入侵恶性杂草豚草和三裂叶豚草土壤种子库特征及其对地上种群的贡献

Characteristics of soil seed banks and their contribution to aboveground population of invasive weeds Ambrosia artemisiifolia and A. trifida

目的土壤种子库是种群地上植被更新的基础,对入侵植物种群形成和危害起决定性作用。方法本文通过研究豚草(Ambrosia artemisiifolia)和三裂叶豚草(Ambrosia trifida)入侵1~6年土壤种子库和地上种群数量的关系,分析土壤种子库对其种群建立、增长和维持的作用。结果 (1)土壤种子库密度随土层深度增加而减小,随入侵时间延长而增大。种子主要集中于0~10 cm土层,最大种子库密度在入侵六年生境0~10 cm土层,分别为525粒·m^(-2)和11 868粒·m^(-2);(2)干瘪、虫食、霉变等类型种子在豚草种子库0~10 cm土层中占总种子库的25%左右,在不同生境三裂叶豚草种子库中占比分别在23%、34%、15%;(3)种群密度随生育期延长而降低,随入侵时间延长而增加。在营养期和繁育期阶段密度下降最快,豚草和三裂叶豚草最多分别减少343株·m^(-2)和637株·m^(-2)。种群定居时间越久种子库累积输入量越大,春季萌发量也越多。结论因此,针对豚草和三叶豚草的入侵防治,应该将其种子库作为重要关注点,从减少输入,控制输出两方面进行治理。

Objective The soil seed bank is the basis of aboveground vegetation regeneration,which plays a decisive role in the formation and damage of invasive plants population. Methods In this paper,the relationship between soil seed bank and aboveground population quantity of Ambrosia artemisiifolia and A. trifida invading for 1 ~ 6 years was studied,and the effects of soil seed bank on population establishment,growth and persistence were analyzed. Results The results show that:(1) The density of soil seed bank decreased with the increase of soil depth and increased with the extension of invasion time. Seeds were mainly concentrated in 0 ~ 10 cm soil layer,and the maximum seed bank density of Ambrosia artemisiifolia and A. trifida were 525 seeds·m^(-2) and 11868 seeds·m^(-2) respectively in this soil layer of six years invasion habitat.(2) Withered,Eaten by insects and moldy seeds accounted for 25% of the total A. artemisiifolia seed bank at 0 to 10 cm,it’s about 23%,34% and 15% in A. trifida seed bank from different habitats.(3) The population density decreased with the prolongation of growth period and increased with the extension of invasion time. Density decreases most rapidly during the nutritional and reproductive stages,the maximum reduction of A. artemisiifolia and A. trifidawas was 343 plants·m^(-2) and 637 plants·m^(-2),respectively. The longer the population settlement,the greater the seed bank accumulation was input and the more seed was germination in spring. Conclusion Therefore in oder to control the invasion of A. artemisifolia and A. trifida,the seed back should the regarded as a key point,and the control chould be carried out from the two aspects of reducing the seed production and controlling seed germination.