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FOLIAR INITIATION AND THE FATE OF THE DWARF‐SHOOT APEX IN PINUS MONOPHYLLA
Author(s) -
Gabilo Emerenciana M.,
Mogensen H. Lloyd
Publication year - 1973
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.1537-2197.1973.tb05972.x
Subject(s) - apex (geometry) , biology , primordium , shoot , botany , pinus <genus> , gene , biochemistry
The dwarf‐shoot apex of Pinus monophylla has a cytohistological zonation typical of pines. Cataphylls are initiated by this apex both before and after the dormant winter period. The needle is initiated in the spring of the same season in which it matures. The cytological details of cataphyll initiation are identical to that of needle initiation; however, the two primordia can be distinguished very early on the basis of their shape and direction of growth. After needle initiation the stem apex becomes inactive, is crowded to one side, and eventually disappears as the base of the needle enlarges. The results of the present work are discussed in relation to earlier conflicting interpretations regarding needle initiation and the subsequent existence of the dwarf‐shoot apex of P. monophylla .