Effects of Heavy Metal Stress on Physiology, Hydraulics, and Anatomy of Three Desert Plants in the Jinchang Mining Area, China

Abstract

The physiological mechanisms and phytoremediation effects of three kinds of native quinoa in a desert mining area were studied. We used two different types of local soils (native soil and tailing soil) to analyze the changes in the heavy metal content, leaf physiology, photosynthetic parameters, stem hydraulics, and anatomical characteristics of potted quinoa. The results show that the chlorophyll content, photosynthetic rate, stomatal conductance, and transpiration rate of Kochia scoparia were decreased, but intercellular CO2 concentration (Ci) was increased under heavy metal stress, and the net photosynthetic rate (Pn) was decreased due to non-stomatal limitation. The gas exchange of Chenopodium glaucum and Atriplex centralasiatica showed a decrease in Pn, stomatal conductance (Gs), and transpiration rate (E) due to stomatal limitation. The three species showed a similar change in heavy metal content; they all showed elevated hydraulic parameters, decreased vessel density, and significantly thickened vessel walls under heavy metal stress. Physiological indicators such as proline content and activity of superoxide dismutase (SOD) and peroxidase (POD) increased, but the content of malondialdehyde (MDA) and glutathione (GSH), as well as catalase (CAT) activity, decreased in these three plants. Therefore, it can be concluded that these three species of quinoa, possibly the most dominant 30 desert plants in the region, showed a good adaptability and accumulation capacity under the pressure of heavy metal stress, and these plants can be good candidates for tailings remediation in the Jinchang desert mining area.

Nickel toxicity to safflower seed germination and seedling morpho-anatomy

“…Although the tracheid diameter did not alter in the root, it increased 1.2 times in the stem. This is consistent with the results of Gao et al (2022), who, in their study on the effects of heavy metals on Atriplex sp. and Chenopodium glaucum L., stated that heavy metal stress reduced the density of vessels in the xylem of plant stems.…”

“…MDA is the nal product of membrane damage and is used to express it numerically. Therefore, MDA facilitates as a stress marker in plants (Gao et al 2022). The amount of MDA signi cantly increased due to Ni exposure in sa ower in our study (Fig.…”

Heavy Metal Contamination in Soil: Implications for Crop Resilience and Abiotic Stress Management

“…The coherence of cellular membranes is paramount for maintaining homeostasis and controlling the movement of substances into and out of the cell. When toxic metals/metalloids, such as Cd and Pb, accumulate in plant tissues, they can interact with membrane lipids and proteins, causing lipid peroxidation, a critical oxidative process damaging cell membranes and modifying membrane viscosity and permeability [79][80][81][82].…”

“…Toxic metals/metalloids can also bind to membrane proteins, affecting their structure and function. This can inhibit the activity of membrane-bound enzymes, disrupt ion channels and transporters, and interfere with membrane receptors, leading to impaired cellular signaling and metabolic dysregulation [79,80,83,84].…”

“…The disruption of membrane integrity by toxic metals/metalloids can have various physiological consequences, including decreased photosynthetic efficiency, altered water relations, and reduced nutrient uptake, ultimately leading to stunted plant growth and development [79][80][81][82].…”