Leaf development and phloem transport in Cucurbita pepo: Maturation of the minor veins (original) (raw)
Summary
Young leaves of Cucurbita pepo L. were examined by whole-leaf autoradiography and serial paradermal sections were examined by light microscopy to determine whether commencement of sugar export depends upon the minor vein phloem achieving structural maturity. Maturation of these veins develops progressively from the largest toward the smallest elements with the minor veins in the distal region of the leaf maturing before those in the proximal region. Commencement of sugar export is coincident with maturation of the abaxial phloem of the minor veins delimiting the areoles. The abaxial phloem elements of the larger minor veins, which are probably capable of vein loading too but border only relatively few areoles, mature before export starts. The adaxial phloem surrounding the areoles and the xylem elements, mature in advance of the abaxial phloem and well before the beginning of sugar export. It is therefore considered unlikely that structural development alone directly governs the initiation of export. The results suggest that some other rate controlling step is involved.
Access this article
Subscribe and save
- Starting from 10 chapters or articles per month
- Access and download chapters and articles from more than 300k books and 2,500 journals
- Cancel anytime View plans
Buy Now
Price excludes VAT (USA)
Tax calculation will be finalised during checkout.
Instant access to the full article PDF.
Similar content being viewed by others
References
- Bonnemain, J.-L.: Transport du 14C assimilé à partir des feuilles de Tomate en voie de croissance et vers celles-ci. C. R. Acad. Sci. (Paris) 269D, 1660–1663 (1969)
Google Scholar - Fellows, R.J., Geiger, D.R.: Structural and physiological changes in sugar beet leaves during sink to source conversion. Plant Physiol. 54, 877–885 (1974)
Google Scholar - Fischer, A.: Studien über die Siebröhren der Dicotylenblätter. Ber. Verh. Kon. Sachs. Ges. Wiss. Leipzig, Math-Phys. Cl. 37, 245–290 (1885)
Google Scholar - Isebrands, J.G., Larson, P.R.: Anatomical changes during leaf ontogeny in Populus deltoides. Amer. J. Bot. 60, 199–208 (1973)
Google Scholar - Larson, P.R., Isebrands, J.G., Dickson, R.E.: Fixation patterns of 14C within developing leaves of eastern cottonwood. Planta (Berl.) 107, 301–314 (1972)
Google Scholar - Peterson, C.A., Currier, H.B.: An investigation of bidirectional translocation in the phloem. Physiologia Plantar. 22, 1238–1250 (1969)
Google Scholar - Turgeon, R., Webb, J.A.: Leaf development and phloem transport in Cucurbita pepo: transition from import to export. Planta (Berl.) 113, 179–191 (1973)
Google Scholar - Turgeon, R., Webb, J.A.: Leaf development and phloem transport in Cucurbita pepo: carbon economy. Planta (Berl.) 123, 53–62 (1975)
Google Scholar - Turgeon, R., Webb, J.A., Evert, R.F.: Ultrastructure of minor veins in Cucurbita pepo leaves. Protoplasma 83, 217–232 (1975)
Google Scholar - Webb, J.A.: The translocation of sugars in Cucurbita melopepo. V. The effect of leaf blade temperature on assimilation and transport. Canad. J. Bot. 48, 935–942 (1970)
Google Scholar - Webb, J.A., Gorham, P.R.: Radial movement of 14C-translocates from Squash phloem. Can. J. Botany 43, 97–103 (1965)
Google Scholar
Author information
Author notes
- Robert Turgeon
Present address: The Rockefeller University, 10021, New York, N.Y., U.S.A.
Authors and Affiliations
- Biology Department, Carleton University Ottawa, K1S 5B6, Ontario, Canada
Robert Turgeon & J. A. Webb
Authors
- Robert Turgeon
- J. A. Webb
Rights and permissions
About this article
Cite this article
Turgeon, R., Webb, J.A. Leaf development and phloem transport in Cucurbita pepo: Maturation of the minor veins.Planta 129, 265–269 (1976). https://doi.org/10.1007/BF00398269
- Received: 07 October 1975
- Accepted: 08 December 1975
- Issue date: January 1976
- DOI: https://doi.org/10.1007/BF00398269