Abstract
Intracanopy variation in net leaf nitrogen (N) resorption and N cycling through leaves in mature walnut (Juglans regia L. cv Hartley) trees were monitored in 3 different years. Differential irradiance among the spurs sampled was inferred from differences among leaves in dry weight per unit area (LW/LA) which varied from 4.0 mg · cm−2 to 7.0 mg · cm−2 in shaded (S) and exposed (E) canopy positions, respectively. Our results, using 15N-depleted (NH4)2SO4 validated the concept that N influx and efflux through fully expanded leaves occurred concurrently during the period of embryo growth. Additionally, it also suggested that N influx into leaves was substantially greater in exposed as compared with shaded canopy positions. Because of its well documented phloem immobility, leaf Ca accumulation was used to better estimate the relative influx of N into exposed and shaded leaves. N cycling varied locally within the tree canopy, i. e. Ca (and presumably N) influx was 100% greater in exposed than shaded tree canopy positions, but influx was not influenced significantly by the proximity of developing fruit. In contrast, both the amount and percentage N efflux was significantly greater during embryo growth in fruit-bearing than defruited spurs. Net leaf N resorption averaged 2–4 times greater (25–30%) in fruit-bearing spurs than the 5–10% decrease in the leaf N content in defruited spurs. Since about 90% of leaf N content reportedly occurs as protein, fruit N demand apparently influenced protein turnover and catalysis in associated spur leaves. The amount of leaf N resorption was greater in exposed than shaded positions in the tree canopy in 2 of the 3 years of data collection. Our data show that like leaf N content, N influx, N efflux and net leaf N resorption vary throughout mature walnut tree canopies under the combined local influences of fruiting and irradiance.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Biddulph O, Nakayama FS, Cory R (1961) Transpiration stream and ascension of calcium. Plant Physiol 36: 429–436
Bremner JM (1965a) Total nitrogen. In: Black CA, Evans DD, White JL, Ensminger LE, Clark FE (eds) Methods of soil analysis. Agronomy no 9, part 2. Am Soc Agron, Madison, Wis., pp 1149–1178
Bremner JM (1965b) Isotope ratio analysis of nitrogen in nitrogen-15 tracer investigations. In: CD Black, Evans DD, White JL, Ensminger LE, Clark FE (eds) Methods of soil analysis. Agronomy no 9, part 2. Am Soc of Agron, Madison, Wis., pp 1256–1283
Dalling MJ (1987) Proteolytic enzymes and leaf senescence. In: Thomson WW, Vothnagel EA, Huffaker RC (eds) Plant senescence: its biochemistry and physiology. American Society of Plant Physiologists, Rockville, MD, pp 54–70
DeJong TM, Day KR, Johnson RS (1989) Partitioning of leaf nitrogen with respect to within canopy light exposure and nitrogen availability in peach (Prunus persica). Trees 3: 89–95
Deng X, Weinbaum SA, DeJong TM (1989) Use of labelled nitrogen to monitor transition in nitrogen dependence from storage to current year uptake in mature walnut trees. Trees 3: 11–16
Ferguson IB, Bollard EG (1976) The movement of calcium in woody stems. Ann Bot 40: 1057–1065
Hansen P, Ryugo K, Ramos DE, Fitch L (1982) Influence of cropping on Ca, K, Mg, and carbohydrate status of ‘French’ prune trees grown on potassium limited soils. J Am Soc Hortic Sci 107: 511–515
Huffaker RC (1990) Tansley Review No. 25. Proteolytic activity during senescence of plants. New Phytol 116: 199–231
Klein I, DeJong TM, Weinbaum SA, Muraoka TT (1991a) Specific leaf weight and nitrogen allocation responses to light exposure within walnut trees. Hortic Sci 26: 183–185
Klein I, Weinbaum SA, DeJong TM, Muraoka TT (1991b) Relationship between fruiting, specific leaf weight, and subsequent spur productivity in walnut. J Am Soc Hortic Sci 116: 426–429
Ledgard SF, Smith GS (1992) Fate of 15N-labelled nitrogen fertilizer applied to kiwifruit (Actinidia deliciosa) vines. II. Temporal changes in 15N within vines. Plant Soil 147: 59–68
Millard P (1988) The accumulation and storage of nitrogen by herbaceous plants. Plant Cell Environ 11: 1–8
Millard P, Thomson CM (1989) The effect of the autumn senescence of leaves on the internal cycling of nitrogen for the spring growth of apple trees. J Exp Bot 40: 1285–1289
Pate JS, Atkins CA (1983) Xylem and phloem transport and the functional economy of carbon and nitrogen of a legume leaf. Plant Physiol 71: 835–840
Pinney K, Polito VS (1983) English walnut fruit growth and development. Sci Hortic 21: 19–28
Rogers BL, Batjer LP, Thompson AH (1953) Seasonal trend of several nutrient elements in Delicious apple leaves expressed on a percent and unit area basis. Proc Am Soc Hortic Sci 61: 1–5
Sanchez EE, Righetti TL (1990) Tree nitrogen status and leaf canopy position influence postharvest nitrogen accumulation and efflux from pear leaves. J Am Soc Hortic Sci 115: 934–937
Sanz A, Monerri C, Gonzalez-Ferrer J, Guardiola JL (1987) Changes in carbohydrates and mineral elements in citrus leaves during flowering and fruit set. Physiol Plant 69: 93–98
Simpson RJ (1986) Translocation and metabolism of nitrogen: whole plant aspects. In: Lambers H, Neeteson JJ, Stulen I (eds) Fundamental, ecological and agricultural aspects of nitrogen metabolism in higher plants. Martinus Nijhoff, Dordrecht, pp 71–97
Simpson RJ, Dalling MJ (1981) Nitrogen redistribution during grain growth in wheat (Triticum aestivum L). III. Enzymology and transport of amino acids from senescing wheat leaves. Planta 151: 447–456
Smith JAC (1991) Ion transport and the transpiration stream. Bot Acta 104: 416–421
Sparks D (1977) Effects of fruiting on scorch, premature defoliation, and nutrient status of ‘Chickasaw’ pecan leaves. J Am Soc Hortic Sci 102: 669–673
Sprugel DG, Hinckley TM, Schaap W (1991) The theory and practice of branch autonomy. Annu Rev Ecol Syst 22: 309–334
Stephenson AG (1981) Flower and fruit abortion: proximate causes and ultimate functions. Annu Rev Ecol Syst 12: 253–279
Thomas H, Stoddart JL (1980) Leaf senescence. Annu Rev Plant Physiol 31: 83–111
Titus JS, Kang SM (1982) Nitrogen metabolism translocation, and recycling in apple trees. Hortic Rev 4: 204–246
Uriu K, Crane JC (1977) Mineral element changes in pistachio leaves. J Am Soc Hortic Sci 102: 155–158
Vessey JK, Raper Jr CD, Henry LT (1990) Cyclic variations in nitrogen uptake rate in soybean plants: uptake during reproductive growth. J Exp Bot 141: 1579–1584
Weinbaum SA (1988) Foliar nutrition of fruit trees. In: Neumann PM (ed) Plant growth and leaf-applied chemicals. CRC, Boca Raton, Florida, pp 81–100
Weinbaum SA, Muraoka TT (1986) Nitrogen redistribution from almond foliage and pericarp to the almond embryo. J Am Soc Hortic Sci 111: 224–228
Weinbaum SA, Southwick SM, Shackel KA, Muraoka TT, Krueger W, Yeager JT (1989) Photosynthetic photon flux influences macroelement weight per unit of leaf area in prune tree canopies. J Am Soc Hortic Sci 114: 720–723
Weinbaum SA, Niederholzer FJ, Ponchner S, Rosecrance R, Whittlesey A, Muraoka TT (1994) Nutrient uptake by cropping and defruited field-grown ‘French’ Prune trees. J Am Soc Hortic Sci (in press)
Wolpert JA, Ferguson L (1990) Inflorescence bud retention in ‘Kerman’ pistachio: effects of defruiting date and branch size. Hortic Sci 25: 919–921
Yates IE, Carter EA, Wilkins TA, Wood BW (1990) Seasonal variation in polypeptide profiles and cellular structure of pecan leaves. J Am Soc Hortic Sci 115: 924–929
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Weinbaum, S.A., Muraoka, T.T. & Plant, R.E. Intracanopy variation in nitrogen cycling through leaves is influenced by irradiance and proximity to developing fruit in mature walnut trees. Trees 9, 6–11 (1994). https://doi.org/10.1007/BF00197863
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00197863