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Journal of Plant Growth Regulation

, Volume 16, Issue 3, pp 141–146 | Cite as

Roles of Soluble Sugars in Protecting Phytochrome- and Gibberellin A3-Mediated Germination Control in Skotodormant Lettuce Seeds

  • A. I.  Hsiao
  • W. A.  Quick

Abstract.

Skotodormant seeds of Lactuca sativa Grand Rapids imbibed in darkness for 10 days (10-day DS) germinated poorly upon terminal treatment with red light (R) or gibberellin A3 (GA3). Soluble sugars in the imbibition solutions influenced the depth of skotodormancy. Ten-day DS seeds, imbibed in 50–500 mm sucrose or 100–500 mm glucose and given terminal GA3 germinated completely and germinated about 80% when imbibed in 100 mm galactose, mannose, lactose, or maltose. In contrast, terminal R applied to 10-day DS seeds caused only 20–50% germination. If given R at day 0 and imbibed for 10 days in darkness in 500 mm sucrose or glucose, seeds washed free of exogenous glucose or sucrose then germinated about 50% in darkness in water. These seeds responded to terminal R or GA3 with complete germination. When seeds were given FR at day 0, germination responses following terminal R or GA3 were significantly lower when the duration of DS was increased from 7–10 day DS to 15 days. In 10-day DS seeds given initial FR and imbibed in either solutions of 50 or 100 mm sucrose and KNO3, either terminal R or GA3 treatment gave complete or near complete germination. It is concluded that seed exposure to certain soluble sugars and/or nitrate during a 10-day DS protected certain substrates and thereby extended the sensitivity of the seeds to terminal R or GA3 treatment. The study provides substantial evidence for nonhormonal factors associated with light and GA action in the control of seed skotodormancy.

Key words. Seed germination—Skotodormancy—Sucrose—Glucose—Nitrate—Lactuca sativa 

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Copyright information

© Springer-Verlag New York Inc. 1997

Authors and Affiliations

  • A. I.  Hsiao
    • 1
  • W. A.  Quick
    • 1
  1. 1.Agriculture and Agri-Food Canada and the Department of Biology, University of Regina, Regina, Saskatchewan S4S 0A2, CanadaCA

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