Chin J Plan Ecolo ›› 2008, Vol. 32 ›› Issue (2): 379-384.DOI: 10.3773/j.issn.1005-264x.2008.02.015

• Research Articles • Previous Articles     Next Articles


WANG Yi-Feng1,2; GAO Hong-Yan1; SHI Hai-Yan1; WANG Jian-Hong1; DU Guo-Zhen2   

  1. 1College of Life Science, Northwest Normal University, Lanzhou 730070, China; 2 Key Laboratory of Arid Agroecology of Ministry of Education, Lanzhou University, Lanzhou 730000, China
  • Online:2008-03-30 Published:2008-03-30
  • Contact: WANG Yi-Feng

Abstract: Aims Saussurea parviflora is the dominant species on the Qinghai-Tibetan Plateau. This study addresses the following: 1) correlations between S. parviflora’s sexual organs and altitude, 2) correlations among S. parviflora’s sexual organs, and 3) reasons for S. parviflora’s adaptation to this stressful environment.
Methods During the flowering phase in August-September 2005, we collected 11 populations of S. parviflora from different altitudes. We harvested 20 individual s from each population and randomly selected 10 capitula from each individual. We randomly selected 20 flowerlets from different capitula from the same altitude and fixed them in FAA (18∶2∶2, alcohol∶formaldehyde∶glacial acetic acid). We measured the length of sexual organs in 20 fully-opened flowerlets and counted pollen in 10 mature flowerlets with undehisced anthers. At the fruiting stage in October 2005 and 2006, we harvested 10 individuals of each population and randomly selected 200 capitula to count the maturation rate. All experimental data were analyzed with the statistical analysis software SPSS11.5. 
Important findings There was a strong positive correlation among filament length, anther length and altitude (p<0.01) and a strong negative correlation between pollen number and altitude (p<0.01). Moreover, there were strong positive correlations among 1) style length, length of style ramification and altitude (p< 0.01 ) and 2) style length, length of style ramification, filament length and anther number (p<0.05), and between maturation rate and altitude (p<0.05). Therefore, variation of intraspecific sexual organs under specific environmental condition made S. parviflora adapted to the Qinghai-Tibetan Plateau. With reduced pollen number and insect diversity, abundance and activity with increased altitude, the style ramification lengthened and maturation rate improved. This enhanced the sensitivity to pollinators, ensuring that the decreased pollen was sufficiently spread by them, resulting in increased success of reproduction and dominance in the stressful environment.