Selenium (Se) improves drought tolerance in crop plants – a myth or fact?

Abstract

Climate change has emerged as one of the most complex challenges of the 21st century and has become an area of interest in the past few decades. Many countries of the world have become extremely vulnerable to the impacts of climate change. The scarcity of water is a serious concern for food security of these countries and climate change has aggravated the risks of extreme events like drought. Oxidative stress, caused by a variety of active oxygen species formed under drought stress, damages many cellular constituents, such as carbohydrates, lipids, nucleic acids and proteins, which ultimately reduces plant growth, respiration and photosynthesis. Se has become an element of interest to many biologists owing to its physiological and toxicological importance. It plays a beneficial role in plants by enhancing growth, reducing damage caused by oxidative stress, enhancing chlorophyll content under light stress, stimulating senesce to produce antioxidants and improving plant tolerance to drought stress by regulating water status. Researchers have adopted different strategies to evaluate the role of selenium in plants under drought stress. Some of the relevant work available regarding the role of Se in alleviating adverse effect of drought stress is discussed in this paper.

Effect of the Application of Foliar Selenium on Canola Cultivars as Influenced by Different Irrigation Regimes

“…More than 60% of Iranian lands is located in the arid and semi-arid regions in which, water scarcity is the most important limiting factor for agricultural activities (Modarres & de Paulo Rodrigues da Silva 2007). Studies have shown that under water deficit condition, oxidative stress reduces plant growth, respiration, and photosynthesis through damaging cellular compounds, such as carbohydrates, lipids, nucleic acids, and proteins (Ahmad et al 2016).…”

Indications of Selenium Protection against Cadmium and Lead Toxicity in Oilseed Rape (Brassica napus L.)

“…Selenium at low concentrations exerts positive effects for plants such as promoting growth, increasing antioxidative capacity, improving yield and quality, and delaying ripening and senescence (Hartikainen et al, 2000; Xue et al, 2001; Turakainen et al, 2004; Broadley et al, 2010; Pukacka et al, 2011; Pezzarossa et al, 2012). Applying Se fertilizer as base fertilizer or foliar spray has been used to increase the Se content in the edible portion of crops and to simultaneously counteract the detrimental effects of diverse environmental stresses, such as heavy metals, water, drought, salt, high temperature, UV radiation, senescence, pathogens, and insect pests (Hartikainen et al, 2000; Pennanen et al, 2002; Hanson et al, 2003; Djanaguiraman et al, 2005, 2010; Germ et al, 2005; Broadley et al, 2010; Yao et al, 2010; Zembala et al, 2010; Hasanuzzaman and Fujita, 2011; Hasanuzzaman et al, 2011; Pukacka et al, 2011; Kumar et al, 2012; Pezzarossa et al, 2012; Feng et al, 2013; Ardebili et al, 2014; Ahmad et al, 2016; Kaur et al, 2016; Wu et al, 2016). …”

The Selenium Supplementation Influences Olive Tree Production and Oil Stability Against Oxidation and Can Alleviate the Water Deficiency Effects

“…Since changes of the chlorophyll-to-carotenoid ratio can indicate water deficient conditions (Jaleel et al, 2009; Ramakrishna and Ravishankar, 2011), the higher ratio in EVOO from the NDS-NT group as compared to the DS-NT one, and from the DS-T group as compared to the DS-NT one, might confirm the capacity of Se to protect plants from drought stress damage (Hasanuzzam et al, 2010; Proietti et al, 2013; Ahmad et al, 2016). In fact, Se has protective effects on chloroplast enzymes with a consequent increase in photosynthetic pigment biosynthesis (Pennanen et al, 2002).…”