Germination Eco-physiology of Angelica glauca Edgew Seeds

Abstract

Aims: Angelica glauca Edgew is a heavily exploited critically endangered medicinal cum aromatic herb of Himalayan region. Poor and erratic seed germination is one of the constraints in its in-situ as well as ex-situ conservation and large scale cultivation. Moreover, our understanding of the eco-physiological aspects of the seed germination in this species is very limited. The present study aimed to understand the effect of different temperature regimes, photoperiodic conditions and sowing depths on seed germination in A. glauca using laboratory and nursery conditions. Study Design: Complete Randomized Design was executed. Place and Duration of Study: G.B. Pant Institute of Himalayan Environment and Development, Mohal-Kullu (HP), India between April 2006 and July 2008. Methodology: Germinability of the seeds were evaluated under different temperature regimes viz.(5, 15, 25 and 30ºC) and photoperiods (light-24 hrs, dark-24 hrs and alternate photoperiods-16 hrs dark and 8 hrs light) in laboratory; and at sowing depths (0.5, 1.0, 1.5 and 2.0 cm) in controlled nursery conditions. Results: In photoperiodic conditions, encouraging results were obtained under alternate light regimes which favored maximum (77.78%; p<0.05) mean germination along with minimum MGT (42.08 days) and Germination Potential Index (114.6) under laboratory condition. All these parameters performed significantly better at 25ºC as compared to other temperature regimes tested. In nursery condition, seed sown at 1.0cm depth gave comparatively higher (p<0.05) seedling emergence. Poor seedling emergence at higher sowing depth clearly indicated the requirement of light for germination in A. glauca seeds. Conclusion: Study concludes that alternate photoperiods (16 hrs dark and 8 hrs light), temperature (25ºC) and soil depths not more than 1.0cm are effective treatments to achieve optimum germination in A. glauca. These technicalities could be easily adopted by the poor and unskilled farmers for economic cultivation of this species.