Morphological adaptation of wild Fritillaria unibracteata to alpine conditions in the eastern Qinghai-Tibet Plateau

Fritillaria unibracteata is a liliaceous perennial forb, mainly distributed in the alpine belt of the eastern QinghaiTibet Plateau. Because of the over-harvest due to its prominent medicinal value, F. unibracteata is becoming endangered in its native habitats. It is important thus to understand the ecological adaptation of F. unibracteata to alpine conditions, which may hopefully promote conservation of its wild populations. This study aimed at answering three scientifi c questions regarding F. unibracteata: 1) Whether environmental factors in alpine belt and the current life stages of the plant affect the morphological characteristics 2) How do the morphological characteristics change along with altitudinal gradients and 3) How do the morphological characteristics vary during the growth and development of the plant Field sampling survey was carried out to collect wild F. unibracteata at different elevations in the alpine belt of Songpan County. Plant height(PH) was measured in the fi eld. Collected samples were cleaned and different organs separated in the laboratory; the horizontal axis length(HAL) and vertical axis length(VAL) of bulbs, single leaf area(LA) of F. unibracteata were measured. Then, the measured leaves were weighed after oven dry at 65 °C to calculate the specifi c leaf area(SLA). The results showed that both elevation and life stage signifi cantly affected PH, LA and SLA, and the interaction between elevation and life stage was signifi cant. Besides, the morphological characteristics of F. unibracteata presented obvious spatial and temporal variations. Firstly, the PH, HAL and VAL of bulbs, LA and SLA of F. unibracteata decreased strikingly with the increase of elevation, showing a similar tendency in response to altitudinal changes at all life stages. In fact, altitude gradient representing a temperature factor was importantin limiting the growth and development of alpine plants such as F. unibracteata. Secondly, with the shift of life stages, the PH increased obviously. Both the HAL and VAL of bulbs increased at fi rst and then decreased with the advance of life history. The LA and SLA, however, showed a decreasing trend along with the growth and development of plants. The results indicated that the morphological characteristics of F. unibracteata can adjust to the alpine environmental variations, which is important for their long-term survival in such a harsh environment.