Trees, shrubs and grasses for saltlands: an annotated bibliography

2013

Agroforestry Systems, 2016

Salt tolerant plants are known to remove excess soluble salts from the soil and thus may be used in land reclamation. We studied the responses of the trees, Balinites aegyptiaca L. (Zygophyllaceae), as well as the Fabaceae, Acacia tortilis (Forssk) Hayne, and Tamarindus indica L. to salinity. Three experiments were conducted on: germination, in the laboratory; seedling performance in a lath house; and, the impact of the tree species on soil productivity in the field in Afar regional state along the Awash river, eastern Ethiopia. Mixtures of salts, composed of chlorides and sulfates were tested at different concentrations in both germination and lath house experiments in randomized complete block designs. Seedling root collar diameter and height were measured every two weeks. Soil samples were collected from randomly selected pots to examine the effect of salinity on soil properties. The effects of trees on in situ soil productivity was studied by collecting 72 soil samples at different distances from the tree and different soil depths. The soil productivity index was calculated by summing the products of sufficiency of available water capacity, aeration, bulk density, pH, electrical conductivity and the Weighting factor for each layer. The study revealed that germination percentage and rate decreased significantly with increasing salt concentrations. The effects of the three tree species on soil properties were significantly different at 12.2 dS m-1 salinity level compared to the control. A. tortilis was the least salt-sensitive. Balancing the key requirements of adequate germination and growth and the ability to reduce the salt concentration of the soil solution, B. aegyptiaca is the species with the most potential. Therefore, the study suggests to use B. aegyptiaca as agroforestry trees in the form of parkland in arid and semi-arid areas where salinity problems are prominent.

Acta Botanica Hungarica, 2002

The reduction in seed germination and seedling growth varies with plant species, salinity level and ionic composition of the salts present in soil solutions. Seed germination of Leucaena leucocephala and Prosopis juliflora were affected in soil extract of all halophytic communities. Significant (p < 0.05) reduction in seed germination of Thespesia populnea was found in soil extract of Cressa-Suaeda-Atriplex and Suaeda-Heliotropium-Tamarix community. The root growth of P. juliflora was significantly reduced in soil extract of Haloxylon-Suaeda-Atriplex community. Significant inhibition in shoot growth of L. leucocephala and P. juliflora were found in soil extract of Haloxylon-Suaeda-Atriplex community. L. leucocephala and T. populnea showed low tolerance in soil extract of Cressa-Suaeda-Atriplex community. P. juliflora demonstrated low tolerance in soil extract of Haloxylon-Suaeda-Atriplex community. The soil collected from different community showed variation for soil conductivity and cations. The highest sodium (11,500 µg/g) was observed in Suaeda-Heliotropium-Tamarix community. Salsola-Fagonia-Zygophyllum community exhibited the lowest concentration of sodium and potassium, 500 and 75 µg/g, respectively. It was found that sodium was directly proportional to the conductivity of the soil extract.

Ecophysiology of high salinity tolerant plants, 2006

Salt tolerance mechanisms of three perennial halophytic grasses (Aeluropus lagopoides (Linn.) Trin. ex Thw., Sporobolus ioclados (Trin.) C.E. Hubbard and Urochondra setulosa (Nees ex Trin.) Nees) were studied to determine if local species employ similar strategies to tolerate high salinity. We found different patterns of growth, water relations and ion uptake among the species tested. Aeluropus lagopoides and U. setulosa were grown in 0-1000 mM NaCl while S. ioclados in 0-500 mM NaCl under ambient conditions. Plants from nonsaline controls had larger fresh and dry weights. Increasing concentrations of salinity from 600 -1000 mM NaCl for A. lagopodides and U. setulosa and 500 mM NaCl for S. ioclados caused high salinity stress. Water and osmotic potential of the plants increased with increasing salinity and pressure potential decreased slightly in all species. Stomatal conductance in all grasses decreased substantially with the increase in salinity. Ash content remained low (~12%) in both shoot and root of all grasses and showed little change with the increase in salinity except for S. ioclados, where in root it increased up to 35%. Na + and Clconcentrations showed a small increase while Ca 2+ , Mg 2+ and K + remained constant with increasing salinity. Various ion ratios for shoot and root also showed variation between the species tested.

Agroforestry Systems, 2014

Unproductive saline and waterlogged wastelands could be beneficially transformed into agroforestry systems using trees tolerant to these stresses. We studied the salinity and waterlogging tolerance of five Australian tree species (Acacia salicina, Casuarina glauca, Casuarina obesa, Eucalyptus camaldulensis and Eucalyptus occidentalis) during seedling stage and their relationships with root and leaf ion concentrations. Eight-month old plants were exposed for five months to five irrigation water salinity treatments (EC values between 2 and 22 dS m -1 ) and two waterlogging treatments (drained or waterlogged). The salinity tolerance of the five species was high, although decreased in waterlogged conditions. Irrespective of salinity, the two Casuarina species were more tolerant and the other three species were less tolerant to waterlogged than drained conditions. In all species, salinity and waterlogging increased leaf Cl − and Na + and decreased leaf Ca 2+ , but not leaf K + . Root Cl − and Na + increased with salinity but not with waterlogging. Salinity tolerance was negatively correlated with Cl − and Na + leaf accumulation rates per unit increase in salinity. Waterlogging reduced the ability of the seedlings to exclude Cl − and Na + from the leaves. The two most salt tolerant Casuarina species under both drained and waterlogged conditions showed the highest leaf Cl − and Na + exclusion and the highest root Cl − and Na + accumulation, suggesting that sequestration of these toxic ions in their roots was a significant salt-tolerant mechanism. Revegetation of saline and waterlogged wastelands with these tolerant Casuarina species could be profitably used for biomass, biofuel and renewable energy production. 2008), but the effects of waterlogging and the interactions between salinity and waterlogging are not fully understood. Waterlogging becomes an additional constraint to plant growth in saline areas because, besides the osmotic and the Na + or Cltoxic effects derived from the accumulation of salts, the soil becomes oxygen deficient (hypoxic) (Barrett-Lennard and Shabala, 2013). The main effects of hypoxic conditions on plants are the reduction of ATP formation, the lower growth of roots and root survival, the lower uptake of nutrients, and the reduction in the capacity of plants to exclude toxic ions like Na + and Cl − from the shoots (Kozlowski 1997; Barrett-Lennard 2003; Barrett-Lennard and Shabala, 2013). This ion-exclusion reduction could exacerbate plant damage under saline conditions since there is considerable evidence that differences in the ability to exclude these ions is one of the most important factors underlying intraspecific differences in tolerance (Allen et al. 1994;). analyzed the seedling performance of seven Australian tree species subject to salinity/waterlogging conditions and concluded that the species with the highest tolerance to non-saline waterlogging were also more tolerant of saline-waterlogging conditions. Aswathappa and Bachelard (1986) found that the more salt-tolerant Casuarina species accumulated less Na + and Clin their shoots and maintained a higher selectivity of K + over Na + than less tolerant species. Furthermore, root Na + and Cl − concentrations in salt tolerant Casuarina species were either similar to or lower than those in moderately tolerant Casuarina species. found that the slowest rates of growth in ten Acacias subject to salt stress were associated with the highest Na + concentrations in the uppermost The objectives of the present study were to establish in five Australian tree species the salinity tolerance under drained and waterlogging conditions, (2) the waterlogging tolerance, and (3) the relationships of Na + , Cl -, K + and Ca 2+ accumulation in leaves and roots to salinity and waterlogging tolerance. The accomplishment of these objectives will enhance the expansion of agroforestry systems cultivated with the most adequate species for high salinity and waterlogged landscapes.

Australian Journal of Experimental Agriculture, 2006

Australian Journal of Experimental Agriculture, 2005

Tree physiology, 1994

Prospects for increasing the salt tolerance of forest trees: a review ... JAMES A. ALLEN,&#x27; JIM L. CHAMBERS2 and MICHAEL STINE2 &#x27; National Biological Survey, National Wetlands Research Center, 700 Cajundome Blvd., Lafayette, LA 70506, USA 2 School of Forestry, Wildlife ...

2000