Impacts of abiotic stresses on the physiology and metabolism of cool‐season grasses: A review

Abstract

Grasslands cover more than 70% of the world's agricultural land playing a pivotal role in global food security, economy, and ecology due to their flexibility and functionality. Climate change, characterized by changes in temperature and precipitation patterns, and by increased levels of greenhouse gases in the atmosphere, is anticipated to increase both the frequency and severity of extreme weather events, such as drought, heat waves, and flooding. Potentially, climate change could severely compromise future forage crop production and should be considered a direct threat to food security. This review aimed to summarize our current understanding of the physiological and metabolic responses of temperate grasses to those abiotic stresses associated with climate change. Primarily, substantial decreases in photosynthetic rates of cool‐season grasses occur as a result of high temperatures, water‐deficit or water‐excess, and elevated ozone, but not CO2 concentrations. Those decreases are usually attributed to stomatal and non‐stomatal limitations. Additionally, while membrane instability and reactive oxygen species production was a common feature of the abiotic stress response, total antioxidant capacity showed a stress‐specific response. Furthermore, climate change‐related stresses altered carbohydrate partitioning, with implications for biomass production. While water‐deficit stress, increased CO2, and ozone concentrations resulted in higher carbohydrate content, the opposite occurred under conditions of heat stress and flooding. The extent of damage is greatly dependent on location, as well as the type and intensity of stress. Fortunately, temperate forage grass species are highly heterogeneous. Consequently, through intra‐ and in particular inter‐specific plant hybridization (e.g., Festuca x Lolium hybrids) new opportunities are available to harness, within single genotypes, gene combinations capable of combating climate change.

Amelioration of high temperature stress by exogenously applied salicylic acid: Genotype‐specific response of physiological traits

“…High temperature stress is one of the most important environmental factors influencing the growth, distribution, and production of turfgrass in many regions of the world, and the effect is rising considerably each year because of climate change (Loka et al., 2018). However, the application of plant growth regulators such as SA has been found to play an important role in regulation of plant growth and development under high temperature stress (He et al., 2005; Khan et al., 2013).…”

“…Our results were in agreement with the findings of several other studies on SA application to crops (He et al., 2005; Khan et al., 2013; Galani, Hameed, & Kazim Ali, 2016). The production of reactive oxygen species (ROS) increases during the high‐temperature conditions, which mainly cause reduction in chlorophyll content, photosynthetic rate, and cell membrane stability (Loka et al., 2018). Therefore, the enhancing effects of SA on photosynthesis pigments could be attributed to its inhibitory effects on ROS, and consequently stimulatory effects on Rubisco activity and photosynthesis (Khan et al., 2013).…”

“…Heat stress is one of the most important abiotic stresses affecting plant growth, development, and the productivity during late spring and summer in most parts of the world (Loka et al., 2018). Several studies in different forage grass species demonstrated that heat stress significantly decreased photosynthetic pigments, stomatal conduce, antioxidant enzyme activities, biomass, growth, and forage yield (Huang, 2004; Liu, Xie, Du, Sun, & Bai, 2008; Wang, Cui, Wang, & Li, 2009; Yu, Yang, Jespersen, & Huang, 2014).…”

Comparative physiological and proteomic analysis indicates lower shock response to drought stress conditions in a self-pollinating perennial ryegrass

“…Therefore, drought stress is the most critical and common environmental stress that limits agricultural production in the country and reduces the efficiency of using semi-arid and rain-fed areas. In cool-season grass species, drought stress adversely affects leaf water potential, photosynthetic and carbohydrate accumulation, respiration, production of reactive oxygen species, lipid peroxidation, and denaturation of proteins (reviewed by Loka et al [6]). However, many cool-season grasses can resist moderate drought and maintain their aerial growth to avoid and tolerate leaf dehydration.…”

Developing Heterotic Groups for Successful Hybrid Breeding in Perennial Ryegrass

“…The development of hardy tetraploid varieties has mitigated some of these problems [2]. However, further improvement is needed as perennial ryegrass yields have recently suffered from weather extremes, damaging pastures across central Europe [3,4].…”