The interactive effect of pH variation and cadmium stress on wheat (Triticum aestivum L.) growth, physiological and biochemical parameters

Abstract

Anthropogenic activities such as mining, manufacturing, and application of fertilizers release substantial quantities of cadmium (Cd) into the environment. In the natural environment, varying pH may play an important role in the absorption and accumulation of Cd in plants, which can cause toxicity and increase the risk to humans. We conducted a hydroponic experiment to examine the impact of pH on cadmium (Cd) solubility and bioavailability in winter wheat (Triticum aestivum L.) under controlled environmental conditions. The results showed that Cd concentration was significantly reduced in wheat with an increase in pH from 5 to 7, while it was dramatically increased at pH ranging from 7 to 9. However, in both cases, a significant reduction in physiological traits was observed. The addition of Cd (20, 50, and 200 μmol L-1) at all pH levels caused a substantial decline in wheat growth, chlorophyll and carotenoids contents, nutrient availability, while elevated cell membrane damage was observed in terms of electrolytic leakage (EL), osmoprotectants, and antioxidants activity. In our findings, the negative effects of acidic pH (5) on wheat growth and development were more pronounced in the presence of Cd toxicities. For instance, Cd concentration with 20, 50, and 200 μmol L-1 at acidic pH (5) reduced shoot dry biomass by 45%, 53%, and 79%, total chlorophyll contents by 26%, 41%, 56% while increased CAT activity in shoot by 109%, 175%, and 221%, SOD activity in shoot by 122%, 135%, and 167%, POD activity in shoot by 137%, 250%, and 265%, MDA contents in shoot by 51%, 83%, and 150%, H2O2 contents in shoot by 175%, 219%, and 292%, EL in shoot by 108%, 165%, and 230%, proline contents in shoot by 235%, 280%, and 393%, respectively as compared to neutral pH without Cd toxicities. On the other hand, neutral pH with Cd toxicities alleviated the negative effects of Cd toxicity on wheat plants by limiting Cd uptake, reduced reactive oxygen species (ROS) formation, and increased nutrient availability. In conclusion, neutral pH minimized the adverse effects of Cd stress by minimizing its uptake and accumulation in wheat plants.

Effect of Organic Amendments in Soil on Physiological and Biochemical Attributes of Vachellia nilotica and Dalbergia sissoo under Saline Stress

“…An LCA-4 ADC portable infrared gas analyzer (Analytical Development Company, Hoddesdon, England) was used to measure the gas exchange parameters. Each plant's second upper fully expanded leaf was selected to measure photosynthetic parameters such as photosynthetic rate, stomatal conductance, sub-stomatal conductance, and transpiration rate measured according to the procedures described earlier in [9,94]. To ensure unchanged photon flux density and temperature, readings were made at a similar time each day (between 10:00 a.m. and 12:00 p.m.) by clamping the central part of the leaf in the chamber of the instrument.…”

“…In the end, the absorption of supernatant was calculated at three different wavelengths, namely 450, 532 and 600, to estimate leaf MDA contents by using the following equation. The details of the determination of the biochemical parameters are given in [94,95].…”

Diminishing Heavy Metal Hazards of Contaminated Soil via Biochar Supplementation

“…Biochar has the ability to immobilize organic contaminants [53] and HMs [54] through different mechanisms, such as physical adsorption [38]; chemical adsorption with Ca 2+ , Mg 2+ , K + , Na + , and S [16,37,38]; complexation with Pb 2+ and Cu 2+ [4,37]; the formation of precipitates through phosphate compounds [4,55,56]; and precipitation as a result of pH elevation [13,57]. So far, the extent to which one or more of these different mechanics contributes to HM immobilization by different feedstock is still unknown, although many researchers have reported that it is mostly affected by soil reaction (pH) [41,58].…”

“…Several factors (feedstock particle size and type, as well as pyrolysis temperature) affect biochar characteristics and functions. The wide range of biochar properties enables it to be the most suitable material for dealing with and remediating various HM-contaminated soils [13]. The key properties of biochar are affected by pre-treatments resulting in enhancing biochar's ability to immobilize HMs [14].…”

The Land Snail, Eobania vermiculata, as a Bioindicator of the Heavy Metal Pollution in the Urban Areas of Sulaimani, Iraq

“…Due to their toxic nature, the regular release of these elements produces risk to both environment and human health through the food chain and other human exposure pathways [1][2][3]. One of the crucial sources of soil contamination are anthropogenic activities such as combustion of fossil fuels, smelting, and the use or production of metallic compounds, which are accountable for most of the trace element contamination [4,5]. Crowded traffic roads may emit massive pollutants such as heavy metals into the environment (soil, air, and water) and can pose severe threats to human health because of their persistency and bioaccumulation in the terrestrial environment [6][7][8].…”