The effect of burnt soils on growth of Xanthorrhoea glauca subsp. angustifolia (Xanthorrhoeaceae) seedlings in box-ironbark ecosystems, northern central Victoria

2015 ◽  
Vol 63 (8) ◽  
pp. 657
Author(s):  
Marc P. Bellette ◽  
Ruth E. Lawrence ◽  
Neal J. Enright

Seedlings of Xanthorrhoea glauca subsp. angustifolia D.J.Bedford (Xanthorrhoeaceae) were grown in burnt, unburnt and ash-rich soils from the box-ironbark ecosystem, northern central Victoria. Analysis of root architecture and the chemistry of leaves and roots demonstrate that burning improves seedling biomass development and acquisition of nutrients. An increased uptake of zinc by seedlings after fire is thought to be ecologically important and may infer vesicular-arbuscular mycorrhizal associations. The early development of a secondary root system is likely to contribute to seedling survivorship. Given the observed high adult mortality after managed fuel-reduction fires, the importance of understanding and manipulating recruitment dynamics through an adaptive and strategic fire management of the remaining populations is likely to define the long-term survival of the species in Victoria.

1990 ◽  
Vol 68 (6) ◽  
pp. 1260-1264 ◽  
Author(s):  
G. Bécard ◽  
Y. Piché

Transformed roots of carrot (Umbelliferae) and sugar beet (Chenopodiaceae) were used as model host and nonhost plant, respectively, for the vesicular–arbuscular mycorrhizal fungus Gigaspora margarita (Becker & Hall). Rapid growth of hyphae from germinating spores of G. margarita and formation of infection units were obtained only in the presence of carrot roots. Root volatiles from both plant species have similar stimulative effects on hyphal growth. However, hyphal growth was stimulated by root exudates of carrot and not by those of sugar beet. These and other results suggest that the nonmycorrhizal roots of sugar beet lack factors that promote mycorrhizal infection rather than producing inhibitory factors. The model used in this study is especially appropriate for further investigations on the recognition mechanisms involved in vesicular–arbuscular mycorrhizal associations.


1985 ◽  
Vol 33 (6) ◽  
pp. 669 ◽  
Author(s):  
Rl Peterson ◽  
AE Ashford ◽  
WG Allaway

Roots of 42 species of angiosperms collected from all vegetation zones on Heron Island were cleared, stained with chlorazol black E and assessed for vesicular-arbuscular mycorrhizae (VAM). Percentage of root length colonized was determined using the gridline intersect method, while stages in internal development of the mycorrhizal association were determined by mounting cleared root pieces on microscope slides and examining them with Nomarski differential interference contrast microscopy. Fifty-seven percent of the species had VAM and of these the percentage of root length colonized varied from 3 to 100%. There were no statistically significant differences among the four vegetation zones of the island in the number of species colonized. About the same proportion of trees and shrubs had VAM as did the herbs. Two species of Brassicaceae, Lepidium virginicum and Sisymbrium orientale, had VAM. All but three species with VAM had both arbuscules and vesicles; arbuscules were not found in Casuarina equisetifolia var. incana, Sisymbrium orientale and Tribulus cistoides.


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