Summary
Both desiccation and depleted carbohydrate reserves have been suggested as causes of fine-root (≤2 mm in diameter) mortality in trees. In this study, Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] seedlings were subjected to four combinations of shading and watering to determine whether shading increases drough-induced root mortality and, if so, whether this effect is due to reduced levels of carbohydrate reserves or increased susceptibility to desiccation. Two correlated measures of root mortality (counting root tips and weighing roots) showed that significantly more fine roots died only when seedlings were both shaded and unwatered. Concentrations of suberin, a compound synthesized by plant roots to control desiccation, were unaffected by any combination of shading and watering; however, carbohydrate reserves were nearly exhausted in the shaded and unwatered treatment — the treatment with highest root mortality. Water stress may have increased root mortality indirectly by increasing root temperature and maintenance respiration and by inhibiting photosynthate transport to the root system, but massive die-off in response to drought was apparent only when starch and sugar reserves were nearly depleted. Drought cannot be considered directly responsible for death of fine roots. Instead, a root's ability to continue to respire, which in turn depends on the status of its starch and sugar reserves, seems to be the primary physiological control of fine-root mortality.
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Agren G I, Axelsson B, Flower-Ellis J G K, Linder S, Persson H, Staaf H and Troeng E 1980 Annual carbon budget for a young Scots pine.In Structural and Function of Northern Coniferous Forests — An Ecosystem Study. Ed. T Persson, Ecol. Bull. (Stockholm) 32, 307–314.
AOAC 1980 Official Methods of Analysis of the Association of Official Analytical Chemists (13th ed). Washington, D.C.
Beardsall N F, Jarvis P G and Davidson B 1972 A null-balance diffusion porometer suitable for use with leaves of many shapes. J. Appl. Ecol. 9, 677–690.
Clarkson D T and Robards A W 1975 The endomermis, its structural development and physiological role.In The Development and Function of Roots. Ed. J G Torrey and D T Clarkson, Academic Press, London, New York, San Francisco, pp 415–436.
Deans J D 1979 Fluctuations of the soil environment and fine root growth in a young Sitka spruce plantation. Plant and Soil 52, 195–208.
Ericsson A and Persson H 1980 Seasonal changes in starch reserves and growth of fine roots of 20-year-old Scots pines.In Structure and Function of Northern Coniferous Forests — An Ecosystem Study. Ed. T Persson, Ecol. Bull. (Stockholm) 32, 239–250.
Ford E D and Deans J D 1977 Growth of a Sitka spruce plantation: spatial distribution and seasonal fluctuations of lengths, weights, and carbohydrate concentrations of fine roots. Plant and Soil 47, 463–485.
Goering H K and Van Soest P J 1970 Forage fiber analysis. USDA Agric. Res. Serv. Agric. Handb. 379, Washington, D.C., 20 p.
Grier C C, Vogt K A, Keyes M R and Edmonds R L 1980 Biomass distributions and aboveand below-ground production in young and matureAbies amabilis zone ecosystems of the Washington Cascades. Can. J. For. Res. 11, 155–167.
Hansen J and Möller I 1975 Percolation of starch and soluble carbohydrates from plant tissue for quantitative determination with anthrone. Anal. Biochem. 68, 87–94.
Harris W F, Kinerson R S and Edwards N T 1978 Comparisons of belowground biomass of natural deciduous forest and loblolly pine plantations. Pedobiologia 7, 369–381.
Head G C 1973 Shedding of roots.In Shedding of Plant Parts. Ed. T T Kozlowski, Academic Press, New York and London, pp 237–293.
Hermann R K 1964 Effects of prolonged exposure of roots on survival of 2-0 Douglasfir seedlings. J. For. 62, 401–403.
Ingestad T 1979 Nitrogen stress in birch seedlings II. N, K, P, Ca, and Mg nutrition. Physiol. Plant. 45, 149–157.
Kolatukuddy P E and Dean B B 1974 Structure, gas chromatographic measurement, and function of suberin synthesized by potato tuber slices. Plant Physiol. 54, 116–121.
Kolatukuddy P E 1980 Biopolyester membranes of plants: cutin and suberin. Science 208, 990–1000.
Leshem B 1965 The annual activity of intermediary roots of the Aleppo pine. For. Sci. 11, 291–298.
Loomis W E 1953 Growth correlation.In Growth and Differentiation in Plants. Ed. W E Loomis, Iowa State College Press, pp 197–217.
Lyr G and Hoffman G 1967 Growth rates and growth periodicity of tree roots.In International Review of Forestry Research. Vol. 2. Eds. J A Romberger and P Mikola, Academic Press, New York, pp 181–236.
McCready R M 1970 Starch and dextrin.In Methods in Food Analysis. Ed. M A Joslyn, Academic Press, pp 541–563.
McDermitt D K and Loomis R S 1981 Elemental composition of biomass in relation to energy content, growth efficiency, and growth yield. Ann. Bot. 48, 275–290.
Molz F J and Peterson C M 1976 Water transport from roots to soil. Agron. J. 68, 901–904.
Nobel P S 1974 Introduction to Biophysical Plant Physiology. W H Freemand and Co., San Francisco.
Persson H 1978 Root dynamics in a young Scots pine stand in central Sweden. Oikos 30, 508–519.
Persson H 1979 Fine-root production, mortality and decomposition in forest ecosystems. Vegetation 41, 101–109.
Persson H 1980 Death and replacement of fine roots in a mature Scots pine stand.In Structure and Function of Northern Coniferous Forests — An Ecosystem Study. Ed. T. Persson, Ecol. Bull. (Stockholm) 32, 251–260.
Redmond D R 1959 Mortality of rootlets in balsam fir defoliated by the spruce budwork. For. Sci. 5, 64–69.
Reynolds E R C 1970 Root distribution and the cause of its spatial variability inPseudotsuga taxifolia (Poir.) Britt. Plant and Soil 32, 501–307.
Robards A W, Clarkson D T and Sanderson J 1979 Structure and permeability of the epiderman/hypodermal layers of the sand sedge (Carex arenaria L.). Protoplasma 101, 331–347.
Sanderson G W and Perera B P M 1966 Removal of polyphenolic compounds interfering with carbohydrate determinations in plant extracts with an insoluble polyphenol adsorbent. Analyst 91, 335–536.
Santantonio D 1982 Production and turnover of fine roots of mature Douglas-fir in relation to site. Ph.D. Thesis, Oregon State University, Corvallis.
Smith D 1979 Removing and analyzing total nonstructural carbohydrates from plant tissue. Univ. Wis., Coll. Agric. Life Sci., Res. Pap. 41.
Steel R and Torrie J 1980 Principles and Procedures of Statistics — A Biometrical Approach (2nd ed.). McGraw-Hill, New York.
Teskey R O and Hinckley T M 1981 Influence of temperature and water potential on root growth of white oak. Physiol. Plant. 52, 363–369.
Wilcox H E 1964 Xylem in roots ofPinus resinosa Ait. in relation to heterorhizy and growth activity.In The Formation of Wood in Forest Trees. Ed. M H Zimmerman, Academic Press, New York, pp 459–478.
Yemm E W and Willis A J 1954 The estimation of carbohydrates in plant extracts by anthrone. Biochem. J. 57, 508–514.
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Marshall, J.D. Drought and shade interact to cause fine-root mortality in Douglas-fir seedlings. Plant Soil 91, 51–60 (1986). https://doi.org/10.1007/BF02181818
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DOI: https://doi.org/10.1007/BF02181818