Salt stress in maize: effects, resistance mechanisms, and management. A review

Abstract

Maize is grown under a wide spectrum of soil and climatic conditions. Maize is moderately sensitive to salt stress; therefore, soil salinity is a serious threat to its production worldwide. Understanding maize response to salt stress and resistance mechanisms and overviewing management options may help to devise strategies for improved maize performance in saline environments. Here, we reviewed the effects, resistance mechanisms, and management of salt stress in maize. Our main conclusions are as follows: (1) germination and stand establishment are more sensitive to salt stress than later developmental stages. (2) High rhizosphere sodium and chloride decrease plant uptake of nitrogen, potassium, calcium, magnesium, and iron. (3) Reduced grain weight and number are responsible for low grain yield in maize under salt stress. Sink limitations and reduced acid invertase activity in developing grains is responsible for poor kernel setting under salt stress. (4) Exclusion of excessive sodium or its compartmentation into vacuoles is an important adaptive strategy for maize under salt stress. (5) Apoplastic acidification, required for cell wall extensibility, is an important indicator of salt resistance, but not essential for better maize growth under salt stress. (6) Upregulation of antioxidant defense genes and β-expansin proteins is important for salt resistance in maize. (7) Arbuscular mycorrhizal fungi improve salt resistance in maize due to better plant nutrient availability. (8) Seed priming is an effective approach for improving maize germination under salt stress. (9) Integration of screening, breeding and ion homeostasis mechanisms into a functional paradigm for the whole plant may help to enhance salt resistance in maize.

The Mitigation Effects of Exogenous Hydrogen Peroxide when Alleviating Seed Germination and Seedling Growth Inhibition on Salinity-Induced Stress in Barley

“…Besides, reductions in stomata counts and sizes of plants exposed to various stress conditions negatively affect photosynthetic activity, causing regressed growth and development [52]. Furthermore, abnormalities in the shapes and numbers of these structures in plants exposed to salt stress can reduce carbon fi xation capacity [53], and ultimately disturb the photosynthetic process [12]. It is thought that reductions in sizes of stomatal structures (width/length) on both surfaces of leaves can have simillar outcomes.…”

“…ROS, including H 2 O 2 , is known to increase under stress factors such as salinity [9] and high temperature [10] in plant tissues [11]. In other words, environmental stresses result in oxidative stress in plants [12], and they are generally considered harmful to plant cells due to the fact that they can cause extreme oxidative damage to biological molecules such as DNA, proteins, and lipids [13], whereas it has been recently discovered that subtoxic concentrations of H 2 O 2 act as the main regulator of plants' responses to environmental stress [14]. Moreover, it functions as a signal molecule [15] in the regulation of plant growth and differentiation [16].…”

Alleviation of Salt Stress in Cucumber (Cucumis sativus) through Seed Priming with Triacontanol

“…Germination is the first stage of plant phenology, which is affected by root zone salinization due to excessive salts in growing medium (Farooq et al, 2015;Almutairi, 2016). Salinity causes an increase in root zone osmotic pressure, which ultimately results in cell dehydration and accumulation of higher amount of Na + and Cl -ions in soil solution that disturbs the availability of the nutrient especially K + (Hasanuzzaman et al, 2013;Farooq et al, 2015).…”

“…Salinity causes an increase in root zone osmotic pressure, which ultimately results in cell dehydration and accumulation of higher amount of Na + and Cl -ions in soil solution that disturbs the availability of the nutrient especially K + (Hasanuzzaman et al, 2013;Farooq et al, 2015). Progressive built up of Na + and Cl -leads to nutrient starvation in seeds through ionic imbalance that restricts the embryo to absorb water and inhibits radicle growth and delays emergence (Gupta et al, 1993;Gao et al, 2014).…”

Identification and characterization of the BZR transcription factor family and its expression in response to abiotic stresses in Zea mays L.

“…Hypoxic stress conditions were achieved by not bubbling air through the liquid solution for the entire experiment. For salt stress, a 100 mM NaCl concentration, which corresponds to severe salt stress in maize (Farooq et al 2015;Henry et al 2015;Zörb et al 2015), was employed. Finally, an intense heat stress, generally greater than 4 °C above optimum that in the case of maize is 25 °C (Hatfield and Prueger 2015), was performed by growing seedlings in a day/night cycle at 35/30 °C air temperature.…”