NaCl-Induced Alternations of Cellular and Tissue Ion Fluxes in Roots of Salt-Resistant and Salt-Sensitive Poplar Species      

Abstract

Using the scanning ion-selective electrode technique, fluxes of H+, Na+, and Cl− were investigated in roots and derived protoplasts of salt-tolerant Populus euphratica and salt-sensitive Populus popularis 35-44 (P. popularis). Compared to P. popularis, P. euphratica roots exhibited a higher capacity to extrude Na+ after a short-term exposure to 50 mm NaCl (24 h) and a long term in a saline environment of 100 mm NaCl (15 d). Root protoplasts, isolated from the long-term-stressed P. euphratica roots, had an enhanced Na+ efflux and a correspondingly increased H+ influx, especially at an acidic pH of 5.5. However, the NaCl-induced Na+/H+ exchange in root tissues and cells was inhibited by amiloride (a Na+/H+ antiporter inhibitor) or sodium orthovanadate (a plasma membrane H+-ATPase inhibitor). These results indicate that the Na+ extrusion in stressed P. euphratica roots is the result of an active Na+/H+ antiport across the plasma membrane. In comparison, the Na+/H+ antiport system in salt-stressed P. popularis roots was insufficient to exclude Na+ at both the tissue and cellular levels. Moreover, salt-treated P. euphratica roots retained a higher capacity for Cl− exclusion than P. popularis, especially during a long term in high salinity. The pattern of NaCl-induced fluxes of H+, Na+, and Cl− differs from that caused by isomotic mannitol in P. euphratica roots, suggesting that NaCl-induced alternations of root ion fluxes are mainly the result of ion-specific effects.

SND1 Transcription Factor-Directed Quantitative Functional Hierarchical Genetic Regulatory Network in Wood Formation in Populus trichocarpa

“…We collected SDX tissue strips (see Supplemental Methods 1 online) and used ;2 to 7 g (fresh weight) for each protoplast isolation. Isolation protocols developed for woody tissues (Teulieres et al, 1991;Manders et al, 1992;Gomez-Maldonado et al, 2001;Sun et al, 2009;Tang et al, 2010) were tested and gave very low yields, particularly from plants 3 to 4 months of age.…”

“…The challenge is that woody plant tissues are generally resistant to protoplast isolation (Teulieres et al, 1991;Manders et al, 1992;Gomez-Maldonado et al, 2001;Sun et al, 2009;Tang et al, 2010;Chen et al, 2011;Li et al, 2012). Even for amenable woody plant tissues, protoplast isolation has never before been designed for yield and quality adequate for transgenesis, transcriptome and chromatin enrichment studies.…”

Effect of NaCl on leaf H+-ATPase and the relevance to salt tolerance in two contrasting poplar species

“…/ H ? antiporters in P. euphratica (Ottow et al 2005b;Lü et al 2007;Wu et al 2007;Sun et al 2009). The transcript levels of PeNhaD1 and PeSOS1 were maintained constant in P. euphratica under saline conditions (Ottow et al 2005b;Wu et al 2007) but declined in a salt-sensitive genotype, P. canescens (PeNhaD1, Ottow et al 2005b;PtSOS1, Escalante-Pérez et al 2009).…”

“…efflux and H ? influx along the root axis of long-term-stressed P. euphratica plants (Sun et al 2009). Evidence by Western blotting proved that the expression of PM H ?…”

Effects of Direct Application of Fertilizers and Hydrogel on the Establishment of Poplar Cuttings

“…For example, P. popularis has been well documented to be salt sensitive [31][32][33][34]. In addition, the higher proportion of NH4 in the solid fertilizer might explain why we observed a more pronounced negative effect than for the liquid fertilizer, as the poplar family (Salicaceae) is considered sensitive to damage form NH4 [35].…”