The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance
Plant photosynthesis scales positively with growth irradiance. The carbon balance, defined here as the daily whole-plant gross CO2 assimilation (A) partitioned in C available for growth and C required for respiration (R), is thus irradiance dependent. Here we ask if R as a fraction of A is also irra...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2014-02-01
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| Series: | Frontiers in Plant Science |
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| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fpls.2014.00012/full |
| _version_ | 1811333466090897408 |
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| author | Thijs Leendert Pons Hendrik ePoorter |
| author_facet | Thijs Leendert Pons Hendrik ePoorter |
| author_sort | Thijs Leendert Pons |
| collection | DOAJ |
| description | Plant photosynthesis scales positively with growth irradiance. The carbon balance, defined here as the daily whole-plant gross CO2 assimilation (A) partitioned in C available for growth and C required for respiration (R), is thus irradiance dependent. Here we ask if R as a fraction of A is also irradiance dependent, whether there are systematic differences in C-balance between shade-tolerant and shade-intolerant species, and what the causes could be. Growth, gas exchange, chemical composition and leaf structure were analyzed for two shade-tolerant and three shade-intolerant herbaceous species that were hydroponically grown in a growth room at five irradiances from 20 µmol m-2 s-1 (1.2 mol m-2 day-1) to 500 µmol m-2 s-1 (30 mol m-2 day-1). Growth analysis showed little difference between species in unit leaf rate (dry mass increase per unit leaf area) at low irradiance, but lower rates for the shade-tolerant species at high irradiance, mainly as a result of their lower light saturated rate of photosynthesis. This resulted in lower relative growth rates in these conditions. Daily whole-plant R scaled with A in a very tight manner, giving a remarkably constant R/A ratio of around 0.3 for all but the lowest irradiance. Although some shade-intolerant species showed tendencies towards a higher R/A and inefficiencies in terms of carbon and nitrogen investment in their leaves, no conclusive evidence was found for systematic differences in C-balance between the shade-tolerant and intolerant species at the lowest irradiance. Leaf tissue of the shade-tolerant species was characterized by high dry matter percentages, C-concentration and construction costs, which could be associated with a better defense in shade environments where leaf longevity matters. We conclude that shade-intolerant species have a competitive advantage at high irradiance due to superior potential growth rates, but that shade-tolerance is not necessarily associated with a superior C-balance at low irradian |
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| format | Article |
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| institution | Directory Open Access Journal |
| issn | 1664-462X |
| language | English |
| last_indexed | 2024-04-13T16:52:16Z |
| publishDate | 2014-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Plant Science |
| spelling | doaj.art-ae2c420b166143e88c675e29d9ae13502022-12-22T02:38:54ZengFrontiers Media S.A.Frontiers in Plant Science1664-462X2014-02-01510.3389/fpls.2014.0001271121The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-toleranceThijs Leendert Pons0Hendrik ePoorter1Utrecht UniversityForschungszentrum Jülich GmbHPlant photosynthesis scales positively with growth irradiance. The carbon balance, defined here as the daily whole-plant gross CO2 assimilation (A) partitioned in C available for growth and C required for respiration (R), is thus irradiance dependent. Here we ask if R as a fraction of A is also irradiance dependent, whether there are systematic differences in C-balance between shade-tolerant and shade-intolerant species, and what the causes could be. Growth, gas exchange, chemical composition and leaf structure were analyzed for two shade-tolerant and three shade-intolerant herbaceous species that were hydroponically grown in a growth room at five irradiances from 20 µmol m-2 s-1 (1.2 mol m-2 day-1) to 500 µmol m-2 s-1 (30 mol m-2 day-1). Growth analysis showed little difference between species in unit leaf rate (dry mass increase per unit leaf area) at low irradiance, but lower rates for the shade-tolerant species at high irradiance, mainly as a result of their lower light saturated rate of photosynthesis. This resulted in lower relative growth rates in these conditions. Daily whole-plant R scaled with A in a very tight manner, giving a remarkably constant R/A ratio of around 0.3 for all but the lowest irradiance. Although some shade-intolerant species showed tendencies towards a higher R/A and inefficiencies in terms of carbon and nitrogen investment in their leaves, no conclusive evidence was found for systematic differences in C-balance between the shade-tolerant and intolerant species at the lowest irradiance. Leaf tissue of the shade-tolerant species was characterized by high dry matter percentages, C-concentration and construction costs, which could be associated with a better defense in shade environments where leaf longevity matters. We conclude that shade-intolerant species have a competitive advantage at high irradiance due to superior potential growth rates, but that shade-tolerance is not necessarily associated with a superior C-balance at low irradianhttp://journal.frontiersin.org/Journal/10.3389/fpls.2014.00012/fullPhotosynthesisgrowth analysisconstruction costsroot respirationscaling slope analysisshoot respiration |
| spellingShingle | Thijs Leendert Pons Hendrik ePoorter The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance Frontiers in Plant Science Photosynthesis growth analysis construction costs root respiration scaling slope analysis shoot respiration |
| title | The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance |
| title_full | The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance |
| title_fullStr | The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance |
| title_full_unstemmed | The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance |
| title_short | The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance |
| title_sort | effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade tolerance |
| topic | Photosynthesis growth analysis construction costs root respiration scaling slope analysis shoot respiration |
| url | http://journal.frontiersin.org/Journal/10.3389/fpls.2014.00012/full |
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