Hormesis and paradoxical effects of pea (Pisum sativum L.) parameters upon exposure to formaldehyde in a wide range of doses

Abstract

Formaldehyde is a widespread pollutant of soil near roads including agricultural lands. Non-monotonic changes (hormesis and paradoxical effects) in chlorophyll (Ch) and carotenoid (Car) contents, the lipid peroxidation (LP) rate in plant leaves and growth parameters (GP) of plants can be caused by various pollutants. Hormesis is a biphasic dose-response phenomenon, characterised by low-dose stimulation and high-dose inhibition. The remaining types of non-monotonic responses are classified as paradoxical effects. While most authors who have studied formaldehyde and plants considered gaseous exposure to shoots, the effect of this pollutant in soil solution has been poorly examined. Thus, we studied the non-monotonic changes in Ch and Car contents, LP rate and GP in pea (Pisum sativum L.) upon exposure to formaldehyde in solution, at a wide range of sublethal concentrations from 0.063 × 10 to 0.16 g L. With formaldehyde exposure, LP and Ch contents had paradoxical effects (triphasic and multiphase changes, accordingly), while Car level did not change and GP exhibited a hormetic response. The date showed that pea parameters display diverse types of non-monotonic responses upon exposure to the same formaldehyde concentrations. High pollutant concentrations (0.08-0.16 g L) increased LP and significantly decreased GP (to 2.3-2.5 times compared to the control), while the Ch content was increased. Lower concentrations (<0.08 g L) caused a moderate deviation in all parameters from the control (not more than 62%) for hormesis and paradoxical effects.

Insight into Physiological and Biochemical Markers against Formaldehyde Stress in Spider Plant (Chlorophytum comosum L.)

“…These ndings are in alignment with the ndings of Khan et al (2023) Formaldehyde application also signi cantly escalated the chlorophyll and carotenoid content in this study. This follows the pattern of previous studies conducted on Pisum sativum and C. comosum against formaldehyde stress (Erofeeva, 2018;Paresh et al 2018;Khan et al 2023). Under paradoxical effects, the toxic impact of higher formaldehyde level is reduced, leading to increased chlorophyll content in plants (Erofeeva, 2018).…”

A general model of hormesis in biological systems and its application to pest management

“…Biological systems exhibit a variety of unexpected, sometimes paradoxical, behaviour. Examples include catastrophic shifts [1] at tipping points in ecosystems [2], phase changes in polyphenic insects [3] and hormesis in toxicology, whereby a cell or organism exhibits a biphasic response when exposed to increasing amounts of a substance or external conditions [4][5][6]. Ecological paradoxes involving interactions between two or more species include coexistence of competing species [7] and the 'paradox of the plankton' [8,9].…”

Change of Leaf Trait Asymmetry Type in Tilia cordata Mill. and Betula pendula Roth under Air Pollution

“…The high frequency of non-monotonic dose-effect relationships was revealed for various plant indices under stressful environments [37][38][39], including the effects of chemical pollutants on physiological and biochemical parameters [43,44,57], as well as on leaf FA [44,58]. In this study, we first found non-monotonic responses in development of leaf bilateral asymmetry type, that is, for leaf morphogenesis.…”

“…However, it is known that non-monotonic dose-response relations (with maximums and/or minimums) which include hormesis [37][38][39] and paradoxical effects [40,41] are frequently found for different plant species and parameters, including various pollutant exposures [42][43][44][45][46][47]. Hence, an increase in the pollution level will not always be accompanied by plant index deteriorations.…”