美洲商陆论文_1[2.22]

入侵种美洲商陆的果实产量、土壤种子库及实生苗自然更新

李娟李新华王庆亚王燕浦伯钧王聪王探

南京农业大学生命科学学院南京210095

摘要2008年4月至2008年9月调查了南京地区美洲商陆(Phytolacca americana )的果实产量、土壤种子库种子密度、实生苗数量以及鸟类取食美洲商陆浆果的数量。结果表明：美洲商陆单株果实产量平均为4287.90±527.11个。在毛竹林、洋槐林、针阔混交林3个生境中标记的美洲商陆果序成熟果实数量为580.8~617个,没有显著差异（F2,30=0.414,p=0.665）；而鸟类取食成熟果实数量79.2~540.2个，取食率为13.10%~87.67%，在毛竹林与洋槐林、针阔混交林之间有显著差异（ANOV A，F=1004.83, df=2, p＜0.0001）。3个生境土壤种子库种子密度为1970.0~5690.0粒/m2，鸟类对美洲商陆浆果的取食率与美洲商陆土壤种子库密度之间呈显著的负相关。5月毛竹林、洋槐林和针阔混交林下美洲商陆实生苗的密度依次为198.2、50.0和

16.5株/m2；8月实生苗的密度依次为25.6、 6.8和5.2株/m2；实生苗的存活率依次为14.7%、

17.91%和25.8%。这表明，密度性制约竞争是导致美洲商陆幼苗高死亡率的一个重要因素。关键词美洲商陆；果实产量；土壤种子库

国家自然科学基金国家基础科学人才培养基金项目（J0730647）资助

Fruit yield, soil seed bank and natural seedling regeneration of Phytolacca americana

Abstract From April 2008 to September 2008, the fruit production, soil seed bank, number of seedling of exotic weed Phytolacca americana ,and number of Phytolacca americana fruits eaten by birds were surveyed in Nanjing. The results showed that the average fruit production of P.

americana was4287.90±527.11 per plant. The number of fully ripe fruit of plant in 3 sample sites varied 580.8±17.0~617±42.1 per plant, there weren’t significant difference in these sample sites （F2,30=0.414,p=0.665）.However, the number of fruits eaten by birds were 79.2±4.0~540.2±37.0 per plant, and the percent of fruits eaten by birds were13.10%~87.67%, there were significant difference among Phyllostachys pubescens forest, broadleaved mixed forest, Robinia peseudoacacia forest（ANOV A，F=1004.83, df=2, p＜0.0001）. Seed density in these sample sites varied between 1970.0~5690.0 seeds.m-2, it was negative relation to the percent of fruits eaten by birds.The seedling density of Phytolacca americana in the Phyllostachys pubescens forest, broadleaved mixed forest and Robinia peseudoacacia forest were98.2, 50.0 and 16.5 plant.m-2 respective in May. The density of survival seedlings decreased to 25.6 ,6.8 and 5.2plant.m-2respective in these sits in August .The seedling livability were14.7%,17.91%and 25.8% respective in these sits. The result indicate strong competition result in Phytolacca Americana seedling mortality when the seedling density was high.

Key words Phytolacca americana, fruit production, soil seed bank

土壤种子库是指埋藏于土壤中的种子储藏库，或是存在于土壤上层凋落物和土壤中全部存活种子的总合（Simposon，1989），属于潜在种群，是植物生活史的一个重要阶段。在联系生境的过去、现在、以及未来的植物种群、群落结构与动态时，土壤种子库起到了重要的生态、进化上的作用（张炜银等，2005；党伟光等，2008）。植物所产生的种子最终要落到土壤中，这些种子在一定时间内仍具活力，当外部条件适宜时就萌发成幼苗，因此，土壤种子库是种群补充更新的基础，对于种群的维持具有重要的作用。

美洲商陆(Phytolacca americana L.)又称为垂序商陆，原产于北美东部，隶属于商陆科商陆属，经常大量出现在受干扰的开阔的生境中（鲁德全，1995）。我国已将其列入外来入侵