Germination and Dormancy in Annual Halophyte <i>Juncus ranarius</i> Song & Perr.
2015
Jeremi KOŁODZIEJEK | Jacek PATYKOWSKI
<p>The effects of cold stratification and gibberellic acid (GA<sub>3</sub>) on dormancy breaking for seeds of the annual halophyte species <em>Juncus ranarius </em>were tested. Germination percentage and recovery responses of salt stressed seeds were also tested. Freshly collected seeds germinated slowly under all incubation conditions. Thus, the seeds of <em>J. ranarius </em>have physiological dormancy, e.g. they are water permeable, have a fully developed embryo and require cold stratification to come out of dormancy. Furthermore, promotion of germination by GA<sub>3</sub> after-ripening in dry storage also indicated that these seeds have non-deep physiological dormancy. In general, the higher the GA<sub>3</sub> concentration, the more germination occurred within the studied range. <em>Juncus ranarius </em>demonstrated a germination preference for light. The highest germination percentage and rate of germination were recorded under constant light conditions at 22 °C after 24 weeks of cold stratification. In saline solutions, the highest percentage of germination was obtained at 25 mM L<sup>-1 </sup> NaCl, and further increase in salinity resulted in a gradual decrease in germination. However, ungerminated seeds were not damaged by salt, showing a high level of recovery. The greater the reduction in salinity, the better the germination rate became. It was concluded that dormancy could be completely broken by cold stratification, indicating spring germination. <em>Juncus ranarius </em>can grow well at lower NaCl concentrations under constant light conditions at 22 °C.</p>
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