Chrono-spatial reproductive phenology of Swertia bimaculata Hook.f. & Thomson ex C.B.Clarke reveals suitability as climate-changing bio-indicator along the Sikkim Himalayan altitude
Jitendra Kumar Shukla,
Kishor Basor,
Preeti Dhakal,
Sandhya Thapa,
Evanylla Kharlyngdoh,
Sunil S. Thorat,
Pardeep Bhardwaj,
Sushil K. Chaudhary,
Pulok K. Mukherjee
Affiliations
Jitendra Kumar Shukla
Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Meghalaya Centre, Upper Shillong, 793 009, Meghalaya, India; Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Sikkim Centre, Gangtok, 737 102, Sikkim, India; Corresponding author. Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Meghalaya Centre, Upper Shillong, 793 009, Meghalaya, India.
Kishor Basor
Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Meghalaya Centre, Upper Shillong, 793 009, Meghalaya, India; Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Sikkim Centre, Gangtok, 737 102, Sikkim, India
Preeti Dhakal
Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Sikkim Centre, Gangtok, 737 102, Sikkim, India
Sandhya Thapa
Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Sikkim Centre, Gangtok, 737 102, Sikkim, India
Evanylla Kharlyngdoh
Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Meghalaya Centre, Upper Shillong, 793 009, Meghalaya, India
Sunil S. Thorat
Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Meghalaya Centre, Upper Shillong, 793 009, Meghalaya, India
Pardeep Bhardwaj
Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Takyelpat, Imphal, 795 001, Manipur, India
Sushil K. Chaudhary
Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Meghalaya Centre, Upper Shillong, 793 009, Meghalaya, India; Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Takyelpat, Imphal, 795 001, Manipur, India
Pulok K. Mukherjee
Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Meghalaya Centre, Upper Shillong, 793 009, Meghalaya, India; Institute of Bioresources and Sustainable Development (IBSD), Department of Biotechnology, Govt. of India, Takyelpat, Imphal, 795 001, Manipur, India
Genus Swertia under the family Gentianaceae is morphologically and taxonomically distinct with about 14 species from Sikkim Himalayan region. A Chrono-spatial floral phenology study was conducted on Swertia bimaculata from 1580 to 2400 m altitude in West Sikkim Himalayan region. The floral phenology was studied in a field nursery at 1200 m altitude and spatial floral phenology was studied over a 1580–2400 m altitudinal range in the West Sikkim Himalayan region. Detailed study on flowering pattern and seed formation in S. bimaculata revealed late flowering at 1200 m compared to 2400 m. Plants at the lower altitude showed prolonged and variable flowering from September to November and seed formation from November to December. During September to mid-October, pentamerous and bisexual flowers were observed, followed by 9–16 % tetramerous until November; and up to 24 % trimerous and 10 % bimerous until the end of flowering season in December. By the end of December, 43 % of flowers become stamen-less (monoclinous). Less than 2 % seed formation was observed in stamen-less flowers. The temporal phenological behavior reveals a successful reproductive adaptive strategy, depicting pentamerous flowers during favorable conditions, reducing to tetramerous, followed by tri- & bimerous with female (monoclinous) flowers until the end of flowering with stressful conditions, suggesting its suitability as a stress indicator to the changing climatic conditions. Along the altitudinal range floral anomalies from the usually observed pentamerous (and very rare hexamerous) flowers in favorable conditions change to tetramerous and/or trimerous, as the environmental conditions become more stressful, suggesting that the changes in this species could be used as an indicator of stress in changing climatic conditions.
