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.

In the era of anthropocene, global warming tends to alter the distribution range of the plant species. Highly fragile to such changes are the species that are endemic, inhabit higher elevations and show narrow distribution ranges. Predicting and plotting the appropriate suitable habitats and keeping knowledge of how climate change will affect future distribution become imperative for designing effective conservation strategies. In the current study we have used BIOMOD ensemble forecasting to study the current and predict the future potential distribution of Dactylorhiza hatagirea and Rheum webbianum and describe their niche dynamics in Himalayan biodiversity hotspots under climate change scenarios using ecospat R package. Results reveal sufficient internal evaluation metrics with area under curve (AUC) and true skill statistic (TSS) values greater than 0.8 i.e. 0.93 and 0.98 and 0.82 and 0.90 for D. hatageria and R. webbianum respectively, which signifies robustness of the model. Among different bioclimatic variables, bio_1, bio_3, bio_8, bio_14 and bio_15 were the most influential, showing greater impact on the potential distribution of these plant species. Range change analysis showed that both the studied species will show significant contraction of their suitable habitats under future climatic scenarios. Representative Concentration Pathway (RCP) 8.5 for the year 2070, indicate that the suitable habitats could be reduced by about 51.41% and 70.57% for D. hatagirea and R. webbianum respectively. The results of the niche comparisons between the current and future climatic scenarios showed moderate level of niche overlap for all the pairs with D. hatageria showing 61% overlap for current vs. RCP4.5 2050 and R. webbianum reflects 68% overlap for current vs. RCP4.5 2050. Furthermore, the PCA analysis revealed that climatic conditions for both the species vary significantly between current and future scenarios. The similarity and equivalence test showed that the niche between present and future climate change scenarios is comparable but not identical. From the current study we concluded that the influence of climate change on the habitat distribution of these plant species in the Himalayan biodiversity hotspots can be considered very severe. Drastic reduction in overall habitat suitability poses a high risk of species extinction and thereby threatens to alter the functions and services of these fragile ecosystems. Present results can be used by conservationists for mitigating the biodiversity decline and exploring undocumented populations on one hand and by policymakers in implementing the policy of conservation of species by launching species recovery programmes in future on the other. The outcomes of this study can contribute substantially to understand the consequences of climate change in the Himalayan biodiversity hotspots.

Epigenetics are the heritable changes in gene expression patterns which occur without altering DNA sequence. These changes are reversible and do not change the sequence of the DNA but can alter the way in which the DNA sequences are read. Epigenetic modifications are induced by DNA methylation, histone modification, and RNA-mediated mechanisms which alter the gene expression, primarily at the transcriptional level. Such alterations do control genome activity through transcriptional silencing of transposable elements thereby contributing toward genome stability. Plants being sessile in nature are highly susceptible to the extremes of changing environmental conditions. This increases the likelihood of epigenetic modifications within the composite network of genes that affect the developmental changes of a plant species. Genetic and epigenetic reprogramming enhances the growth and development, imparts phenotypic plasticity, and also ensures flowering under stress conditions without changing the genotype for several generations. Epigenetic modifications hold an immense significance during the development of male and female gametophytes, fertilization, embryogenesis, fruit formation, and seed germination. In this review, we focus on the mechanism of epigenetic modifications and their dynamic role in maintaining the genomic integrity during plant development and reproduction.

The structure and distribution patterns of Himalayan vegetation are poorly explored, and research on species composition along the elevation gradient in these mountain ranges is still deficient. The current study was undertaken to analyze the variation and pattern of plant species composition along a vertical gradient in northwestern Himalaya, India. A total of 18 sites were selected along an elevation gradient ranging from 2200 to 3900 m asl positioned at an interval of 100 m. The Renyi diversity profile, non-metric multidimensional scaling based on the Bray–Curtis dissimilarity metric and beta diversity components among the elevation belts were calculated. Furthermore, to study the influence of altitude on species richness and diversity, a generalized additive model was created. Two hundred and ten plant species representing 66 families and 147 genera were recorded. The Renyi diversity profiles show that the lower and mid-altitudes had rich species diversity. The results of the non-metric multidimensional scaling analysis show a considerable variation in the total plant species composition among the studied elevation belts. The observed multiple-site Sorensen dissimilarity index across the studied elevation belts was very high. The contribution of species replacement or the turnover component to the observed dissimilarity was much higher than the nestedness component. Furthermore, the herbaceous and tree richness showed a significant decrease with increase in elevation; however, the richness of shrubs showed a bimodal pattern. The present study increases our understanding of the trends and patterns of species richness along the vertical gradient in the Himalayan region.

Elevational gradient, slope, and aspect offer a unique opportunity to explore the response of plant species under changing environmental conditions. The present study aimed to analyze the species diversity and distribution patterns with respect to altitude, aspect, and habitat types in the Kashmir Himalayas. Considering major aspects and habitats, a total of 123 representative sites were selected along the elevational gradients for the present study. The plant species composition of each selected site was studied by organized sampling following the standard ecological methods. During the present study, a total of 361 vascular plant species belonging to 71 families and 214 genera were identified in the study area. At the lower altitudes, the southern aspect and drier habitats showed the highest diversity. Moreover, a significant amount of compositional dissimilarity was observed between the studied aspects, habitats, and elevation belts and was mainly due to species turnover rather than the nestedness component. Further, among the studied variables, altitude was the most important contributing variable, explaining the greatest variation in the species composition. The paired effects of altitude and habitat explained the maximum variation in plant species composition. It may be concluded that floristic diversity should be studied not only with reference to elevational gradients but should also include aspects and habitats. The current study will act as a reference in this direction. A similar study must be replicated in other parts of the Himalayan region in the future to improve our understanding of the distribution and preferences of plant species in mountainous zones. This, in turn, will be immensely helpful in the conservation and sustainable utilization of resources in these ecologically fragile regions.

Climate change is one of the significant factors influencing global species redistribution. As a result, a better understanding of the species' possible range change in future climate conditions is needed. Therefore, this study compiles global geographic occurrence data of a wild olive sub-species, Olea europaea subsp. cuspidate, and projected potential distribution models in current and future climate scenarios. This study using ensemble modeling predicted that the species will undergo a significant decrease in habitat suitability under future climatic conditions with a contraction ranging from ca. 41 and 42% under RCP4.5 2050 and to about 56 and 61% under RCP8.5 2070 for committee averaging and weighted mean, respectively. More specifically, there will be a decrease in habitat suitability in regions of the southeastern part of the United States in North America; coastal regions in South America; coastal regions in the majority of eastern Africa; coastal parts of Spain, France, Italy, and Greece in Europe; coastal parts of Yemen and Saudi Arabia; the southeastern parts of Pakistan and the southern part of China in Asia; and southwestern and eastern parts of Australia when compared to current habitat suitability. The results of this ensemble modeling could be extremely valuable in identifying cultivation hotspots for the effective restoration and protection of this olive lineage under future climatic conditions.