Oxidative stress, driven by reactive oxygen, nitrogen, and sulphur species (ROS, RNS, RSS), poses a significant threat to cellular integrity and human health. Generated during mitochondrial respiration, inflammation, UV exposure and pollution, these species damage cells and contribute to pathologies like cardiovascular issues, neurodegeneration, cancer, and metabolic syndromes. Lifestyle factors exert a substantial influence on oxidative stress levels, with mitochondria emerging as pivotal players in ROS generation and cellular equilibrium. Phytochemicals, abundant in plants, such as carotenoids, ascorbic acid, tocopherols and polyphenols, offer diverse antioxidant mechanisms. They scavenge free radicals, chelate metal ions, and modulate cellular signalling pathways to mitigate oxidative damage. Furthermore, plants thriving in high-altitude regions are adapted to extreme conditions, and synthesize secondary metabolites, like flavonoids and phenolic compounds in bulk quantities, which act to form a robust antioxidant defence against oxidative stress, including UV radiation and temperature fluctuations. These plants are promising sources for drug development, offering innovative strategies by which to manage oxidative stress-related ailments and enhance human health. Understanding and harnessing the antioxidant potential of phytochemicals from high-altitude plants represent crucial steps in combating oxidative stress-induced disorders and promoting overall wellbeing. This study offers a comprehensive summary of the production and physio-pathological aspects of lifestyle-induced oxidative stress disorders and explores the potential of phytochemicals as promising antioxidants. Additionally, it presents an appraisal of high-altitude medicinal plants as significant sources of antioxidants, highlighting their potential for drug development and the creation of innovative antioxidant therapeutic approaches.

Large cardamom (Amomum subulatum Roxb.) is an economically important cash crop that provides a livelihood option for the rural communities in Sikkim Himalaya. However, its production has declined drastically over the past few decades due to climate change and other factors affecting the livelihood of marginal cardamom-dependent farmers in the region. Climate change causes a shift in elevational distributions of mountain species, and it is pivotal to understand its effect on yield and yield-related traits for economically important plant species like large cardamom. For this, we randomly studied 41 large cardamom cultivation sites in Sikkim (India) with elevations ranging between 975 and 2069 m asl and evaluated the yield-related traits (number of capsules per spike, capsule length, capsule width, fresh capsule weight, dry capsule weight, number of seeds per locule, fresh seed weight, and dry seed weight) in five cultivars (Dzongu Golsey, Sawney, Seremna, Ramsey, and Varlangey). We observed a significant variability (P < 0.05) for morphometric traits in each of the five cultivars cultivated in different elevations. The cultivation of low-elevation cultivars like Seremna and Dzongu Golsey (suitable in elevation < 975 m) has shifted upward to mid (975–1515 m) and high-elevation (> 1515 m), while cultivation of high-elevation Ramsey cultivar (suitable in elevation > 1515 m) has shifted downward (< 1515 m). The Dzongu Golsey, Sawney, and Seremna cultivated in mid-elevation (975–1515 m) performed better in terms of yield-related traits than the same cultivars cultivated in high-elevation (> 1515 m) and showed moderate to high negative correlation between elevation and yield-related traits, indicating the negative effect of elevation on their yield. Likewise, Ramsey and Varlangey cultivated in high elevation (> 1515 m) performed better than the one cultivated in mid-elevation (975–1515 m) and depicted moderate to high positive correlation between elevation and yield-related traits, suggesting a positive influence of elevation on their yield. Although there is an elevational shift in the cultivation of large cardamom cultivars, the elevation influences the performance of the large cardamom cultivars, and it also suggests cultivating the cultivars in their suitable elevation range for better productivity.

Studies from different parts of the world have generated pieces of evidence of climate change’s effects on plant phenology as indicators of global climate change. However, datasets or pieces of evidence are lacking for the majority of regions and species, including for the climate-sensitive Himalayan biodiversity hotspot. Realizing this gap in information, and the wide-ranging implications of such datasets, we integrated real-time field observations and long-term herbarium records to investigate the changes in the spring flowering phenology of Olea ferruginea Royle, commonly known as the Indian Olive, in response to the changing climate in the western Himalayas. We attempted to create phenological change model using the herbarium records and field observations after recording the current dates of flowering and overall temperature trends from the study area over the last four decades from the five regional meteorological observatories of the Jammu province managed by Indian Meteorological Department (IMD) in Jammu and Kashmir. When considering current flowering dates along with herbarium information (years 1878–2008) for O. ferruginea, our Generalized Additive Model (GAM) showed 15–21 days-early flowering over the last 100 years significantly (p < 0.01). Results of the Mann–Kendall test showed increasing trends of T_Min for all seasons significantly (p < 0.05) for Jammu province whereas T_Max was only for the spring season. The increasing T_Min of spring, summer, and autumn seasons also influenced the flowering phenology of O. ferruginea significantly (p < 0.01). By demonstrating the integrated use of methodological tools for finding long-term phenological changes in response to climate change, this work bridges knowledge gaps in phenological research from the developing world in general and the Himalayas in particular.

The terrestrial ecosystem, particularly mountain regions, influences species distribution by providing diverse climatic conditions that vary with rising altitude. These climatic factors play a significant role in determining species phenology and niche width. However, the environmental factors influencing pollination dynamics of specific plant species across altitudes remain unexplored. Considering the gaps, we assess how the composition and abundance of pollinator fauna associated with the important medicinal plant Berberis lyciumRoyle (Berberidaceae) vary across five distinct altitudinal gradients (800–2200 m) in the Pir-Panjal mountain range in the northwestern part of the Indian Himalayan region. Pollinators, including bees, butterflies, wasps, and flies were monitored over two consecutive flowering seasons (2022–2023). A total of 39 insect species representing five orders and 17 families, were recorded visiting B. lycium during its flowering period across the altitudinal range. The linear regression model indicated that all four pollination indices exhibited a declining trend with increasing altitude when data were pooled together. However, only foraging speed (FS) and index of visiting rate (IVR) were showed significant declines. Among individual pollinator groups, only Lepidoptera displayed a significant relationship with altitude, while other groups exhibited asynchrony along the altitudinal gradient. Furthermore, reproductive output (fruit and seed production) declined significantly with increasing altitude. Our findings suggest that while altitude influences species distribution but also differentially shapes plant-pollinator interactions, pollinator foraging behaviour, and reproductive success. This study highlights the importance of monitoring plant-pollinator interactions in fragile Himalayan ecosystem, where environmental changes could have cascading effects on ecological stability.

Large cardamom (Amomum subulatum Roxb.) is the main cash crop and an important livelihood option for farming communities in the eastern Himalayas – especially Sikkim, parts of West Bengal, eastern Nepal, and southern Bhutan. The crop is self-fertile but requires cross pollination for production of capsules. Scientific information on the eco-biology of large cardamom pollination is scarce, but studies have shown bumblebees to be the main pollinators. Previous studies have indicated contradictory results on the role of indigenous honeybees, particularly Apis cerana, in pollination of large cardamom. Some studies reported that Apis cerana was a ‘pollen robber’ that collects all the pollen from a flower without actually pollinating it, resulting in severe crop decline. However, beekeeping is common in large cardamom farming areas of Sikkim and Nepal and the bee is a common visitor to the flowers. Farmers in these areas have never observed a decline in large cardamom yield due to the presence of Apis cerana. This publication describes the results of a detailed investigation into the role of Apis cerana in large cardamom pollination, designed to establish whether the bee is a pollinator or pollen robber and determine its impact on crop yield and quality. The research was conducted on farmers’ fields located at different sites in Sikkim, India: Lingee Payong (1,100 masl) and Hee Martam (1,500 masl) in West Sikkim, and Jaubari (2,000 masl) in South Sikkim. The methodology consisted of on-farm experimental research and data collection through regular field observations, and a review of the literature on large cardamom pollination. Three experimental procedures were used at each site: (i) observations of the foraging behaviour of Apis cerana bees on cardamom flowers, and the impact of pollination by Apis cerana and other pollinators on capsule yield and quality (capsule weight and number of seeds per capsule), in a plot with a medium-sized healthy colony of Apis cerana placed at the centre; (ii) observations of the foraging behaviour of bumblebees and other pollinators, and of capsule yield and quality, in a plot about 250 m away from the plot containing the Apis cerana colony; and (iii) observations of capsule yield and quality in plants caged in a nylon net (3 x 3 x 3 m) to exclude all pollinators as a control. The results of the study showed that Apis cerana is an effective pollinator of large cardamom. Although the Apis cerana bees are relatively small, they landed on the anther-stigma column of the cardamom flowers multiple times from different directions while collecting pollen which ensured that they also touched the stigma and thus pollinated the flowers. Other favourable foraging attributes included foraging throughout the day, visiting all flowers on a panicle and then moving on to another, and multiple visits to flowers. The favourable attributes translated into a 45% increase in yield compared to natural pollination in fields with a supplementary Apis cerana colony. The fruit set, seed set, and fruit and seed weight (capsule quality) were all significantly higher in plots with an Apis cerana colony than in plots without a colony or with all pollinators excluded. The results suggest that especially in areas where bumblebee populations and other natural pollinators are scarce, Apis cerana can be used to pollinate large cardamom to ensure a reasonable harvest and better quality capsules.