Characterization of natural variation in steady- and non-steady-state photosynthesis and its underlying mechanisms to improve productivity in rice (Oryza sativa)

Rice is a staple crop that is critical to food security, especially throughout Asia. Despite tremendous yield increases during the Green Revolution, yields have begun to stagnate in recent decades. Improving the photosynthetic performance of rice presents an opportunity to both increase yields and resource-use efficiencies. Historically, most of our understanding of photosynthesis has come through measurements made at a steady-state. However, these measurements fail to account for the constantly fluctuating light environment that is more commonly seen in agricultural field settings where steady-state conditions seldom occur. Steady-state and non-steady-state photosynthesis were characterized and compared with the aim of understanding underlying mechanisms, limitations, and potential for improvement of photosynthesis in the future. Significant variation was found for photosynthetic traits both in steady- and non-steady-state light conditions within cultivated rice (Oryza sativa) accessions and two wild rice species. In most cases, more natural variation was found in non-steady-state conditions, suggesting that variation may have been overlooked through the focus on steady-state measurements. Little significant correlation was found between the performance of photosynthetic parameters measured in steady- and non-steady-state conditions, suggesting that photosynthesis may be regulated by different factors and sometimes competing factors in different light environments. Rice plants were found to be predominately limited by biochemistry during photosynthetic induction, as opposed to stomatal limitation. Evidence was found that selection for yield in breeding may have inadvertently selected for the improvement of some photosynthetic traits. However, new opportunities were also identified, particularly with regard to non-steady-state traits. Finally, the potential to improve intrinsic water-use efficiency and some photosynthetic traits at elevated [CO2] by emerging high-throughput technologies was identified, providing an opportunity for more sustainable and productive future rice.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Crop Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2020

Author dc:creator

• Acevedo-Siaca, Liana G.

Contributors dc:contributor

• Long, Stephen P
• Ort, Donald R
• Ainsworth, Elizabeth
• Studer, Anthony

• photosynthesis
• rice
• photosynthetic induction
• Rubisco
• Rubisco activase
• water-use efficiency
• food security
• global change

Statement dc:rights

• Copyright 2020 Liana Acevedo-Siaca

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/108560

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/108560