In the past and present, human activities have been involved in triggering global warming, causing drought stresses that affect animals and plants. Plants are more defenseless against drought stress; and therefore, plant development and productive output are decreased. To decrease the effect of drought stress on plants, it is crucial to establish a plant feedback mechanism of resistance to drought. The drought reflex mechanisms include the physical stature physiology and biochemical, cellular, and molecular-based processes. Briefly, improving the root system, leaf structure, osmotic-balance, comparative water contents and stomatal adjustment are considered as most prominent features against drought resistance in crop plants. In addition, the signal transduction pathway and reactive clearance of oxygen are crucial mechanisms for coping with drought stress via calcium and phytohormones such as abscisic acid, salicylic acid, jasmonic acid, auxin, gibberellin, ethylene, brassinosteroids and peptide molecules. Furthermore, microorganisms, such as fungal and bacterial organisms, play a vital role in increasing resistance against drought stress in plants. The number of characteristic loci, transgenic methods and the application of exogenous substances [nitric oxide, (C28H48O6) 24-epibrassinolide, proline, and glycine betaine] are also equally important for enhancing the drought resistance of plants. In a nutshell, the current review will mainly focus on the role of phytohormones and related mechanisms involved in drought tolerance in various crop plants.

Statement of Novelty. Poultry feed contamination due to mycotoxins is one of the major threats to the growing poultry industry. Surveillance of different mycotoxins, including aflatoxin, is very important to control economic and health hazards associated with these toxins. Studies reporting aflatoxin levels in poultry feed are limited. Therefore, this study was conducted to examine the occurrence of total aflatoxin in poultry feed. This study is the first-ever documentation about the frequency and quantitative estimations of total aflatoxin levels in poultry feed consumed to provide solid feedback to the poultry industrialists and researchers involved in studying the mycotoxins. Objective. Contamination of poultry feed with mycotoxins such as aflatoxin is a major concern for the poultry industry that results in a significant economic loss and directly affects consumers. Monitoring the aflatoxin levels in poultry feed is crucial for controlling economic loss and decreasing the health hazards to the population. This study was conducted to examine the occurrence of total aflatoxin in poultry feed in a high consumption area. Three different poultry feeds, i.e., starter, grower, and finisher, were assessed through continuous sampling from farms. The incidence of positive samples for aflatoxin contamination was 92.5%. Grower feed had the highest frequency (100%) of aflatoxin positive samples and aflatoxin levels with a mean value of 56.34 ppb. Further, the range of moisture content was around 6.8%-10.98%. No significant correlation between humidity and aflatoxin contamination was revealed when analyzed by Pearson’s correlation coefficient with r 2 of 0.05 and p value of 0.13. The results warrant the need for constant monitoring programs for the prevention of aflatoxin contamination in local poultry farms

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Silicon (Si) is an important plant-derived metabolite that is significantly involved in maintaining the stability of a plant’s metabiological, structural and physiological characteristics under the abiotic stressed environment. We conducted the present study using maize (Zea mays L.) cultivars (Sadaf and EV-20) grown in sand artificially contaminated with cadmium (500 µM) in Hoagland’s nutrient solution to investigate its efficiency. Results from the present study evidenced that the toxic concentration of Cd in sand significantly reduced shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight by 88, 94, 89, 86 99 and 99%, respectively, in Sadaf while decreasing by 98, 97, 93, 99, 84 and 91%, respectively, in EV-20. Similarly, Cd toxicity decreased total chlorophyll and carotenoid content in both varieties of Z. mays. Moreover, the activities of various antioxidants (superoxidase dismutase, peroxidase and catalase) increased under the toxic concentration of Cd in sand which was manifested by the presence of membrane permeability, malondialdehyde (MDA), and hydrogen peroxide (H2O2). Results additionally showed that the toxic effect of Cd was more severe in EV-20 compared with Sadaf under the same conditions of environmental stresses. In addition, the increased concentration of Cd in sand induced a significantly increased Cd accumulation in the roots (141 and 169 mg kg−1 in Sadaf and EV-20, respectively), and shoots (101 and 141 mg kg−1 in Sadaf and EV-20, respectively), while; EV-20 accumulated higher amounts of Cd than Sadaf, with the values for both bioaccumulation factor (BAF) and translocation factor (TF) among all treatments being less than 1. The subsequent negative results of Cd injury can be overcome by the foliar application of Si which not only increased plant growth and biomass, but also decreased oxidative damage induced by the higher concentrations of MDA and H2O2 under a Cd-stressed environment. Moreover, external application of Si decreased the concentration of Cd in the roots and shoots of plants, therefore suggesting that the application of Si can ameliorate Cd toxicity in Z. mays cultivars and results in improved plant growth and composition under Cd stress by minimizing oxidative damage to membrane-bound organelles.

Barley (Hordeum vulgare L.) is a salt-tolerant crop with considerable economic value in salinity-affected arid and semiarid areas. In the laboratory experiment, the halothermal time (HaloTT) model was used to examine barley seed germination (SG) at six constant cardinal temperatures (Ts) of 15, 20, 25, 30, 35, and 40 °C under five different water potentials (ψs) of 0, −0.5, −1.5, −1.0, and −2.0 MPa. Results showed that at optimum moisture (0 MPa), the highest germination percentage (GP) was recorded at 20 °C and the lowest at 40 °C. Moreover, GP increased with the accelerated aging period (AAP) and significantly (p ≤ 0.05) decreased with high T. In addition, with a decrease of ψ from 0 to −0.5, −1, 1.5, and −2.0 MPa, GP decreased by 93.33, 76.67, 46.67, and 33.33%, respectively, in comparison with 0 MPa. The maximum halftime constant (θHalo) and coefficient of determination (R2) values were recorded at 20 °C and 30 °C, respectively. The optimum temperature (To) for barley is 20 °C, base Ψ of 50th percentile (Ψb (50)) is −0.23 Mpa, and standard deviation of Ψb (σΨb) is 0.21 MPa. The cardinal Ts for germination is 15 °C (Tb), 20 °C (To), and 40 °C (Tc). The GP, germination rate index (GRI), germination index (GI), coefficient of the velocity of germination (CVG), germination energy (GE), seed vigor index I and II (SVI-I & II), Timson germination index (GI), and root shoot ratio (RSR) were recorded maximum at 0 MPa at 20 °C and minimum at −2.0 MPa at 40 °C. Mean germination time (MGT) and time to 50% germination (T 50%) were maximum at −2 MPa at 40 °C, and minimum at 20 °C, respectively. In conclusion, the HaloTT model accurately predicted the germination time course of barley in response to T, Ψ, or NaCl. Therefore, barley can be regarded as a salt-tolerant plant and suitable for cultivation in arid and semi-arid regions due to its high resistance to salinity.