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Accueil du site → Doctorat → Australie → Management of dryland salinity in Central-west New South Wales, Australia : remediation trials using salt-tolerant plants

Charles Sturt University (2016)

Management of dryland salinity in Central-west New South Wales, Australia : remediation trials using salt-tolerant plants

Bhuiyan, Mohammad

Titre : Management of dryland salinity in Central-west New South Wales, Australia : remediation trials using salt-tolerant plants

Auteur : Bhuiyan, Mohammad

Université de soutenance : Charles Sturt University

Grade : Doctor of Philosophy (PhD) 2016

Résumé partiel
In this thesis, I present details of the trials made towards the management of dryland salinity in Central-west New South Wales using selected salt-tolerant plants belonging to Fabaceae, Amaranthaceae (Salicornidiodeae), and Poaceae. _ To provide a comprehensive context, Chapter 1 reviews earlier literature in the areas of (i) salinity in Australia, the state of New South Wales, and Central west New South Wales, (ii) salinity-remediation strategies and phytoremediation trialled in Australia, the state of New South Wales, and Central-west New South Wales, besides other parts of the world, (iii) effect of salinity on plant growth and photosynthetic performance, and (iv) physiology of salt-tolerance in plants. Against these contextual notes, I have outlined the purpose and goals of this study. _ Chapter 2 explains how I evaluated the experimental sites and selected some of the naturally occurring plants in two salt-affected Gumble and Cundumbul sites in Central-west New South Wales, Australia. Gumble and Cundumbul. Cynodon dactylon (Poaceae) and Thinopyrum ponticum (Poaceae) are selected two most abundant naturally occurring populations in both sites. The concentrations of Na+, K+, Ca2+, and Mg2+ in roots and shoots of C. dactylon and T. ponticum, bioaccumulation factor (BF), and translocation factor (TF) were also measured to evaluate their phytoremediation capacity. Salinity monitoring results revealed that Cundumbul site is more saline than Gumble besides a positive correlation exists between the EM38 result and soil : water1:5 extraction results. Ion-accumulation results indicated that T. ponticum accumulated greater quantity of Na+, K+, and Ca2+ than C. dactylon irrespective of locations. Cynodon dactylon accumulated greater Mg2+ than T. ponticum in Gumble site. The BF values of Ca2+, K+ and Na+ were significantly higher in T. ponticum than C. dactylon while BF value of Mg2+ was significantly higher in C. dactylon than T. ponticum irrespective of locations. At Gumble site, the TF value of Na+ was significantly greater in T. ponticum than C. dactylon whereas, this TF value was opposite in Cundumbul site. The overall salt accumulation (root+ shoot) was greater in T. ponticum than C. dactylon ; therefore, I suggest that T. ponticum can be used for restoration of salt-affected land in Central-west New South Wales (Bhuiyan et al. 2016d). _ Chapter 3 explains the salt-ion accumulation and stress-tolerance capacities of the selected plants, viz., C. dactylon and T. ponticum. I evaluated Na+, K+, Mg2+, and Ca2+ levels in their roots and shoots and in the supporting soil. The physiological parameters of these species, including net photosynthetic rate (Pn), stomatal conductance (gs), and intercellular CO2 concentration (Ci) were investigated using LI-COR 6400 XT, a portable photosynthesis measurement system. Increasing salinity levels in the topsoil had a significant influence on Ci and gs, whereas no significant effect occurred on Pn in C. dactylon and T. ponticum. The Pn values in C. dactylon and T. ponticum were greater at Cundumbul than Gumble. The greater Mg2+ concentration facilitated greater Pn in C. dactylon and T. ponticum populations at Cundumbul than Gumble. Accumulation of Na+, K+, Mg2+, and Ca2+ was higher in T. ponticum than C. dactylon ; therefore, T. ponticum impresses as a better salt accumulator than C. dactylon. Thinopyrum ponticum could be used in the phytoremediation of salt affected pasture landscape in Central-west New South Wales (Bhuiyan et al. 2015a).

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