Biologic Markers of Air-Pollution Stress and Damage in Forests (1989) / Chapter Skim
Currently Skimming:
Evaluation of Root-Growth and Functioning of Trees Exposed to Air Pollutants
Evaluation of Root-Growth and Functioning of Trees Exposed to Air Pollutants
Pages 169-182
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From page 169... ...
Application of a 32p/33p dual-isotope labeling technique would allow determination of root and mycorrhizal nutrient uptake capacity in the field as affected by experimental air pollution exposure. Root ingrowth cores enriched with limiting nutrients may be useful in evaluation of the degree of nutrient stress or root growth capacity of trees in the field.
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From page 170... ...
indicate clearly that root production, which reflects the partitioning of assimilates to root growth, is usually reduced before effects are detected in the shoot system or to a greater extent than shoot growth. Numerous studies on herbaceous plants and tree seedlings suggest that root growth and physiological activity are dependent upon a continuing supply of current assimilate.
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From page 171... ...
Even if sampling could be conducted to insure reliable estimates of fine root production through time, large spatial variation, including variation due to stand age, species composition, understory composition and site nitrogen availability (e.g., Persson 1983, Aber et al.
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From page 172... ...
showed that fine roots of Douglas fir died as their carbohydrate reserves were depleted, in trees where carbohydrate concentrations of fine root elements are affected by air pollution exposure, longevity of fine root elements should be reduced compared with longevity in undamaged trees. The relationship between root elongation and suberization and development of root hairs as well as mycorrhizal or pathogenic relationships could also be studied with
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From page 173... ...
Root samples from cores could also be utilized to determine mycorrhizal development in fine roots and element concentrations in fine root tissues. These topics are addressed by other papers in these proceedings (Antibus and Linkins; Shortle; Marx and Shafer)
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From page 174... ...
Nevertheless, if the depth distribution or seasonal pattern of water uptake of forest trees was affected by air pollution, this could be determined through neutron attenuation or other techniques for detecting water uptake by root systems (see Caldwell and Virginia 1988~. Here again, as with determinations of root production, temporal and spatial variation and availability of interspersed controls sets a limit on the inference that can be made from these measurements.
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From page 175... ...
Because numerous ingrowth cores can be utilized for the same tree or for damaged and undamaged trees on the same site, this technique has potential for monitoring both the development of nutrient stress in trees that might result from chronic pollutant exposure as well as revealing changes in the capacity to respond to nutrient-enriched ingrowth cores. If ingrowth cores were enriched in a nutrient that became more limiting as air pollution damage increased (e.g.
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From page 176... ...
development and sampling considerations will require careful of root measures as indicators of air pollution damage to SUMMARY 1. Techniques that have been discussed have promise for determining effects of air pollution exposure on roots of forest trees.
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From page 177... ...
1985. Fine root turnover in forest ecosystems in relation to quantity and form of nitrogen availability: a comparison of two methods.
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From page 178... ...
1984. Methods of calculating root production and nitrogen uptake in an annual crop.
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From page 179... ...
1985. Predicting fine root production and turnover Canadian Journal of Forest Massimino, D., M
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From page 180... ...
1984. Bias and random errors in estimators of net root production: a simulation approach.
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From page 181... ...
1968. Hydraulic properties of a clay loam soil and the field measurement of water uptake by roots.
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From page 182... ...
1984. Bias and random errors in estimators of net root production: a simulation approach.
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