Chlorophyll fluorescence is a potential indicator to measure photochemical efficiency in early to late soybean maturity groups under changing day lengths and temperatures

Authors: MATHUR, SONAL - Oak Ridge Institute For Science And Education (ORISE); SEO, BEOMSEOK - University Of Washington; JAJOO, ANJANA - Devi Ahilya Vishwavidyalaya, Indore; REDDY, KAMBHAM - Mississippi State University; Reddy, Vangimalla

Submitted to: Journal of Integrative Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2023
Publication Date: 10/23/2023
Citation: Mathur, S., Seo, B., Jajoo, A., Reddy, K.R., Reddy, V. 2023. Chlorophyll fluorescence is a potential indicator to measure photochemical efficiency in early to late soybean maturity groups under changing day lengths and temperatures. Journal of Integrative Plant Biology. 14.Article e1228464. https://doi.org/10.3389/fpls.2023.1228464.
DOI: https://doi.org/10.3389/fpls.2023.1228464

Interpretive Summary: High and low temperatures and changing daylengths (photoperiods) are significant challenges for soybean growth and development. Soybean is one of the major crops adversely impacted by temperatures and daylengths. Chlorophyll a fluorescence is a nondestructive and noninvasive technique that provides enormous information about a plant's health status in a fraction of a second. In this study, we have used chlorophyll a fluorescence technique, to indicate the health status of early to late soybean maturity groups commonly used in the USA under changing daylengths and temperatures. It is a rarely explored technique for studying photosynthetic responses (light reactions of PSII) in early to late soybean maturity groups. The shape of chlorophyll a transient curve, and some other traits made it possible to identify changes in early and late soybean maturity groups under changing temperatures and daylengths. The studied traits can be deciding criteria for developing stress tolerant and susceptible inbreed soybean lines. Chlorophyll a fluorescence could be used as a potential technique for high-throughput phenotyping.

Technical Abstract: In this study, we employed chlorophyll a fluorescence technique, to indicate plant health and status in response to changing daylengths (photoperiods) and temperatures in soybean early and late maturity groups (MG). Experiments were performed for three daylengths and five temperatures, respectively, for early and late soybean maturity groups. Chlorophyll a fluorescence study was conducted in the soybean maturity groups to indicate the changes in the light reactions of photosystem (PS) II. The behavior of each maturity group was different from another maturity group individually with the treatments. Inflection points I-P declined for changing daylengths. Active reaction centers decreased at long day length (14.5 hours) for MG III. It was observed that low temperature impacted the acceptor side of photosystem II and partially impacted electron transport towards photosystem I end electron acceptor. Results obtained from the fluorescence study emphasized that higher temperature triggered damage at the oxygen-evolving complex (OEC), resulting in decreased electron transport and photosynthesis. Further, we studied specific leaf area and above-ground mass. The above-ground parameters and other traits were consistent with the fluorescence study. Chlorophyll fluorescence can be used as a potential technique for high-throughput phenotyping methods. The traits selected in the study proved to be possible indicators to provide information on the health status of various maturity groups under changing temperatures and daylengths. These traits can also serve as deciding criteria for breeding programs to develop in-breed soybean lines for stress tolerance and sensitivity based on latitudinal variations.