Intra- and interspecific diversity in the response to waterlogging of two co-occurring white oak species (Quercus robur and Q. petraea).
Quercus robur L. and Quercus petraea (Matt.) Liebl. are sympatric oak species with different ecological requirements. Quercus robur is more tolerant to waterlogging than Q. petraea. This ecological divergence may play a role in the maintenance of the two species despite the absence of an insurmountable reproductive barrier between them. We predicted that the genetic architecture of traits related to waterlogging tolerance differs between the species. To gain insight into this architecture in the absence of genetic markers for waterlogging tolerance, we compared populations of seedlings of each species for diversity in the expression of quantitative phenotypic traits induced by severe hypoxia. To determine the capacity for hypertrophied lenticel formation, we applied gas-impermeable mastic to stems of seedlings. Two months after application, the mastic treatment had induced the formation of 3 (+/- 2) cm(-2) hypertrophied lenticels in the absence of root hypoxia. Leaf epinasty during root hypoxia was an early predictor of seedling mortality. Four weeks of waterlogging resulted in greater epinasty in Q. petraea than in Q. robur, but fewer hypertrophied lenticels (16 +/- 6 versus 21 +/- 9 cm(-2)) and adventitious roots (2.7 +/- 4.7 versus 5.2 +/- 5.9). Differences between species in these traits were associated with differences in the frequencies of extreme phenotypes rather than with a generally higher tolerance to waterlogging in Q. robur seedlings.
Parelle
Julien
J
INRA, UMR INRA-UHP 1137, Ecologie et Ecophysiologie Forestières, IFR 110 Génomique, Ecophysiologie et Ecologie Fonctionnelle, Centre INRA de Nancy, 54280 Champenoux, France.
Brendel
Oliver
O
Jolivet
Yves
Y
Dreyer
Erwin
E
D010100:Oxygen / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism / Q000502:physiology; D029963:Quercus / Q000378:metabolism / Q000502:physiology*; D036226:Seedlings / Q000378:metabolism / Q000502:physiology*; D013045:Species Specificity; D014867:Water / Q000378:metabolism*
D014867:Water; D010100:Oxygen