Adaptation of Halophytes to Different Habitats

Abstract

In recent years, global climate change has been altering environmental (severe drought, soil salinization, irregular precipitation, etc.), around world, decreasing crop yield and upsetting the balance of ecosystems. Nonetheless, a group of plants known as halophytes have the ability to survive and develop in saline soils (wetlands, deserts or temperate zones), may be used in agriculture as a possible alternative to crops (salt-sensitive), as well as for fodder, energy production, medicinal purposes, and desalination of salt-affected areas (phytoremediation). This chapter provides a comprehensive summary of the adaptive strategies used by the annual and perennial halophytes on ecophysiological perspectives, to survive in diverse habitats. The results show a great diverse strategies, such as heteromorphism, seed banks, dormancy, rapid germination, and recovery capacity, from saline shock, favoring the chances of seed survival, although these mechanisms depend on light, moisture, temperature, and the type of salt, in which seeds germinate. In addition, it has been included some molecular, and biochemical aspects, discovered in last years, that might improve our understanding of physiology of these plants. It can conclude that halophytes may be as a possible alternative to ease pressure on cropping systems, restored lands degraded, or confer stress tolerance trough gene transfer.

With a little help from my friends: physiological integration facilitates invasion of wetland grass Elymus athericus into flooded soils

“…Anoxia, as a separate stressor, can impede plant nutrient uptake via energetic constraints of the root tissue as oxygen supply from aboveground tissues is insufficient to maintain aerobic dissimilation (Colmer and Flowers 2008). High soil salinity, as a separate stressor, can induce osmotic and ionic stresses in plants that interfere with nutrient uptake, although halophytes are equipped with several adaptations to reduce their negative impacts (Brown et al 2006, Engels et al 2011, González 2019). However, the most prominent stressor to impede nutrient uptake in marsh plants is the accumulation of phytotoxic sulfides in the root zone (Bradley and Morris 1990, Alldred et al 2017).…”

Salinity Tolerance in Fraxinus angustifolia Vahl.: Seed Emergence in Field and Germination Trials

“…Salinity reduced seed germination in plants [98][99][100][101], even in halophytes [102][103][104], delaying or preventing germination beyond tolerance limits [105]. Although the issue of critical values' determination for salinity is complex and controversial-due to the diversity of saline environments and responses induced by salts, such as: osmotic and oxidative stresses, ion-toxicity and/or nutritional disorder [106]-generalized relationships between germination curves and salinity were suggested.…”

Variation in desert shrub foliar pH in relation to drought and salinity in Xinjiang, China

“…This function is required for the normal functioning of cell metabolism (Breckle, 2002; Zhao & Fan, 2005), and can alleviate the toxic effects of salt ions on cells and the water stress caused by salt stress (Zhao & Fan, 2005). Since salt ions enter the euhalophytes’ cells, they are constantly exchanged in the inner membrane system, resulting in foliar pH of euhalophytes being higher than in other species (Flowers et al, 1977; Xi et al, 2006; González, 2019). Glycophytes are particularly sensitive to salt (Zhao & Li, 1986; González, 2019).…”

“…According to their preferences regarding soil salinity, halophytes have developed a variety of anatomical and morphological adaptations to ensure their survival in salty environments (Flowers et al, 1977; Zhao & Fan, 2005; Zhao & Li, 2013), such as salt glands, salt bladders (for selective exclusion or accumulation of ions), or development of succulence (dilution of ion concentration) in the plant tissue (Flowers et al, 1977; González, 2019). These physiological adaptation features can potentially affect foliar pH, of great importance in maintaining plant physiological and metabolic functions.…”