Gas exchange, nitrate assimilation and dry-matter accumulation of<i>Theobroma cacao</i>seedlings submitted to different irradiances and nitrogen levels

Costa, Luis Claudio; Almeida, Francisco de Assis Cardoso; Valle, R. R.

doi:10.1080/14620316.2001.11511355

Cited by 7 publications

(7 citation statements)

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“…Pois, baixa disponibilidade desse nutriente para as plantas pode ocasionar diminuição do número e do tamanho dos componentes fotossintéticos, ao passo que um suprimento maior de n pode promover uma redução na abertura dos estômatos, devido ao efeito negativo de doses elevadas de n sobre a condutância do mesofilo (CRUZ et al, 2005). O mesmo fato foi observado também em plantas jovens de Theobroma cacao, onde os efeitos de diferentes níveis de sombreamento e doses de n proporcionaram acréscimo de A até uma determinada dose de n, e decréscimo em doses de n mais elevadas (CoSTA et al, 2001).…”

Section: Trocas Gasosas Foliaresunclassified

Características morfofisiológicas de plantas clonais de Passiflora alata crescidas em diferentes doses de nitrogênio e níveis de sombreamento

Freitas¹,

Almeida²,

Lago³

et al. 2012

Rev. Bras. Frutic.

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Plantas clonais de Passiflora alata foram submetidas a quatro níveis de sombreamento (0; 25; 50 e 75%) aos 75 dias após o estaqueamento (DAE). Dez dias após, aplicou-se nitrogênio (N) nas dosagens de 0; 25;50; 100 e 200 mg N kg-1 de solo. Verificou-se, aos 175 DAE, interação significativa (p<0,05) entre níveis de sombreamento (NS) e doses de N, para todos os parâmetros fotossintéticos avaliados. Observou-se um aumento na taxa fotossintética líquida com a elevação de NS e de N até a dose de 146 mg N kg-1. A taxa transpiratória apresentou efeito quadrático tanto para NS quanto para N, tendendo a aumentar com o incremento de NS e N até 50% de sombreamento e 137 mg N kg-1, respectivamente. A espessura dos tecidos do mesofilo foliar foi reduzida com a intensificação de NS. Os teores de clorofila a, b e total aumentaram com a elevação de NS e N. Todos os parâmetros de crescimento analisados não apresentaram diferenças significativas (p<0,05) para a interação NSxN. O maior acúmulo de biomassa seca total foi obtido em 69% de sombreamento e na dose de 113 mg N kg-1, ocorrendo um declínio nos NS nas e doses de N subsequentes. Em suma, os resultados demonstraram que o sombreamento moderado (50%), associado a um suprimento moderado de N, promoveu maior eficiência fotossintética e, consequentemente, incremento na biomassa seca, na planta toda.

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Section: Trocas Gasosas Foliaresunclassified

Características morfofisiológicas de plantas clonais de Passiflora alata crescidas em diferentes doses de nitrogênio e níveis de sombreamento

Freitas¹,

Almeida²,

Lago³

et al. 2012

Rev. Bras. Frutic.

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“…Light saturated photosynthetic rates in cacao have been recorded in the region of 2 -8 µmol(CO 2 ) m -2 s -1 (e.g. Hutcheon 1977, Balasimha et al 1991, Costa et al 2001), compared with values in the region of 10 µmol (CO 2 ) m 2 s -1 for soybean (Huang et al 2006) and 20 -30 µmol(CO 2 ) m -2 s -1 for wheat (e.g. Yang et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Genotypic variation in photosynthesis in cacao is correlated with stomatal conductance and leaf nitrogen

Daymond¹,

Tricker²,

Hadley³

2011

Biol. plant.

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Traits such as transpiration efficiency (TE) that are influenced by plant water use can be used to characterise the adaptability of crops to specific growth environments. TE is defined as the amount of biomass produced per unit of water used, and can ensure continued crop production in drought-prone regions. Where TE is associated with reduced use of soil water during the vegetative growth phase, water availability during grain filling may be greater, which can delay the onset of drought stress and increase grain yield under water-limited conditions. This may become even more pertinent with predicted increases in severity and frequency of droughts with climate change. The aims of this study were to firstly dissect TE into its leaf-level physiological components to better understand the effects of genetic variation in these components on TE in sorghum. Secondly, to examine whether TE responses observed under well-watered conditions were preserved under drought, and whether transpiration response was an adaptive response to drought. Twenty-seven genotypes were screened for TE under well-watered conditions using a fully automated lysimetry platform to obtain accurate plant water use data. To determine whether variation in TE among these genotypes was associated with differences in maximum photosynthesis (Amax) or leaf conductance (g) we measured the net carbon assimilation rate of the second last fully expanded leaf at high light intensity, using an infrared gas analyser, and leaf water flux was measured using a porometer, as a proxy for conductance. Genotypic variation in TE among the sorghum germplasm used was mainly associated with differences in the response of transpiration rates to vapour pressure deficit (VPD). Genotypes with low transpiration rates per unit green leaf area (T/GLA) tended to have high TE. Variation in Amax explained some of the differences in TE that could not be explained by T/GLA and may have been a result of mechanisms associated with differences in biochemical pathways that affect the efficiency of conversion of CO2 into photosynthate. While drought tended to increase TE, genotypic variation in TE was largely conserved. However, the response of transpiration rates to drought stress differed across genotypes, with some genotypes showing reduced T/GLA under drought when VPD was high, whereas others did not. These contrasting responses were associated with differences in stomatal responses to drought stress, such that some genotypes were better able to conserve water under drought stress than others. This adaptive response was not related to TE per se and may have important implications for adaptation to drought stress. Hence, the phenotyping of sorghum lines using the associated physiological traits underpinning TE differences is beneficial in identifying traits that may support growth in certain environments and can optimise grain yield production under water-limited conditions. III

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“…The differences among the means were determined with Tukey's test at 5% probability. The "agricolae" package (De Mendiburu, 2013) included in the R project statistical environment software was used (R Core Team, 2017).…”

Section: Discussionmentioning

confidence: 99%

“…The VPD is considered one of the main factors in stomatal opening and closing (Dos Santos et al, 2017). An increase in the VPD was observed after 10:00 hours, where a direct relationship for all distances (4 m, 7 m, 10 m, 13 m) was found with A, g s , and E. The maximum VPD (0.645 kPa) was recorded at 11:30 hours.…”

Section: Diurnal Gas Exchangementioning

confidence: 90%

“…The shade tree is a significant factor to consider in the design and planting of agroforestry systems with cocoa (Galyuon et al, 1996). Cocoa is a crop with shade plants characteristics and that it requires this condition for better production because the cocoa plant has a low light saturation, with 95% of the maximum photosynthesis between 200 and 600 μmol CO 2 m -2 s -1 (Almeida et al, 2014).…”

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confidence: 99%

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Gas exchange efficiency in Cocoa – Spanish elm agroforestry system in the northwest Antioquia, Colombia

Gómez-Yarce

Mompotes-Largo

López-Castro

et al. 2020

Rev. Fac. Nac. Agron. Medellín

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The cultivation of cocoa (Theobroma cacao L.) under agroforestry systems, generates beneficial environmental conditions for cocoa crop physiology. An experiment was conducted to evaluate the effect of shade trees (Spanish elm trees - Cordia alliodora (Ruiz & Pavon) Oken) planted along with cocoa (clone CCN51) under an agroforestry system on cocoa’s gas exchange parameters regarding the reduction of the light intensity over the cocoa-leaf canopy. The experiment was developed in the Centro de Investigación el Nus - Agrosavia, located in the municipality of San Roque, Antioquia. The experimental design used was a randomized complete block design for the cocoa planting distances from the first row of Spanish elm trees interfacing with the cocoa plantation (4 m, 7 m, 10 m, 13 m). The statistical analysis was performed by estimating the area under the curve (AUC) of each variable, using the trapezoid equation of the statistical environment SAS® 9.4, an analysis of variances was performed to determine if there were statistical differences between treatments, and Tukey’s test at 5% probability was used to estimated statistical differences between means. There were significant differences in the treatments regarding the net photosynthetic rate (A), stomatal conductance (gs), and transpiration rate (E). The highest values of gas exchange parameters were found in the plants located 13 m from elm trees, while the lowest values were presented at 4 m. Plants at 7 m and 10 m always showed intermediate values for all gas exchange parameters. In the same sense, plants at 13 m had a higher radiation use efficiency (RUE) compared to plants at 4 m. The arboreal component modified the environmental conditions on cocoa trees regarding its distribution, generating a differential response to the physiological behavior of cocoa plants.

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Gas exchange, nitrate assimilation and dry-matter accumulation ofTheobroma cacaoseedlings submitted to different irradiances and nitrogen levels

Cited by 7 publications

References 0 publications

Características morfofisiológicas de plantas clonais de Passiflora alata crescidas em diferentes doses de nitrogênio e níveis de sombreamento

Características morfofisiológicas de plantas clonais de Passiflora alata crescidas em diferentes doses de nitrogênio e níveis de sombreamento

Genotypic variation in photosynthesis in cacao is correlated with stomatal conductance and leaf nitrogen

Gas exchange efficiency in Cocoa – Spanish elm agroforestry system in the northwest Antioquia, Colombia

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