Abstract
Different parameters that vary during leaf development may be affected by light intensity. To study the influence of different light intensities on primary leaf senescence, sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1. Plants grown under HI exhibited greater specific leaf mass referred to dry mass, leaf area and soluble protein at the beginning of the leaf development. This might have resulted from the increased CO2 fixation rate observed in HI plants, during early development of primary leaves. Chlorophyll a and b contents in HI plants were lower than in LI plants in young leaves. By contrast, the carotenoid content was significantly higher in HI plants. Glucose concentration increased with the leaf age in both treatments (HI and LI), while the starch content decreased sharply in HI plants, but only slightly in LI plants. Glucose contents were higher in HI plants than in LI plants; the differences were statistically significant (p<0.05) mainly at the beginning of the leaf senescence. On the other hand, starch contents were higher in HI plants than in LI plants, throughout the whole leaf development period. Nitrate reductase (NR) activity decreased with leaf ageing in both treatments. However, the NR activation state was higher during early leaf development and decreased more markedly in senescent leaves in plants grown under HI. GS activity also decreased during sunflower leaf ageing under both PFD conditions, but HI plants showed higher GS activities than LI plants. Aminating and deaminating activities of glutamate dehydrogenase (GDH) peaked at 50 days (senescent leaves). GDH deaminating activity increased 5-fold during the leaf development in HI plants, but only 2-fold in LI plants. The plants grown under HI exhibited considerable oxidative stress in vivo during the leaf senescence, as revealed by the substantial H2O2 accumulation and the sharply decrease in the antioxidant enzymes, catalase and ascorbate peroxidase, in comparison with LI plants. Probably, systemic signals triggered by a high PFD caused early senescence and diminished oxidative protection in primary leaves of sunflower plants as a result.
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Claims 20
Claim · model-written summary
Under high irradiance, sunflower plants had greater specific leaf mass referred to dry mass, leaf area and soluble protein at the beginning of leaf development than under low irradiance.
- Taxon
- sunflower (Helianthus annuus L.)
Helianthus annuuse0 - Organ / stage
- beginning of the leaf developmente1
- Treatment
- high irradiance (HI)e0
- Outcome
- specific leaf mass referred to dry mass, leaf area and soluble proteine1
- Direction
- greatere1
- Comparator
- low irradiance (LI)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e1“Plants grown under HI exhibited greater specific leaf mass referred to dry mass, leaf area and soluble protein at the beginning of the leaf development. This might have resulted from the increased CO2 fixation rate observed in HI plants, during early development of primary leaves.”
Claim · model-written summary
The greater leaf mass, leaf area and soluble protein under high irradiance may have resulted from an increased CO2 fixation rate in early leaf development.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Outcome
- specific leaf mass referred to dry mass, leaf area and soluble proteine1
- Qualifier
- increased CO2 fixation ratee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e1“Plants grown under HI exhibited greater specific leaf mass referred to dry mass, leaf area and soluble protein at the beginning of the leaf development. This might have resulted from the increased CO2 fixation rate observed in HI plants, during early development of primary leaves.”
Claim · model-written summary
Chlorophyll a and b contents in high-irradiance sunflower plants were lower than in low-irradiance plants in young leaves.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Organ / stage
- young leavese2
- Treatment
- HI plantse2
- Outcome
- Chlorophyll a and b contentse2
- Direction
- lowere2
- Comparator
- LI plantse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e2“Chlorophyll a and b contents in HI plants were lower than in LI plants in young leaves. By contrast, the carotenoid content was significantly higher in HI plants.”
Claim · model-written summary
Carotenoid content was significantly higher in high-irradiance sunflower plants.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Treatment
- HI plantse2
- Outcome
- carotenoid contente2
- Direction
- highere2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e2“Chlorophyll a and b contents in HI plants were lower than in LI plants in young leaves. By contrast, the carotenoid content was significantly higher in HI plants.”
Claim · model-written summary
Starch content decreased sharply in high-irradiance plants but only slightly in low-irradiance plants as leaves aged.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Treatment
- HI plantse3
- Outcome
- starch contente3
- Direction
- decreasede3
- Comparator
- LI plantse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e3“Glucose concentration increased with the leaf age in both treatments (HI and LI), while the starch content decreased sharply in HI plants, but only slightly in LI plants.”
Claim · model-written summary
Glucose concentration increased with leaf age in both treatments.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Organ / stage
- leaf agee3
- Treatment
- both treatments (HI and LI)e3
- Outcome
- Glucose concentratione3
- Direction
- increasede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e3“Glucose concentration increased with the leaf age in both treatments (HI and LI), while the starch content decreased sharply in HI plants, but only slightly in LI plants.”
Claim · model-written summary
Glucose contents were higher in high-irradiance plants than in low-irradiance plants, significantly so mainly at the beginning of leaf senescence.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Treatment
- HI plantse4
- Outcome
- Glucose contentse4
- Direction
- highere4
- Qualifier
- mainly at the beginning of the leaf senescencee4
- Comparator
- LI plantse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e4“Glucose contents were higher in HI plants than in LI plants; the differences were statistically significant (p<0.05) mainly at the beginning of the leaf senescence. On the other hand, starch contents were higher in HI plants than in LI plants, throughout the whole leaf development period.”
Claim · model-written summary
Starch contents were higher in high-irradiance plants than in low-irradiance plants throughout the leaf development period.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Treatment
- HI plantse4
- Outcome
- starch contentse4
- Direction
- highere4
- Qualifier
- throughout the whole leaf development periode4
- Comparator
- LI plantse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e4“Glucose contents were higher in HI plants than in LI plants; the differences were statistically significant (p<0.05) mainly at the beginning of the leaf senescence. On the other hand, starch contents were higher in HI plants than in LI plants, throughout the whole leaf development period.”
Claim · model-written summary
Nitrate reductase (NR) activity decreased with leaf ageing in both treatments.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Gene
- Nitrate reductase (NR)e5
- Outcome
- Nitrate reductase (NR) activitye5
- Direction
- decreasede5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e5“Nitrate reductase (NR) activity decreased with leaf ageing in both treatments. However, the NR activation state was higher during early leaf development and decreased more markedly in senescent leaves in plants grown under HI. GS activity also decreased during sunflower leaf ageing under both PFD conditions, but HI plants showed higher GS activities than LI plants.”
Claim · model-written summary
The NR activation state was higher during early leaf development.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Gene
- NRe5
- Outcome
- NR activation statee5
- Direction
- highere5
- Qualifier
- during early leaf developmente5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e5“Nitrate reductase (NR) activity decreased with leaf ageing in both treatments. However, the NR activation state was higher during early leaf development and decreased more markedly in senescent leaves in plants grown under HI. GS activity also decreased during sunflower leaf ageing under both PFD conditions, but HI plants showed higher GS activities than LI plants.”
Claim · model-written summary
The NR activation state decreased more markedly in senescent leaves of plants grown under high irradiance.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Organ / stage
- senescent leavese5
- Treatment
- plants grown under HIe5
- Gene
- NRe5
- Outcome
- NR activation statee5
- Direction
- decreased more markedlye5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e5“Nitrate reductase (NR) activity decreased with leaf ageing in both treatments. However, the NR activation state was higher during early leaf development and decreased more markedly in senescent leaves in plants grown under HI. GS activity also decreased during sunflower leaf ageing under both PFD conditions, but HI plants showed higher GS activities than LI plants.”
Claim · model-written summary
GS activity decreased during sunflower leaf ageing under both light conditions.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Treatment
- both PFD conditionse5
- Gene
- GSe5
- Outcome
- GS activitye5
- Direction
- decreasede5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e5“Nitrate reductase (NR) activity decreased with leaf ageing in both treatments. However, the NR activation state was higher during early leaf development and decreased more markedly in senescent leaves in plants grown under HI. GS activity also decreased during sunflower leaf ageing under both PFD conditions, but HI plants showed higher GS activities than LI plants.”
Claim · model-written summary
GS activities were higher in high-irradiance plants than in low-irradiance plants.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Treatment
- HI plantse5
- Gene
- GSe5
- Outcome
- GS activitiese5
- Direction
- highere5
- Comparator
- LI plantse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e5“Nitrate reductase (NR) activity decreased with leaf ageing in both treatments. However, the NR activation state was higher during early leaf development and decreased more markedly in senescent leaves in plants grown under HI. GS activity also decreased during sunflower leaf ageing under both PFD conditions, but HI plants showed higher GS activities than LI plants.”
Claim · model-written summary
Aminating and deaminating activities of glutamate dehydrogenase peaked at 50 days in senescent leaves.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Organ / stage
- senescent leavese6
- Gene
- glutamate dehydrogenase (GDH)e6
- Outcome
- Aminating and deaminating activitiese6
- Qualifier
- peaked at 50 dayse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e6“Aminating and deaminating activities of glutamate dehydrogenase (GDH) peaked at 50 days (senescent leaves). GDH deaminating activity increased 5-fold during the leaf development in HI plants, but only 2-fold in LI plants.”
Claim · model-written summary
GDH deaminating activity increased 5-fold during leaf development in high-irradiance plants.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Organ / stage
- the leaf developmente6
- Treatment
- HI plantse6
- Gene
- GDHe6
- Outcome
- GDH deaminating activitye6
- Direction
- increasede6
- Value
- 5-folde6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e6“Aminating and deaminating activities of glutamate dehydrogenase (GDH) peaked at 50 days (senescent leaves). GDH deaminating activity increased 5-fold during the leaf development in HI plants, but only 2-fold in LI plants.”
Claim · model-written summary
GDH deaminating activity increased only 2-fold in low-irradiance plants.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Treatment
- LI plantse6
- Gene
- GDHe6
- Outcome
- GDH deaminating activitye6
- Direction
- increaseinferrede6
- Value
- 2-folde6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e6“Aminating and deaminating activities of glutamate dehydrogenase (GDH) peaked at 50 days (senescent leaves). GDH deaminating activity increased 5-fold during the leaf development in HI plants, but only 2-fold in LI plants.”
Claim · model-written summary
High irradiance caused considerable oxidative stress in vivo during leaf senescence, compared with low irradiance.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Treatment
- HIe7
- Outcome
- oxidative stress in vivoe7
- Qualifier
- during the leaf senescencee7
- Comparator
- LI plantse7
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e7“The plants grown under HI exhibited considerable oxidative stress in vivo during the leaf senescence, as revealed by the substantial H2O2 accumulation and the sharply decrease in the antioxidant enzymes, catalase and ascorbate peroxidase, in comparison with LI plants. Probably, systemic signals triggered by a high PFD caused early senescence and diminished oxidative protection in primary leaves of sunflower plants as a result.”
Claim · model-written summary
High irradiance increased H2O2 accumulation in sunflower leaves compared with low irradiance.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Treatment
- HIe7
- Outcome
- H2O2 accumulatione7
- Direction
- increaseinferrede7
- Comparator
- LI plantse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e7“The plants grown under HI exhibited considerable oxidative stress in vivo during the leaf senescence, as revealed by the substantial H2O2 accumulation and the sharply decrease in the antioxidant enzymes, catalase and ascorbate peroxidase, in comparison with LI plants. Probably, systemic signals triggered by a high PFD caused early senescence and diminished oxidative protection in primary leaves of sunflower plants as a result.”
Claim · model-written summary
High irradiance decreased the antioxidant enzymes catalase and ascorbate peroxidase compared with low irradiance.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Treatment
- HIe7
- Gene
- catalase and ascorbate peroxidasee7
- Outcome
- antioxidant enzymese7
- Direction
- decreasee7
- Comparator
- LI plantse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e7“The plants grown under HI exhibited considerable oxidative stress in vivo during the leaf senescence, as revealed by the substantial H2O2 accumulation and the sharply decrease in the antioxidant enzymes, catalase and ascorbate peroxidase, in comparison with LI plants. Probably, systemic signals triggered by a high PFD caused early senescence and diminished oxidative protection in primary leaves of sunflower plants as a result.”
Claim · model-written summary
Systemic signals triggered by high PFD probably caused early senescence and diminished oxidative protection in primary leaves.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuuse0
- Outcome
- early senescence and diminished oxidative protectione7
- Qualifier
- systemic signals triggered by a high PFDe7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1”
e7“The plants grown under HI exhibited considerable oxidative stress in vivo during the leaf senescence, as revealed by the substantial H2O2 accumulation and the sharply decrease in the antioxidant enzymes, catalase and ascorbate peroxidase, in comparison with LI plants. Probably, systemic signals triggered by a high PFD caused early senescence and diminished oxidative protection in primary leaves of sunflower plants as a result.”
The same questions in other papers
light · physiology: oxidative · Helianthus annuus (common sunflower)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- negative
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