Effects of microhabitat, light and temperature on seed germination of a critically endangered Himalayan medicinal herb,Swertia chirayita: Conservation implications

Abstract

Swertia chirayita, a critically endangered medicinal herb, is being over-harvested in the wild. Understanding seed germination is a pre-requisite to ensure species conservation. The germination of seeds collected from six microhabitats was studied at 208C, 258C, and 308C, both under a 14/10 h light/dark photoperiod and in continuous darkness. Two-way ANOVA indicated that microhabitat and temperature significantly affect seed germination, germination rate, germination recovery (GR), and GR rate. Overall, the seeds collected from under canopy showed a significantly (p 5 0.05) higher germination than those from open habitats, at 208C, 258C, and 308C (14/10 h light/dark photoperiod). Germination was negligible in continuous darkness but after transfer to a 14/10 h light/dark photoperiod, the seeds from under canopy significantly recovered at 208C and at 258C (p 5 0.05), and showed the highest germination percentage compared to seeds collected from tree base, stump base, shrubberies, and grassy slope. Similarly, at 308C, seeds from under canopy recorded the highest GR percentage. In general, seed germination, mean germination rate, seed GR, and GR rate were significantly greater (p 5 0.05) at 258C. Among the microhabitats tested, variation in GR rate was significant (p 5 0.05). Seeds were confirmed to be positively photoblastic.

A preliminary evaluation of lake morphometric traits influence on the maximum growing depth of macrophytes

“…Temperature affects plant germination in various ways (see, among others Carasso et al, 2012;Pradhan and Badola, 2012). Water temperature exerts a strong influence on macrophyte life phases, such as reproduction, germination and seedling emergence (Barko et al, 1982;Madsen and Adams, 1988;Spencer and Ksander, 1992;Leck, 1996;Xiao et al, 2010).…”

Germinative response of redroot pigweed (Amaranthus retroflexusL.) to environmental conditions: Is there a seasonal pattern?

“…Previous researches on cosmopolitan weeds as well as endangered species have indicated that fruit set and dormancy occurring during seed-set are likely to be influenced by environmental conditions that occur in a specific habitat (Luzuriaga et al 2006;Pradhan & Badola 2012;Valtueñ a et al 2012). Gallagher and Cardina (1998) found that the emergences of redroot pigweed were stimulated by the presence of light, even though such an effect was partially overcome by a temperature of 308C.…”

Swertia chirayta, a Threatened High-Value Medicinal Herb: Microhabitats and Conservation Challenges in Sikkim Himalaya, India

“…Studies have found that species performance varies among microhabitats (Shrestha and Jha 2010;Pradhan and Badola 2012). Species with habitat specialization and a narrow range of microhabitats have greater risk of extinction than species with a broad habitat range (Brys et al 2005;Samant et al 1996).…”

“…Species with habitat specialization and a narrow range of microhabitats have greater risk of extinction than species with a broad habitat range (Brys et al 2005;Samant et al 1996). Therefore, knowledge of threatened plants' microhabitat requirements would help in planning their conservation and management (Hegland et al 2001;Colling and Matthies 2006;Kalliovirta et al 2006;Pradhan and Badola 2012). This necessitates undertaking microlevel habitat assessment, which can help determine the performance of a species under different conditions and provide information on its ecological requirements (Hegland et al 2001;Pradhan and Badola 2012).…”