ABSTRACT
Thiourea (TU) is considered an essential and emerging biostimulant against the negative impacts of severe environmental stresses, including drought stress in plants. However, the knowledge about the foliar application of TU to mitigate drought stress in Linum usitatissimum L., has yet to be discovered. The present study was designed to assess the impact of foliar application of TU for its effects against drought stress in two flax cultivars. The study comprised two irrigation regimes [60% field capacity (FC) and the control (100% FC)], along with TU (0, 500, 1000 mg L-1) application at the vegetative stage. The findings indicated that drought stress reduced the shoot fresh weight (44.2%), shoot dry weight (67.5%), shoot length (41.5%), total chlorophyll (51.6%), and carotenoids (58.8%). Drought stress increased both cultivars' hydrogen peroxide (H2O2) and malondialdehyde (MDA). Foliar application of TU (1000 mg L-1) enhanced the growth and chlorophyll contents with or without drought stress. Under drought stress (60% FC), TU decreased MDA and H2O2 contents up to twofold. Moreover, TU application increased catalase (40%), peroxidase (13%), superoxide dismutase (30%), and total soluble protein contents (32.4%) differentially in both cultivars. Nevertheless, TU increased calcium (Ca2+) (42.8%), potassium (K+) (33.4%), and phosphorus (P) (72%) in shoots and decreased the elevated sodium (Na+) (28.2%) ions under drought stress. It is suggested that TU application (1000 mg L-1) enhances the growth potential of flax by enhancing photosynthetic pigment, nutrient uptake, and antioxidant enzymes under drought stress. Research outcomes, therefore, recommend that TU application can ameliorate drought-induced negative effects in L. usitatissimum L. seedlings, resulting in improved plant growth and mineral composition, as depicted by balanced primary and secondary metabolite accumulation.
ABSTRACT
Wastewater irrigation is a substitute for surface water scarcity, but traces of heavy metals (HMs) result in deleterious implications for soil, crop productivity, and in humans. Crops presenting HMs tolerance in genetic behavior are important for producing tolerant genotypes cultivated under wastewater irrigation. In the first part of this experiment, the results obtained previously are re-assessed in a hydroponic system and similar patterns and concentrations of HMs are found in different tomato organs. Following this trial, the tomato's (Solanum lycopersicum L.) genetic basis of traits conferring HMs tolerance and yield are assessed when irrigated with waste or canal water. The North Carolina Mating II analysis illustrate the amount of gene action, nature, and inheritance pattern. Genetic components depict the involvement of non-additive, additive, and maternal genetic effects in HMs tolerance inheritance and yield. A noticeable increase in cumulative additive variance for the number of flowers (11,907.2) and the number of fruits (10,557.9) is recorded for tomato plants irrigated with wastewater, illustrating additive gene action. However, female and male (MSf/MSm) square ratios also show an association with cytoplasmic inheritance. For HMs tolerance, both additive and dominant variances appeared to be significant; cumulative dominance variance (4.83, 16.1, 4.69, 76.95, and 249.37) is higher compared to additive variance (0.18, 2.36, 0.19, −0.27, and 14.14) for nickel (Ni), chromium (Cr), lead (Pb), manganese (Mn), and zinc (Zn), respectively, indicating dominance gene action. The genotype RIOGRANDI accumulated and translocated fewer HMs to the aerial part of the plant compared to CLN-2418A and PB-017906, thus presenting a tolerant tomato genotype according to the hydroponic experiment. This also exhibited a differential pattern of gene action for HMs tolerance, suggesting that genotypes possess significant differences for HMs tolerance.
ABSTRACT
The individual application of pure and active compounds such as methionine may help to address water scarcity issues without compromising the yield of wheat. As organic plant growth stimulants, amino acids are popularly used to promote the productivity of crops. However, the influence of the exogenous application of methionine in wheat remains elusive. The present investigation was planned in order to understand the impact of methionine in wheat under drought stress. Two wheat genotypes were allowed to grow with 100% field capacity (FC) up to the three-leaf stage. Twenty-five-day-old seedlings of two wheat genotypes, Galaxy-13 and Johar-16, were subjected to 40% FC, denoted as water deficit-stress (D), along with 100% FC, called control (C), with and without L-methionine (Met; 4 mM) foliar treatment. Water deficit significantly reduced shoot length, shoot fresh and dry weights, seed yield, photosynthetic, gas exchange attributes except for transpiration rate (E), and shoot mineral ions (potassium, calcium, and phosphorus) in both genotypes. A significant increase was recorded in superoxide dismutase (SOD), catalase (CAT), hydrogen peroxide (H2O2), malondialdehyde (MDA), and sodium ions (Na+) due to water deficiency. However, foliar application of Met substantially improved the studied growth, photosynthetic, and gas exchange attributes with water deficit conditions in both genotypes. The activities of SOD, POD, and CAT were further enhanced under stress with Met application. Met improved potassium (K), calcium (Ca2+), and phosphorus (P) content. In a nutshell, the foliar application of Met effectively amended water deficit stress tolerance by reducing MDA and H2O2 content under water deficit conditions in wheat plants. Thus, we are able to deduce a positive association between Met-induced improved growth attributes and drought tolerance.
ABSTRACT
[This corrects the article DOI: 10.3389/fpls.2022.850567.].
ABSTRACT
It has been established that wheat (Triticum aestivum L.) has a higher Cd absorption capacity than other cereal crops causing an excess daily Cd intake and a huge threat for public health. Therefore, the reduction of Cd accumulation in wheat from the soil is a crucial food-security issue. A pot trial was performed on Cd-stressed wheat seedlings to evaluate the morphological and physio-biochemical responses via foliage spray of two different bio-stimulants, i.e., ascorbic acid (AsA) and moringa leaf extract (MLE). Two wheat cultivars (Fsd-08 and Glxy-13) were exposed to cadmium (CdCl2.5H2O) stress (0, 500, and 1,000 µM), along with foliar spray of AsA (0 and 50 mM) and MLE (0 and 3%). The most observable growth reduction was documented in plants that are exposed to a higher Cd concentration (1,000 µM), followed by the lower Cd level (500 µM). The wheat growth attributes, such as number of leaves per plant, number of tillers per plant, biomass yield, shoot/root length, and leaf area, were greatly depressed under the Cd stress, irrespective of the cultivar. Under the increasing Cd stress, a significant diminution was observed in maximum photochemical efficiency (Fv/Fm), photochemical quenching (qP), and electron transport rate (ETR) accompanied with reduced gas exchange attributes. However, Cd-induced phytotoxicity enhanced the non-photochemical quenching (NPQ) and internal carbon dioxide concentration (Ci), which was confirmed by their significant positive correlation with Cd contents in shoot and root tissues of both cultivars. The contents of proline, AsA, glycine betaine (GB), tocopherol, total free amino acid (TFAA), and total soluble sugar (TSS) were greatly decreased with Cd stress (1,000 µM), while MLE and AsA significantly enhanced the osmolytes accumulation under both Cd levels (especially 500 µM level). The Cd accumulation was predominantly found in the root as compared to shoots in both cultivars, which has declined after the application of MLE and AsA. Conclusively, MLE was found to be more effective to mitigate Cd-induced phytotoxicity up to 500 µM Cd concentration, compared with the AsA amendment.