J Plant Ecol ›› 2008, Vol. 1 ›› Issue (3): 197-202 .DOI: 10.1093/jpe/rtn018

• Research Articles • Previous Articles     Next Articles

Effects of enhanced UV-B radiation on fitness of an alpine species Cerastium glomeratum Thuill

Ying Wang1,2,*, Nianwei Qiu1, Xingan Wang1, Zongqi Ma1 and Guozhen Du2   

  1. 1 College of Life Science, Qufu Normal University, Qufu 273165, People's Republic of China; 2 Key Laboratory of Arid and Grassland Agroecology at Lanzhou University, Ministry of Education, Lanzhou 730000, People's Republic of China
  • Received:2008-03-18 Accepted:2008-07-04 Published:2008-08-25
  • Contact: Wang, Ying

Effects of enhanced UV-B radiation on fitness of an alpine species Cerastium glomeratum Thuill

Abstract: Aims Information about how species respond to extreme environments, such as high UV-B radiation, is very useful in estimating natural ecosystem structure and functions in alpine areas. Our aim is to examine the effect of enhanced UV-B radiation on the fitness of an alpine meadow annual species on Qinghai-Tibet Plateau.
Methods Plants of Cerastium glomeratum Thuill. were exposed to ambient (control) or ambient plus supplemental UV-B radiation (enhanced), simulating a 9% ozone depletion over Gannan, China (102°53′E, 34°55′N, 2900 m in altitude), up to leaf senescence and fruit maturation. Plant height, flower phenology, biomass allocation and reproductive parameters of the species were measured.
Important findings Plant height in C. glomeratum was reduced by enhanced UV-B radiation at early growth stages and compensated with ongoing development. Fruit biomass, aboveground biomass, total biomass and reproductive effort (fruit dry mass/aboveground biomass) were not affected by enhanced UV-B radiation, but a significant increase in root/shoot ratio was found. Enhanced UV-B radiation delayed onset of flowering by 1 day and shortened duration of flowering by 5 days in C. glomeratum. But because of the long period of flowering time (83–88 days), this did not make any significant effect on flower number, seed number, pollination success (number of seeds per fruit) or reproductive success (fruit to flower ratio) in C. glomeratum. Enhanced UV-B radiation had no effect on seed germination and seed mass either. And the high production and low germination rate of the seed might be the strategy of C. glomeratum to survive the extreme environments on alpine meadow. All these results showed that C. glomeratum was tolerant to enhanced UV-B radiation.

Key words: UV-B radiation, fitness, flowering, reproduction, Qinghai-Tibet Plateau

摘要:
Aims Information about how species respond to extreme environments, such as high UV-B radiation, is very useful in estimating natural ecosystem structure and functions in alpine areas. Our aim is to examine the effect of enhanced UV-B radiation on the fitness of an alpine meadow annual species on Qinghai-Tibet Plateau.
Methods Plants of Cerastium glomeratum Thuill. were exposed to ambient (control) or ambient plus supplemental UV-B radiation (enhanced), simulating a 9% ozone depletion over Gannan, China (102°53′E, 34°55′N, 2900 m in altitude), up to leaf senescence and fruit maturation. Plant height, flower phenology, biomass allocation and reproductive parameters of the species were measured.
Important findings Plant height in C. glomeratum was reduced by enhanced UV-B radiation at early growth stages and compensated with ongoing development. Fruit biomass, aboveground biomass, total biomass and reproductive effort (fruit dry mass/aboveground biomass) were not affected by enhanced UV-B radiation, but a significant increase in root/shoot ratio was found. Enhanced UV-B radiation delayed onset of flowering by 1 day and shortened duration of flowering by 5 days in C. glomeratum. But because of the long period of flowering time (83–88 days), this did not make any significant effect on flower number, seed number, pollination success (number of seeds per fruit) or reproductive success (fruit to flower ratio) in C. glomeratum. Enhanced UV-B radiation had no effect on seed germination and seed mass either. And the high production and low germination rate of the seed might be the strategy of C. glomeratum to survive the extreme environments on alpine meadow. All these results showed that C. glomeratum was tolerant to enhanced UV-B radiation.