ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Plant morphology in the field in Virginia, USA, and growth responses to applied NaCl in a glasshouse were determined for two populations of Opuntia humifusa (Rafinesque) Rafinesque, one from an inland site and the other from the marine strand, which differed in potential exposure to salinity. Cladode dimensions, plant height and rooting depth varied significantly between the populations. Application of NaCl in 50 mM increments up to 400 mM every 3 days for 6 weeks caused the cladodes to decrease up to 30% in thickness, the decrease being about 20% more at 50 to 150 mM NaCl for plants from the inland site than from the marine strand. Inhibition by 150 mM NaCl of the maximum rate of net CO2 uptake and of the total CO2 uptake over a 24-h period was greater for the inland population. Growth, especially of roots, was inhibited by applied NaCl, with a decrease in biomass above 200 mM NaCl for plants from the inland site and not until 400 mM for those from the marine strand. Although the root Na+ level was the same for plants from the two populations, reaching a maximum of about 8 mg (g dry weight)−1 at 200 mM NaCl, the cladode Na+ level was two-fold higher for plants from the marine strand than from the inland site. Thus, exclusion of Na+ from the cladodes is not the reason for the greater NaCl tolerance of O. humifusa from the marine strand, which is a habitat that can experience periodic episodes of high salinity.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1399-3054.1988.tb05843.x
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