The influence of elevated temperature, elevated atmospheric CO2 concentration and water stress on net photosynthesis of loblolly pine (Pinus taeda L.) at northern, central and southern sites in its native range

We examined the influence of elevated temperature (ambient +2 °C) and atmospheric CO2 concentration ([CO2]) (700 µmol·mol–1), applied singly and in combination, on biomass accumulation and the temperature response of net photosynthesis (Anet) and leaf respiration (Rd) of loblolly pine ( Pinus taeda L.) seedlings grown simultaneously at a northern and a southern site within the species’ range. We used this experimental approach to determine if the response to future climate conditions would differ between a warm and cool location within a species’ range. Seedling biomass accumulation and the temperature responses of Anet and Rd were measured throughout the growing season. Biomass accumulation was substantially greater at the warmer site compared with the cooler site regardless of treatment. At each site, biomass accumulation was greater in the elevated temperature treatment compared with the ambient treatment. There was substantial acclimation of Rd, but not Anet, to site and to temperature treatment at each site. Elevated [CO2] increased biomass accumulation and Anet at both sites and in both temperature treatments. Our study provides an indication that future projected increases in [CO2] and air temperature of 700 µmol·mol–1 and +2 °C, respectively, are likely to increase loblolly pine growth in most, if not all, of its current range.

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Responses of woody Cerrado species to rising atmospheric CO2 concentration and water stress: gains and losses

Functional Plant Biology ◽

10.1071/fp16138 ◽

2016 ◽

Vol 43 (12) ◽

pp. 1183 ◽

Cited By ~ 6

Author(s):

João Paulo Souza ◽

Nayara M. J. Melo ◽

Eduardo G. Pereira ◽

Alessandro D. Halfeld ◽

Ingrid N. Gomes ◽

...

Keyword(s):

Water Stress ◽

Elevated Co2 ◽

Global Climate ◽

Net Photosynthesis ◽

Co2 Concentration ◽

Atmospheric Co2 ◽

Ecosystem Functions ◽

Total Biomass ◽

High Co2 ◽

Atmospheric Co2 Concentration

The rise in atmospheric CO2 concentration ([CO2]) has been accompanied by changes in other environmental factors of global climate change, such as drought. Tracking the early growth of plants under changing conditions can determine their ecophysiological adjustments and the consequences for ecosystem functions. This study investigated long-term ecophysiological responses in three woody Cerrado species: Hymenaea stigonocarpa Mart. ex Hayne, Solanum lycocarpum A. St.-Hil. and Tabebuia aurea (Silva Manso) Benth. and Hook. f. ex S. Moore, grown under ambient and elevated [CO2]. Plants were grown for 515 days at ambient (430 mg dm–3) or elevated [CO2] (700 mg dm–3). Some plants were also subjected to water stress to investigate the synergy between atmospheric [CO2] and soil water availability, and its effect on plant growth. All three species showed an increase in maximum net photosynthesis (PN) and chlorophyll index under high [CO2]. Transpiration decreased in some species under high [CO2] despite daily watering and a corresponding increase in water use efficiency was observed. Plants grown under elevated [CO2] and watered daily had greater leaf area and total biomass production than plants under water stress and ambient [CO2]. The high chlorophyll and PN in cerrado plants grown under elevated [CO2] are an investment in light use and capture and higher Rubisco carboxylation rate, respectively. The elevated [CO2] had a positive influence on biomass accumulation in the cerrado species we studied, as predicted for plants under high [CO2]. So, even with water stress, Cerrado species under elevated [CO2] had better growth.

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Effects of competition control and annual nitrogen fertilization on gas exchange of different-aged Pinus taeda

Canadian Journal of Forest Research ◽

10.1139/x03-034 ◽

2003 ◽

Vol 33 (6) ◽

pp. 1076-1083 ◽

Cited By ~ 28

Author(s):

Gregory T Munger ◽

Rodney E Will ◽

Bruce E Borders

Keyword(s):

Gas Exchange ◽

Pinus Taeda ◽

Loblolly Pine ◽

Positive Impact ◽

Leaf Gas Exchange ◽

Nitrogen Concentration ◽

Net Photosynthesis ◽

Stand Age ◽

Competition Control ◽

Pinus Taeda L

To determine the importance of competition control and annual fertilization on leaf gas exchange, light-saturated net photosynthesis (Asat), stomatal conductance (gs), and internal CO2 concentration (Ci) were measured multiple times in different-aged loblolly pine (Pinus taeda L.) stands growing at a Piedmont (BF Grant) and Coastal Plain (Waycross) location in Georgia, U.S.A. At both locations, competition control decreased Asat and gs (Asat from 4.53 to 4.12 µmol·m2·s1, gs from 0.058 to 0.050 mol·m2·s1 at BF Grant; Asat from 4.22 to 4.01 µmol·m2·s1, gs from 0.054 to 0.049 mol·m2·s1 at Waycross). Overall, fertilization did not have a positive impact on Asat, even though fertilization significantly increased foliar nitrogen concentration. At BF Grant, fertilization significantly decreased gs from 0.057 to 0.051 mol·m2·s1 and Ci from 217 to 205 µmol·mol1. In addition, the decrease in Ci associated with fertilization became larger with stand age. At Waycross, fertilization decreased Ci from 211 to 203 µmol·mol1 and the interaction between fertilization and stand age was significant for gs and Ci. These results indicate that silivcultural practices that increase resource availability and stand growth did not enhance leaf gas exchange.

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