Germination ecology of invasive alien Anthemis cotula helps it synchronise its successful recruitment with favourable habitat conditions

Abstract

Anthemis cotula is a widespread invasive alien species in Kashmir Himalaya. Being a winter annual, the species reproduces entirely by achenes and synchrony between germination requirements of the species and the habitat conditions must be of critical importance in its invasiveness. To examine how the achenes of different ages respond to different environmental cues, two laboratory experiments were performed wherein effects of different nitrogen applications and growth hormones under continuous light and dark conditions were explored. Results show that the achenes are positively photoblastic and have requirement for after-ripening. Nitrogen applied either as potassium nitrate NO À 3 or as thiourea NH þ 4 significantly improved achene germination both under continuous light and dark conditions. Although kinetin (6-furfurylaminopurine) did not influence achene germination, gibberellic acid (GA 3 ) applied at 1.0 mM concentration had the most significant effect on the final percentage germination under both light and dark conditions. These results suggest that the achenes have an elaborate mechanism of sensing the habitat conditions that helps them to synchronise their germination with favourable environmental conditions -a strategy that aids the species in ensuring recruitment, survival and its spread in Kashmir Himalaya.

Nitrogen fertilization and water supply affect germination and plant establishment of the soil seed bank present in a semi-arid Mediterranean scrubland

“…Seed emergence can be influenced both positively and negatively by soil nitrate or ammonium concentration (Rashid et al 2007). Since restoration of disturbed arid or semi-arid environments is often hindered by low seedling establishment, information on seed biology and germination is a valuable tool for restoration practices (Commander et al 2009).…”

Hydrothermal thresholds for seed germination in winter annual forbs from old‐field Mediterranean landscapes

“…Similarly, storing for >1 year increased germination in A. cotula from the cold Himalayan deserts (Rashid et al . ), suggesting a species‐level trait of losing dormancy during long periods of storage. Other studies found that seeds of M. moricandioides collected from wild Spanish populations and stored at 5 °C for 4–8 months germinated to nearly 90% under the alternating temperatures of 20/7 °C (Herranz et al .…”

Morphology, anatomy and germination response of heteromorphic achenes ofAnthemis chrysanthaJ. Gay (Asteraceae), a critically endangered species

“…There have been studies on the morphology of the capitulum and the fruit in order to establish phylogenetic classifications within the Asteraceae (Chehregani and Mahanfar, 2007;Kreitschitz and Vallés, 2007), and some have described relationships between fruit morphology and germination capacity (Porras and Muñ oz, 2000;Imbert, 2002;Brändel, 2004;Sun et al, 2009), but very few have addressed germination in the genus Anthemis (Rashid et al, 2007). Anthemis L. is the second largest genus within the Asteraceae (tribe Anthemidae), with more than 210 species in the Mediterranean region, south-west Asia and eastern Africa (Oberprieler, 2001); about 62 species are distributed in Europe and 14 in the Iberian Peninsula.…”