Growth and chlorophyll a fluorescence in Erythrina crista-galli L. plants under flooding conditions

Abstract

The present study aimed to analyse the alterations in the growth and chlorophyll content of Erythrina crista-galli plants in response to flooding and to evaluate possible photosystem II (PSII) damage through chlorophyll a fluorescence transient analysis using the JIP test. Plants cultured from seeds were grown in 0.5-L pots in a greenhouse and transferred to 5-L pots. Two treatments were employed: plants were either flooded at the root and maintained with a sheet of water above the soil or not flooded (control). Evaluations were performed at 10, 20, 30 and 40 days after the treatment was initiated. The experiment was set up in a randomised block design, and the results were subjected to analysis of variance (ANOVA). The means were compared by Tukey’s test at a 5 % significance level. The flooding of the plants induced the formation of lenticels, adventitious roots and larger intercellular spaces in the root cortex and inhibited the growth of shoots at early time points compared to control plants. However, growth resumed by the end of the experimental period. The Erythrina crista-galli plants manifested a reduction in chlorophyll content as a function of the duration of exposure to flooding. However, there were changes in the chlorophyll fluorescence parameters, indicating impairment of the structure and function of PSII, and the performance indices were the most representative parameters to describe the effects of flooding. The results showed that the Erythrina crista-galli tolerated flooding by initially investing energy into the formation of morpho-anatomical structures to maintain oxygen diffusion and ATP production. The effect of flooding on the leaves was reflected in increased energy dissipation through chlorophyll a fluorescence, likely as a mechanism to protect the photosynthetic apparatus.