Water potential and ionic effects on germination and seedling growth of two cold desert shrubs

We investigated seed germination and seedling growth responses to salinity for two desert shrubs that are differentially distributed along a steep salinity gradient at Mono Lake, CA

Geraldine L Dodd

2006

Scholarcy highlights

  • We tested expectations that two desert shrubs would differ in germination and seedling relative growth rate responses to Na and Ψs stress
  • We investigated seed germination and seedling growth responses to salinity for two desert shrubs that are differentially distributed along a steep salinity gradient at Mono Lake, CA
  • Inhibition of germination in PEG‐treated seeds is attributed to osmotic effects, and any difference in germination of salt‐treated relative to PEG‐treated seeds is attributed to ionic effects
  • For germination in the remaining six Ψs treatments, the results of a three‐way analysis of variance indicated that the main effects of species, water potential, and osmotica were all highly significant
  • We confirmed our prediction that seeds and seedlings of Sarcobatus would be more tolerant of salinity stress than those of Chrysothamnus
  • Germination fell below 10% for Chrysothamnus at −1.64 MPa, and for Sarcobatus at −2.4 MPa PEG
  • Increasing NaCl had a strong Ψs or osmotic effect that decreased germination of both species. This finding of highest germination at zero salinity is consistent with previous findings for Sarcobatus and for C. nauuseosus ssp. viridulus, which has alternatively been classified as a variety of ssp. consimilis
  • Under moderately saline field conditions, Ψw stress inhibition of Chrysothamnus germination and seedling growth would be exacerbated by the presence of Na. Faced with the same declining Ψw, Sarcobatus seeds and seedlings would take up Na ions and proceed with greater germination and growth than would have been possible in a drying soil without Na. McNulty, I.1969

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