Plant Diversity ›› 2007, Vol. 29 ›› Issue (06): 682-686.

• Articles • Previous Articles     Next Articles

The Effects of Temperature and Osmotic Stress on the Germination of Scorzonera pusilla (Compositae) Seeds

TIAN Mei-Hua1 , 2 , TANG An-Jun2 , 3 , SONG Song-Quan4   

  1. 1 Xishuangbanna Tropical Botanical Garden , Chinese Academy of Sciences, Kunming 650223 , China;
    2 Graduate University of Chinese Academy of Sciences, Beijing 100049 , China ;
    3 Kunming Institute of Botany , Chinese Academy of Sciences, Kunming 650204 , China ;
    4 Institute of Botany , Chinese Academy of Sciences, Beijing 100093 , China
  • Received:2007-03-28 Online:2007-12-25 Published:2007-12-25
  • Contact: SONG Song-Quan

Abstract: Scorzonera pusilla is one of the early-spring short- lived perennial desert plants. Non-dormant seeds of S. pusilla are very small and light , and able to absorb water very quickly . Suitable temperature for germination was between 0℃ and 15℃, and the optimum temperature was 4℃ . With the increasing temperature, the germination percentage decreased evidently
. Especially , temperature fluctuations had not significant effect on seed germination. Final germination percentages decreased distinctly with decreasing water potential of PEG and NaCl solution. The relationship between water potential of different solutions and germination was negative. The stronger the osmotic stress was, the more the proline content of seedlings was. The effects of NaCl on germination and seedlings were much stronger than that of iso-osmotic PEG in spite of two different temperatures, and the proline content of seedlings confronting increasing water stress was increased sharply .When the concentration of NaCl increased to some extent , the salt toxicity occurred besides water stress . The results are valuable
to elucidate the ecogeographical patterns and mechanisms for adaptation of such early-spring ephemeral plants in the desert environments

Key words: Scorzonera pusilla

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