Photosynthetic acclimation to elevated CO2 concentration in a sweet pepper (Capsicum annuum) crop under Mediterranean greenhouse conditions: influence of the nitrogen source and salinity

2017 ◽  
Vol 44 (6) ◽  
pp. 573 ◽  
Author(s):  
Manuel E. Porras ◽  
Pilar Lorenzo ◽  
Evangelina Medrano ◽  
María J. Sánchez-González ◽  
Ginés Otálora-Alcón ◽  
...  

In many plant species, long-term exposure to elevated CO2 concentration results in a reduction in photosynthetic capacity, known as acclimation. This process is mainly explained by a feedback inhibition mechanism. The supply of a fraction of the nitrogen (N) in the nutrient solution as NH4+ can play an important role in the maintenance of photosynthetic activity and could mitigate the acclimation process. The aims of the present work were to study the photosynthetic response of sweet pepper (Capsicum annuum L.) to CO2 enrichment in Mediterranean greenhouse conditions, throughout the crop growth cycle and to evaluate the supply of NH4+ in the nutrient solution as a strategy to enhance the long-term response to CO2 at different levels of salinity. The experiment was conducted in two identical greenhouses: one with CO2 enrichment according to the ventilation, maintaining a high concentration when the vents were closed and a near-atmospheric level when the vents were open and one without. Sweet pepper plants were grown in both greenhouses, being irrigated with two levels of water salinity and two N sources: (i) NO3– and (ii) NO3– plus NH4+. A reduction in the response of photosynthesis to high CO2 concentration was found in the enriched plants after 135 days of CO2 supply, with respect to the reference plants. The leaf photosynthesis rate measured at high CO2 concentration showed a closer relationship with the leaf N concentration than the non-structural carbohydrate concentration. The relative yield gain of the CO2-enriched plants progressively decreased after reaching a maximum value; this was probably associated with the photosynthetic acclimation process. This decrease was delayed by the use of NH4+ in the nutrient solution at low salinity. Knowledge of the crop phase when acclimation to high CO2 concentration occurs can be the basis for deciding when to impose an early cessation of CO2 application, as a strategy to improve the economic efficiency of CO2 supply in Mediterranean conditions.

2002 ◽  
Vol 29 (9) ◽  
pp. 1097 ◽  
Author(s):  
Roberto Tognetti ◽  
Antonio Raschi ◽  
Mike B. Jones

Seasonal changes in hydraulic properties and tissue elasticity were evaluated in Erica arborea L., Myrtus�communis L. and Juniperus communis L., three Mediterranean shrubs that differ in adaptations to drought. These parameters were analysed over 12 months under field conditions, by comparing plants grown in the proximity of a natural CO2 spring (about 700 μmol mol–1 atmospheric CO2 concentration, [CO2]) with plants in ambient conditions. Plants at the CO2-spring site have been growing for generations at elevated [CO2]. At both sites, stem hydraulic and structural properties followed the prevailing climatic constraints. However, these shrub species co-occurring in the same environment differed in their capacity to tolerate water deficits, in xylem efficiency, and in strategies for regulating water movement between plant compartments. Either an increase or a decrease in tissue elasticity was effective in promoting resistance to drought stress, depending on the species. Long-term elevated [CO2] influenced all the studied parameters. Species-dependent differences existed in hydraulic architecture between the CO2-spring plants and control plants of E. arborea and M. communis, while J. communis plants rarely showed differences between sites. Less distinct differences between sites were observed for wood structure. The three species showed somewhat lower tissue elasticity under elevated [CO2], in particular during stress periods. The effects of elevated [CO2] on stem hydraulic pathway and structure and shoot elastic properties persist in the long term, but differ in absolute values and sign among the studied species and with the seasonal course, and thus might alter competitive relations between these shrubs.


2017 ◽  
Vol 24 (11) ◽  
pp. 10893-10899 ◽  
Author(s):  
María Carmen Piñero ◽  
Margarita Pérez-Jiménez ◽  
Josefa López-Marín ◽  
Francisco M. del Amor

1998 ◽  
Vol 152 (4-5) ◽  
pp. 413-419 ◽  
Author(s):  
Vladimír Špunda ◽  
Jiří Kalina ◽  
Martin Čajánek ◽  
Hana Pavlíčková ◽  
Michal V. Marek

2001 ◽  
Vol 149 (2) ◽  
pp. 247-264 ◽  
Author(s):  
B. E. Medlyn ◽  
C. V. M. Barton ◽  
M. S. J. Broadmeadow ◽  
R. Ceulemans ◽  
P. De Angelis ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document