Predicting the potential distribution of Dactylorhiza hatagirea (D. Don) Soo-an important medicinal orchid in the West Himalaya, under multiple climate change scenarios.

Climate variability coupled with anthropogenic pressures is the most critical driver in the Himalayan region for forest ecosystem vulnerability. Dactylorhiza hatagirea (D.Don) Soo is an important yet highly threatened medicinal orchid from the Himalayan region. Poor regenerative power and growing demand have resulted in the steep decline of its natural habitats populations. The present study aims to identify the habitat suitability of D. hatagirea in the Western Himalaya using the maximum entropy model (MaxEnt). The community climate system model (CCSM ver. 4) based on representative concentration pathways (RCPs) was used to determine suitable future areas. Sixteen least correlated (< 0.8) bioclimatic, topographical and geomorphic variables were used to construct the species climatic niche. The dominant contributing variables were elevation (34.85%) followed by precipitation of the coldest quarter (23.04%), soil type (8.77%), land use land cover (8.26%), mean annual temperature (5.51%), and temperature seasonality (5.11%). Compared to the present distribution, habitat suitability under future projection, i.e., RCP 4.5 and RCP 8.5 (2050 and 2070), was found to shift to higher elevation towards the northwest direction, while lower altitudes will invariably be less suitable. Further, as compared to the current distribution, the climatic niche space of the species is expected to expand in between11.41-22.13% in the near future. High habitats suitability areas are mainly concentrated in the forest range like Dharchula and Munsyari range, Pindar valley, Kedarnath Wildlife Sanctuary, West of Nanda Devi Biosphere Reserve, and Uttarkashi forest division. The present study delineated the fundamental niche baseline map of D. hatagirea in the Western Himalayas and highlighted regions/areas where conservation and management strategies should be intensified in the next 50 years. In addition, as the species is commercially exploited illegally, the information gathered is essential for conservationists and planners who protect the species at the regional levels.

Physiological and metabolic changes in two Himalayan medicinal herbs under drought, heat and combined stresses.

Valeriana jatamansi Jones and Hedychium spicatum Ham-ex-Smith are important medicinal herbs of the Himalayan region, which are highly demanded by pharmaceutical industries. Climatic variability especially increasing temperature and water deficit affects the growth and productivity of these species. In addition, increased temperature and water deficit may trigger the biosynthesis of medicinally important bioactive metabolites, which influence the quality of raw plant material and finished products. Therefore, V. jatamansi and H. spicatum plants were undertaken and subjected to different levels of drought (no irrigation), heat (35 °C), and combined stresses for investigating their physiological and metabolic responses. Both the treatments (individually and in combination) reduced relative water content, photosynthesis, carboxylation efficiency, chlorophyll content, while increased intracellular CO2, malondialdehyde and H2O2 content in both the species. Transpiration and stomatal conductance increased under heat and reduced under drought stress as compared to control. Water use efficiency was found to be increased under drought, while reduced under heat stress. Protein, proline, carotenoid content and antioxidant enzymes activities (superoxide dismutase, peroxidise, catalase) initially increased and thereafter decreased during late stages of stress. Exposure of plants to combined stress was more detrimental than individual stress. In V. jatamansi, exposure to drought stress significantly (p < 0.05) increased valerenic acid content in all plant parts (1.0-6.9 fold) with maximum increase after 20 days of exposure, while under heat stress, valerenic acid content increased (1.0-1.2 fold) in belowground part of V. jatamansi, and decreased (1.1-1.3 fold) in aerial part as compared to control. In H. spicatum, exposure of individual heat stress for 25-30 days and combined stress for 5-15 days significantly (p < 0.05) increased linalool content to 6.2-6.5 fold and 8.3-19.6 fold, respectively, as compared to control. Higher accumulation of bioactive compounds after exposure to mild stress provides encouraging prospects for enhancing pharmaceutical properties of these Himalayan herbs. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-021-01027-w.

Seasonal trends in morpho-physiological attributes and bioactive content of Valeriana jatamansi Jones under full sunlight and shade conditions.

Valeriana jatamansi Jones, an important medicinal herb of the Himalayan region, is an essential source of many therapeutic compounds and is traded/consumed in very high volume. The hypothesis of this study was that different seasons and light conditions may affect the content of medicinally valuable components with changes in the morpho-physiological attributes of the plant. Growing plants under suitable light conditions and harvesting of appropriate plant parts in optimum season is crucial for harnessing the full potential of the crop. Thus, the study was carried out to determine the seasonal response of V. jatamansi plants (genetically identical plants of same age) in terms of growth and phytochemical content under two different light conditions (full sunlight and 50% shade). During all seasons, growth parameters (plant height, leaf number, leaf area, relative water content, plant biomass) and the principle bioactive compounds (valerenic acid) were higher under shade conditions, while total flavonoids, tannins, phenolic compounds and antioxidant activities were higher under full sunlight conditions. HPLC analysis revealed that valerenic acid and most of the phenolic content were higher during summer season, especially in leaf part of the plant. The study suggested harvesting of V. jatamansi plants (especially leaf), during summer season to harness high quality raw material and to prevent loss of belowground parts. This strategy can be adopted by farmers for large scale cultivation of species. SUPPLEMENTARY INFORMATION: The online version of this article contains supplementary material available at 10.1007/s12298-021-00944-0.

Impact of Altitudes and Habitats on Valerenic Acid, Total Phenolics, Flavonoids, Tannins, and Antioxidant Activity of Valeriana jatamansi.

The changes in total phenolics, flavonoids, tannins, valerenic acid, and antioxidant activity were assessed in 25 populations of Valeriana jatamansi sampled from 1200 to 2775 m asl and four habitat types of Uttarakhand, West Himalaya. Significant (p < 0.05) variations in total phenolics, flavonoids, valerenic acid, and antioxidant activity in aerial and root portions and across the populations were observed. Antioxidant activity measured by three in vitro antioxidant assays, i.e., 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) (ABTS) radical scavenging, 2,2'-diphenyl-1-picryylhydrazyl (DPPH) free radical scavenging, and ferric-reducing antioxidant power (FRAP) assays, showed significant (p < 0.05) differences across the populations. However, no clear pattern was found in phytochemicals across the altitudinal range. Among habitat types, (pine, oak, mixed forest, and grassy land), variation in phytochemical content and antioxidant activity were observed. Equal class ranking, neighbor-joining cluster analysis, and principal component analysis (PCA) identified Talwari, Jaberkhet, Manjkhali, and Khirshu populations as promising sources with higher phytochemicals and antioxidant activity. The results recommended that the identified populations with higher value of phytochemicals and antioxidants can be utilized for mass multiplication and breeding program to meet the domestic as well as commercial demand.

Effect of pre-germination treatments on seed physiology and germination of central Himalayan oaks?

The continuous decline in regeneration of two important species of central Himalayan oak, namely Quercus glauca and Q. leucotrichophora, is of great concern. A study was therefore, carried out to improve germination ability of these species using various presoaking treatments. Seeds of both the species lost viability following storage; tetrazolium staining pattern and germination capacity of seeds following different period of storage at 4 °C and 20 °C indicated retainment of viability for a period of 12 months at 4 °C. Of the various physical, chemical and plant growth regulator treatments examined to improve seed germination, only KNO3 1.0 % was found to be effective. Seeds scarified at the chalazal end exhibited significant improvement in germination in both the species (94.4 % compared to 56.7 % in control in Q. glauca and 82.7 % compared to 64.0 % in control in Q. leucotrichophora). The results of this study impart simple methods to improve seed germination for developing nurseries for commercial purposes.