Growth and Water Potential of Root Crops as Influenced by Salinity and Relative Humidity1
- G. J. Hoffman and
- S. L. Rawlins2
The interaction of relative humidity and salinity on garden beet, onion, and radish was studied in sunlit climate chambers at temperatures cycling daily between 26 and 10 C. Average daytime relative humidity (RH) was controlled at 45 and 90%. The root medium of each crop was maintained at four different osmotic potentials, the range depending on the crop's salt tolerance.
With a nonsaline root medium, increasing RH from 45 to 90% increased the yield of beet by 50% and radish by 15%, but did not enhance the yield of onion. In saline root media, high RH significantly raised the salinity level at which the yield was reduced to 50% of the nonsaline yield for onion and radish, but did not affect this level for beet.
Linear relationships between leaf water (ΨL) and osmotic (πL) potentials and the osmotic potential of the root medium (πS) were found for all three crops. Except low values of πS (high salinity), ΨL and πL were lower at 45% RH than at 90% RH. Leaf turgot potential was not affected by salinity in beet and onion but was reduced in radish.
The relationship between crop yield and ΨL was linear. The difference in ΨL for plants between full yield and almost no yield was only 13 bars for beet, 6 bars for radish, and 4 bars for onion.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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