Effects of NaCl on shoot growth, transpiration, ion compartmentation, and transport in regenerated plants of Populus euphratica and Populus tomentosa

Abstract

The effect of a 20-day NaCl treatment on shoot growth, transpiration, ion uptake and transport, and intracellular ion compartmentation was investigated in regenerated plants of Populus euphratica Oliv. and Populus tomentosa Carr. Plants watered with 100 mM NaCl for 8 days and then 200 mM NaCl for 12 days exhibited soil NaCl concentrations of 60 and 95 mM, respectively. Unit transpiration rates and relative growth rates of P. tomentosa were restricted more by salinity as compared with P. euphratica. Salinized P. tomentosa exhibited leaf necrosis whereas no damage was seen in stressed P. euphratica. Compared with P. tomentosa, P. euphratica had considerably lower rates of net root uptake and transport of salt ions (Na+ and Cl–) to the shoots under salinity. The relatively lower unit transpiration rates of P. euphratica and the lower salt concentrations in the xylem of salinized P. euphratica contribute to its greater capacity for salt exclusion. X-ray microanalysis showed that P. euphratica had a greater ability to restrict radial salt transport in roots by blocking apoplasmic salt transport and sequestering more Cl– in cortical vacuoles. In addition, P. euphratica maintained higher K+ uptake and transport than P. tomentosa in the presence of high external Na+ concentrations.

Genomic insights into salt adaptation in a desert poplar

“…2b). HKT1 transporters have a key role in limiting Na þ transport from roots to shoots in Arabidopsis 19 , and may account for the lower rate of ion uptake and transport recorded in P. euphratica 9,20,21 . The gene family encoding P-type H þ -ATPases also had more copies in the P. euphratica genome than in the P. trichocarpa genome (Fig.…”

“…We further compared the expression profiles of the P. euphratica calluses in response to salt stress with those of the P. tomentosa (a salt-sensitive poplar 21 ) calluses (Supplementary Table S31, Supplementary Figs S22 and S23). The results showed that many of the DEGs (2,278) were specific to P. euphratica (Fig 3b), and that more genes involved in 'cation transporter', 'oxidoreductase activity' and 'response to abiotic stimulus' were induced in P. euphratica than in P. tomentosa (Fig.…”

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

“…Similarly, we found that more Na ? and Cl -ions accumulated in the cortical walls of P. euphratica roots, as compared to the salt-sensitive poplar species (Chen et al 2002(Chen et al , 2003. It is Communicated by H. Rennenberg.…”

“…noteworthy that P. euphratica has a greater ability to sequester salt ions, especially Cl -in root cortical vacuoles (Chen et al 2002(Chen et al , 2003. The effective salt compartmentation in P. euphratica roots (including salt exclusion and vacuolar salt sequestration) is suggested to make a contribution to the restriction of ion loading into the root xylem during radial transport, and thus limits subsequent axial transport (Chen et al 2002(Chen et al , 2003.…”

Effects that nutritional and saline gradients have on the growth of Passiflora mucronata Lam. and Canavalia rosea (Sw.) DC. found in the restinga of Brazil

“…Some symptoms of nutritional and saline stress are quite similar. Such symptoms include a reduction in biomass and in the percentage of survival of the plants (Benlloch-González et al 2005), as well as lower growth rates (Chen et al 2003;Cuzzuol et al 2005a), low foliar succulence, higher root/shoot ratio (R:SR, Garg & Singla 2004;Cambraia 2005) and a reduction in photosynthetic activity (Lee et al 2004;Cuzzuol et al 2008).…”