Acclimation to light in seedlings of Quercus petraea (Mattuschka) Liebl. and Quercus pyrenaica Willd. planted along a forest-edge gradient

Abstract

Photosynthetic acclimation of two co-occurring deciduous oaks (Quercus petraea and Quercus pyrenaica) to a natural light gradient was studied during one growing season. In the spring of 2003, 90 seedlings per species were planted along a transect resulting from a dense Pinus sylvestris stand, an adjacent thinned area and a 10-mwide firebreak (16.5-60.9% Global Site Factor (GSF)). In two dates of the following summer, we measured leaf gas exchange, carboxylation efficiency (CE), chlorophyll and nitrogen content, light-response curves of chlorophyll a fluorescence parameters, and leaf mass per area (LMA). Summer was mild, as evidenced by leaf predawn water potential ( pd ), which reduced the interactive effect of water stress on the response of seedlings to light. Q. pyrenaica had higher LMA, CE, stomatal conductance (g s max ) and photosynthesis per unit area (A a max ) than Q. petraea at all growth irradiances. A a max , LMA, g s max and electron transport rate (ETR) all increased with light availability (GSF) in a similar fashion in both species. Light had also a clear effect on the organization of Photosystem II (PS II), as deduced by chlorophyll a fluorescence curves. Chlorophyll concentration (Chl m ) deCommunicated by U. Lüttge creased with increasing light availability in Q. pyrenaica but it did not in Q. petraea. Seedlings of Q. petraea acclimated to higher irradiances showed a greater non-photochemical quenching (NPQ) than those of Q. pyrenaica. This suggests a higher susceptibility to high light in Q. petraea, which would be consistent with a better adaptation to shade, inferred from the lower LMA or the lower rate of photosynthesis.

Influence of overstory density on understory light, soil moisture, and survival of two underplanted oak species in a Mediterranean montane Scots pine forest

“…Overall lower survival of sessile oak than pyrenean oak is consistent with the more drought-sensitive features of the former (Aranda et al, 1996;Rodríguez-Calcerrada et al, 2007a). Besides, the greater root to shoot ratio of seedlings of pyrenean oak, together with their higher resprouting ability (Rodríguez-Calcerrada et al, 2007b) could have enhanced their resistance to browsing damages over those of sessile oak.…”

“…Survival of pyrenean oak was higher in thinned than in uncut plots probably in relation with the associated increase in soil moisture and light. Small increases in soil water content can greatly affect the plant water potential, whereas small increases in light can have profound effects on the photosynthetic capacity and can be sufficient to reach maximum values of photosynthetic capacity in shade-tolerant species (Gardiner et al, 2001;Rodríguez-Calcerrada et al, 2007a). In turn, increased carbon gain may result both in a greater capacity to withstand water stress (Augé et al, 1990) and to develop new roots after outplanting (Grossnickle, 2005), resulting in a better establishment.…”

Long-term physiological and morphological acclimation by the evergreen shrub Buxus sempervirens L. to understory and canopy gap light intensities

“…At the leaf scale, understory species have evolved low light compensation points (LCP) (Walters and Reich 1996;Craine and Reich 2005), carboxylation efficiency (Givnish et al 2004) and leaf nitrogen content per unit area (Sack et al 2003), resulting in a tendency for reduced dark respiration rates (R d ), but also lower net photosynthesis rates at light saturation (A max ). In contrast, high light specialists exhibit high electron transport rates (ETR) (Rodríguez-Calcerrada et al 2007), leaf nitrogen content per unit area (Gratani et al 2006) and A max , but also high R d . To cope with the stresses associated with strong irradiance, including photoinhibition and desiccation, high light specialists also show higher leaf inclination angles, leaf clumping and turnover rates than shade specialists (Valladares and Niinemets 2008), at the expense of light interception efficiency (Falster and Westoby 2003) and leaf lifespan (Hikosaka 2003).…”

Comparative Leaf Characteristics of Quercus Mongolica and Rhododendron Schilippenbachii Plants Inhabiting at South- and North- Facing Slopes around Mountain Ridge

“…Sometimes non-linear relationship was revealed and no significant effect of light on leaf nitrogen concentration is shown as water stress effect is exerted (Rodriguez-Calcerrada et al, 2007). Leaves of R. schlippenbachii in north-facing slope that showed low LMA must be shade-typed leaf (Fig.…”