Abstract

Dr. Pallavi Kodle*, Dr. Shraddha Sharma and Dr. Sameeksha Gupta

ABSTRACT

Rheum nobile Hook.f. & Thomson (Polygon aceae), commonly known as Himalayan rhubarb or Sikkim sundari, is an unique, precious and vulnerable alpine species endemic to the eastern Himalayas, a subtropical alpine zone located within a global biodiversity hotspot. The diverse flora of the Himalayas , including R. nobile , contributes significantly to the region's rich biodiversity, this species exhibits remarkable adaptations to the challenging environmental conditions characteristic of its high altitude habitat, including low temperatures, high level s of solar radiation, strong desiccating winds, and a short growing season. It’s morphological and physiological features contribute in survival and reproductive success in this harsh alpine environment. Prominent among these are the large, translucent bra cts that enclose the developing inflorescence. These bracts, in conjunction with the green basal bracts, create a greenhouse like microclimate, effectively trapping solar radiation and elevating the temperature surrounding the reproductive structures. This localized warming is crucial for development in the face of low ambient temperatures. Furthermore, the bracts provide protection from ultraviolet radiation and strong winds, mitigating potential damage. The compact inflorescence itself minimizes exposure to wind and cold, reducing convective heat loss . R. nobile exhibits a monocarpic life cycle, characterized by a single reproductive episode after a period of vegetative growth. This strategy allows the p lant to accumulate resources over multiple years before investing heavily in a single, large reproductive effort, maximizing reproductive output under resource limited conditions. The unique morphology and physiology of R. nobile make it a valuable subject for research in diverse fields. The common name "glasshouse plant" aptly reflects the functional role of the translucent bracts in creating a greenhouse like environment that promotes the development of the inflorescence, ensuring successful reproduction in this challenging habitat.