Summary
Diurnal changes in the carbohydrates of leaf laminae and fruits and in the bleeding of sugar and amino acids from fruit phloem were followed by successive sampling from a population of Lupinus albus L. plants. Phloem sap was collected for a standard 5 min period from cut distal tips of attached fruits. Daily fluctuations in leaf dry matter resulted largely from changes in starch and sugar. Leaf sugar rose to a maximum in the afternoon, starch to a maximum at, or shortly after, dusk. Leaves lost sugar and starch from dusk to dawn. Phloem bleeding rate varied little over a daily cycle but sucrose levels fluctuated from a noon maximum of 12–13% (w/v) to a dawn minimum of 9–10%. The rhythm of phloem sugar levels matched closely those of fruit and leaf. Phloem amino acid levels fluctuated in phase with that of sucrose: the relative composition of the amino fraction did not vary significantly over the daily cycle. Pulse feeding of source leaves with 14CO2 at different times in the photoperiod allowed study of the pattern of release of labelled photosynthate to the fruit phloem and the build up and depletion of 14C starch in leaves. Plants transferred to continuous darkness showed a rapid decline in output and concentration of phloem sap solutes, and translocated nitrogen to their fruits at only one quarter of the rate of control plants retained in natural daylight. The combined data from the experiments showed that the rate of output of sugar from cut phloem of a fruit was directly related to the current level of sugar in leaves. When leaf sugar levels were low (5–10 mg ml tissue water-1) sugar in phloem was 10–11 times more concentrated than in source leaves, but at high leaf sugar levels (25–30 mg ml-1) this concentration difference was only 3–4 fold.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Atkins, C.A., Pate, J.S., Sharkey, P.J.: Asparagine metabolism—key to the nitrogen nutrition of developing legume seeds. Plant Physiol. (in press)
Bailey, R.W.: Carbohydrates in pasture species. I. The starch content of clovers and rye-grass. J. Sci. Food Agric. 9, 743–747 (1958)
Canny, M.J.: Phloem translocation. Cambridge University Press 1973
Crafts, A.S., Crisp, C.E.: Phloem transport in plants. San Francisco: Freeman 1971
van Die, J., Tammes, P.M.L.: Studies on phloem exudation from Yucca flaccida Haw. II. Translocation of assimilates. Acta bot. neerl. 13, 84–90 (1964)
van Die, J., Tammes, P.M.L.: Studies on phloem exudation from Yucca flaccida Haw. III. Prolonged bleeding from isolated parts of the young inflorescence. Proc. kon. ned. Akad. Wet. C. 69, 648–654 (1966)
van Die, J., Vonk, C.R., Tammes, P.M.L.: Studies on phloem exudation from Yucca flaccida Haw. XII. Rate of flow of 14C-sucrose from a leaf to the wounded inflorescence top. Evidence for a primary origin of the major part of the exudate sucrose. Acta bot. neerl. 22, 446–451 (1973)
Geiger, D.R., Batey, J.W.: Translocation of 14C sucrose in sugar beet during darkness. Plant Physiol. 42, 1743–1749 (1967)
Geiger, D.R., Giaquinta, R.T., Sovonick, S.A., Fellows, R.J.: Solute distribution in sugar beet leaves in relation to phloem loading and translocation. Plant Physiol. 52, 585–589 (1973)
Hall, S.M., Milburn, J.A.: Phloem transport in Ricinus: Its dependence on the water balance of the tissues. Planta (Berl.) 109, 1–10 (1973)
Hartt, C.E., Kortschak, H.P.: Translocation of 14C in the sugarcane plant during the day and night. Plant Physiol. 42, 89–94 (1967)
Hassid, W.Z., Neufeld, E.F.: Quantitative determination of starch in plant tissues. In: Methods of carbohydrate chemistry. Vol. 4, pp. 33–36. Ed.: Whistler, M.B., New York: Academic Press 1964
Hüber, B., Schmidt, E., Jahnel, H.: Untersuchungen über die Assimilatstrom. Tharandt. forstl. Jb. 88, 1017–1050 (1937)
McCready, R.M., Guggolz, J., Silviera, V., Owens, H.S.: Determination of starch and amylose in vegetables. An. Chem. 22, 1156–1158 (1950)
Mason, T.G., Maskell, E.J.: Studies on the transport of carbohydrates in the cotton plant. I. A study of diurnal variation in the carbohydrates of leaf, bark and wood, and the effects of ringing. Ann. Bot. 42, 189–253 (1928a)
Mason, T.G., Maskell, E.J.: Studies on the transport of carbohydrates in the cotton plant. II. The factors determining the rate and the direction of movement of sugars. Ann. Bot. 42, 571–636 (1928b)
Melvin, J.F.: Variations in the carbohydrate content of lucerne and the effect of ensilage. Aust. J. agric. Res. 16, 951–959 (1965)
Milburn, J.A.: Phloem transport in Ricinus. Pestic. Sci. 3, 653–665 (1972)
Milburn, J.A.: Phloem transport in Ricinus: Concentration gradients between source and sink. Planta (Berl.) 117, 303–319 (1974)
Pate, J.S., Sharkey, P.J., Lewis, O.A.M.: Phloem bleeding from legume fruits—a technique for study of fruit nutrition. Planta (Berl.) 120, 229–243 (1974)
Pate, J.S., Sharkey, P.J., Lewis, O.A.M.: Xylem to phloem transfer of solutes in fruiting shoots of legumes, studied by a phloem bleeding technique. Planta (Berl.) 122, 11–26 (1975)
Pearson, C.J.: Daily changes in stomatal aperture and in carbohydrates and malate within epidermis and mesophyll of leaves of Commelina cyanea and Vicia faba. Aust. J. biol. Sci. 26, 1035–1044 (1973)
Pearson, C.J.: Daily changes in carbon-dioxide exchange and photosynthate translocation of leaves of Vicia faba. Planta (Berl.) 119, 59–70 (1974)
Porter, H.K., Martin, R.V., Bird, I.F.: Synthesis and dissolution of starch labelled with 14carbon in tobacco leaf tissue. J. exp. Bot. 10, 264–276 (1959)
Taylor, A.O.: The influence of temperature and time of day on the level of readily fermentable carbohydrate in white clover leaves. N.Z. agric. Sci. 2, 172–173 (1968)
Upmeyer, D.J., Koller, H.R.: Diurnal trends in net photosynthetic rate and carbohydrate levels of soybean leaves. Plant Physiol. 51, 871–874 (1973)
Yemm, E.W., Willis, A.J.: The estimation of carbohydrates in plant extracts by anthrone. Biochem. J. 57, 508–514 (1954)
Weatherley, P.E., Peel, A.J., Hill, G.P.: The physiology of the sieve tube. J. exp. Bot. 10, 1–16 (1959)
Ziegler, H.: Untersuchungen über die Leitung und Sekretion der Assimilate. Planta (Berl.) 47, 447–500 (1956)
Zimmerman, M.H.: Translocation of nutrients. In: Physiology of plant growth and development. Ed.: Wilkins, M.B., London-New York: McGraw Hill 1969
Zimmerman, M.H.: Transport in the phloem. In: Trees, structure and function. pp. 221–279. Eds.: Zimmerman, M.H., Brown, C.L., Berlin-Heidelberg-New York: Springer 1971
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Sharkey, P.J., Pate, J.S. Translocation from leaves to fruits of a legume, studied by a phloem bleeding technique: Diurnal changes and effects of continuous darkness. Planta 128, 63–72 (1976). https://doi.org/10.1007/BF00397180
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00397180