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Networks of Malay-Indonesian and Middle Eastern 'Ulamā' in the Seventeenth and Eighteenth Centuries
Author: A. Azra

The North Western Himalaya region is characterized by extreme seasonal variability and local changes in microclimate. Plants adapted to this region demonstrate marked variability to the extreme winter conditions. This region, designated as a biodiversity hotspot, is rich in medicinal herbs, which exhibit diverse growth and adaptation mechanisms to the harsh environment. In the present study, physiological mechanisms of adaptation to the winter season conditions were compared in five medicinal herbs. Components of the photosynthetic machinery, and osmoregulation which are of importance for secondary metabolism is not well known in these alpine herbs and was studied. The medicinal herbs Rumex dentatus, Atropa accuminata, Lupinus polyphyllus, Hyoscyamus niger, and Lavandula officinalis were collected before snowfall in September–November to evaluate variability in metabolic and physiological responses to the varied seasonal regimes. Plants were followed over a period of 8 weeks (summer to early winter) in three sites which vary in altitude and thereby climatic conditions: Site I, 4175 m (Pahalgam); Site II, 3748 m (Duksum Sinthan Top); and Site III, 4100 m (Mount Apharwat). Variations in photosynthetic capacity and components of the photosynthetic machinery, a range of antioxidants, antioxidant enzymes and total non-structural carbohydrates (TNC) were studied to test their involvement in adaptation schemes and secondary metabolism under the harsh winter conditions. The results demonstrate a range of adaptations to the freezing stress conditions including high photon energy use efficiency; an increase in the proportion of Chl b, carotenoid content; specific activity of the antioxidant enzymes superoxide dismutase, catalase, glutathione reductase, ascorbate peroxidase activity, and TNCs.

In: Israel Journal of Plant Sciences