Biotechnology enhances utilization of Australian woody species for pulp, fuel and land rehabilitation

Selection and micropropagation of superior genotypes of species of Australian genera such as Eucalyptus, Acacia, Melaleuca and Casuarina offers a way of capitalizing on Australia's genetic resources without necessarily breaking the tradition of unrestricted export of seed for international forestry. A collaborative program of research and development between Alcoa (Australia), CSIRO Division of Forestry and Forest Products, The University of Western Australia, Murdoch University, North Broken Hill Ltd (APPM Forest Products) and Plantex (Australia) has examined the potential for the use of selected clones of species tolerant to saline waterlogging, and elite selections of E. Globulus and E. nitens for paper pulp production

Comparisons of selected and cloned plantlets against seedlings for rehabilitation of saline and waterlogged discharge zones in Australian agricultural catchments

Clonal lines of Australian tree species have been developed for tolerance to saline and/or waterlogged conditions. These clonal plants have been shown to be more tolerant under glasshouse and field conditions when compared with seedling lines. Selection procedures included the initial collection of seed from trees growing naturally in seasonally waterlogged and/or saline soils. Following germination and establishment, three-month-old seedlings were stressed in glasshouse trials using progressively increased levels of salinity, either in freely drained or saturated conditions, and the most tolerant individuals were micropropagated. Under conditions of saturation and salinity stress, in both glasshouse trial conditions and under field situations, selected and cloned Eucalyptus cawaldulensis. E. spathulata subspecies spathulata, Casuarina obesa and C. glauca plants showed higher survival rates and the surviving plants grew faster than provenance-matched seedlings

Development of salt tolerant clonal trees in Australia

More than one billion hectares, or 7.6% of the world's land, consists of salt affected soils (1). Much of this area is naturally occurring saltland, such as mangrove forests, internally draining basins, and floodplains. However, an increasing proportion of land is becoming saline as the result of agricultural practices. In Western Australia about 12 million hectares of land has been classified as salt-affected, of which about 650,000 ha (5 4 %) is induced salinity as a result of artificially high watertables, or as scalds caused by wind and water erosion (4). Saltland forestry is one of the many strategies proposed for making productive use of salt affected soils. Planting trees is an attractive option because of the primary benefits of salinity control and land reclamation and the secondary benefits of wood products, livestock shelter, windbreaks, and ecological habitat construction

Comparisons of growth of Eucalyptus camaldulensis from seeds and tissue culture: root, shoot and leaf morphology of 9-month-old plants grown in deep sand and sand over clay

Comparisons of early growth of tissue culture clones and seedlings of Eucalyptus camaldulensis indicated strong morphological differences between genotypes within the species, but no architectural differences, either above-or below-ground, were attributable to micropropagation. Clonal 9-month-old plants were less variable than seedling populations. Both seed-origin plants and clonal-origin plants generally developed a number of deep sinker roots and showed equal ability to penetrate heavy clay soils. One clonal line, however, had a compact habit and a root architecture concentrated in the upper 20 cm of the soil profile. Under favourable nutrient and water conditions, the largest of the 9-month-old plants from both seed and tissue culture exceeded 2.5 m in height, produced more than 500 g of above-ground biomass and developed root lengths exceeding 8 km. Clonal Eucalyptus camaldulensis have advantages in plantation conditions with saturated, saline and heavy soil conditions

Root growth of seedlings and tissue cultured plants of Eucalyptus

Plants of dicotyledonous trees raised in tissue culture initially have many adventitious roots rather than the single tap root produced by a seedling. Little is known about the subsequent development of the root morphology of tissue cultured trees. Root architecture affects both survival after planting in the field and the likelihood of windthrow when trees are taller. The seedling tap root of eucalypts does not normally persist as the dominant root. Several lateral roots develop as sinker roots, grow to equal thickness and penetrate to great depths (Dell et al, 1989)