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DEVELOPMENT OF THE LAMINA IN XANTHIUM ITALICUM REPRESENTED BY THE PLASTOCHRON INDEX
Author(s) -
Maksymowych Roman,
Erickson Ralph O.
Publication year - 1960
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1960.tb10611.x
Subject(s) - lamina , xanthium , biology , primordium , meristem , botany , mitotic index , palisade cell , anatomy , mitosis , shoot , microbiology and biotechnology , biochemistry , gene
M aksymowych , R oman (Villanova U., Villanova, Pa.), and R alph O. E rickson . Development of the lamina in Xanthium italicum represented by the plastochron index. Amer. Jour. Bot. 47(6):51–459. Illus. 1960.— Xanthium plants were grown vegetatively, and leaves, whose developmental age was specified by a previously described leaf plastochron index ( L.P.I .), were measured and studied histologically. Leaf initiation occurs before L.P.I .–6.0. Initiation of the lamina occurs at about L.P.I . –4.8, when the primordium is about 0.22 mm. long. Mitotic divisions in the marginal and plate meristems continue until about L.P.I . 1.7, when the leaf is about 37 mm. long, a period of about 23 days. Between L.P.I . 1.0 and 3.0, approximately, there is a rapid 4‐fold increase in thickness of the lamina, with development of the characteristic palisade and spongy mesophyll tissues. Virtually no further increase in thickness occurs after L.P.I . 4.0, but the lamina continues to increase in length until about L.P.I. 6.0, when it has reached a mature length of about 180 mm. A statistical analysis has been made of planes of division in the marginal meristem, which in some respects fails to support published histogenetic schemes for this meristem.