Fitting net photosynthetic light-response curves with Microsoft Excel - a critical look at the models

Lobo, Francisco; Barros, Miguel; Dalmagro, Higo J.; Dalmolin, Ândrea Carla; Pereira, Walter Esfrain; Souza, É. C. de; Vourlitis, George L.; Ortiz, Carmen Eugênia Rodríguez

doi:10.1007/s11099-013-0045-y

Cited by 195 publications

(135 citation statements)

References 38 publications

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“…We considered the case in which ramet performance first increases linearly with an increased external resource supply and then levels off with a further increase in resource supply, as could be the case when a different resource then limits performance. This type of relationship between plant performance and resource supply is frequently observed (Alpert 1991;Vermeulen et al 2009;Lobo et al 2013), although modifications such as zero performance at a very low resource supply or a decrease in performance at a very high resource supply are also common (Jackson 2000;Lambers et al 2008).…”

Section: Introductionmentioning

confidence: 93%

Clonal integration in homogeneous environments increases performance of Alternanthera philoxeroides

et al. 2015

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Physiological integration between connected ramets can increase the performance of clonal plants when ramets experience contrasting levels of resource availabilities in heterogeneous environments. It has generally been shown or assumed that clonal integration has little effect on clonal performance in homogeneous environments. However, a conceptual model suggests that integration could increase performance in a homogeneous environment when connected ramets differ in uptake ability and external resource supply is high. We tested this hypothesis in a greenhouse experiment with the amphibious plant Alternanthera philoxeroides. Ramets in clonal fragments containing three rooted and two unrooted ramets were either left connected or divided into a basal part with two rooted ramets and an apical part with the other ramets. To simulate realistic, homogeneous environments of the species with different levels of resource supply, plants were grown at 0, 20, or 40 cm of water depth. Water depth had a positive effect on most measures of growth, indicating that resource supply increased with depth. Connection had negative to neutral effects on total growth of fragments at a water depth of 0 cm, and neutral to positive effects at 20- and 40-cm depths; effects on the apical part were generally positive and larger at greater depth; effects on the basal part were generally negative and smaller at greater depth. Results largely supported the hypothesis and further suggest that clonal integration of allocation and reproduction may modify benefits of resource sharing in homogeneous environments.

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Section: Introductionmentioning

confidence: 93%

Clonal integration in homogeneous environments increases performance of Alternanthera philoxeroides

et al. 2015

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“…Sigma Plot 11 (Systat Software, USA) was used to fit photosynthetic model equations to empirical data. A nonrectangular hyperbola model of photosynthesis [18] was fitted to light response data and maximal light saturated photosynthesis (A max ), dark respiration (R d ), curvature factor (Θ), and quantum yield of photosynthetic CO 2 assimilation (Φ) were estimated. Two phase model of photosynthesis [19] was fitted to the A/C i measurements assuming that data points with C i < 400 µmol mol −1 represented photosynthesis that was limited by amount, activity or kinetics of Rubisco, whereas those with C i > 400 µmol mol −1 represented photosynthesis limited by the rate of electron transport required for the regeneration of ribulose 1,5-biphosphate (RuBP) [20].…”

Section: Gas Exchange Analysismentioning

confidence: 99%

Chloroplast protease/chaperone AtDeg2 influences cotyledons opening and reproductive development in Arabidopsis

et al. 2018

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AtDeg2 is a chloroplast protein with dual protease/chaperone activity. Since data on how the individual activities of AtDeg2 affect growth and development of Arabidopsis thaliana plants is missing, two transgenic lines were prepared that express mutated AtDeg2 versions that have either only protease or chaperone activity and a comprehensive ontogenesis stage-based study was performed comprising wild type (WT) plants and insertional mutants that do not express AtDeg2, as well as the two transgenic lines. The repression of both AtDeg2 activities in deg2-3 mutants altered just a few phenotypic traits including the time when cotyledons were fully opened, the time when 10% flowers were open as well as the number of inflorescence branches and seed length in plants which have completed their generative development. It was demonstrated that complete opening of cotyledons as well as the number of inflorescence branches and seed length in plants which have completed their generative development required involvement of both AtDeg2 activities, whereas the time when 10% of flowers were open was controlled by AtDeg2 protease activity. These results show for the first time that the chaperone activity of AtDeg2 is needed for some elements of generative development of A. thaliana plants to proceed normally. So far, the chaperone activity of AtDeg2 was confirmed based on in vitro assays only.

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“…AxDFFFA ascending curves of PAR (photosynthetically active radiation) at irradiation intensities of 0; 50; 200; 500; 700; 1,000 and 1,200 μmol photons m -2 s -1 were determined on the median region of the fourth fully expanded leaf of plants in all treatments. The values of maximum photosynthesis and respiration net in the dark were calculated by the adjustment of curve model as proposed by Lobo et al (2013) a fl uorescence was performed on the fourth fully expanded leaf pre-adapted to dark, according to the pulse method (SCHREIBER et al, 1994), using an OS5p+ Advanced Modulated Fluorometer (Opti-Sciences). The initial (F 0 ) and maximum ( F m ) fl uorescence values were determined after induction of total darkness (60 minutes) with clips on the leaves.…”

Section: Seedlings Ofmentioning

confidence: 99%

Gas exchange and chlorophyll a fluorescence parameters of ornamental bromeliads

Silva

Ferreira

et al. 2017

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Gas exchange and chlorophyll a fluorescence are widely used in physiological and ecological studies; however, few studies have used these techniques with ornamental plants. This study tested the potential contribution of gas exchange and chlorophyll a fluorescence to evaluate the water and nutrients uptake by the tank and root system of epiphyte bromeliad Guzmania lingulata. For this purpose, we conducted an experiment with different water regime and another with different concentrations of nitrogen. The experiments were: 1 -Watering: Control (application of water into Tank and Root), Tank (watering into Tank), Root (watering Root) and Drought (water suspension during the 90 days of experimentation) and 2 -Nitrogen: Plants fertilized with Hoagland and Arnon nutrient solution exclusively into Tank or Root with nitrogen concentrations of control and 2.62 or 5.34 mM N applied as urea. The F v /F m ratio allowed comparing the treatments between experiments, demonstrating that Root and Tank both have the capacity to maintain G. lingulata photosynthetic activity and growth, while Drought treatment (water suspension) was the limiting factor for energy conversion efficiency of PSII. However, gas exchange was more permissive as a parameter for comparing treatments in the nitrogen experiment, providing important information about the general aspects of the photosynthetic process in the watering experiment. Both gas exchange and chlorophyll a fluorescence can support the evaluation of G. lingulata physiological status and can be useful tools in ornamental horticultural studies. Keywords: Bromeliaceae, nutrition, drought stress, IRGA, fluorometer. RESUMOTrocas gasosas e fluorescência da clorofila a de bromélias ornamentais Os parâmetros de trocas gasosas e fluorescência da clorofila a são amplamente utilizados em estudos fisiológicos e ecológicos, no entanto essas técnicas tem tido pouco destaque em estudos com plantas ornamentais. Neste estudo, foi testado o potencial de contribuição dessas técnicas para avaliação da absorção de água e nutrientes pelo tanque e sistema radicular da bromélia epífita Guzmania lingulata. Para tanto foram desenvolvidos experimentos com diferentes regimes hídricos e diferentes concentrações de nitrogênio. Os experimentos foram: 1 -Irrigação: Controle (aplicação de água no Tanque e Raiz), Tanque (regas no Tanque), Raiz (regas no substrato), Seca (suspensão hídrica durante os 90 dias de experimento) e o segundo as plantas foram submetidas a adubação com solução nutritiva de Hoagland and Arnon exclusivas no Tanque ou na Raiz nas concentrações de nitrogênio de 0.00, 2.62 ou 5.34 mM N aplicadas na forma de ureia. Nos dois experimentos a razão F v /F m foi eficiente para comparação dos tratamentos, demonstrando que tanto a raiz como o tanque apresentam a capacidade de manter a atividade fotossintética e o crescimento de G. lingulata, sendo que o maior limitante para a eficiência de conversão de energia do PSII é a suspensão hídrica. Os parâmetros de trocas gasosas foram mais eficientes no expe...

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Fitting net photosynthetic light-response curves with Microsoft Excel - a critical look at the models

Cited by 195 publications

References 38 publications

Clonal integration in homogeneous environments increases performance of Alternanthera philoxeroides

Clonal integration in homogeneous environments increases performance of Alternanthera philoxeroides

Chloroplast protease/chaperone AtDeg2 influences cotyledons opening and reproductive development in Arabidopsis

Gas exchange and chlorophyll a fluorescence parameters of ornamental bromeliads

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