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 reportedMaterialGeneCompoundOrgan / stageInteractorInteractor roleSecond interactorSecond interactor roleSettingDirectionValue
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.”
Title
L. De La Mata; P. Cabello; P. De La Haba; et al. Photosynthetica 2013. doi:10.1007/s11099-013-0001-x
Other claims from this paper (19)
- Intervention effect 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.
- Mechanism 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.
- Intervention effect Chlorophyll a and b contents in high-irradiance sunflower plants were lower than in low-irradiance plants in young leaves.
- Intervention effect Carotenoid content was significantly higher in high-irradiance sunflower plants.
- Intervention effect Starch content decreased sharply in high-irradiance plants but only slightly in low-irradiance plants as leaves aged.
- Association Glucose concentration increased with leaf age in both treatments.
- Intervention effect Glucose contents were higher in high-irradiance plants than in low-irradiance plants, significantly so mainly at the beginning of leaf senescence.
- Intervention effect Starch contents were higher in high-irradiance plants than in low-irradiance plants throughout the leaf development period.
- Association Nitrate reductase (NR) activity decreased with leaf ageing in both treatments.
- Association The NR activation state was higher during early leaf development.
- Association The NR activation state decreased more markedly in senescent leaves of plants grown under high irradiance.
- Association GS activity decreased during sunflower leaf ageing under both light conditions.
- Intervention effect GS activities were higher in high-irradiance plants than in low-irradiance plants.
- Observation Aminating and deaminating activities of glutamate dehydrogenase peaked at 50 days in senescent leaves.
- Association GDH deaminating activity increased 5-fold during leaf development in high-irradiance plants.
- Association GDH deaminating activity increased only 2-fold in low-irradiance plants.
- Intervention effect High irradiance increased H2O2 accumulation in sunflower leaves compared with low irradiance.
- Intervention effect High irradiance decreased the antioxidant enzymes catalase and ascorbate peroxidase compared with low irradiance.
- Mechanism Systemic signals triggered by high PFD probably caused early senescence and diminished oxidative protection in primary leaves.