Spatiotemporal Dynamics of Land and Vegetation Cover in Cold Desert Region of the Ladakh Himalaya

Henbane (Hyoscyamus niger L.), an economically important medicinal plant, has an endangered status in Himachal Pradesh (India) that needs appropriate conservation interventions. We have examined seed physiological aspects of H. niger from Lahaul (Himachal Pradesh, India), a cold desert region. The freshly harvested seeds exhibited complete dormancy. Gibberellic acid (GA3) and chilling treatment strongly promoted seed germination which was accompanied by increased α-amylase activity. KNO3, NaN3 and sodium nitroprusside (SNP), an NO donor, also promoted germination. During storage, the seeds retained high viability even after a storage of 72 months under ambient conditions. However, they remained dormant during the entire storage period. The responsiveness of seeds to GA3 and chilling treatment gradually declined with progression of storage period. Concomitantly, the triphenyl tetrazolium chloride (TTC) reduction ability of seeds was lowered. The seed responsiveness to KNO3, NaN3 and SNP during storage increased until one year and decreased thereafter. With the progression of the storage period, seeds exhibited elevated lipid peroxidation and reduced catalase activity implying a role of oxidative stress in observed changes. The involvement of phenolics in seed dormancy of H. niger was not evident. The findings are of significance for conservation and cultivation of H. niger through seeds in the arid mountain region.