Genotypic variability in ponderosa pine responses to combined ozone and drought stresses
- Univ. of California, Riverside, CA (United States)
Five-year-old ponderosa (Pinus ponderosa Laws.) seedlings from 18 half-sib and one full-sib families obtained from the California Tree Improvement Program were harvested after 1, 2, and 3 growing seasons of exposure to three levels of ozone (O{sub 3}) and two levels of available soil water (ASW) in open-top chambers in the California Sierras. Seedlings were evaluated for O{sub 3} injury symptoms, biomass, and radial growth in response to these stresses. Ozone injury responses were highly variable across families, but family rankings for O{sub 3} injury were consistent across years. Family rankings for O{sub 3} injury were highly correlated with those for reductions in biomass and radial growth for trees in the high ASW treatment, but drought-stressed trees showed no consistent relation between foliar 03 injury and reductions in growth. After three seasons of exposure to 88 ppb O{sub 3}, foliar biomass of the three most susceptible families averaged 60% less than trees in the low-O{sub 3} control, while O{sub 3} had no effect on growth of the three most resistant families. Variability across families of growth responses to drought was significantly less than the variability in seedling responses to O{sub 3}.
- OSTI ID:
- 95891
- Report Number(s):
- CONF-9507129--
- Journal Information:
- Bulletin of the Ecological Society of America, Journal Name: Bulletin of the Ecological Society of America Journal Issue: 2 Vol. 76; ISSN BECLAG; ISSN 0012-9623
- Country of Publication:
- United States
- Language:
- English
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