Salt tolerance of frost-resistant eucalypts

Abstract

Application . Frost resistance is a prerequisite for establishment of trees exposed to harsh winters irrespective of soil conditions . Seedlings of frost-resistant eucalypts from the subgenus Symphyomyrtus were shown to be much more salt-tolerant than those from the subgenus Monocalyptus, and are therefore likely to be more suitable for planting on dryland saline sites exposed to cold winters .Abstract . Nineteen frost-resistant Eucalyptus species were screened for salt tolerance under glasshouse conditions . This study was undertaken in order to determine the potential of these species for planting on dryland salt-affected sites in the frost-prone Tablelands of south-eastern Australia. Seedlings were established in sand-filled pots and exposed to a step-wise increase in NaCl concentration to a maximum of 500 mol m -' . Salt tolerance was assessed on the basis of mortality, leaf damage and height growth . All species in the subgenus Symphyomyrtus*, particularly those in the Section Maidenaria Series Ovatae, were moderately salt-tolerant (no mortality at 300 mol m -' NaCl) whereas those in the subgenus Monocalyptus* proved to be very salt-sensitive (no survival at 300 mol m-, NaCI) .Eucalyptus camaldulensis, E . tereticornis and E. occidentalis were the most salt-tolerant species of those included in this study. Salt-sensitive species had shoot Na' and CIconcentrations of up to 2 .25 mmol g ' dry wt .

Screening Eucalyptus Clones for Salt Tolerance

“…In this short-term greenhouse study, the performance of all five Eucalyptus clones across salinity levels was generally in agreement with earlier results from saline field trials with other E. camaldulensis genotypes (Dunn et al, 1994;Farrell et al, 1996b) and glasshouse pot cultures (Blake, 1981;Marcar, 1989). Sands (1981) reported a high survival rate for E. camaldulensis seedlings grown for 3 months in saline (400 mM NaCl) pot cultures.…”

Does Biochar Improve Establishment of Tree Seedlings in Saline Sodic Soils?

“…The mechanism related to the increased Na uptake in A. mearnsii with biochar addition in the highly saline sodic soil is unclear and further research on this mechanism is required. Both species showed evidence of chlorosis, necrosis and leaf curl in the moderately and highly sodic soils, which is suggestive of osmotic stress and nutrient limiting impacts because of the saline sodic soil conditions (Marcar, 1989;Marcar et al, 1995;Rengasamy, 2006). The application of 5 Mg ha À1 biochar had no beneficial effect on plant condition.…”

“…The adverse effects of high salinity have been shown in the reduced growth of Eucalypt sp. (Niknam & McComb, 2000) and in the observations of necrosis and death of E. viminalis when irrigated with ≥ 300 mol m À3 NaCl (Marcar, 1989). No amelioration attempts to improve Eucalyptus and Acacia sp.…”

“…(Niknam & McComb, ) and in the observations of necrosis and death of E . viminalis when irrigated with ≥ 300 mol m −3 NaCl (Marcar, ). No amelioration attempts to improve Eucalyptus and Acacia sp .…”

“…Both species showed evidence of chlorosis, necrosis and leaf curl in the moderately and highly sodic soils, which is suggestive of osmotic stress and nutrient limiting impacts because of the saline sodic soil conditions (Marcar, ; Marcar et al ., ; Rengasamy, ). The application of 5 Mg ha −1 biochar had no beneficial effect on plant condition.…”