Solute accumulation and elastic modulus changes in six radiata pine breeds exposed to drought

Abstract

Drought is one of the main abiotic factors that determine forest species growth, survival and productivity. For this reason, knowledge of plant drought response and the identification of physiological traits involved in stress tolerance will be of interest to breeding programs. In this work, several Pinus radiata D. Don breeds from different geographical origins were evaluated along a water stress period (4 weeks) and subsequent rewatering (1 week), showing different responses among them. Leaf water potential (Ψ(leaf)) and osmotic potential decreases were accompanied by a variation in the total relative water content (RWC, %). The most tolerant breeds presented the lowest leaf water potential and RWC at turgor loss point, and showed the lowest elastic modulus (ε) values. A high ε value was a characteristic of a less-drought-tolerant plant and was related to membrane alterations (high electrolyte leakage percentages) that could favor cell water loss. Of the group of solutes that contributed to osmotic adjustment, soluble carbohydrates were the most abundant, although stressed plants also increased their content of free amino acids [mainly proline (Pro) and glutamic acid (Glu), and γ-aminobutyric acid (GABA)] and free polyamines. In addition, the most sensitive breeds had a higher GABA/Glu ratio. After rewatering, Pro and GABA were higher in rehydrated plants than in controls.

Different combinations of morpho‐physiological traits are responsible for tolerance to drought in wild tomatoes Solanum chilense and Solanum peruvianum

“…accumulation of solutes in tomatoes caused a slight decrease in osmotic potential during RW treatment that was significantly correlated with sugar and proline accumulation in leaves. Indeed, sugars and proline are compatible solutes that play a role in tolerance to abiotic stress (Loutfy et al 2012;Sperdouli & Moustakas 2012;De Diego et al 2013;Liu et al 2015). Additionally, the increased level of proline and total carbohydrates during RW was dependent on the species: proline primarily accumulated in S. chilense, whereas the preferred solute in S. peruvianum was total carbohydrates (Figs 3, 8).…”

Metabolites and hormones are involved in the intraspecific variability of drought hardening in radiata pine

“…In our preliminary studies, we demonstrated that exposure to a short drought period of four weeks induced a different osmotic response in each P. radiata breed (De Diego et al, 2013b). In addition, although all plants recovered their osmotic potential after rewatering, some solutes, especially amino acids, were maintained at high levels, including l-proline (Pro) and ␥-aminobutyric acid (GABA) as the most abundant ones.…”

“…In addition, although all plants recovered their osmotic potential after rewatering, some solutes, especially amino acids, were maintained at high levels, including l-proline (Pro) and ␥-aminobutyric acid (GABA) as the most abundant ones. Controversially, amino acids contributed in less extent to plant osmotic adjustment, pointing out their possible role as signal molecules that activate protection mechanisms to mitigate the effects of water stress (Kinnersley and Turano, 2000;Vendruscolo et al, 2007), and suggesting their possible implication in improving tolerance against future water stress situations (De Diego et al, 2013b).…”

“…Therefore, in this work we focused on the study of drought hardening at the metabolic level to clarify the possible implication of free soluble amino acids and plant growth regulators in this process. In this respect, as the most drought tolerant breeds kept accumulating Pro and GABA after rewatering (De Diego et al, 2013b) and altered the concentration of several phytohormones during first drought cycle and rewatering (De Diego et al, 2012), we hypothesized that these molecules are strongly implicated in plant tolerance and drought hardening. Moreover, we intended to clarify whether this response is species-dependent.…”

Evidence of stress imprinting with population‐level differences in two moss species

“…Others, such as auxins, gibberellins, and cytokinins, are also involved in stress responses via complex signaling networks (Verma et al, 2016;Verslues, 2016). Phytohormones regulate stress responses that often include increases in antioxidant capacity and accumulation of osmolytes (Cvikrová et al, 2012;De Diego et al, 2013;Hüve, Bichele, Tobias, & Niinemets, 2006;Nagao, Minami, Arakawa, Fujikawa, & Takezawa, 2005;Zhao, Shi, Liu, Jia, & Li, 2015). Furthermore, information about experienced stresses ("stress memories" or "stress imprints") can be stored in plants and may often increase their tolerance of recurrent stresses (Bruce et al, 2007;Nikiforou & Manetas, 2018).…”