Effects of elevated CO2 on development and morphology of spring wheat grown in cooled and non-cooled open-top chambers

1998 ◽  
Vol 25 (5) ◽  
pp. 617 ◽  
Author(s):  
M. van Oijen ◽  
A.H.C.M. Schapendonk ◽  
M.J.H. Jansen ◽  
C.S. Pot ◽  
J. van Kleef ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Spring Wheat ◽  
Cooling System ◽  
Co2 Concentration ◽  
Triticum Aestivum L ◽  
Ambient Conditions ◽  
Morphological Response ◽  
Open Top Chambers ◽  
Temperature Interaction ◽  
Doubled Co2 Concentration

Facilities for studying effects of elevated CO2 on crops affect the microclimate in the crop. Open-top chambers may increase temperature by 1–3˚C compared to ambient conditions. This paper describes a newly developed cooling system for open-top chambers. In 1995 and 1996, experiments were carried out to test the system and analyse the effects of temperature on crop phenological and morphological response to elevated CO2. Spring wheat (Triticum aestivum L. cv. Minaret) was subjected to ambient and doubled CO2 concentration in both cooled and non-cooled chambers. The cooling system reduced temperature by 1.6–2.4˚C, and this delayed maturity by 10 days. In contrast, elevated CO2 did not affect phenological development. Elevated CO2 reduced tiller density, green leaf number per tiller and specific leaf area, thereby reducing the capacity for light interception of the crop. Crop height growth before anthesis mainly responded to temperature, but after anthesis it was only affected by CO2, indicating a shift from sink- to source-limited growth. For none of the parameters studied, a significant statistical interaction of CO2 and temperature was found. The cooling system proved effective. Atemperature difference of about 2˚C affected crop development and morphology more strongly than CO2 doubling. However, the absence of CO2-temperature interaction suggests that CO2 effects may validly be investigated even without a cooling system.

Effects of elevated CO2 concentration on photosynthetic acclimation and productivity of two potato cultivars grown in open-top chambers

2000 ◽  
Vol 27 (12) ◽  
pp. 1119 ◽  
Author(s):  
Ad H.C.M. Schapendonk ◽  
Marcel van Oijen ◽  
Paul Dijkstra ◽  
C. Sander Pot ◽  
Wilco J.R.M. Jordi ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Potato Cultivar ◽  
Co2 Concentration ◽  
Growing Season ◽  
Photosynthetic Acclimation ◽  
Area Index ◽  
Open Top Chambers ◽  
Fluorescence Measurements ◽  
Low Co2 ◽  
Rate Of Photosynthesis

In two subsequent years, an early maturing potato cultivar with low leaf area index (LAI) and a late cultivar with high LAI were grown at concentrations of 350 and 700 L CO2 L–1 in open-top chambers. The average increase of tuber dry matter yield by elevated CO2 was 27% in 1995 and 49% in 1996. During the first weeks after planting, elevated CO2 stimulated the light-saturated rate of photosynthesis (Amax) of both cultivars by 80%. However, Amax under elevated CO2 declined to the level of the low-CO2 treatment in the course of the growing season. In 1995 this convergence due to acclimation of photosynthesis was completed within 6 weeks, but in 1996, acclimation proceeded until the end of the growing season. Photosynthetic acclimation was accompanied by a reduced Rubisco content, and was correlated more closely with accumulation of sucrose than of starch. From fluorescence measurements it was concluded that, in contrast to the carboxylation efficiency, the efficiency of photosynthetic reactions centers was not affected by acclimation to elevated CO2. The faster photosynthetic acclimation in 1995 coincided with overall lower values of Amax, crop growth rate and growth response to elevated CO2. It is shown that the indeterminate growth pattern of potato with its large sink capacity does not preclude acclimation. The effect of acclimation on yield was quantified by computer simulations. The simulated results indicated that photosynthetic acclimation reduced the positive effect of elevated CO2 on tuber yield by 50%.

Seasonal changes in tissue elasticity and water transport efficiency in three co-occurring Mediterranean shrubs under natural long-term CO2 enrichment

2002 ◽  
Vol 29 (9) ◽  
pp. 1097 ◽  
Author(s):  
Roberto Tognetti ◽  
Antonio Raschi ◽  
Mike B. Jones
Keyword(s):  
Elevated Co2 ◽  
Seasonal Changes ◽  
Water Movement ◽  
Co2 Enrichment ◽  
Co2 Concentration ◽  
Tissue Elasticity ◽  
Ambient Conditions ◽  
Mediterranean Shrubs ◽  
Competitive Relations

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.

Sign in / Sign up

Export Citation Format

Share Document