Effect of environmental factors, growth traits, and chlorophyll a fluorescence OJIP transients on lutein content of spinach (Spinacia oleracea) for frozen processing

Lutein is an antioxidant known to promote good health, and it is found in high concentrations in spinach leaves.
Spinach is grown specifically for frozen processing in certain regions of Japan.
However, there is a limited understanding of variation factors that affect the lutein content of spinach for frozen processing.
Therefore, to gain a better understanding of these factors, we analyzed the relationship between the lutein content of spinach, environmental conditions, growth traits (flower bud differentiation, leaf numbers, plant height and weight, SPAD value, and sugar content), and chlorophyll a fluorescence OJIP transients to identify the factors that influence the lutein content.
During the cultivation period (October 13, 2020 to April 1, 2021), lutein content, growth traits, and OJIP parameters were measured every month until flowering.
Air temperature, solar radiation, and photoperiod increased from February until the end of the measurement period.
Lutein content was approximately 6.6 mg 100 g^‑1 from November to January, but it decreased significantly to 3.5 mg 100 g^‑1 in February and March.
Although the lutein content did not correlate with all of the growth traits, the period during which the lutein content decreased was coincident with the period from the flower bud differentiation of an apical meristem to bolting.
Furthermore, the maximum fluorescence intensity in the OJIP was the highest in February, and the energy dissipation flux of the OJIP parameters was the highest in February.
Therefore, the development of flower buds and the high energy dissipation in the photosynthetic apparatus with increased solar radiation may decrease in lutein content in February and March.
In conclusion, we found that the development of flower buds may contribute to the decrease in lutein content and that the OJIP parameter may serve as an indicator of variation in the lutein content of spinach for frozen processing.

IV Asian Horticultural Congress – AHC2023

T. Nakamura, K. Zushi

energy dissipation, flower bud differentiation, OJIP parameters

https://doi.org/10.17660/ActaHortic.2024.1404.114