Thiourea-Capped Nanoapatites Amplify Osmotic Stress Tolerance in Zea mays L. by Conserving Photosynthetic Pigments, Osmolytes Biosynthesis and Antioxidant Biosystems

Abstract

Salinity is one of the most prevalent abiotic stresses which not only limits plant growth and yield, but also limits the quality of food products. This study was conducted on the surface functionalization of phosphorus-rich mineral apatite nanoparticles (ANPs), with thiourea as a source of nitrogen (TU–ANPs) and through a co-precipitation technique for inducing osmotic stress tolerance in Zea mays. The resulting thiourea-capped apatite nanostructure (TU–ANP) was characterized using complementary analytical techniques, such as EDX, SEM, XRD and IR spectroscopy. The pre-sowing of soaked seeds of Zea mays in 1.00 µg/mL, 5.00 µg/mL and 10 µg/mL of TU–ANPs yielded growth under 0 mM, 60 mM and 100 mM osmotic stress of NaCl. The results show that Ca and P salt acted as precursors for the synthesis of ANPs at an alkaline pH of 10–11. Thiourea as a source of nitrogen stabilized the ANPs’ suspension medium, leading to the synthesis of TU–ANPs. XRD diffraction analysis validated the crystalline nature of TU–ANPs with lattice dimensions of 29 nm, calculated from FWHM using the Sherrer equation. SEM revealed spherical morphology with polydispersion in size distribution. EDS confirmed the presence of Ca and P at a characteristic KeV, whereas IR spectroscopy showed certain stretches of binding functional groups associated with TU–ANPs. Seed priming with TU–ANPs standardized germination indices (T50, MGT, GI and GP) which were significantly declined by NaCl-based osmotic stress. Maximum values for biochemical parameters, such as sugar (39.8 mg/g at 10 µg/mL), protein (139.8 mg/g at 10 µg/mL) and proline (74.1 mg/g at 10 µg/mL) were recorded at different applied doses of TU–ANP. Antioxidant biosystems in the form of EC 1.11.1.6 catalase (11.34 IU/g FW at 10 µg/mL), EC 1.11.1.11 APX (0.95 IU/G FW at 10 µg/mL), EC 1.15.1.1 SOD (1.42 IU/g FW at 5 µg/mL), EC 1.11.1.7 POD (0.43 IU/g FW at 5 µg/mL) were significantly restored under osmotic stress. Moreover, photosynthetic pigments, such as chlorophyll A (2.33 mg/g at 5 µg/mL), chlorophyll B (1.99 mg/g at 5 µg/mL) and carotenoids (2.52 mg/g at 10 µg/mL), were significantly amplified under osmotic stress via the application of TU–ANPs. Hence, the application of TU–ANPs restores the growth performance of plants subjected to induced osmotic stress.

Combined application of plant growth-promoting bacteria and iron oxide nanoparticles ameliorates the toxic effects of arsenic in Ajwain (Trachyspermum ammi L.)

“…High concentrations of heavy metals significantly reduce plant productivity and crop yields ( Javed et al., 2020 ; Rana et al., 2020 ; Saleem et al., 2020c ; Alsafran et al., 2022a ). Arsenite ( +3 ) and arsenate ( +5 ) are toxic anions of As that are readily absorbed by plants ( Shahid et al., 2019 ) because both arsenate and phosphate share the same transport pathway: As (V) interferes with metabolic processes, and As (III) reacts with sulfhydryl groups (−SH) and tissue proteins, thereby disturbing the enzymatic activities ( Irshad et al., 2020 ; Faizan et al., 2021 ; Faryal et al., 2022 ). As has no known essential function in plant growth, and generally causes damaging effects to the plant growth and photosynthetic pigments.…”

Assessment of phytoremediation potential of native plant species naturally growing in a heavy metal-polluted industrial soils

“…Plants absorb cadmium through the roots, and there are several factors that can affect availability of cadmium to plants, such as above-mentioned pH, the rhizosphere, and organic acids (Ismael et al, 2019;Saleem et al, 2022). Cd affects plants by inhibiting photosynthesis and respiration, reducing water and nutrient uptake, altering gene and protein expression, inducing and inhibiting enzymes, enhancing accumulation of reactive oxygen species (ROS), enhancing lipid peroxidation, and disturbing metabolism (Semane et al, 2010;Faryal et al, 2022). The objectives of this study were 1) to determine the concentration of Cadmium and to find out ways and means for eradicating its environmental impacts, 2) to quantify the concentration levels of Cadmium soil and their transfer and accumulation in plants, 3) to investigate the uptake potential of Cadmium of the collected plants by calculating bioconcentration factor (BCF) and to calculate the translocation of the accumulated Cadmium from root to shoots by calculating translocation factor.…”

Plant Microbiome Engineering: Hopes or Hypes

“…Drought [ 3 , 4 ], salinity [ 5 , 6 ], osmotic and heavy metals [ 7 , 8 , 9 , 10 , 11 ], and high temperatures [ 12 ], are examples of abiotic stress that have detrimental impacts on agricultural yield. These stressors lower water absorption, nutrient acquisition [ 13 , 14 ], cause disease susceptibility [ 13 ], interrupt hormonal imbalance, and affect the plant’s photosynthetic efficiency. Certain environmental factors, i.e., temperature, CO 2 concentration, and water availability, define the disease conditions of plants, which increase the susceptibility of plants [ 15 , 16 , 17 ].…”