Comparison of the Early Growth Characteristics of the Eucalyptus Subgenera Monocalyptus and Symphyomyrtus

Abstract

The early growth characteristics of six Tasmanian species from each of the Eucalyptus subgenera Monocalyptus and Symphyomyrtus were examined. The species chosen from each subgenus came from a range of habitats extending from low altitude dry sclerophyll sites to subalpine sites. Marked differences in the rate of germination, percentage of viable seeds, total dry weight, and the root to shoot ratio were observed after 3 and 7 months' growth, as well as different responses to the level of nutrient provided. These subgeneric differences were generally larger than the differences observed between species chosen from one subgenus but from different ecological sites. The most striking differences were possibly the higher root to shoot ratio found in the subgenus Symphyomyrtus and the generally faster establishment of species from this subgenus. The results show that the two subgenera possess different early growth patterns. This may suggest that the subgenera exploit their environment in slightly different ways and may, at least partly, explain the frequent occurrence of mixed stands of eucalypts in south-eastern Australia. where stands frequently contain one species from each subgenus.

Cyclitols and carbohydrates in leaves and roots of 13 Eucalyptus species suggest contrasting physiological responses to water deficit

“…Several authors have attempted to delineate Eucalyptus species based on initial growth rates (Davidson & Reid 1980;Duff, Reid & Jackson 1983), foliar nutrient concentrations (Lambert & Turner 1983), volatile leaf oils (Li, Madden & Potts 1995, 1996 and respiratory metabolism (Anekonda et al 1999) and combinations of these parameters (Noble 1989). It is likely, however, that the geographical distribution of Eucalyptus species is dependent on a variety of these factors, but particularly related to the availability of water (Adams 1996).…”

Targeted metabolite profiling provides a functional link among eucalypt taxonomy, physiology and evolution

“…For example, even among the large group of 'multistemmed' eucalypts that are generally drought-tolerant, speciation has been attributed to between-habitat variation in water availability of a few percent (Parsons, 1969a,b). At a larger scale, there are many seemingly clear instances of speciation among Australian tree genera that are attributed to isolation of gene pools within environments that differed mainly in the availability of water (Davidson and Reid, 1980;Noble, 1989;Adams, 1996).…”

Variation in the Eucalyptus gunnii-archeri Complex. III. Reciprocal Transplant Trials

“…internode length, lamina size, height, habit; see Table 2) and large treatment effects are frequently reported for such characters in Eucalyptus (e.g. Clucas and Ladiges 1979;Davidson and Reid 1980). In contrast, other characters such as glaucousness and those associated with leaf shape exhibit relatively little environmental modification (e.g.…”