Germination and emergence of Ambrosia artemisiifolia L. under changing environmental conditions in China

Abstract

Laboratory and greenhouse studies were conducted to determine the effects of key environmental factors on germination and seedling emergence of the invasive weed Ambrosia artemisiifolia L. (common ragweed) collected from Mudanjiang (temperate climate), Nanjing (temperate-subtropical) and Nanchang (subtropical) in China. Germination of seeds occurred at temperatures ranging from 5 to 40°C, under both a 12-h photoperiod and continuous darkness. Germination success exceeded 48% in solutions with pH values between 4 and 12, with maximum rates occurring in distilled water at pH 5.57. Germination was greatly reduced in solutions with osmotic potentials below -0.8 MPa. Accordingly, the final germination ratio exceeded 69% at <200 mmol/L NaCl, but only reached 8% at 400 mmol/L NaCl. Emergence was greater than 75% at burial seed depths of 1-4 cm; no seedlings emerged from a soil depth of 8 cm. Seeds collected from Mudanjiang, Nanjing and Nanchang had very similar germination traits, with the main differences occurring in relation to temperature. The great germination success of common ragweed over highly variable conditions throughout its Chinese distribution range explains its successful large-scale invasion.

Germination bi­ology of Parthenocissus quinquefolia (L.) Planch. (Vi­taceae)

“…It was shown in Banksia woodlands in south-western Australia by Pérez-Fernández et al (2000) as well as by Young et al (2015) for perennial grasslands in north-central California. These results were obtained for Ambrosia artemisiifolia L. (Sang. et al 2011), Malva pusilla Sm.…”

“…Usually, invasive species have wide range of temperatures under which they germinate. Such data were obtained for Ambrosia artemisiifolia which corresponds with the wide distribution of the species in China (Sang et al 2011), and is again reflected by other successful invasive weeds, such as Cortaderia jubata (Lem.) Stapf (8-35°C) (Drewitz & DiTomaso 2004), Solanum viarum Dunal (10-35°C) (Akanda et al 1996) and Pueraria lobata (Willd.)…”

“…(Lu et al 2006), strict range of pH tolerance (germination is possible only in buffer solutions of pH 5 to 7) was shown. Other studied invasive species Ambrosia artemisiifolia (Sang et al 2011), Urochloa subquadripara (Trin.) R. D. Webster.…”

Antioxidant response of the invasive herb Ambrosia artemisiifolia L. to different irradiance levels

“…These ecophysiological adaptive traits in A. artemisiifolia have likely contributed to the the successful invasion and range expansion of this species in many parts of temperate Europe (Fumanal et al 2008), and also in subtropical regions such as observed recently in southern China Qi et al 2011). This better understanding of how acclimation to irradiance in A. artemisiifolia may affect its colonizing and invasive success will facilitate the prediction of future invasions and range transformations in relation to the projected climate change and general evolutionary potential of invasive plants (Clements and DiTommaso 2011;Sang et al 2011).…”

The History of Ragweed in the World

“…The species continue their southward spread into the subtropical regions of the country (Qin et al, 2012). The reason of the large-scale invasion of A. artemisiifolia in China is its great germination success over the highly variable climatic conditions (Sang et al, 2011). Li et al (2012) found that high levels of genetic variation in China indicate that there has been no erosion of genetic variance due to a bottleneck during the introduction process.…”