Drought effects on leaf abscission and leaf production in Populus clones

Abstract

Leaf abscission and foliation responses to water stress were studied in potted plants of five Populus clones grown in a greenhouse. As predawn leaf water potential (Ψ₁) fell to -3 MPa, drought-induced leaf abscission increased progressively to 30% for data pooled across clones. As predawn Ψ₁ fell below -3 MPa, drought-related abscission was about 50%. When combined with abscission rates in well-watered "phenological control" plants, abscission exceeded 80-90% in the most severely water-stressed plants. Clonal variation in water stress-induced abscission was statistically significant, but appeared to be confounded with clonal differences in leaf loss in control plants. Production of new leaf area ranged from 0 to 1,389 cm². Pooled across clones, maximum production of leaf area occurred in plants previously subjected to moderate water stress (-0.5 to -0.75 MPa). This stimulation of leaf development was associated with greater areas of individual leaves. At predawn Ψ₁ < -2 mpa leaf area production was greatly decreased (

Citation

Pallardy, Stephen G.; Rhoads, Julie L. 1997. Drought effects on leaf abscission and leaf production in Populus clones. In: Pallardy, Stephen G.; Cecich, Robert A.; Garrett, H. Gene; Johnson, Paul S., eds. Proceedings of the 11th Central Hardwood Forest Conference; Gen. Tech. Rep. NC-188. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station: 373-383