Seed germination ecology of Ageratum houstonianum: A major invasive weed in Nepal

Autoři: Anju Lamsal aff001;  Mohan P. Devkota aff001;  Deepa S. Shrestha aff002;  Srijana Joshi aff003;  Anil Shrestha aff004
Působiště autorů: Department of Botany, Tribhuvan University, Amrit Campus, Kathmandu, Nepal aff001;  National Gene Bank, Nepal Agricultural Research Council, Lalitpur, Nepal aff002;  International Centre for Integrated Mountain Development, Lalitpur, Nepal aff003;  Department of Viticulture and Enology, California State University, Fresno, California, United States of America aff004
Vyšlo v časopise: PLoS ONE 14(11)
Kategorie: Research Article
doi: 10.1371/journal.pone.0225430


In recent years, spread of invasive alien plant species (IAPS) has been a major concern in Nepal. One such IAPS is Ageratum houstonianum, an Asteraceae, that is a prolific seed producer and difficult-to-control in farmland and various ecological regions causing crop yield and biodiversity losses. However, very little information is available on the germination biology and ecology of this species. Therefore, experiments were conducted to assess the effect of water stress, pH level, and light requirement on seed germination, and the effect of seed burial depth on seedling emergence. Water stress was simulated by polyethylene glycol solutions ranging from 0–5.56 MPa and pH solutions ranging from 4 to 9 were prepared using hydrochloric acid and sodium hydroxide. Germination tests were conducted in petri dishes lined with filter paper and placed in a controlled environment chamber set at 20° C. Light requirement comparisons were made by having petri dishes wrapped with aluminum foil or left unwrapped. Seedling emergence was evaluated by placing seeds at depths ranging from 0 to 20 mm in the soil. Results indicated that this species was moderately drought-tolerant because germination ceased beyond 0.51 MPa. Greater germination occurred at neutral to acidic than at alkaline pH levels. The seeds were positively photoblastic because no germination occurred under dark condition. No seedlings emerged from seeds placed more than 2 mm deep in the soil, indicating that this is a primarily surface germinating species. These findings will help predict future invasions and in development of management strategies for this IAPS.

Klíčová slova:

Evolutionary emergence – Filter paper – Invasive species – Light – Seed germination – Seedlings – Seeds – Weeds


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Článek vyšel v časopise


2019 Číslo 11