Net Carbon Dioxide Exchange Rates and Predicted Growth Patterns in Alstroemeria `Jacqueline' at Varying Irradiances, Carbon Dioxide Concentrations, and Air Temperatures

Abstract

<jats:p>The influence of irradiance, CO<jats:sub>2</jats:sub> concentration, and air temperature on leaf and whole-plant net C exchange rate (NCER) of <jats:italic>Alstroemeria</jats:italic> `Jacqueline' was studied. At ambient CO<jats:sub>2</jats:sub>, leaf net photosynthesis was maximum at irradiances above 600 μmol·m<jats:sup>-2</jats:sup>·s<jats:sup>-1</jats:sup> photosynthetically active radiation (PAR), while whole-plant NCER required 1200 μmol·m<jats:sup>-2</jats:sup>·s<jats:sup>-1</jats:sup> PAR to be saturated. Leaf and whole-plant NCERs were doubled under CO<jats:sub>2</jats:sub> enrichment of 1500 to 2000 μl CO<jats:sub>2</jats:sub>/liter. Leaf and whole-plant NCERs declined as temperature increased from 20 to 35C. Whereas the optimum temperature range for leaf net photosynthesis was 17 to 23C, whole-plant NCER, even at high light and high CO<jats:sub>2</jats:sub>, declined above 12C. Dark respiration of leaves and whole plants increased with a Q<jats:sub>10</jats:sub> of ≈2 at 15 to 35C. In an analysis of day effects, irradiance, CO<jats:sub>2</jats:sub> concentration, and temperature contributed 58%, 23%, and 14%, respectively, to the total variation in NCER explained by a second-order polynomial model (<jats:italic>R</jats:italic><jats:sup>2</jats:sup> = 0.85). Interactions among the factors accounted for 4% of the variation in day C assimilation. The potential whole-plant growth rates during varying greenhouse day and night temperature regimes were predicted for short- and long-day scenarios. The data are discussed with the view of designing experiments to test the importance of C gain in supporting flowering and high yield during routine harvest of <jats:italic>Alstroemeria</jats:italic> plants under commercial greenhouse conditions.</jats:p>

The effect of source or sink temperature on photosynthesis and 14C-partitioning in and export from a source leaf of Alstroemeria

“…The data in Eigs 4 and 5 suggest that above 25°C export of photoassimilates during photosynthesis from the source leaves to developing sinks may be limiting to Alstroemeria growth and development at ambient CO2. These data also show that CO, enrichment would suppress photorespiration and help maintain export of assimilates in the light and increase bioproductivity at elevated greenhouse temperatures (Leonardos et al 1994).…”

“…cv. Jacqueline plants were grown in 15to 30-cm (1.75-to 5-i)_ pots containing Promix-BX (Les tourbieres Premier LTEE, Riviere du Loup, QC, Canada) in a glasshouse under natural sunlight, as described earlier (Leonardos et al, 1994), Temperatures were set at 15 ± 3 and 12 ± 2°C day and night, respectively. However, temperatures higher than 25°C were recorded during warm sunny days, A commercial fertilizer solution (20N-8.7P-16.6K) (Plant Products Co., Bramalea, ON, Canada) was applied during each watering.…”

“…cv. Jacqueline showed that irradiance, CO2 concentration, temperature, and the interactions among them contributed 58, 23, 15, and 4%, respectively, to the total variation io whole-plant net photosynthesis described by a second-order polynomial model (Leonardos et al 1994). In order to differentiate between the effect of changes in leaf temperature on photosynthesis and those on export, the influence of varying irradiance levels ( Fig.…”

Two different strategies for light utilization in photosynthesis in relation to growth and cold acclimation

“…The whole‐plant net CO 2 exchange analysis system has been described in detail previously (Leonardos, Tsujita & Grodzinski 1994; Jiao, Leonardos & Grodzinski 1996). It consisted of four plexiglass plant‐holding chambers computerized to analyse and control the environment of each chamber separately.…”

Carbon use efficiency depends on growth respiration, maintenance respiration, and relative growth rate. A case study with lettuce

“…Although these differences in CO 2 concentration may have affected the CO 2 exchange rate, these effects probably were small, because the low photosynthetic photon flux (PPF) level during the measurements (200 µ mol m −2 s −1 ) probably was the main factor limiting canopy photosynthesis. For example, P n of Alstroemeria did not change appreciably with an increase in CO 2 concentration from 280 to 365 µ mol mol −1 , when the PPF level was 200 µ mol m −2 s −1 , but increased by approximately 25% at a PPF level of 1200 µ mol m −2 s −1 (Leonardos et al . 1994).…”