Title: Shoot and Root Growth of Wheat Seedlings Exposed to Several Levels of Matric Potential and NaCl‐Induced Osmotic Potential of Soil Water<sup>1</sup>
Abstract: Abstract In saline media the osmotic potentials are often of the same magnitude as the matric potential. Thus their interaction effects on plant growth are important. This study was conducted to determine the interaction effects of osmotic potentials of soil water induced by NaCl (0, −4, −8, and −12 bars) and matric potentials induced by Carbowax 4000 (−0.3, −2.5, −5.0, and −7.5 bars) on the shoot and root growth and root elongation rate of 2‐week‐old wheat seedlings ( Triticum aestivum L.) in a walk‐in growth room. Seedlings of spring wheat, ‘Fielder’, were grown in a Xerollic Durargids loam soil separated from the surrounding nutrient solution by a semipermeable, cellulose‐acetate membrane. Leaf water potential was measured with a pressure chamber apparatus. Root length was estimated by line‐intersection counting of stained root segments during microscopic examination. Plant growth was measured by the determination of dry weights of shoots and roots at the beginning and end of an 11‐day experimental period. Growth was more reduced by decreases in matric potential than by decreases in the osmotic potential. A greater interaction between the effects of the osmotic potential of the soil water and the soil matric potential occurred with shoot growth than with root growth. The 50% reduction, Y 50 , occurred at osmotic potentials of the soil water ranging from −6.8 to −8.8 bars for shoot growth and at potentials ranging from −6.8 to −8.4 bars for root growth at the soil matric potentials ranging from −0.3 to −7.5 bars, respectively. Shoot growth showed lower tolerance to the decreasing osmotic potentials at soil matric potentials less than −2.5 bars. The Y 50 values of potential were −8.6 and −5.4 bars for NaCl‐induced (osmotic) and Carbowax induced (matric) potentials, respectively. Shoot growth ceased at the leaf water potentials of −19.7and −15.3 bars at the NaCl and Carbowax‐induced potentials, respectively. Decrease in root density occurred at the soil matric potentials lower than −5.0 bars while it was reduced at all the experimental levels of osmotic potential. Root elongation rates ceased at matric potentials of −11, −12, −12, and −7 bars at osmotic potentials of 0, −4, −8, and −12 bars. respectively. Osmotic adjustment in the plant cells and possible toxic effects of Na and Cl ions or ionic imbalances on shoot growth and root elongation have been discussed.
Publication Year: 1979
Publication Date: 1979-09-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 24
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