Assessment of the salinity tolerance, response mechanisms and nutritional imbalance to heterogeneous salt supply in Populus alba L. clone ‘Marte’ using a split-root system

Abstract

Salinity responses of Populus alba L. clone ‘Marte’ were evaluated using a split-root system to simulate the heterogeneous soil conditions in the field and to assess the salinity tolerance of clone ‘Marte’. During the 26 days of experiment, we measured morpho-physiological parameters as well as the mineral content in substrate and plant organs in split-root plants watered with no salt on both sides of the system (0/0 mM - S1), salt on one side (0/100 mM – S2) and salt on both sides (100/100 mM – S3). Shoot elongation, stem diameter increase, and number of new leaves were not significantly different among and within each salt treatment. Leaf relative chlorophyll content and chlorophyll a fluorescence did not show any difference, while there was a decrease of 85% in terms of net photosynthesis (Pn) and 88% in stomatal conductance (gs) in S3 plants compared to S1. Na, absorbed by one side of the 0/100 mM plants, was equally distributed in all aerial organs and reached a concentration in-between the other two groups, as a confirmation of the physiological results obtained. An increase in Mn concentrations in woody cutting, stems and leaves of S2 and S3 system compared to S1 group was observed. Moreover, S3 plants showed an increase of K concentration in leaves. In ‘Marte’ poplar, Na increment was only translated in a reduction of photosyntetic performances, and the increase of some key mineral elements at leaf level such as K and Mn suggested an attempt to overcome the stress.

Ecophysiological response of Populus alba L. to multiple stress factors during the revitalisation of coal fly ash lagoons at different stages of weathering

“…At L3, P. alba was found to have lower vitality, but significant differences in the content of Chl a, Chl b, Tot Carot, Anthoc, Ph Free, Ph Bound, and MDA compared to control individuals were not found. This may be the result firstly of NPK fertilisation, as N application improves the drought tolerance of poplars ( Song et al., 2019 ), secondly of the higher Mn content in leaves compared to the other two sites as one of the mechanisms for overcoming stress ( Della Maggiora et al., 2023 ), and thirdly the higher total antioxidant capacity of P. alba at this lagoon (<IC 50) as an indicator of the activation of enzymatic and non-enzymatic antioxidant systems ( Zhang et al., 2019 ; Rosso et al., 2023 ). Also, the localisation of high concentrations of accumulated B in chlorotic and necrotic tissues in the tips and marginal parts of leaves is another adaptive mechanism of plants, which thus ensures a significant proportion of photosynthetic tissue remains functional ( Rees et al., 2011 ).…”

“…Abiotic stresses such as high temperatures, drought, high salinity, and heavy metal pollution, as well as the combination of these stresses, disrupt the metabolic balance of cells, leading to increased production of ROS ( Qadir et al., 2021 ; Mishra et al., 2023 ). In plants, this causes oxidative damage that disrupts many physiological processes, including photosynthesis as the main process of plant metabolism ( Pavlović et al., 2007 ; Mitrović et al., 2012 ; Huang et al., 2019 ; Muhammad et al., 2021 ; Della Maggiora et al., 2023 ). Despite all the physical and chemical limitations and toxicity of FA, various plant species have been found growing on it ( Kostić et al., 2012 ; Técher et al., 2012 ; Mukhopadhyay et al., 2017 ; Yadav et al., 2022 ).…”