Abstract
Integrative mechanisms involving photosynthetic and antioxidant protection regulated by light intensity during in vitro and ex vitro plantlets acclimatization are poorly understood. Tobacco plantlets grown under in vitro and ex vitro environments were exposed to different light regimes to evaluate the role of photosynthesis and antioxidant protection. In vitro plantlets displayed a narrow photosynthetic capacity to cope with light as revealed by low net CO2 assimilation (PN), decreased actual quantum efficiency of photosystem II (ΦPSII) associated with non-induction of non-photochemical quenching (NPQ). In contrast, acclimated ex vitro plants showed strong stimulation in PN whereas ΦPSII and NPQ remained at high levels. In vitro plantlets exposed to moderate light suffered strong oxidative stress associated with increased activities of superoxide dismutases, catalases and ascorbate peroxidases, revealing an ineffective antioxidant system. In contrast, ex vitro plants presented lower oxidative damage in parallel to unchanged enzymatic activities, indicating an efficient antioxidant steady state. The levels of reduced ascorbate (ASC) and glutathione (GSH) were also increased only in ex vitro plants in response to excess light. An integrative study based on correlation networks and principal component analyses (PCA) corroborate that the two plant groups indeed displayed contrasting acclimation processes. In conclusion, during in vitro to ex vitro transition, tobacco plantlets exposed to increasing light display physiological adjustments involving photosynthesis and improvement of the enzymatic and non-enzymatic antioxidant systems. These findings highlight the importance of integrative approaches to understand ex vitro acclimatization to environmental stimuli.
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Claims 5
Claim · model-written summary
In vitro tobacco plantlets had low net CO2 assimilation and decreased photosystem II efficiency under light.
- Taxon
- tobacco
Nicotiana tabacumt0 - Outcome
- net CO2 assimilation (PN), decreased actual quantum efficiency of photosystem II (ΦPSII)e0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In vitro plantlets displayed a narrow photosynthetic capacity to cope with light as revealed by low net CO2 assimilation (PN), decreased actual quantum efficiency of photosystem II (ΦPSII)”
t0“tobacco plantlets”
Claim · model-written summary
Ex vitro plants showed stimulated net CO2 assimilation while photosystem II efficiency and quenching remained high.
- Taxon
- tobaccoNicotiana tabacumt0
- Outcome
- PN whereas ΦPSII and NPQe0
- Direction
- strong stimulatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“acclimated ex vitro plants showed strong stimulation in PN whereas ΦPSII and NPQ remained at high levels”
t0“tobacco plantlets”
Claim · model-written summary
Moderate light caused oxidative stress and increased antioxidant enzyme activities in vitro.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- moderate lighte0
- Outcome
- oxidative stresse0
- Direction
- stronge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In vitro plantlets exposed to moderate light suffered strong oxidative stress associated with increased activities of superoxide dismutases, catalases and ascorbate peroxidases”
t0“tobacco plantlets”
Claim · model-written summary
Ex vitro plants had lower oxidative damage with unchanged enzyme activities.
- Taxon
- tobaccoNicotiana tabacumt0
- Outcome
- oxidative damagee0
- Direction
- lowere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ex vitro plants presented lower oxidative damage in parallel to unchanged enzymatic activities”
t0“tobacco plantlets”
Claim · model-written summary
Reduced ascorbate and glutathione increased only in ex vitro plants under excess light.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- excess lighte0
- Outcome
- levels of reduced ascorbate (ASC) and glutathione (GSH)e0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The levels of reduced ascorbate (ASC) and glutathione (GSH) were also increased only in ex vitro plants in response to excess light.”
t0“tobacco plantlets”
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