Recovery period of long-term waterlogging exacerbates damage to photochemical phase of photosynthesis in bush beans (Phaseolus vulgaris L.).

Abstract

Beans are considered one of the basic products of the farmer economy and food security. In some regions of the tropics, the presence of climatic phenomena involves the increase in the frequency and intensity of rainfall and causes different waterlogging periods. The objective of this work was to determine the effect of waterlogging duration and recovery on the growth and photosynthesis of bean plants. The experiment was carried out in the greenhouses, using a completely randomized design with four replicates per treatment. Bush bean plants that were subjected when they had 3-4 true leaves, to two periods of waterlogging, short-term (STW) and long-term (LTW), 7 and 14 days, respectively and 7 days of recovery period in both treatments, and one control in drainage condition. The STW caused a significant decrease in photosynthesis (Pn) (82%), stomatal conductance (gs) (83%) and an increase in the content of malondialdehyde (MDA) and electrolyte leakage (EL) compared to control plants. In STW-RP, Pn, WUE, Ci/gs ratio and photochemical quenching (qP) increased. Otherwise, the LWT reduced Pn (94%) and gs (93%) compared to control plants. At the LTW-RP there was a reduction in the maximum photochemical efficiency of PSII (Fv/Fm), the content of chlorophyll and carotenoids and an increase in non-photochemical quenching (NPQ). Proline increase in LTW-RP was not enough to avoid damage to the PSII. The STW caused moderate stress on the photosynthesis of bean plants although plants can recover their photosynthetic activity in a low proportion. The LTW increases the damage of the photosynthetic apparatus, and its effect is exacerbated in the subsequent LTW-RP.