Growth, Gas Exchange, Abscisic Acid, and Calmodulin Response to Salt Stress in Three Poplars

Abstract

In the present study, we investigated the effects of increasing salinity on growth, gas exchange, abscisic acid (ABA), calmodulin (CaM), and the relevance to salt tolerance in seedlings of Populus euphratica Oliv. and cuttings of P. "pupularis 35-44" (P. popularis) and P. × euramericana cv. I-214 (P. cv. Italica). The relative growth rates of shoot height (RGR H ) for P. cv. Italica and P. popularis were severely reduced by increasing salt stress, whereas the growth reduction was relatively less in P. euphratica. Similarly, P. euphratica maintained higher net photosynthetic rates (P n ) and unit transpiration rates (TRN) than P. cv. Italica and P. popularis under conditions of higher salinity. Salinity caused a significant increase in leaf ABA and CaM in the three genotypes after the onset of stress, but NaCl-induced ABA and CaM accumulation was more pronounced in P. euphratica, suggesting that P. euphratica plants are more sensitive in sensing soil salinity than the other two poplars. Furthermore, P. euphratica maintained relatively higher ABA and CaM concentrations under conditions of high salinity. The higher capacity to synthesize stress signals, namely ABA and CaM, in P. euphratica and the contribution of this to the salt resistance of P. euphratica are discussed. (2006). Growth, gas exchange, abscisic acid, and calmodulin response to salt stress in three poplars. J Integrat Plant Biol 48(3), 286−293.

Salt stress affects xylem differentiation of grey poplar (Populus × canescens)

“…These high levels in leaves were maintained for 1 week and further increased (fourfold) during the second week. This observation with the salt-sensitive grey poplar is not consistent with the hypothesis by Chang et al (2006) predicting that continuously high ABA levels are important for salt resistance of P. euphratica.…”

“…9). In contrast to the salt-sensitive poplar investigated previously (Chang et al 2006), grey poplar throughout the experiment exhibited similar ABA values in leaves to those measured in the salt tolerant P. euphratica (Chang et al 2006). These high levels in leaves were maintained for 1 week and further increased (fourfold) during the second week.…”

“…Role of ABA Salinity in general causes increased ABA biosynthesis and accumulation, which in turn modulates alterations in plant physiology (Karmoker and van Steveninck 1979;Behl et al 1981;Chen et al 2001;Chang et al 2006). With 50 mM NaCl in the roots of the salt-tolerant Populus euphratica, ABA synthesis is increased (Chen et al 2001(Chen et al , 2002.…”

“…The physiological basis of genetic variation in salinity tolerance of the genus Populus has been studied in recent years (Bolu and Polle 2002;Ottow et al 2005a, b and references therein). Moreover the role of ABA in salt stress was the focus of several studies (Shinozaki and Yamaguchi-Shinozaki 2000;Chen et al 2001Chen et al , 2002Chang et al 2006). In addition, eVects of salinity on poplar growth, water relations, stomatal conductance and CO 2 assimilation have been explored (Fung et al 1998).…”

Upgrading Root Physiology for Stress Tolerance by Ectomycorrhizas: Insights from Metabolite and Transcriptional Profiling into Reprogramming for Stress Anticipation

“…However, the best known functions of ABA are related to the recruitment of stress-signaling networks. ABA accumulates in plants exposed to salt stress (Chen et al, 2003;Chang et al, 2006), and deficiency makes plants more stress sensitive (Xiong et al, 2002). Genevestigator analysis of our PiRGs showed that many stress-related genes were activated by ABA or salt in Arabidopsis (RD26, LPT family protein, aldehyde dehydrogenase 7B4, galactinol synthase, phospholipase 2A, photoassimilate-responsive protein, WRKY40, and glutathione S-transferase), whereas a common feature of genes in the category Signaling was that their transcript abundance decreased in response to ABA (Supplemental Fig.…”