Altitudinal Variation in the Photosynthetic Characteristics of Snow Gum, Eucalyptus pauciflora Sieb. Ex Spreng. I. Seasonal Changes Under Field Conditions in the Snowy Mountains Area of South-Eastern Australia

Slayter, RO; Morrow, P. A.

doi:10.1071/bt9770001

Cited by 106 publications

(64 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It dominates forest canopies in subalpine areas as well as at lower elevations around the floor of valleys receiving cold air drainage, and occurs over an enormous climatic range from the subalpine tree line to the southern coast of Australia (Austin et al 1990). Temperaturedependent changes in photosynthetic capacity (Slatyer and Morrow 1977) and shoot growth (Green 1969) occur seasonally. Like many tree species, growth of snow gum seedlings is strongly suppressed by grass, a phenomenon that is usually attributed to competition for resources (Noble 1980;Egerton and Wilson 1993).…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of competition: thermal inhibition of tree seedling growth by grass

et al. 2002

View full text Add to dashboard Cite

The relative importance of thermal interference and competition for below-ground resources in the inhibition of tree seedling growth by grass was determined under field conditions. Snow gum (Eucalyptus pauciflora) seedlings were grown in bare soil or soil covered with either live grass or straw. Covering soil with straw produced thermal conditions in soil and air that were indistinguishable from those associated with live grass. In contrast, seedlings grown in bare soil experienced more rapid increase in soil temperatures during late winter and spring, less frequent and less severe frosts, and temperature maxima that more closely followed those of the atmosphere than seedlings growing in live grass or straw. After 1 year, seedlings in bare soil had four times the biomass of those grown in grass or straw. Inhibition of seedling growth by grass was attributed to alteration of the thermal environment which caused (1) seedlings to have a short growing season largely restricted to summer, (2) temporal separation in competition for resources with consumption of below-ground resources by grass in spring reducing availability of resources to support tree seedling growth in early summer, and (3) seedlings to be more subject to stress from temperature extremes. These results show that thermal interference plays a major role in interactions between plants.

show abstract

Section: Introductionmentioning

confidence: 99%

Mechanisms of competition: thermal inhibition of tree seedling growth by grass

et al. 2002

View full text Add to dashboard Cite

show abstract

“…However, variations in plant performance with altitude are difficult to predict, partly because of the complexity of the geophysical effects of altitude and partly because of biological responses to these changes. Indeed, maximum rates of CO 2 assimilation in plants from different elevations, measured at ambient CO 2 partial pressure, have been found to be equal (Benecke et al, 1981;Cordell et al, 1999;Körner and Diemer, 1987), lower (Kao and Chang, 2001;Slatyer and Morrow, 1977;Zhang et al, 2005), or higher at high elevation (Premoli and Brewer, 2007).…”

Section: Introductionmentioning

confidence: 99%

Augmentation de la capacité photosynthétique avec l’altitude: mesures d’échanges gazeux à pressions partielles de CO2 ambiante et constante

et al. 2009

View full text Add to dashboard Cite

Abstract• Because all microclimatic variables change with elevation, it is difficult to compare plant performance and especially photosynthetic capacity at different elevations. Indeed, most previous studies investigated photosynthetic capacity of low-and high-elevation plants using constant temperature, humidity and light but varying CO 2 partial pressures (P CO2 ).• Using gas exchange measurements, we compared here maximum assimilation rates (A max ) at ambient and constant-low-elevation P CO2 for two temperate tree species along an altitudinal gradient (100 to 1600 m) in the Pyrénées mountains.• Significant differences in A max were observed between the CO 2 partial pressure treatments for elevations above 600 m, the between-treatment differences increasing with elevation up to 4 µmol m −2 s −1 . We found an increase in A max with increasing elevation at constant-low-elevation P CO2 but not at ambient P CO2 for both species. Given a 10% change in P CO2 , a proportionally higher shift in maximum assimilation rate was found for both species.• Our results showed that high elevation populations had higher photosynthetic capacity and therefore demonstrated that trees coped with extreme environmental conditions by a combination of adaptation (genetic evolution) and of acclimation. Our study also highlighted the importance of using constant CO 2 partial pressure to assess plant adaptation at different elevations. Mots-clés :adaptation / acclimatation / gradient altitudinal / pression partielle / capacité photosynthétique Résumé -Augmentation de la capacité photosynthétique avec l'altitude : mesures d'échanges gazeux à pressions partielles de CO 2 ambiante et constante.• Les conditions microclimatiques étant très variables avec l'altitude, il est difficile de comparer les performances d'une espèce végétale à différentes altitudes, particulièrement la capacité photosynthé-tique. En effet, la plupart des études antérieures ont estimé le taux maximal d'assimilation à basses et hautes altitudes en maintenant la température, l'humidité de l'air et la lumière constantes mais en laissant varier la pression partielle de CO 2 (P CO2 ).• Afin de comparer le taux maximum d'assimilation (A max ) à pressions partielles de CO 2 constantes de basse altitude et variables, nous avons effectué des mesures d'échanges gazeux sur deux espèces d'arbres tempérés le long d'un gradient altitudinal de 1600 m de dénivelé dans les Pyrénées françaises.• La différence entre les deux traitements de P CO2 est significative au-dessus de 600 m d'altitude et atteint un maximum de 4 µmol m −2 s −1 . Pour les deux espèces, nous avons mis en évidence une augmentation de A max avec l'altitude à P CO2 constantes mais pas à P CO2 ambiantes. Pour une modification de P CO2 de 10 %, le changement du taux maximum d'assimilation est proportionnellement supérieur chez les deux espèces.• Nos résultats montrent que les populations de hautes altitudes possèdent une capacité photosynthétique supérieure, démontrant que les arbres font face aux conditions environnement...

show abstract

“…Altitudinal change in A sat has been investigated in a few temperate and subtropical mountains (for example, Benecke and others 1981;Zhang and others 2005;Premoli and Brewer 2007;Wieser and Tausz 2007;Bresson and others 2009) showing either no change (Benecke and others 1981;Wieser and Tausz 2007;Bresson and others 2009;Wieser and others 2010), an increase (Premoli and Brewer 2007) or a decrease with increasing altitude (Slayter and Morrow 1977;Zhang and others 2005). Thus, no consistent pattern has yet been detected.…”

Section: Introductionmentioning

confidence: 99%

Altitudinal Change in the Photosynthetic Capacity of Tropical Trees: A Case Study from Ecuador and a Pantropical Literature Analysis

et al. 2012

View full text Add to dashboard Cite

In tropical mountains, trees are the dominant life form from sea level to above 4,000-m altitude under highly variable thermal conditions (range of mean annual temperatures: <8 to >28°C). How light-saturated net photosynthesis of tropical trees adapts to variation in temperature, atmospheric CO 2 concentration, and further environmental factors, that change along elevation gradients, is not precisely known. With gas exchange measurements in mature trees, we determined light-saturated net photosynthesis at ambient temperature (T) and [CO 2 ] (A sat ) of 40 tree species from 21 families in tropical mountain forests at 1000-, 2000-, and 3000-m elevation in southern Ecuador. We tested the hypothesis that stand-level averages of A sat and leaf dark respiration (R D ) per leaf area remain constant with elevation. Standlevel means of A sat were 8.8, 11.3, and 7.2 lmol CO 2 m -2 s -1 ; those of R D 0.8, 0.6, and 0.7 lmol CO 2 m -2 s -1 at 1000-, 2000-, and 3000-m elevation, respectively, with no significant altitudinal trend. We obtained coefficients of among-species variation in A sat and R D of 20-53% (n = 10-16 tree species per stand). Examining our data in the context of a pan-tropical A sat data base for mature tropical trees (c. 170 species from 18 sites at variable elevation) revealed that area-based A sat decreases in tropical mountains by, on average, 1.3 lmol CO 2 m -2 s -1 per km altitude increase (or by 0.2 lmol CO 2 m -2 s -1 per K temperature decrease). The A sat decrease occurred despite an increase in leaf mass per area with altitude. Local geological and soil fertility conditions and related foliar N and P concentrations considerably influenced the altitudinal A sat patterns. We conclude that elevation is an important influencing factor of the photosynthetic activity of tropical trees. Lowered A sat together with a reduced stand leaf area decrease canopy C gain with elevation in tropical mountains.

show abstract

Altitudinal Variation in the Photosynthetic Characteristics of Snow Gum, Eucalyptus pauciflora Sieb. Ex Spreng. I. Seasonal Changes Under Field Conditions in the Snowy Mountains Area of South-Eastern Australia

Cited by 106 publications

References 0 publications

Mechanisms of competition: thermal inhibition of tree seedling growth by grass

Mechanisms of competition: thermal inhibition of tree seedling growth by grass

Augmentation de la capacité photosynthétique avec l’altitude: mesures d’échanges gazeux à pressions partielles de CO2 ambiante et constante

Altitudinal Change in the Photosynthetic Capacity of Tropical Trees: A Case Study from Ecuador and a Pantropical Literature Analysis

Contact Info

Product

Resources

About