Periodicity of Fine Root Growth in Jarrah (Eucalyptus marginata Donn Ex Sm.)

Dell, B.; Wallace, IM

doi:10.1071/bt9830247

Cited by 19 publications

(11 citation statements)

References 9 publications

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“…How this was achieved is uncertain. However, interspecific differences in root distribution in the top 2 cm of soil (the depth to which rain penetrated) or direct water uptake by the leaves (Connor et al 1977;Cremer & Svensson 1979;Dell & Wallace 1983) may be involved. After extensive rains, E. pulchella exhibited a more rapid return to normal diurnal fluctuation in stomatal conductance and water potential ( Fig.…”

Section: Discussionmentioning

confidence: 99%

Response of eucalypt species to drought

Davidson

Reid

1989

Australian Journal of Ecology

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The response of three eucalypt species (Eucalyptus pulchella. Eucalyptus coccifera and Eucalyptus delegatensisj to a severe drought in the summer of 1982/83 was examined at Snug Plains, south-eastern Tasmania. Few large differences in leaf water potential (\j/i) or stomatal conductance (gs) were apparent even at the height of the drought when both ii/i and soil water potentials (y/s) reachedca. -4.5 MPa. However. E. pulchella maintained a higher relative water content (RWC) in its leaves than E. coccifera and E. delegatensis, and showed less severe crown damage. After the first light rains substantial interspecific differences in i^/ and gs occurred. Eucalyptus pulchella restored normal \j/i, gs and RIVC more rapidly than the other two species and. even for severely droughted trees, crown growth commenced via epicormic buds near the ends of its branches while for E. delegatensis and E. coccifera crown regeneration was via epicormic buds arising from stems and larger branches. This resulted in a change in dominance in certain stands and showed that E. pulchella was more drought-resistant than E. coccifera. which was in turn more resistant than E. delegatensis. This conclusion was confirmed during competition experiments using potted seedlings. However, potted seedlings differed from mature field trees by maintaining moderate gs at high vapour pressure deficits and closing stomata at fl below ca. -2.0 MPa. Substantial variation in the severity of drought symptoms was observed over short distances. This variation appeared to be determined by the moisture-holding capacity of the .soil and the biomass of the stand. Although differences in the rooting patterns of seedlings were evident, field measurements of i/// and ij/s suggested that all three species were exploiting the same water resource.In contrast to previous studies, the results suggest that large interspecific differences in tissue hydration and crown damage may be present, even though differences in i///, gs and characteristics of the root system may appear small.

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Section: Discussionmentioning

confidence: 99%

Response of eucalypt species to drought

Davidson

Reid

1989

Australian Journal of Ecology

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“…Any rainfall pattern promoting moist soil conditions over summer will allow rapid lesion extension within the host (Tippett & Hill 1983;Shearer & Tippett 1989) and thus may cause significant disease expression. These circumstances not only provide ideal conditions for the growth of this tropical organism, but also favour the initiation and growth of fine roots which are an important avenue of invasion for the pathogen (Dell & Wallace 1983;Shearer & Tippett 1989). It seems probable that the construction of management tracks from 1965 to 1970 during a period of consistently high rainfall may have facilitated the dispersal of and infection by the fungus.…”

Section: Disease Expression and Distribution Of P Cinnamomi In The Parkmentioning

confidence: 99%

The ecological impact of Phytophthora cinnamomi in the Stirling Range National Park, Western Australia

Wills¹

1993

Australian Journal of Ecology

120

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An assessment of the impact of the soil-borne pathogenic fungus, Phytophthora cinnamomi (Oomycetes, Peronosporales), on the plant communities of the Stirling Range National Park was carried out between December 1988 and April 1989. A total of 541 plant species were collected, with the Proteaceae and the Myrtaceae the two largest families in the study region. Of the 330 species assessed for susceptibility to P. cinnamomi, 118 (36%) were recorded as having at least some individuals in a population judged to have been killed by the fungus and 33 (10%) were highly sensitive to the pathogen (more than 80% of plants in a population killed). Several families had large numbers of susceptible species, while others were apparently unaffected by the pathogen. Notably, 85% of proteaceous species assessed were rated as susceptible to P. cinnamomi. Proteaceous elements had a mean projective foliage cover of 40% in healthy plant communities, but had a mean cover of only 10% atsites that had along history of infestation with the fungus. In contrast, some species with low levels of susceptibility to the pathogen, such as some monocotyledons, were found to be more abundant at oldinfested sites than at healthy sites. Growth form may also influence susceptibility, with herbaceous perennials, annuals and geophytes assessed in this survey apparently unaffected by the fungus whereas 48% of woody perennials surveyed were susceptible.Changes in the floristic structure of plant communities may influence the composition of associated animal communities. In particular, vertebrate flower visitors may be vulnerable since 59% of the species with vertebrate-pollinated flowers were found to be susceptible to the pathogen. This research highlights the serious ecological impact of P. cinnamomi on native plant communities and suggests that significant components of the flora and associated fauna of the southwest of Western Australia are endangered by this virulent pathogen.

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“…It is possible that low soil temperatures hamper fine root growth in thi s period, while fine root mortality is maintained at an equal rate; together this could result in a low in live fine root mass. Stimulation of fine root growth by moisture availability has been shown elsewhere in interruptedly dry, nutrient-poor ecosystems (Kummerow 1981;Kummerow et al 1978;Caldwelll979;Haines in Specht 1981;Dell & Wallace 1983), while the reported higher density of fine roots below plant crowns as against unshaded areas in such ecosystems may be regarded as additional indirect evidence. On the other hand, a number of studies have shown adverse results (Lyr & Hoffmann 1967;Rutherford 1983).…”

Section: Discussionmentioning

confidence: 76%

Fine roots in a dryCallunaheathland

Tinhout

Werger

1988

Acta Botanica Neerlandica

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SUMMARY The fine roots in a dry Calluna vulgaris heathland are concentrated in the top soil. Over a 21‐month period their dry mass varied from 303 to 612 g m−2, or from 15.7 to 55.2% of the total root mass in the top 5 cm of soil. In early summer and in late autumn to early winter there appeared to be peaks in fine root mass. Data suggest that fine root mass is correlated with moisture availability in the top soil. Nitrogen concentration of the fine roots averaged 17.3 mg g−1 and showed seasonal variation; Phosphorus concentration averaged 0.56 mg g−1 and did not show such variation.

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Periodicity of Fine Root Growth in Jarrah (Eucalyptus marginata Donn Ex Sm.)

Cited by 19 publications

References 9 publications

Response of eucalypt species to drought

Response of eucalypt species to drought

The ecological impact of Phytophthora cinnamomi in the Stirling Range National Park, Western Australia

Fine roots in a dryCallunaheathland

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