpoint that the invasion of M. boisiana is non-selective should be modified, and the prevention measures of M. boisiana remain to be break through. Integrative control should be the first choice. Additionally, protecting the natural ecosystem from disturbance, and reconstructing and optimizing the destroyed ecosystem would be the necessary strategies and measures.     

金钟藤-广东分布新记录

报道广东新发现一种隶属于旋花科(Convolvulaceae)的危害森林的大型藤本植物-金钟藤(Merremia boisiana),并对其形态进行描述。     

金钟藤―广东分布新记录

报道广东新发现一种隶属于旋花科(Convolvulaceae)的危害森林的大型藤本植物―金钟藤(Merremiaboisiana),并对其形态进行描述。     

金钟藤入侵危害的群落学特征初探

对入侵广州市东北郊龙眼洞林场的金钟藤生长状况及其对三种不同森林群落的危害进行研究。结果表明,这种多年生木质藤本植物的无性繁殖能力极强,带根茎比例高,生存策略明确,目前未发现其天敌。金钟藤通过极强的攀附能力,盖幕危害附主植物,且对群落的入侵并无选择性,对群落中所有的乔木都具有危害性,尤其是对物种多样性指数较低的马占相思林危害相对最为严重。它可能还可以通过改变所在森林生态系统的氮循环,间接影响群落中其他植物的生长。     

金钟藤叶绿素荧光特征初探

利用叶绿素荧光技术初步观测丁金钟藤在不同作用光下的光合生理特征,并对其离体叶片在低温、高温及脱水胁迫下的光能利用状况作了比较。结果显示,随着作用光强的增加,叶片Fv＇/Fm＇、qP和ΦPSⅡ呈下降趋势,qN和NPQ表现为上升。离体叶片在5℃处理6h后,其Fv＇/Fm＇、qP和ΦPSⅡ高于25℃和45℃处理的,而NPQ在5℃和45℃处理6h后明显低于对照（25℃）,qN则略有降低。离体叶片脱水胁迫12h后,仍有一定的光能转化能力,但脱水24h和36h后,qP、ΦPSⅡ、qN、NPQ都明显下降。这表明金钟藤对于环境因子,如光强、温度及水分的变化具有较强的适应性,这可能是其在森林中能快速蔓延扩散的一个重要原因。     

五指山市金钟藤种群分布格局分析

在五指山市金钟藤生长区域内选取3 个样地对其分布格局进行野外调查分析。利用方差/均值比率法计算得到, A1 和A3 样地金钟藤种群呈集群分布, 而A2 样地金钟藤种群呈随机分布。此外, 通过聚集强度指数分析发现, A1、A3 样地金钟藤种群聚集强度指数I、m*/ x 、Iδ对1.0 的偏离程度明显, m*较大, 且K 值较小, 符合种群聚集分布特征。A2 样地金钟藤种群K 值较大, 其种群聚集强度指数I、m*/ x 、Iδ对1.0 的偏离程度不明显, 且m*较小, 符合种群随机分布特征。     

金钟藤叶片的气体交换特性

用LI-6400便携式光合测定系统(Li-CorInc.,USA)对广州林区新发现的入侵杂草金钟藤(Merremiaboisiana)叶片的气体交换进行了测定。结果表明(1)净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(E)的日变化均表现为单峰型曲线,中午金钟藤未出现光合作用抑制;最大光合速率可达20μmolCO2.m-2.s-1左右,Pn日平均值为8.8±0.75μmolCO2.m-2.s-1。(2)金钟藤光合作用的光饱和点较高,为1000~1200μmolphotons.m-2.s-1,表现出比较典型的阳生植物的特性。结果表明,金钟藤在自然环境中具有快速生长的特性可能与其较强和较稳定的光合能力有关。研究的初步结果对了解金钟藤迅速生长、具有高生产力和强大入侵力的原因提供了进一步深入探讨的思路和基础数据。     

金钟藤分类考证及补充描述

旋花科植物金钟藤在中国华南地区已蔓延暴发成为\"森林杀手\",已引起各界的高度关注。该文对金钟藤的系统归隶、基名与异名、模式标本、分类文献,以及相关种进行考证和分析,澄清了一些误解和标本鉴定的错误,论证了金钟藤变种黄毛金钟藤在中国仅产于广西,而云南产的黄毛金钟藤实为铜钟藤,并把Merremia biosiana var.sumatrana van Ooststr.作黄毛金钟藤的新异名处理。     

金钟藤中酚类化合物的研究

从金钟藤(Merremia boisiana(Gagnep.)V.Ooststr.)的地上部分分离得到8个酚类化合物。通过光谱分析,分别鉴定为东莨菪内酯(1)、七叶内酯(2)、N-p-香豆酰酪胺(3)、3,5-二咖啡酰基奎尼酸甲酯(4)、3,4-二咖啡酰基奎尼酸甲酯(5)、3,4,5-三咖啡酰基奎尼酸甲酯(6)、槲皮素(7)以及山奈酚-3-β-D-半乳糖甙(8)。这些化合物均是首次从鱼黄草属(Merremia)植物中发现。     

金钟藤和葛藤在干旱与复水条件下的生理比较

对外来入侵种金钟藤和本地种葛藤进行干旱胁迫和水分恢复处理,比较了两种植物抗氧化酶(SOD、CAT)活性、丙二醛(MDA)含量及叶绿素荧光参数的变化。研究表明,干旱胁迫下两种植物SOD、CAT活性均高于复水后,金钟藤高于相同处理下的葛藤;金钟藤在干旱与复水条件下的MDA含量无差异,而葛藤干旱下高于复水后,不同处理下葛藤均高于金钟藤;干旱条件下金钟藤比葛藤有更强的抗氧化能力,膜脂过氧化水平明显较低,MDA与SOD、CAT呈明显的负相关。两种植物在复水后Fv/Fm、ETR与ΦPSⅡ值均显著高于干旱时,葛藤变化程度略大于金钟藤。复水后金钟藤的NPQ值增加而葛藤降低,且干旱时葛藤大于金钟藤,复水后金钟藤大于葛藤。综合比较,金钟藤比葛藤对干旱的生理适应能力强,这可能是其入侵性的重要特征。     

Seed, cutting and air-layering reproductive inefficiency of noxious woody vine Merremia biosiana and its implications for management strategy

Merremia boisiana (Gagnep) van Ooststr. is a noxious fast growing woody vine and is able to grow overtop other plants, causing the death of plants under-neath and forming monospecies stands. To formulate management responses, we assessed its seed and vegeta-tive reproduction efficacy through indoor and field experiments. The number of flowers counted from bagged infructescences in Guangzhou ranged from 25 to 172, with an average of 80.80. Counting the seeds of bagged infructescences had shown that there were only 1.58 hard testa seeds in each infructescence. Seed vitality tests using red ink indicated that only 68.6% of hard testa and filled seeds were viable. The emergence rate of scarified hard testa seeds in the sand bed was 31.96%. Under imitated natural conditions, 8% of hard testa seeds could germinate, and 9% still retained their germination potential in one year. Thus, seedlings should be monitored and removed in a timely fashion after any attempt of clearing. Moving soil or transplanting plant from infested patches should be strictly prohibited at least for several years. All considered, an infructescence contributed 0.3 seedlings. The investiga-tion in the field found no seedlings either inside or at the perimeter of the patch, suggesting scant expansion by means of seed dispersal. Therefore, the elimination effort could be focused on a relatively restricted scale of patches. Of 630 cuttings of young shoots, old shoots and old lying shoots with or without growth regulators, there were only four (or 0.63%) established individuals. Air-layering shoots all died in two months. Poor cuttings and air-layering reproduction indicated that regeneration from fragments of removed stems or accidentally dropped ones was quite unlikely, and thus mechanical removal was safe.