Abstract
Photosynthesis of plantlets in tissue culture containers is not considered important, compared to photosynthesis of ex vitro plants, due to the exogenous source of carbohydrates present in tissue culture media. However, CO2 starvation can generate a burst of reactive oxygen species (ROS). We examined this phenomenon in tissue culture, since CO2 levels may become very low during the light period. The research was carried out with lily scales, regenerating adventitious bulblets, and with Arabidopsis seedlings. CO2 starvation was achieved by placing a small vial of concentrated KOH solution in the culture container. CO2 removal reduced the growth of regenerated lily bulblets by 33% or 23%, with or without sucrose in the medium, respectively. In Arabidopsis seedlings, CO2 removal decreased growth by 50% or 78% in the presence or absence of sucrose in the medium, respectively. Therefore, the addition of sucrose as a replacement for photosynthesis resulted in only partial recovery of growth. Staining with nitroblue tetrazolium (NBT) showed little to no ROS in ex vitro growing seedlings, while abundant ROS were detected in seedlings grown under in vitro CO2 starvation. Seedlings grown under normal tissue culture conditions (no CO2 withdrawal) showed low levels of ROS. In lily tissue culture, CO2 starvation decreased the maximum quantum efficiency of photosystem II (Fv/Fm) from 0.69 to 0.60, and in Arabidopsis from 0.76 to 0.62. Fv/Fm of ex vitro lily and Arabidopsis seedlings was 0.77 and 0.79, respectively. This is indicative of a disturbance in photosynthesis functionality and the occurrence of in vitro stress under reduced CO2 concentrations. We conclude that poor growth, in the absence of CO2, was partly due to strongly reduced photosynthesis, while the detrimental effects were most likely due to a burst of ROS.
Highlights
The CO2 concentration in an air-tight vessel with green plantlets is often lower than 100 μL L−1 which is much lower than the normal atmospheric CO2 concentration of
We aimed to investigate growth, photosynthetic performance, and the occurrence of oxidative stress in tissue cultures of Arabidopsis seedlings and lily bulblets, regenerating from scale explants under in vitro CO2 starvation
In different addi- kinds of Lilybulblets scale fragments cultured vitroor onmay nutrient display tion, roots, which growth
Summary
CO2 starvation can generate a burst of reactive oxygen species (ROS) We examined this phenomenon in tissue culture, since CO2 levels may become very low during the light period. Fv /Fm of ex vitro lily and Arabidopsis seedlings was 0.77 and 0.79, respectively This is indicative of a disturbance in photosynthesis functionality and the occurrence of in vitro stress under reduced CO2 concentrations. Apart from organic nutrition (sucrose), high external levels of plant growth regulators, and low light intensity, the tissue culture environment is characterized by a very unusual atmosphere: extremely high relative humidity (RH, 98–99.5%), high levels of organic gases, such as ethylene, and fluctuating high and low levels of CO2 and O2 [2,3]. Even in loosely capped vessels, or vessels capped with gas permeable film, the concentration is often lower than 200 μL L−1 [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
