The Defensive Role of Endogenous H2S in Brassica rapa against Mercury-Selenium Combined Stress

Abstract

Plants are always exposed to the environment, polluted by multiple trace elements. Hydrogen sulfide (H2S), an endogenous gaseous transmitter in plant cells, can help plant combat single elements with excess concentration. Until now, little has been known about the regulatory role of H2S in response to combined stress of multiple elements. Here we found that combined exposure of mercury (Hg) and selenium (Se) triggered endogenous H2S signal in the roots of Brasscia rapa. However, neither Hg nor Se alone worked on it. In roots upon Hg + Se exposure, the defensive role of endogenous H2S was associated to the decrease in reactive oxygen species (ROS) level, followed by alleviating cell death and recovering root growth. Such findings extend our knowledge of plant H2S in response to multiple stress conditions.

Mercury Content and Amelioration of Its Toxicity by Nitric Oxide in Lichens

“…The microscopic photos presented herein show strong ROS induction in response to Hg (see −Hg/0 SNP versus +Hg/0 SNP) using the reagent CM-H 2 DCFDA; a mycobiont is also visible (empty black areas are algal colonies, see Figure 2 ). The same ROS stimulation has been observed in the green alga exposed to 100 µM Hg, but not Pb [ 14 ], or in plant roots exposed to Hg [ 30 ], providing evidence that Hg is more toxic than many other common metallic contaminants. It is also known that oxidative stress markers differ in lichens treated by metals in relation to morphology and even depleted H 2 O 2 content was observed after spray application of Cd [ 31 ], while immersion in Cd-enriched solutions led to enhanced ROS or H 2 O 2 formation detected by fluorescence microscopy and standard spectrophotometry [ 18 ].…”

A near-infrared fluorescent probe for detection of H2S and its application in monitoring meat freshness and plant growth under aluminium-induced stress

“…It can be clearly observed that wheat seeds are relatively insensitive to 5 mM aluminium ions and their lengths and germination percentage are almost the same with those germinated in pure water; this is probably because the low-degree stress induced by the low level of aluminium ions (5 mM) can be offset by the H 2 S produced upon the stimulation of abiotic stress. Upon exposure to 10 mM aluminium ions, the intensity of fluorescence signals enhance; this is probably because the relatively high abiotic stress inhibits the growth, and in the meantime, it also stimulates the overproduction of H 2 S to fight against the stress, 29 hence the length of the seedlings shortens slightly and around 60% of germination percentage can still be observed. However, As the concentration of aluminium ions continues to increase to 25 mM, the intensity of fluorescence decreases obviously, which may be attributed to the serious stress leading to the decline of l -cysteine desulfhydrase activity 28,30 and consequently H 2 S is underproduced in vivo in the plants that can barely fight against the stress, therefore both the length of the seedlings and the germination percentage decline obviously.…”

Physiological, Morphological, and Biochemical Responses of Soybean [Glycine max (L.) Merr.] to Loquat (Eriobotrya japonica Lindl.) Leaf Extract Application on Pb-Contaminated Soil

“…Heavy metals in the soil suppress plant growth by inhibiting the uptake and movement of essential nutrients [6,7]. Intracellular accumulation of non-essential heavy metals such as Pb, cadmium (Cd), mercury (Hg), and silver (Ag) leads to the production of reactive oxygen species (ROS) [7][8][9][10].…”