Abstract:

Assessments of adaptability are crucial for success in plant ex situ conservation. In this paper, we evaluated the adaptability of 172 Rhododendron species (including 17 subspecies or variations) by examining growth indices, tolerance to environmental stress and reproductive ability. These species, belonging to 33 subsections, 7 sections, and 5 subgenera, were ex situ cultivated at Longchi Base (1,800 m elevation) in Dujiangyan of Sichuan Province. A total of 246 evaluations were assessed with 5-20 individuals for each evaluation. We found that the adaptability of Rhododendron plants under ex situ conservation was closely related to floristic elements, elevation similarity between ex situ sites and native habitats, evolutionary degree and key functional traits of Rhododendron. The adaptability of the Sino-Japanese floristic elements was higher than that of the Sino-Himalayan elements. The groups or species whose native habitats were similar to this region’s elevation more successfully adapted. Primitive groups or intermediate groups distributed in the east China adapted better than the advanced groups especially distributed in alpine zones of west China; Rhododendron groups or species with some key functional traits, such as big leaf, without hair or hair-less, scale-less, were more adaptable in moist and shady sites. Our results indicate that ex situ conservation for Rhododendron plants can be explained by theories of adaptation, but with limitations.

Key words: Rhododendron, ex situ conservation, adaptability, functional traits