Ecophysiological Plasticity and Cold Stress Adaptation in Himalayan Alpine Herbs: Bistorta affinis and Sibbaldia procumbens

Abstract

Plants have evolved several metabolic pathways as a response to environmental stressors such as low temperatures. In this perspective, it is paramount to highlight physiological mechanisms of plant responses to altitudinal gradients as a proxy to evaluate changing environments. Here, we aimed to determine the impact of elevation on the physiological attributes of two plant species along an altitudinal gradient. Our hypothesis was that the altitudinal gradient influences proline, protein, and sugar contents, as well as abscisic acid (ABA) and indole acetic acid (IAA) concentrations. We studied these physiological components in leaves collected from four different altitudinal ranges in Himalayan region of Pakistan from two native herbs, namely Bistorta affinis and Sibbaldia procumbens. Leaves were collected at the initial blooming phase from each altitudinal range, viz. 2850 m, 3250 m, 3750 m and 4250 m. We observed that most abiotic factors decrease with altitude which induces cold acclimation. A significant increase in the concentration of physiological components was observed as altitude increased, except for IAA, which decreased. Furthermore, we did not find variations in proline, ABA and IAA concentrations between species; only sugar and protein, with higher values for B. affinis. We conclude that altitudinal gradients significantly affect the physiological components of B. affinis and S. procumbens in Himalayan region. This result contributes to the understanding of how plants adapt to environmental pressures, acting as a proxy for the evaluation of impacts caused by climate changes.

Environmental variables drive plant species composition and distribution in the moist temperate forests of Northwestern Himalaya, Pakistan

“…Indeed, there is no order of importance of environmental variables, but studies are unanimous in showing that there is a consensus on the explanations for the variables' influences. For instance, in two recent studies we showed that the altitude-temperature relationship significantly influenced the physiological attributes of some plant species in the Northwestern Himalayan region [22,23], which can be a proxy for understanding plant adaptation to climate change. Any change in soil parameters has a significant effect on the growth of plant communities [19].…”

“…However, despite this high endemism of species greatly influenced by various environmental gradients, such as edaphic, climatic and physiographic variables [19], these areas suffer a major impact from climate change [20,21]. Plant species present in these gradients have great adaptive power [22,23]; however, the speed with which climate change is advancing might not be sufficiently achieved by plant species adaptation in these areas, leading to a strong impact on the biodiversity of these areas [24][25][26], ultimately leading to variations in the community structure [27].…”

“…Kluge et al [31] found a hump-shaped diversity pattern for seed plants in the Eastern Himalayas, even though endemic species richness peaks at higher elevations due to increasingly isolated habitats and smaller surface area in mountainous ecosystems, which promotes speciation [32]. Although there has been a considerable increase in the number of phytosociological studies in these altitudinal regions considered hotspots of biodiversity [7,19,22,23,33], there is still limited knowledge of how and which environmental variables drive the distribution and composition of plant species along altitudinal gradients in specific hotspots regions, such as the Northwestern Himalaya.…”

Typology of Pure Deodar Forests Driven by Vegetation–Environment Relations in Manoor Valley, Northwestern Himalaya

“…The current field investigation was conducted in the pure Deodar forests of the Manoor valley, which is a hilly valley (Figure 1) in Pakistan's Northwestern Himalayan region [27][28][29][30], with elevations ranging from 1580.8 m to 2373.8 m. In the Himalayas, monsoon winds are the principal source of precipitation as well as the primary governing factor of erosion, topography, environment, and vegetation [31]. The valley's vegetation features Sino-Japanese characteristics [32,33].…”