University of California

Developmental anatomy of major lateral leaf veins of healthy and of pear-decline diseased pear trees


Kengo Soma
Henry Schneider

Authors Affiliations

Kengo Soma was Visiting Assistant Plant Pathologist, Department of Plant Pathology, University of California, Riverside, from April 1, 1967, to March 30, 1968. He is a member of the teaching and research staff in the Department of Botany, Faculty of Science, Tokyo Kyoiku University, Otsuka, Tokyo, Japan; Henry Schneider was Plant Pathologist and Lecturer, Department of Plant Pathology, University of California, Riverside.

Publication Information

Hilgardia 40(13):471-504. DOI:10.3733/hilg.v40n13p471. January 1971.

PDF of full article, Cite this article


Following the initiation of a leaf primordium in healthy Pyrus sp. ‘Variolosa,’ the marginal meristems initiate the wings of the lamina. A superficial sheet of anticlinally dividing cells gives rise to the protoderm. Submarginally, a uniseriate strand of initial cells gives rise by anticlinal divisions to the adaxial and abaxial subprotodermal layers, and by periclinal divisions to the middle layer. The abaxial subprotoderm, by periclinal divisions, also contributes cells to the middle layer.

The procambia that give rise to lateral veins differentiate from undifferentiated cells in the middle layer. Sieve tubes that form in the primary phloem from the procambium are arranged somewhat irregularly, while the cambium produces radially arranged rows of secondary phloem.

In trees affected by pear decline necrosis does not occur in the primary phloem of new shoots that form following chilling; possibly they are pathogen free. Sieve-tube necrosis in secondary phloem is accompanied by excessive and prolonged abnormal phloem formation, and groups of sieve tubes in this abnormal phloem also become necrotic. The necrotic process consists of degeneration of organelles, membranes, and ground cytoplasm.

Literature Cited

Avery G. S. Jr. Structure and development of the tobacco leaf. Amer. Jour. Bot. 1933. 20:565-92. DOI: 10.2307/2436259 [CrossRef]

Bond T. E. T. Studies in the vegetative growth and anatomy of the tea plant (Camellia thea Link.) with special reference to the phloem. I. The flush shoot. Ann. Bot. N. S. 1942. 6:607-30.

Cross G. L. The morphology of the bud and the development of the leaves of Viburnum rufidulum. Amer. Jour. Bot. 1937. 24:266-76. DOI: 10.2307/2436612 [CrossRef]

Cross G. L. A comparative histogenetic study of the bud scales and foliage leaves of Viburnum opulus. Amer. Jour. Bot. 1938. 25:246-58. DOI: 10.2307/2436651 [CrossRef]

Duloy Margaret, Mercer F. V., Rathgeber N. Studies in translocation II. Submicroscopic anatomy of the phloem. Australian Jour. Biol. Sci. 1961. 14:506-18.

Esau Katherine. Ontogeny of phloem in the sugar beet (Beta vulgaris L.). Amer. Jour. Bot. 1934. 21:632-44. DOI: 10.2307/2436282 [CrossRef]

Esau Katherine. Ontogeny of the phloem in sugar beets affected by the curly-top disease. Amer. Jour. Bot. 1935. 22:149-63. DOI: 10.2307/2436006 [CrossRef]

Esau Katherine. Development and structure of the phloem tissue. Bot. Rev. 1939. 5:373-432. DOI: 10.1007/BF02878295 [CrossRef]

Esau Katherine. Phloem anatomy of tobacco affected with curly top and mosaic. Hilgardia. 1941. 13:437-90. DOI: 10.3733/hilg.v13n08p435 [CrossRef]

Esau Katherine. An anatomist’s view of virus diseases. Amer. Jour. Bot. 1956. 43:739-48. DOI: 10.2307/2438842 [CrossRef]

Esau Katherine. Phloem degeneration in celery infected with yellow leaf roll virus of peach. Virology. 1958. 6:348-56. DOI: 10.1016/0042-6822(58)90088-6 [CrossRef]

Esau Katherine. Plant anatomy. 1965. 2nd Ed. N.Y. London, Sydney: J. Wiley à Sons, Inc. 767p.

Esau Katherine. Minor veins in beta leaves: structure related to function. Proc. Amer. Phil. Soc. 1967. 111:219-33.

Esau Katherine, Cheadle V. I. Wall thickening in sieve elements. Natl. Acad. Sci. Proc. 1958. 44:546-53. DOI: 10.1073/pnas.44.6.546 [CrossRef]

Esau Katherine, Cheadle V. I., Risley E. B. Development of sieve-plate pores. Bot. Gaz. 1962. 123:233-43. DOI: 10.1086/336155 [CrossRef]

Esau Katherine, Cronshaw J. Tubular components in cells of healthy and tobacco mosaic virus-infected Nicotiana. Virology. 1967. 33:26-35. DOI: 10.1016/0042-6822(67)90090-6 [CrossRef]

Esau Katherine, Cronshaw J., Hoefert L. L. Relation of beet yellow virus to the phloem and to movement in the sieve tube. Jour. Cell Biol. 1967. 32:71-87. DOI: 10.1083/jcb.32.1.71 [CrossRef]

Foster A. S. A histogenetic study of foliar determination in Carya buckleyi var. arkansana. Amer. Jour. Bot. 1935. 22:88-147. DOI: 10.2307/2436175 [CrossRef]

Foster A. S. Leaf differentiation in angiosperms. Bot. Rev. 1936. 2:349-72. DOI: 10.1007/BF02870152 [CrossRef]

Gifford E. M. Jr. Early ontogeny of the foliage leaf in Drimys winteri var. chilensis. Amer. Jour. Bot. 1951. 38:93-105. DOI: 10.2307/2437831 [CrossRef]

Gifford E. M. Jr. Effect of 2,4-D upon the development of the cotton leaf. Hilgardia. 1953. 21:606-44. DOI: 10.3733/hilg.v35n11p273 [CrossRef]

Girolami G. Leaf histogenesis in Linum usitatissium. Amer. Jour. Bot. 1954. 41:264-73. DOI: 10.2307/2438983 [CrossRef]

Girolami G. Comparative anatomical effects of the curly-top and aster-yellows viruses on the flax plant. Bot. Gaz. 1955. 116:305-22. DOI: 10.1086/335876 [CrossRef]

Gunning B. E. S., Pate J. S., Briarty L. G. Specialized “transfer cells” in minor veins of leaves and their possible significance in phloem translocation. Jour Cell Biol. 1968. 37:C7-C12. DOI: 10.1083/jcb.37.3.C7 [CrossRef]

Hara N. On the types of the marginal growth in dicotyledonous foliage leaves. Bot. Mag. Tokyo. 1957. 70:108-14.

Hara N. Structure of the vegetative shoot apex and development of the leaf in the Ericaceae and their allies. Jour. Fac. Sci., Univ. Tokyo, Sect. III. 1958. 7:367-450.

Hibino H., Schneider H. Mycoplasma-like bodies in sieve tubes of pear trees affected with pear decline. Phytopathology. 1970. 60(3):499-501. DOI: 10.1094/Phyto-60-499 [CrossRef]

Hoefert L. L., Gifford E. M. Jr. Grapevine leafroll virus—history and anatomic effects. Hilgardia. 1967. 38(11):403-26. DOI: 10.3733/hilg.v38n11p403 [CrossRef]

Hooper G. R., Schneider H. The anatomy of tumors induced on citrus by citrus vein-enation virus. Amer. Jour. Bot. 1969. 56:238-47. DOI: 10.2307/2440712 [CrossRef]

Jensen W. A. Botanical histochemistry. 1962. San Francisco and London: W. H. Freeman and Company. 408p.

MacDaniels L. H., Cowert F. F. The development and structure of the apple leaf. Cornell Univ. Agr. Exp. Sta. Mem. 1944. 258:1-29.

Maksymowych R., Erickson R. O. Development of the lamina in Xanthium italicum represented by the plastochron index. Amer. Jour. Bot. 1960. 47:451-59. DOI: 10.2307/2439558 [CrossRef]

Nasu S., Jensen D. D., Richardson J. Electron microscopy of mycoplasma-like bodies associated with insects and plant hosts of peach Western X-disease. Virology. 1970. 41:583-95. DOI: 10.1016/0042-6822(70)90424-1 [CrossRef]

Pray T. R. Foliar venation of angiosperms. II. Histogenesis of the venation of Liriodendron. Amer. Jour. Bot. 1955. 42:18-27. DOI: 10.2307/2438589 [CrossRef]

Quanjer H. M. The methods of classification of plant viruses, and an attempt to classify and name potato viruses. Phytopathology. 1931. 21:577-613.

Reimer F. C. Blight resistance in pears and characteristics of pear species and stocks. Oregon Agr. College: Exp. Sta. Bul. 1925. 214:99

Rehder A. Manual of cultivated trees and shrubs. 1927. New York: The MacMillan Co. 930p.

Schneider H. The anatomy of peach and cherry phloem. Bull. Torrey Bot. Club. 1945a. 72:137-56. DOI: 10.2307/2481271 [CrossRef]

Schneider H. Anatomy of buckskin-diseased peach and cherry. Phytopathology. 1945b. 35:610-35.

Schneider H., Wallace J. M. In: Citrus virus diseases. The anatomy of tristeza-virus-infected citrus. 1959. Univ. of Calif. Div. Agr. Sci. p. 73-84.

Schneider H. Anatomy of greening-diseased sweet orange shoots. Phytopathology. 1968. 58:1155-60.

Schneider H. Graft transmission and host range of the pear decline causal agent. Phytopathology. 1970. 60(2):204-07. DOI: 10.1094/Phyto-60-204 [CrossRef]

Schneider R. Histogenetische Untersuchungen über den Bau der Laubblätter, insbesondere ihres Mesophylls. Österreich. Bot. Zeitschr. 1952. 99:245-85.

Shih C. Y., Currier H. B. Fine structure of phloem cells in relation to translocation in the cotton seedling. Amer. Jour. Bot. 1969. 56:464-72. DOI: 10.2307/2440824 [CrossRef]

Shtromberg A. Y. Cambial activity in leaves of several woody dicotyledonous plants. Akad. Nauk. SSSR (Proc. Bot. Sci., AIBS). 1959. 124:4-7.

Tsao Pamela W., Schneider H., Kaloostian G. H. A brown leaf-vein symptom associated with greenhouse-grown pear plants infected with pear decline virus. Plant Dis. Rep. 1966. 50:270-74.

Tsao Pamela W., Schneider H. Pathological anatomy of pear tissues sensitive to pear-decline virus. Phytopathology. 1967. 57:103

Wooding F. B. P., Northcote D. H. The fine structure and development of the companion cell of the phloem of Acer pseudoplatanus. Jour. Cell Biol. 1965. 24:117-28. DOI: 10.1083/jcb.24.1.117 [CrossRef]

Wrischer Mercedes. Elektronenmikroskopische Untersuchungen der Zellnekrobiose. Protoplasma. 1965. 60:355-400. DOI: 10.1007/BF01247888 [CrossRef]

Soma K, Schneider H. 1971. Developmental anatomy of major lateral leaf veins of healthy and of pear-decline diseased pear trees. Hilgardia 40(13):471-504. DOI:10.3733/hilg.v40n13p471
Webmaster Email: sjosterman@ucanr.edu