AREA OF VEIN‐ISLETS IN LEAVES OF CERTAIN PLANTS AS AN AGE DETERMINANT
AREA OF VEIN‐ISLETS IN LEAVES OF CERTAIN PLANTS AS AN AGE DETERMINANT
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某些植物叶子中脉岛面积作为年龄决定因素
DOI：
10.1002/j.1537-2197.1921.tb05638.x
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发表时间：
1921
影响因子：
3
通讯作者：
M. Ensign
中科院分区：
文献类型：
--
作者：
M. Ensign
The available evidence in support of a theory of senescence in plants is very meager. The work of Minot (7), Child (2), Hertwig (5), Conklin (3) and others establishes quite definitely that complex animal forms are subject to a gradual retardation of physiological functions; also, that this retardation begins in the embryo and continues with more or less acceleration until death ensues. Benedict (i) has attempted to show that plants are subject to similar changes of physiological functions. These, he claims, are initiated immediately after fertilization and are registered in the increasing complexity of the vascular ramifications in the leaves of certain dicotyledonous plants. In other words, the relative age of such perennial plants as vines, trees, and shrubs can be detected by determining the relative area of the "tissue islands" or vein-islets formed by the intersecting veins surrounding them. Old or senile plants, therefore, produce leaves whose vein-islets are smaller in area than those in leaves of young plants of the same species grown under similar environmental conditions. Beginning with these premises, the writer (4) studied the venation of leaves produced by polyembryonic Citrus seedlings (Citrus grandis). During the progress of this work certain questions arose regarding the accuracy of the methods employed by Benedict in determining the area of vein-islets in the leaves which he used. In order to shed some light upon this point the work herein reported was undertaken. The data collected are not as extensive as might be desired, but inasmuch as further investigation had to be postponed indefinitely, they are presented for what they may be worth. METHODS AND MATERIALS
