Abstract
Young coffee plants ( Coffea arabica L. cv. Catuaí), originally from a shaded habitat, were separated in three groups to be grown under different levels of N fertilization: 0.3 mmol N supplements were given to the soil every 7 days (high N treatment, 2N), every 15 days (medium N treatment, 1N) and every 45 days (low N treatment, 0N). These plants were later exposed to a high sunlight irradiance (noon PPFD up to 1500 µmol m–2 s–1 ) for a period of 12 or 15 days. Among others, the values of electron trans-port capacity, maximum carboxylation activity, photosynthetic capacity ( A max) and several fluorescence parameters ( F v/ F m, F v´/ F m´, qP, &phis;e) first showed a reduction (until the 4th–7th day) in all N treatments, followed by an N-dependent recovery. The 2N plants were less affected in the first few days and, at the end of the stress period, showed a better recovery for most of the studied parameters and the highest increase in the saturating PPFD for net photosynthesis and A max . The present work shows that the ability to acclimate displayed by the mature leaves of 2N plants was accompanied by an increase in energy dis-sipation mechanisms. These include an increase in the ‘high energy’ quenching and, mostly, the presence of higher contents of some xanthophylls (zeaxanthin and lutein) and carotenes, which helped to decrease the energetic overcharge in the photosystems. Pigment changes in mature leaves suggest that N can promote specific mechanisms of acclimation others than those that might be expected from a preferential partition of the element N into photosynthetic components.
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Claims 6
Claim · model-written summary
Electron transport capacity, maximum carboxylation activity and photosynthetic capacity (Amax) first showed a reduction until the 4th-7th day in all N treatments under high sunlight.
- Taxon
- Coffea arabica
Coffea arabicat0 - Treatment
- high sunlight irradiancee0
- Outcome
- electron trans-port capacity, maximum carboxylation activity, photosynthetic capacity ( A max)e1
- Direction
- reductione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea arabica L.”
e0“exposed to a high sunlight irradiance”
e1“electron trans-port capacity, maximum carboxylation activity, photosynthetic capacity ( A max) and several fluorescence parameters ( F v/ F m, F v´/ F m´, qP, &phis;e) first showed a reduction”
Claim · model-written summary
Several chlorophyll fluorescence parameters first showed a reduction until the 4th-7th day in all N treatments under high sunlight.
- Taxon
- Coffea arabicaCoffea arabicat0
- Treatment
- high sunlight irradiancee0
- Outcome
- several fluorescence parameterse1
- Direction
- reductione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea arabica L.”
e0“exposed to a high sunlight irradiance”
e1“several fluorescence parameters ( F v/ F m, F v´/ F m´, qP, &phis;e) first showed a reduction (until the 4th–7th day) in all N treatments”
Claim · model-written summary
The high-N (2N) plants were less affected initially and showed a better recovery for most studied parameters at the end of the stress period.
- Taxon
- Coffea arabicaCoffea arabicat0
- Treatment
- 2Ne0
- Outcome
- recovery for most of the studied parameterse0
- Direction
- better recoverye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea arabica L.”
e0“The 2N plants were less affected in the first few days and, at the end of the stress period, showed a better recovery for most of the studied parameters”
Claim · model-written summary
The 2N plants showed the highest increase in the saturating PPFD for net photosynthesis and Amax.
- Taxon
- Coffea arabicaCoffea arabicat0
- Treatment
- 2Ne0
- Outcome
- saturating PPFD for net photosynthesis and A maxe1
- Direction
- highest increasee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea arabica L.”
e0“The 2N plants”
e1“the highest increase in the saturating PPFD for net photosynthesis and A max”
Claim · model-written summary
The ability of mature 2N leaves to acclimate was accompanied by an increase in energy dissipation mechanisms.
- Taxon
- Coffea arabicaCoffea arabicat0
- Treatment
- 2Ne0
- Outcome
- energy dis-sipation mechanismse0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea arabica L.”
e0“the ability to acclimate displayed by the mature leaves of 2N plants was accompanied by an increase in energy dis-sipation mechanisms”
Claim · model-written summary
Higher contents of some xanthophylls (zeaxanthin and lutein) and carotenes helped decrease the energetic overcharge in the photosystems.
- Taxon
- Coffea arabicaCoffea arabicat0
- Compound
- xanthophyllse0
- Outcome
- energetic overcharge in the photosystemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Coffea arabica L.”
e0“the presence of higher contents of some xanthophylls (zeaxanthin and lutein) and carotenes, which helped to decrease the energetic overcharge in the photosystems”
The same questions in other papers
light · physiology: photosynthesis · Coffea arabica (arabica coffee)Positive and negative results
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