1. We investigated whether reserves stored in the lignotubers of two Mediterranean shrubs, Arbutus unedo and Erica arborea, were significantly mobilized to support the demands of regrowth and respiration after clipping the tops at different frequencies.

2. After a single clipping, Arbutus showed a 29% decrease of phosphorus concentration by the end of the first growing season. Two years after recovery from clipping, the starch levels remained lower than those of unclipped plants. Similarly, Erica showed depletion of starch, but no nutrient reserves were depleted significantly.

3. Regrowth after multiple clippings mobilized a large fraction of the starch and nutrients stored in the lignotuber. Mean starch concentrations were depleted by 87–93% after multiple clippings and concentrations of nitrogen, phosphorus, potassium and magnesium were depleted by 10–45%, 27–41%, 19–39% and 23–31%, respectively.

4. An average-sized lignotuber produced 288 resprouts for Arbutus and 1990 resprouts for Erica during a 27 month period of multiple clippings, at the end of which the first plants died.

5. Plant mortality after multiple clipping was 10% for Arbutus and 30% for Erica, and was primarily attributed to exhaustion of carbon reserves because starch concentrations decreased by 96% in dead plants.

https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2435.1998.00154.x

Lignotuber reserves support regrowth following clipping of two Mediterranean shrubs

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% at sites that had a long 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 old-infested 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.

The ecological impact of Phytophthora cinnamomi in the stirling range national park, Western Australia

This review examines current understandings of how the belowground characteristics of urban settings affect tree roots as well as how tree roots contribute to biogeochemical processes in this belowground environment. Soil characteristics common to the urban environment in- clude soil compaction and other physical impediments to root exploration, elevated pH, altered temperature and moisture patterns, and the pres- ence of contaminants. These conditions may alter the growth dynamics, morphology, and physiology of roots. At the same time, roots have a profound effect on the soil environment, with trees directing 40%-73% of assimilated carbon below ground. Urban rhizosphere ecology is a top- ic of renewed interest for research not only because of its critical role in the urban ecosystem, but also because of its role in global environmen- tal issues. In addition to its obvious contribution to aboveground growth, root exploration of the soil environment can influence environmen- tal sustainability through root contributions to soil structure and drainage. Root influence is further mediated by the intimate role of roots in soil biological activity and thus carbon storage and nutrient cycling. Current advances and implications for emerging research are discussed.

/pdf/tree-root-ecology-in-the-urban-environment-and-implications-316u8g2ah4.pdf

Tree Root Ecology in the Urban Environment and Implications for a Sustainable Rhizosphere

This survey included 109 plants native to the jarrah forest (a mediterranean eucalypt woodland in south-western Australia dominated by Eucalyptus marginata and E. calophylla). Mycorrhizal formation by seedlings of these plants was examined after inoculation with isolates of vesicular-arbuscular mycorrhizal (VAM) fungi, or after growth in intact cores of natural habitat soil containing VAM and ectomycorrhizal (ECM) fungi. These methods were supplemented by examining roots from mature forest-grown plants, so that different methods and criteria for designating mycorrhizal association types could be considered. Most plants had one of the following types of mycorrhizal association: VAM only (56% of species); both ECM and VAM (16% of species); or non-mycorrhizal roots (25% of species, which also had long root hairs and/or cluster roots). Plants with dual ECM/VAM associations often formed ECM more readily than VAM. With the exception of the large and diverse families, Papilionaceae, Myrtaceae and Anthericaceae, plants within a family had consistent mycorrhizal relations, as did the members of most genera.

Roots of Jarrah Forest Plants. I. Mycorrhizal Associations of Shrubs and Herbaceous Plants

Summary

Despite its importance as one of the most notorious, globally distributed, multihost plant pathogens, knowledge on the survival strategy of Phytophthora cinnamomi in seasonally dry climates is limited. Soil and fine roots were collected from the rhizosphere of severely declining or recently dead specimens of 13 woody species at 11 dieback sites and two dieback spots and from healthy specimens of five woody species at four dieback-free sites in native forests, woodlands and heathlands of the south-west of Western Australia (WA). Phytophthora cinnamomi was recovered from 80.4, 78.1 and 100% of tested soil, fine root and soil–debris slurry samples at the 11 dieback sites, in some cases even after 18-month storage under air-dry conditions, but not from the small dieback spots and the healthy sites. Direct isolations from soil–debris slurry showed that P. cinnamomi colonies exclusively originated from fine roots and root fragments not from free propagules in the soil. Microscopic investigation of P. cinnamomi-infected fine and small woody roots and root fragments demonstrated in 68.8, 81.3 and 93.8% of samples from nine woody species the presence of thick-walled oospores, stromata-like hyphal aggregations and intracellular hyphae encased by lignitubers, respectively, while thin-walled putative chlamydospores were found in only 21.2% of samples from five woody species. These findings were confirmed by microscopic examination of fine roots from artificially inoculated young trees of 10 woody species. It is suggested that (i) the main function of chlamydospores is the survival in moderately dry conditions between consecutive rain events and (ii) selfed oospores, hyphal aggregations, and encased hyphae and vesicles in infected root tissue of both host and non-host species are the major long-term survival propagules of P. cinnamomi during the extremely dry summer conditions in WA.

New insights into the survival strategy of the invasive soilborne pathogen Phytophthora cinnamomi in different natural ecosystems in Western Australia.

The timing of new surface root growth in jarrah (Eucalyptus marginata) was followed for a 15-month period in the field. The periodicity of new root growth was similar for long roots, non-mycorrhizal and mycorrhizal root clusters. Root growth was initiated during two peak periods in spring (September-October) and following autumn rain (May-June). Little new root activity was recorded in late winter (August) or during summer drought. Rapid root growth occurred within 2 days of a storm (47 mm rain) in February. In addition, short roots formed after very light showers of rain (<5 mm) in late summer. Much of the framework for fine feeder roots was built up after autumn rain. In contrast to new long root growth which was equally spread between spring and late autumn, the majority of new mycorrhizal roots were produced from May to July. Root growth ceased when warm surface soils dried out and commenced when the soils were moist after rain. Much of the new root growth in jarrah occurred when the root pathogen Phytophthora cinnamomi was active in the soil.

Periodicity of fine root growth in Jarrah (Eucalyptus marginata Donn ex Sm.)

Jarrah seedlings were grown in six virgin Western Australian soils for up to 27 months. Lignotubers were produced in all soils and formed 10-16% of plant dry weight. The phosphorus concentration in the lignotuber (250-800 μg g -1) was nearly twice that in the stem and roots. The lignotuber contained 10-30% of total plant phosphorus and like the leaves was a sink for phosphorus. In one lateritic soil the phosphorus concentrations of lignotuber and stem barks were similar. However, in the same plants the concentration of phosphorus in the lignotuber wood was five times the phosphorus concentration in stem wood. Hence both lignotuber bark and sap wood in young jarrah seedlings are storage sites for phosphorus. X-ray probe analysis showed that wood phosphorus was associated with the ray parenchyma. Unlike phosphorus, nitrogen did not accumulate in the lignotuber and the concentrations of nitrogen were similar for roots, lignotubers and stems.

Phosphorus accumulation by lignotubers of jarrah (Eucalyptus marginata Donn ex Sm.) seedlings grown in a range of soils

Recovery of Phytophthora cinnamomi from naturally infected jarrah roots

The anatomy of surface feeder roots of Eucalyptus marginata was investigated. Two types of long roots were recognized: (a) those with thick-walled epidermal cells, and (b) those with a lignified outer cortex. The hypodermis of short roots was often suberized and the inner layers of the cortex had lignified secondary walls. The occurrence of lignified and suberized layers is discussed in relation to possible infection by Phytophthora cinnamomi.

Surface Root System of Eucalyptus marginata Sm.: Anatomy of Non-Mycorrhizal Roots.

The relationships of seven levels of zinc supply to dry matter and zinc concentration were assessed for jarrah (Eucalyptus marginata Donn ex Smith) seedlings grown for 84 days in a zinc-deficient sand in the glasshouse. Zinc deficiency symptoms appeared within 28 days of sowing as a change in leaf colour of young leaves from green to bronze. Later, red areas developed and these became necrotic in severe cases. These symptoms were accompanied by decreased shoot and root dry weights. Zinc concentrations in various plant parts were low and, with the exception of the shoot apex, showed little response to zinc supply. Concentrations at the shoot apex varied from 3µg/g in deficient plants to 12µg/g in plants with adequate zinc supply. We suggest that of the plant parts analysed, the shoot apex is the only one which may be useful in defining zinc status of jarrah seedlings. Critical zinc concentration for this tissue was between 10 and 12 µg/g dry matter. Phosphorus concentrations in all plant parts, except the shoot apex, increased to very high levels with increasing zinc deficiency. It is suggested that some zinc deficiency symptoms of jarrah seedlings, e.g. necrosis, may have resulted from phosphorus accumulation due to zinc deficiency.

Zinc Nutrition of Jarrah (Eucalyptus marginata Donn ex Smith) Seedlings

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

IM Wallace

Author Tools

Chat about Author