Abiotic Stress Tolerance in Grasses. From Model Plants to Crop Plants

Abstract

Abiotic stresses, notably extremes in temperature, photon irradiance, and supplies of water and inorganic solutes, frequently limit growth and productivity of major crop species such as wheat (Triticum aestivum; http://www.cimmyt.org/Research/Wheat/map/research_results/wphysio/wphysio.html). In addition, more than one abiotic stress can occur at one time. For example, high temperature and high photon irradiance often accompany low water supply, which can in turn be exacerbated by subsoil mineral toxicities that constrain root growth. Furthermore, one abiotic stress can decrease a plant's ability to resist a second stress. For example, low water supply can make a plant more susceptible to damage from high irradiance due to the plant's reduced ability to reoxidize NADPH and thus maintain an ability to dissipate energy delivered to the photosynthetic light-harvesting reaction centers. If a single abiotic stress is to be identified as the most common in limiting the growth of crops worldwide, it most probably is low water supply (Boyer, 1982; Araus et al., 2002). However, other abiotic stresses, notably salinity and acidity, are becoming increasingly significant in limiting growth of both forage grasses and the cereals. Globally, low temperature also is a major limitation of plant growth, and this has a major impact on grasses via, for example, vernalization and low temperature damage at anthesis. In this focus issue, there are articles addressing three aspects of these abiotic stresses.