Functional characterisation of three Italian Populus alba L. genotypes under salinity stress

Abstract

The functional response to salt stress was studied in three Populus alba L. genotypes, from three localities of Italy: genotype 6K3 from northern Italy, genotype 2AS11 from middle-southern Italy, and genotype 14P11 from a coastal zone in southern Italy. Plants of the three genotypes were submitted to a progressive salt stress by NaCl irrigation during 4 weeks. The severity of symptoms was linked to the sodium accumulated in leaves of salt-stressed plants. Genotype 2AS11 accumulated significantly less sodium in leaves than the other genotypes, arising the hypothesis that mechanisms for sodium exclusion at root level could exist in this genotype. Its height growth was significantly reduced by salt stress but diameter growth and leaf abscission were not affected. 14P11 and 6K3 accumulated significantly more sodium in leaves and they were significantly affected by leaf abscission and reduction of height and diameter growth. Genotype 6K3 was the most salt-sensitive and its leaves had more extensive necrosis than 14P11 and 2AS11. The transcription profile of plasma membrane H + -ATPase and tonoplast H + -ATPase genes revealed a different regulation in response to salt stress in 2AS11 and 14P11, but it was unchanged in 6K3. The different response to salinity could be related to different ability to exclude sodium in roots and to different regulation of ion transport across membranes of leaf cells. The differences observed could be the expression of evolutive adaptation to the ecological conditions of original provenances. Likely a different genetic basis underlies the different degree of salt tolerance observed.

Salt-induced changes on H+-ATPase activity, sterol and phospholipid content and lipid peroxidation of root plasma membrane from dwarf-cashew (Anacardium occidentale L.) seedlings

“…and Cl -exclusion in the apoplast and/or compartmentalization in leaf vacuoles. Evidences that this mechanism exists in leaves of tree species have been demonstrated (Ma et al 2002;Beritognolo et al 2007). In addition, it should be noted that although salt-sensitive genotype (CCP06) presented higher reduction of E under salinity conditions (Table 2), it did not contribute to limit the transport of Na ?…”

“…The presence of a mechanism for sodium exclusion in roots has also been inferred by the level of Na ? accumulated and the severity of symptoms in leaves of salt-stressed plants (Beritognolo et al 2007). Despite these physiological evidences, the biochemical mechanisms controlling ion fluxes across tonoplast and plasma membrane in roots of salt-stressed tree species have been poorly characterized.…”

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

“…-ATPases, as compared to P. popularis (Ding et al 2010). Accordingly, the two salt-tolerant Italian P. alba clones, 14P11 and 2AS11, up-regulated V-ATPase genes at intermediate salinity (14 days) (Beritognolo et al 2007). In the present study, the immuno-reactive band of the membrane was not clear, which was mainly due to (1) the lower abundance of H 1 -ATPase in the PM, and/or (2) the lower Fig.…”

Distribution and concentration of cadmium in root tissue of Populus alba determined by scanning electron microscopy and energy-dispersive x-ray microanalysis

“…These genotypes from contrasting environ ments were compared under salt stress con ditions by measurement of growth, Na accu mulation, and expression of PM-ATPase and V-ATPase genes in leaves of control and salt-stressed plants (Beritognolo et al 2007). The different response to salinity showed by these clones was related to a different ability in excluding Na at the root level and to a dif ferent regulation of ion transport across membranes in leaf cells, which could be the expression of adaptation to ecological condi tions of original provenances.…”