Isozyme markers associated with O(3) tolerance indicate shift in genetic structure of ponderosa and Jeffrey pine in Sequoia National Park, California.
Effects of canopy ozone (O(3)) exposure and signatures of genetic structure using isozyme markers associated with O(3) tolerance were analyzed in approximately 20-, approximately 80-, and >200-yr-old ponderosa (Pinus ponderosa Dougl. ex Laws.) and Jeffrey pine (Pinus jeffreyi Grev. & Balf.) in Sequoia National Park, California. For both species, the number of alleles and genotypes per loci was higher in parental trees relative to saplings. In ponderosa pine, the heterozygosity value increased, and the fixation index indicated reduction of homozygosity with increasing tree age class. The opposite tendencies were observed for Jeffrey pine. Utilizing canopy attributes known to be responsive to O(3) exposure, ponderosa pine was more symptomatic than Jeffrey pine, and saplings were more symptomatic than old growth trees. We suggest that these trends are related to differing sensitivity of the two species to O(3) exposure, and to higher O(3) exposures and drought stress that younger trees may have experienced during germination and establishment.
Staszak
J
J
A Mickiewicz University, Genetics Department, ul. Umultowska 89, 61-614 Poznan, Poland.
Grulke
N E
NE
Marrett
M J
MJ
Prus-Glowacki
W
W
D000393:Air Pollutants / Q000009:adverse effects*; D000483:Alleles; D002140:California; D002980:Climate; D003247:Conservation of Natural Resources; D017753:Ecosystem; D005838:Genotype; D006579:Heterozygote; D010103:Oxygen Isotopes / Q000032:analysis*; D010126:Ozone / Q000009:adverse effects*; D028223:Pinus / Q000235:genetics* / Q000254:growth & development; D041604:Pinus ponderosa / Q000235:genetics / Q000254:growth & development; D018515:Plant Leaves / Q000737:chemistry*; D011998:Recreation; D013995:Time
D000393:Air Pollutants; D010103:Oxygen Isotopes; D010126:Ozone