Zinc and selenium as modulating factors of the anatomy and physiology of Billbergia zebrina (Bromeliaceae) during in vitro culture

Abstract

Deleterious effects induced by high zinc (Zn) concentrations can be alleviated with selenium (Se) co-exposure. Therefore, we analyzed the morphophysiological changes of Billbergia zebrina in response to Zn and Se co-exposure. Plants were cultured in media containing three Zn concentrations (0, 30, and 300 μM) combined with two Se concentrations (0 and 4 μM), for a total of six treatments. At 75 d of culture, the leaf anatomy, chlorophyll (Chl) a fluorescence, and contents of photosynthetic pigments (Chl) and nutrients were analyzed. The total Chl content declined with rising Zn concentrations. Plants cultured with Se presented a decrease in the Chl a/b ratio and greater total Chl content. Positive L-and K-bands were verified under Se absence and with 30 and 300 μM Zn. Plants showed bioaccumulation capacity and tolerance to excess Zn. Se acted as a modulator to alleviate the Zn stress.

Photosynthetic apparatus performance and anatomical modulations of Alcantarea imperialis (Bromeliaceae) exposed to selenium during in vitro growth

“…An increase of V I may indicate partial inhibition on the acceptor side of PSII due to a relative change in the QB-nonreducing PSII RCs (Jiang et al 2008). It can result in a lower efficiency/probability of electron movement from PSII to the PSI acceptor side (Martins et al 2020b). Therefore, the decreased values of VI, verified in this work, corresponded to a relative improvement of electron transport to PSI, which was reflected in increased values of ψR0 and φR0.…”

“…In this study, the A. imperialis plants had φP0 values greater than 0.78, meaning there was no sign of photoinhibition at 56 d of growth, irrespective of Se treatments. Besides no changes in these parameters, the plants also had similar values of W L, VK, FK/FJ, FV/F0, and WK, together denoting no damage to the functional and structural integrity of the thylakoid membranes and in the oxygen-evolving complex (OEC) (Oukarroum et al 2009, Zhang et al 2018, Faseela et al 2020, Martins et al 2020b.…”

“…In contrast, Se excess can induce physiological disturbances or even plant death (Sotoodehnia-Korani et al 2020, Szarka et al 2020. Souza et al (2019) and Martins et al (2020b) already have reported the positive effects of Se on the physiological status of a bromeliad species (Billbergia zebrina) during in vitro culture.…”

“…Likewise, the photosynthetic performance of in vitro plants can be monitored by measurement of chlorophyll (Chl) a fluorescence (Martins et al 2018, Rosa et al 2018, Souza et al 2019. This analysis also provides an overview of the stress status of plants through investigation of PSII and PSI performance (Rosa et al 2018, Martins et al 2020b).…”

In vitro morphophysiological responses of Alternanthera tenella colla (Amaranthaceae) to stress induced by cadmium and the attenuating action of silicon

“…Various methods have been employed to minimize the effects of Cd contamination of ecosystems, ranging from the use of physical-chemical methods to the use of living organisms, such as plants, bacteria, and fungi that can extract and store high concentrations of this metal in their structure (Liu et al 2018;Roychowdhury et al 2018;Haider et al 2021). Besides this, studies have shown that the cultivation of plants with the presence of stress-mitigating elements such as selenium (Se) and silicon (Si) is promising to diminish the deleterious effects of trace elements on the plants' systems (Ding et al 2017; Martins et al 2020a;Haider et al 2021;Huang et al 2021). However, more comprehensive studies are necessary to understand better the relationship among plants, heavy metals, and stress-mitigating elements to ascertain whether this mitigation is really feasible as part of a strategy for the recovery of ecosystems.…”