Chin J Plant Ecol ›› 2007, Vol. 31 ›› Issue (6): 1046-1053.DOI: 10.17521/cjpe.2007.0132

• Research Articles • Previous Articles     Next Articles

SEED POLYMORPHISM AND GERMINATION BEHAVIOR OF SALSOLA BRACCHITA, A DOMINANT DESERT ANNUAL INHABITING JUNGGAR BASIN OF XINJIANG, CHINA

WANG Hong-Fei1, WEI Yan1,*(), HUANG Zhen-Ying2   

  1. 1College of Forestry Sciences, Xinjiang Agricultural University, Urumqi 830052, China
    2Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
  • Received:2006-09-06 Accepted:2007-04-24 Online:2007-09-06 Published:2007-11-30
  • Contact: WEI Yan

Abstract:

Aims Salsola bracchita has four types of perianth-enclosed utricles, utricles and seeds. We investigated the role of utricle polymorphism in seed dispersal and germination to better understand how S. bracchita is adapted to its desert habitat.

Methods Twenty plants of S. bracchita were selected randomly to observe the morphology of perianth-enclosed utricles, including persistence of perianth and wings, utricle shape and color and location of fruit on mother plant. Seeds of the four types were germinated in incubators with 12 h photoperiod and 12 h thermoperiods (dark/light) of 5 ℃/15 ℃, 5 ℃/25 ℃, and 15 ℃/25 ℃ for 20 d. Type D seed was scarified and then germinated for 20 d at the three different thermoperiods to determine its dormancy characteristics.

Important findings Salsola bracchita produces four types of fruits (utricles) that differ in shape, size, seed color and external structure. Type A and B fruits can be dispersed by wind far from mother plants. Germination percentages of type A seeds at all three thermoperiods were >70%, and there were no significant differences (p>0.05). Germination percentages of type B seeds were all >68%, and there were significant differences (p<0.05), with highest germination percentage and germination index at 5 ℃/25 ℃ (dark/light) (>80%). Type C fruits have tepals without wings and are dispersed near mother plants. Germination percentages of type C seeds were all >80%, and there were no significant differences (p>0.05). Rate and final percentages of germination of type B and type C seeds were higher than that of type A seeds. Type D fruits also are mainly dispersed near mother plants. Freshly matured type D seeds are in physiological dormancy because its germination is slow and low (<20%). Seed coat scarification of type D seeds can hasten and increase the seed germination percentage (p<0.01) and germination index (p<0.01) in each of the thermoperiods.

Key words: Salsola bracchita, seed polymorphism, seed germination, physiological dormancy, scarification