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Growth response and drought susceptibility of red spruce seedlings exposed to simulated acidic rain and ozone

Journal Article · · Forest Science; (USA)
OSTI ID:6318744
; ;  [1]
  1. Virginia Polytechnic Institute and State Univ., Blacksburg (USA)

One-year-old seedlings of red spruce were exposed to O{sub 3} ({le} 0.025 or 0.10 {mu}l 1{sup {minus}1}, 4 h d{sup {minus}1}, 3 d wk{sup {minus}1}) in combination with simulated rain (pH 5.6 or 3.0, 1 h d{sup {minus}1}, 2 d wk{sup {minus}1}, 0.75 cm h{sup {minus}1}) for 10 weeks. After pollutant treatments, seedlings were subjected to two successive drought cycles. Whole-plant fresh weight increment (FWT) and dry weight were reduced after O{sub 3} exposure, whereas FWT and shoot height growth were increased after simulated rain exposure at pH 3.0 compared to pH 5.6. No interaction between O{sub 3} and rain treatments was observed for any growth variable measured. Foliar concentrations of K and S were greater in seedlings exposed to simulated rain at pH 3.0 compared with those at pH 5.6. Root hydraulic conductivity was highest in seedlings exposed to 0.10 {mu}l l{sup {minus}1} O{sub 3} + pH 3.0 rain solution compared with all other treatments after the first drought cycle. There were no significant O{sub 3} effects on net photosynthesis (Pn), transpiration or water-use efficiency prior to the drought cycles. However, during the second drought cycle, Pn was more sensitive to branch water potential in seedlings exposed to 0.10 {mu}l l{sup {minus}1} O{sub 3} + pH 3.0 solution compared with seedlings exposed to low O{sub 3} + pH 5.6 solution.

OSTI ID:
6318744
Journal Information:
Forest Science; (USA), Journal Name: Forest Science; (USA) Vol. 36:2; ISSN FOSCA; ISSN 0015-749X
Country of Publication:
United States
Language:
English