Author:
Groves RH,Hocking PJ,Mcmahon A
Abstract
The heathland form of Banksia marginata Cav. regenerates rarely from seed but commonly by resprout-
ing from buds on lateral roots, whereas Banksia ornata F. Muell. regenerates only from seed, usually
released after fire. The two species co-occur in heath vegetation on nutrient-poor soils in south-eastern
South Australia and western Victoria. Shoots were sampled from stands of B. marginata aged from 1
to 25 years and of B. ornata aged from 1 to 50+ years after fire in the Little Desert National Park,
western Victoria.
B. marginata, the resprouter, distributed a greater proportion of the total shoot dry matter and
content of all nutrients to vegetative growth over its shorter life span than B. ornata, the non-sprouter.
About 50% of the total phosphorus in B. ornata shoots at 50+ years was present in cones (including
seeds) compared with only about 20% in B. marginata shoots at a comparable stage of senescence (25
years). This difference between the species was also true to a lesser degree for nitrogen. There were
considerable differences between other nutrients in their distribution patterns in shoots. Nutrients could
be grouped together on the basis of distribution in shoots more satisfactorily than on presumed physio-
logical roles. Stems were major sites of nutrient accumulation in both species. The content of a particular
nutrient in seeds as a proportion of the content in the living parts of the shoot ranged from 0.03% (Na,
Mn) to 2.0% (P) in B. marginata, and from 0.3% (Na) to as high as 31% (P) in B. ornata. Concen-
trations of all nutrients except sodium were much higher in seeds than in the woody cones or vegetative
organs of both species; seeds of B. ornata were particularly rich in calcium and manganese.
We conclude that the different patterns of distribution of biomass and nutrients, especially nitrogen
and phosphorus, within shoots of the two species reflect their different regenerative modes after fire.
Introduction
Phosphorus and, to a lesser extent, nitrogen limit the growth of sclerophyllous shrubs
on nutrient-poor soils in southern Australia
Subject
Plant Science,Ecology, Evolution, Behavior and Systematics
Cited by
21 articles.
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