Physiological and Nutritive Effects of K-Pretreatment and KCl Sprays on Water-stressed and Unstressed Apple Seedlings1

in Journal of the American Society for Horticultural Science
Authors:
Dariusz SwietlikU.S. Department of Agriculture. Agricultural Research Service. Beltsville, MD 20705

Search for other papers by Dariusz Swietlik in
ASHS
Google Scholar
PubMed
Close
,
R. F. KorcakU.S. Department of Agriculture. Agricultural Research Service. Beltsville, MD 20705

Search for other papers by R. F. Korcak in
ASHS
Google Scholar
PubMed
Close
, and
Miklos FaustU.S. Department of Agriculture. Agricultural Research Service. Beltsville, MD 20705

Search for other papers by Miklos Faust in
ASHS
Google Scholar
PubMed
Close

Abstract

Low- and high-K pretreated ‘York Imperial’ apple seedlings (Malus domestica Borkh.) were grown in nutrient solution cultures. Addition of polyethylene glycol (PEG) to the nutrient solution to reduce water potential to −1.0 bar reduced water consumption, fresh weight, specific leaf weight (SLW), and leaf water potential and increased the amount of water consumed per unit of fresh weight gain. High-K pretreatment increased water consumption of unstressed seedlings but decreased water consumption of PEG-stressed plants. Daily sprays with 0.5% KCl applied in early afternoon had no effect on water consumption rate in apple seedlings. However, sprays probably induced wider stomatal opening, since K-sprayed trees had lower leaf water potential when measured at noon than unsprayed trees. This effect was not observed when water potential was measured in the morning (0800 hr). High-K plants had higher leaf water potential than low-K plants in the morning. Potassium pretreatment and PEG stress as well as K-sprays had numerous effects on plant mineral composition. The K-pretreatment or K-sprays did not alleviate the detrimental effects of PEG-induced water stress despite the effects of K-pretreatment and K-sprays on mineral composition and leaf water potential.

Contributor Notes

Received for publication Oct. 26. 1981.

The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.

Visiting Scientist. Research Institute of Pomology. Skierniewice. Poland.

Soil Scientist and Plant Physiologist, Fruit Laboratory, Horticultural Science Institute.

  • Collapse
  • Expand