| 释义 |
eustele, n. Bot.|juːˈstiːl|
[f. eu- + stele n.]
A highly evolved stele, found in the stems of most dicotyledons, consisting of a central core of pith largely surrounded by discrete bundles of vascular tissue.
1902G. Brebner in Ann. Bot. XVI. 519 The Dicotyledons are looked upon as the highest expression of plant life, and it therefore seems appropriate to apply the term eustele to their well-known type of vascular cylinder. 1944Jrnl. Arnold Arboretum XXV. 455 If viewed in three dimensions, the primary vascular system is a series of leaf-traces, the lower extensions of which form a eustele whose bundles are arranged cylindrically. 1961A. J. Eames Morphol. Angiosperms i. 24 The eustele, with reduced vascular tissue, is perhaps the advanced stelar form. 1987H. C. Bold et al. Morphol. Plants & Fungi (ed. 5) xv. 376/2 Although the xylem and phloem are present as discrete strands (eustele) in the internodes of Equisetum, serial sections through the nodes reveal that they join there to form a short siphonostele.
Hence euˈstelic a.
1944Jrnl. Arnold Arboretum XXV. 455 It is questionable..whether foliar gaps, comparable to those found in siphonostelic ferns, are recognizably present in a primary vascular cylinder of the eustelic type. 1965K. Esau Plant Anat. (ed. 2) xv. 373 The interfascicular regions and later the leaf gaps are commonly discontinued as such..and the eustelic condition ceases to be recognizable. 1988Taxon XXXVII. 381 The character correlation of eustelic or sympodial primary vascular system of stem, [etc.]..indicate a relationship..with the progymnosperm-seed plant line. |