Abstract
Two coffee species (Coffea arabica L. cv. Catuai Vermelho and Coffea canephora L. cv. Apoata) were grown in pots placed outdoor under three irradiance regimes, full sunlight (S), 50% of shade (50% S) and 80% of shade (80% S), and evaluated for stable carbon isotope discrimination (Δ), photosynthetic gas exchange, and growth. The rate of CO 2 assimilation in S and 50% S plants was higher in C. arabica than in C. canephora, but there was no difference between the two species in 80% S. Both species showed similar response to the irradiance regimes. CO 2 assimilation rate at 80% S was 0.49 and 0.58 of CO 2 assimilation in full sunlight, respectively, for C. arabica and C. canephora. There was no significant difference in CO 2 assimilation between S and 50% S plants for either species. Stomatal conductance in C. arabica increased with the irradiance level, but the increase was less evident than that observed for CO 2 assimilation. Consequently, the CO 2 assimilation/stomatal conductance ratio (A/g), expressing intrinsic water use efficiency, was greater in the S plants and 50% S plants than in the 80% S plants. Irradiance regimes did not affect stomatal conductance in C. canephora, which had a lower A/g ratio than C. arabica for the same irradiance regime. Leaf Δ values were lower in S plants than in 80% S plants for both species, but there was no difference between S and 50% S treatments. The decrease in Δ was associated with a greater increase in the CO 2 assimilation rate (106%) than in the stomatal conductance (54%) in C. arabica. In C. canephora the decrease in Δ was associated with an increase in CO 2 assimilation (73%), because stomatal conductance values were not influenced by the irradiance regime. Leaf tissue Δ was negatively correlated with instantaneous measurements of CO 2 assimilation (r = - 0.92; P = 0.0109) and with stomatal conductance (r = - 0.80; P = 0.0570). Full sunlight grown plants exhibited higher leaf nitrogen content than 80% S plants. The increase in leaf nitrogen content with increasing irradiance levels was strongly correlated with CO 2 assimilation rate (r = 0.99, P = 0.0007) and negatively with Δ (r = - 0.94, P = 0.0071). Additional index terms: CO 2 assimilation rate, growth, leaf N, stomatal conductance.
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Claims 20
Claim · model-written summary
In full sunlight and 50% shade, carbon assimilation was higher in C. arabica than C. canephora.
- Material
- C. arabicae0
- Outcome
- rate of CO 2 assimilatione0
- Direction
- highere0
- Qualifier
- S and 50% S plantse0
- Comparator
- C. canephorae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea species”
e0“The rate of CO 2 assimilation in S and 50% S plants was higher in C. arabica than in C. canephora”
Claim · model-written summary
At 80% shade, carbon assimilation did not differ between the two coffee species.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea species”
e0“there was no difference between the two species in 80% S.”
Claim · model-written summary
Carbon assimilation of C. arabica at 80% shade was 0.49 of its full-sunlight rate.
- Taxon
- C. arabica
Coffea arabicae0 - Treatment
- 80% Se0
- Outcome
- CO 2 assimilation ratee0
- Value
- 0.49e0
- Comparator
- full sunlighte0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CO 2 assimilation rate at 80% S was 0.49 and 0.58 of CO 2 assimilation in full sunlight, respectively, for C. arabica and C. canephora.”
Claim · model-written summary
Carbon assimilation of C. canephora at 80% shade was 0.58 of its full-sunlight rate.
- Taxon
- C. canephora
Coffea canephorae0 - Treatment
- 80% Se0
- Outcome
- CO 2 assimilation ratee0
- Value
- 0.58e0
- Comparator
- full sunlighte0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CO 2 assimilation rate at 80% S was 0.49 and 0.58 of CO 2 assimilation in full sunlight, respectively, for C. arabica and C. canephora.”
Claim · model-written summary
Assimilation did not differ significantly between full sunlight and 50% shade for either coffee species.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea species”
e0“There was no significant difference in CO 2 assimilation between S and 50% S plants for either species.”
Claim · model-written summary
Stomatal conductance increased with irradiance in C. arabica.
- Taxon
- C. arabicaCoffea arabicae0
- Treatment
- irradiance levele0
- Outcome
- Stomatal conductancee0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stomatal conductance in C. arabica increased with the irradiance level”
Claim · model-written summary
The conductance increase was less evident than the assimilation increase in C. arabica.
- Taxon
- C. arabicaCoffea arabicae1
- Outcome
- Stomatal conductancee1
- Direction
- less evidente0
- Comparator
- CO 2 assimilatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increase was less evident than that observed for CO 2 assimilation.”
e1“Stomatal conductance in C. arabica increased with the irradiance level”
Claim · model-written summary
Intrinsic water-use efficiency was greater in sunlight and 50% shade than 80% shade.
- Treatment
- S plants and 50% S plantse0
- Outcome
- intrinsic water use efficiencye0
- Direction
- greatere0
- Comparator
- 80% S plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea species”
e0“the CO 2 assimilation/stomatal conductance ratio (A/g), expressing intrinsic water use efficiency, was greater in the S plants and 50% S plants than in the 80% S plants.”
Claim · model-written summary
Irradiance did not affect stomatal conductance in C. canephora.
- Taxon
- C. canephoraCoffea canephorae0
- Treatment
- Irradiance regimese0
- Outcome
- stomatal conductancee0
- Direction
- did not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Irradiance regimes did not affect stomatal conductance in C. canephora”
Claim · model-written summary
C. canephora had a lower A/g ratio than C. arabica under the same irradiance.
- Taxon
- C. canephoraCoffea canephorae0
- Outcome
- A/g ratioe0
- Direction
- lowere0
- Comparator
- C. arabicae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“C. canephora, which had a lower A/g ratio than C. arabica for the same irradiance regime.”
Claim · model-written summary
Leaf carbon isotope discrimination was lower in sunlight than 80% shade for both species.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea species”
e0“Leaf Δ values were lower in S plants than in 80% S plants for both species”
Claim · model-written summary
Leaf carbon isotope discrimination did not differ between sunlight and 50% shade.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea species”
e0“there was no difference between S and 50% S treatments.”
Claim · model-written summary
In C. arabica, reduced Δ was associated with a 106% assimilation increase.
- Taxon
- C. arabicaCoffea arabicae0
- Outcome
- CO 2 assimilation ratee0
- Direction
- increasee0
- Value
- 106%e0
- Qualifier
- decrease in Δe0
Not reportedOrgan / stage
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decrease in Δ was associated with a greater increase in the CO 2 assimilation rate (106%) than in the stomatal conductance (54%) in C. arabica.”
Claim · model-written summary
In C. arabica, reduced Δ was associated with a 54% conductance increase.
- Taxon
- C. arabicaCoffea arabicae0
- Outcome
- stomatal conductancee0
- Direction
- increasee0
- Value
- 54%e0
- Qualifier
- decrease in Δe0
Not reportedOrgan / stage
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decrease in Δ was associated with a greater increase in the CO 2 assimilation rate (106%) than in the stomatal conductance (54%) in C. arabica.”
Claim · model-written summary
In C. canephora, reduced Δ was associated with a 73% assimilation increase.
- Taxon
- C. canephoraCoffea canephorae0
- Treatment
- irradiance regimee0
- Outcome
- CO 2 assimilatione0
- Direction
- increasee0
- Value
- 73%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In C. canephora the decrease in Δ was associated with an increase in CO 2 assimilation (73%), because stomatal conductance values were not influenced by the irradiance regime.”
Claim · model-written summary
Leaf Δ was negatively correlated with instantaneous carbon assimilation.
- Outcome
- Leaf tissue Δe0
- Direction
- negatively correlatede0
- Value
- r = - 0.92e0
- Comparator
- CO 2 assimilatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea species”
e0“Leaf tissue Δ was negatively correlated with instantaneous measurements of CO 2 assimilation (r = - 0.92; P = 0.0109)”
Claim · model-written summary
Leaf Δ was negatively correlated with stomatal conductance.
- Outcome
- Leaf tissue Δe0
- Direction
- negatively correlatede0
- Value
- r = - 0.80e0
- Comparator
- stomatal conductancee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea species”
e0“Leaf tissue Δ was negatively correlated with instantaneous measurements of CO 2 assimilation (r = - 0.92; P = 0.0109) and with stomatal conductance (r = - 0.80; P = 0.0570).”
Claim · model-written summary
Full-sunlight plants had higher leaf nitrogen than 80% shade plants.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea species”
e0“Full sunlight grown plants exhibited higher leaf nitrogen content than 80% S plants.”
Claim · model-written summary
Leaf nitrogen increased with irradiance and was strongly correlated with assimilation.
- Treatment
- increasing irradiance levelse0
- Outcome
- leaf nitrogen contente0
- Direction
- increasee0
- Value
- r = 0.99e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea species”
e0“The increase in leaf nitrogen content with increasing irradiance levels was strongly correlated with CO 2 assimilation rate (r = 0.99, P = 0.0007)”
Claim · model-written summary
Leaf nitrogen increase was negatively correlated with Δ.
- Treatment
- increasing irradiance levelse0
- Outcome
- leaf nitrogen contente0
- Direction
- negativelye0
- Value
- r = - 0.94e0
- Comparator
- Δe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea species”
e0“The increase in leaf nitrogen content with increasing irradiance levels was strongly correlated with CO 2 assimilation rate (r = 0.99, P = 0.0007) and negatively with Δ (r = - 0.94, P = 0.0071).”