Actual and potential photosynthetic rates of tropical crop species

Matta, F. M. Da; Loos, Rodolfo Araujo; Rodrigues, Rodrigo Schütz; Barros, Raimundo Santos

doi:10.1590/s0103-31312001000100003

Cited by 44 publications

(35 citation statements)

References 15 publications

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“…The mean SLA was 130 cm 2 g -1 similar to those reported for Nacional Ecuadorian cacao grown in full sunlight in the region of Esmeraldas, Ecuador (Tezara et al, 2015) and lower than the SLA (170 and 239 cm 2 g -1 ) reported by Daymond et al, (2011) andDa Matta et al, (2001). However, more research in order to know the relationship between environmental conditions and SLA along the north and central of the Ecuadorian coast is necessary.…”

Section: Specific Leaf Areasupporting

confidence: 76%

Photosynthetic response to low and high light of cacao growing without shade in an area of low evaporative demand

et al. 2018

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Cacao (Theobroma cacao L.) breeding programmes in Ecuador have focused on obtaining high-yield clones with improved disease resistance. Cacao clones should also have photosynthetic characteristics which support increased productivity. Regarding the weather conditions at the coast of Ecuador, where most of the year there are overcasts and low air evaporative demand, there is the possibility to grow cacao without overhead shade. This study focused on the photosynthetic response at two different photosynthetic photon flux densities (PPFD) of Ecuadorian cacao clones. Seven-year old cacao clones were evaluated: eight clones of Nacional type and two commercial clones (CCN 51 and EET 103), used as controls. All clones showed an increase of 35 % on average in net photosynthetic rate (A) with increasing PPFD from the light saturation point for cacao (i.e. 400 µmol m -2 s ). Such light responsiveness in A has not been reported before. Higher A was associated with higher apparent electron transport rate, while high stomatal conductance was maintained under both PPFD conditions. Under high PPFD, low non-photochemical quenching values were found, suggesting low energy dissipation. All clones showed high maximum quantum yields of PSII (F v /F m ), suggesting the absence of damage of the photochemical system. Keywords: cacao yield, chlorophyll fluorescence, CO 2 assimilation rate, gas exchange. RESUMENLos programas de mejoramiento de cacao (Theobroma cacao L.) en Ecuador se han centrado en la obtención de clones de alto rendimiento con mayor resistencia a las enfermedades. Estos clones también deben tener características fotosintéticas que apoyen una mayor productividad. En las condiciones climáticas en la costa de Ecuador, donde la mayor parte del año hay alta densidad de nubes y baja demanda evaporativa, existe la posibilidad de cultivar cacao sin sombra. Este estudio se centró en la respuesta fotosintética de clones de cacao del Ecuador en dos diferentes densidades de flujo de fotones fotosintéticos (PPFD). Se evaluaron diez clones de cacao de siete años de edad: ocho clones de tipo Nacional recientemente desarrollados por el Instituto Nacional de investigaciones Agropecuarias, y dos clones comerciales utilizados como controles (CCN 51 y EET 103). Todos los clones de cacao mostraron un aumento del 35 % en promedio en la tasa fotosintética neta (A) con el incremento del PPFD desde el punto de saturación de luz para el cacao (400 μmol m -2 s -1 ) hasta valores altos (1000 μmol m -2 s -1 ). Dicha respuesta de A a estas condiciones de luz alta no se ha

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Section: Specific Leaf Areasupporting

confidence: 76%

Photosynthetic response to low and high light of cacao growing without shade in an area of low evaporative demand

et al. 2018

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“…Cacao seedlings show increasing rates of net photosynthesis (A) as the photosynthetically active radiation (PAR) increases to values in the range from near 400 (Joly, 1988) to 750 (Da Matta et al, 2001) µmol m -2 s -1 , corresponding to 20-30% of PAR at full sunlight, when SI is reached. About 95% of the maximum A is obtained with half SI.…”

Section: Effects Of Abiotic Factors On Growth and Development Of Cacamentioning

confidence: 99%

Ecophysiology of the cacao tree

Almeida

Valle

2007

Braz. J. Plant Physiol.

232

137

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Cacao, one of the world's most important perennial crops, is almost exclusively explored for chocolate manufacturing. Most cacao varieties belong to three groups: Criollo, Forastero and Trinitario that vary according to morphology, genetic and geographical origins. It is cropped under the shade of forest trees or as a monocrop without shade. Seedlings initially show an orthotropic growth with leaf emission relatively independent of climate. The maturity phase begins with the emission of plagiotropic branches that form the tree crown. At this stage environmental factors exert a large influence on plant development. Growth and development of cacao are highly dependent on temperature, which mainly affects vegetative growth, flowering and fruit development. Soil flooding decreases leaf area, stomatal conductance and photosynthetic rates in addition to inducing formation of lenticels and adventitious roots. For most genotypes drought resistance is associated with osmotic adjustment. Cacao produces caulescent flowers, which begin dehiscing in late afternoon and are completely open at the beginning of the following morning releasing pollen to a receptive stigma. Non pollinated flowers abscise 24-36 h after anthesis. The percentage of flowers setting pods is in the range 0.5 -5%. The most important parameters determinants of yield are related to: (i) light interception, photosynthesis and capacity of photoassimilate distribution, (ii) maintenance respiration and (iii) pod morphology and seed fermentation, events that can be modified by abiotic factors. Cacao is a shade tolerant species, in which appropriate shading leads to relatively high photosynthetic rates, growth and seed yield. However, heavy shade reduces seed yield and increases incidence of diseases; in fact, cacao yields and light interception are tightly related when nutrient availability is not limiting. High production of non-shaded cacao requires high inputs in protection and nutrition of the crop. Annual radiation and rainfall during the dry season explains 70% of the variations in annual seed yields. Key words: root growth, flowering, pod set, flushing, mineral nutrition Ecofisiologia do cacaueiro: O cacau, um dos mais importantes cultivos perenes no mundo, é quase exclusivamente explorado para a fabricação de chocolate. A maioria das variedades de cacau pertence a três grupos: Criollo, Forasteiro e Trinitário, que variam de acordo com a morfologia, genética e origem geográfica. É cultivado sob sombra de árvores de floresta ou como monocultivo sem sombra. As plântulas inicialmente mostram um crescimento ortotrópico com emissão de folhas relativamente independente do clima. A fase de maturidade inicia-se com a emissão de ramos plagiotrópicos que formam a copa. Nesse estádio, fatores ambientes exercem grande influência no desenvolvimento da planta. O crescimento e o desenvolvimento do cacaueiro são dependentes da temperatura, que afeta principalmente o crescimento vegetativo, florescimento e desenvolvimento do fruto. O alagamento do solo diminui a área fol...

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“…Plants generally have specific light needs, predominantly in the red and blue wavelengths (Messinger et al 2006). Under unfavorable light intensities in the vegetation canopy, plants are impelled to adapt because the balance in the red and far-red wavelengths is affected by shading, thereby influencing photosynthetic efficiency (Da Matta et al 2001).…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, plants occasionally do not show these variations or may even display distinct physiological behaviors based on light intensity (Da Matta et al 2001, Lima Jr. et al 2006. The phenotypic plasticity of a species and its interactions with abiotic factors in the environment could be associated with its response to light.…”

Section: Introductionmentioning

confidence: 99%

Phenotypic plasticity of Neonotonia wightii and Pueraria phaseoloidesgrown under different light intensities

Santos

Cruz

Santos

et al. 2015

An. Acad. Bras. Ciênc.

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Plants have the ability to undergo morphophysiological changes based on availability of light. The present study evaluated biomass accumulation, leaf morphoanatomy and physiology of Neonotonia wightii and Pueraria phaseoloides grown in full sunlight, as well as in 30% and 50% shade. Two assays were performed, one for each species, using a randomized block design with 10 replicates. A higher accumulation of fresh mass in the shoot of the plants was observed for both species under cultivation in 50% shade, while no differences were detected between the full sunlight and 30% shade. N. wightii and P. phaseoloides showed increase in area and reduction in thickness leaf when cultivated in 50% shade. There were no changes in photosynthetic rate, stomatal conductance, water use efficiency and evapotranspiration of P. phaseoloides plants because growth environment. However, the shade treatments caused alterations in physiological parameters of N. wightii. In both species, structural changes in the mesophyll occurred depending on the availability of light; however, the amount of leaf blade tissue remained unaltered. Despite the influence of light intensity variation on the morphophysiological plasticity of N. wightii and P. phaseoloides, no effects on biomass accumulation were observed in response to light.

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Actual and potential photosynthetic rates of tropical crop species

Cited by 44 publications

References 15 publications

Photosynthetic response to low and high light of cacao growing without shade in an area of low evaporative demand

Photosynthetic response to low and high light of cacao growing without shade in an area of low evaporative demand

Ecophysiology of the cacao tree

Phenotypic plasticity of Neonotonia wightii and Pueraria phaseoloidesgrown under different light intensities

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