154:– a protostele in which plate-like regions of xylem appear in transverse section surrounded by phloem tissue, thus appearing to form alternating bands. These discrete plates are interconnected in longitudinal section. Some modern club mosses have plectosteles in their stems. The plectostele may be derived from the actinostele.
80:. Now, at the beginning of the 21st century, plant molecular biologists are coming to understand the genetics and developmental pathways that govern tissue patterns in the stele. Moreover, physiologists are examining how the anatomy (sizes and shapes) of different steles affect the function of organs.
164:
206:
may be used. The numerous leaf gaps and leaf traces give a dictyostele the appearance of many isolated islands of xylem surrounded by phloem. Each of the apparently isolated units of a dictyostele that serve a single leaf can be called a
198:, or this term may be used to refer to cases where the cylinder of vascular tissue contains no more than one leaf gap in any transverse section (i.e. has non-overlapping leaf gaps). This type of stele is primarily found in
89:
148:(protoxylem external to the metaxylem) and consist of several to many patches of protoxylem at the tips of the lobes of the metaxylem. Exarch protosteles are a defining characteristic of the lycophyte lineage.
167:
Three basic types of siphonostele. The siphonostele shown on the left may also be called an amphiphloic siphonostele. The eustele shown on the right is collateral, i.e. with all the phloem on one side of the
176:, with the vascular strand comprising a hollow cylinder surrounding the pith. Siphonosteles often have interruptions in the vascular strand where leaves (typically megaphylls) originate (called leaf gaps).
234:
flowering plants. The vascular bundles in a eustele can be collateral (with the phloem on only one side of the xylem) or bicollateral (with phloem on both sides of the xylem, as in some
Solanaceae).
202:
stems today. Where there are large overlapping leaf gaps (so that multiple gaps in the vascular cylinder exist in any one transverse section), the term
65:
61:
527:
479:
214:
Most seed plant stems possess a vascular arrangement which has been interpreted as a derived siphonostele, and is called a
122:– consisting of a cylindrical core of xylem surrounded by a ring of phloem. An endodermis generally surrounds the stele. A
138:– a variation of the protostele in which the core is lobed or fluted. This stele is found in many species of club moss (
126:(protoxylem in the center of a metaxylem cylinder) haplostele is prevalent in members of the rhyniophyte grade, such as
569:
550:
501:
112:
that regulated the flow of water into and out of the vascular system. Such an arrangement is termed a protostele.
471:
594:
88:
187:(with phloem both external and internal to the xylem). Among living plants, many ferns and some
589:
47:, which, if present, defines the outermost boundary of the stele. Outside the stele lies the
100:
had stems with a central core of vascular tissue. This consisted of a cylindrical strand of
8:
489:
249:(characteristic of monocot stems). However, it is really just a variant of the eustele.
538:
511:
456:
565:
546:
523:
516:
497:
475:
452:
145:
123:
77:
263:
258:
219:
36:
211:. Among living plants, this type of stele is found only in the stems of ferns.
97:
69:
20:
583:
245:. The variation has numerous scattered bundles in the stem and is called an
418:
416:
413:
300:
140:
109:
48:
32:
58:
44:
54:
The concept of the stele was developed in the late 19th century by
226:. In addition to being found in stems, the eustele appears in the
35:
containing the tissues derived from the procambium. These include
492:; Alexopoulos, Constantine J. & Delevoryas, Theodore (1987).
231:
188:
172:
Siphonosteles have a central region of ground tissue called the
312:
218:– in this arrangement, the primary vascular tissue consists of
163:
128:
105:
55:
461:(1st ed.). New York and London: McGraw-Hill Book Company.
237:
There is also a variant of the eustele found in monocots like
238:
101:
428:
227:
223:
199:
183:(phloem present only external to the xylem) or they can be
173:
73:
40:
28:
324:
288:
276:
68:
as a model for understanding the relationship between the
488:
422:
306:
242:
379:
377:
375:
564:(2nd ed.). Cambridge: Cambridge University Press.
336:
108:. Around the vascular tissue there might have been an
545:(3rd ed.). New York: W. H. Freeman and Company.
401:
389:
372:
360:
348:
115:There are usually three basic types of protostele:
51:, which is the innermost cell layer of the cortex.
560:Stewart, Wilson N. & Rothwell, Gar W. (1993).
515:
581:
144:and related genera). Actinosteles are typically
559:
318:
76:, and for discussing the evolution of vascular
522:(2nd ed.). San Francisco: W. H. Freeman.
536:
510:
434:
330:
294:
282:
496:(5th ed.). New York: Harper & Row.
194:An amphiphloic siphonostele can be called a
191:flowering plants have an amphiphloic stele.
543:Morphology and Evolution of Vascular Plants
518:Comparative Morphology of Vascular Plants
423:Bold, Alexopoulos & Delevoryas (1987)
307:Bold, Alexopoulos & Delevoryas (1987)
222:, usually in one or two rings around the
162:
562:Paleobotany and the Evolution of Plants
465:
407:
395:
383:
366:
354:
582:
451:
342:
13:
87:
14:
606:
158:
92:Three basic types of protostele
39:, in some cases ground tissue (
494:Morphology of Plants and Fungi
458:An Introduction to Paleobotany
16:Central part of a root or stem
1:
514:& Gifford, E. M. (1974).
444:
319:Stewart & Rothwell (1993)
83:
269:
179:Siphonosteles can be called
104:, surrounded by a region of
7:
435:Gifford & Foster (1988)
331:Gifford & Foster (1988)
295:Gifford & Foster (1988)
283:Foster & Gifford (1974)
252:
27:is the central part of the
10:
611:
472:Royal Botanic Gardens, Kew
537:Gifford, Ernest M. &
468:The Kew Plant Glossary
466:Beentje, Henk (2010).
169:
93:
166:
91:
470:. Richmond, Surrey:
62:P. E. L. van Tieghem
539:Foster, Adriance S.
453:Arnold, Chester A.
170:
94:
529:978-0-7167-0712-7
481:978-1-84246-422-9
345:, pp. 66–68.
321:, pp. 85–89.
602:
595:Plant morphology
575:
556:
533:
521:
507:
485:
462:
438:
432:
426:
420:
411:
405:
399:
393:
387:
381:
370:
364:
358:
352:
346:
340:
334:
328:
322:
316:
310:
304:
298:
292:
286:
280:
220:vascular bundles
78:plant morphology
610:
609:
605:
604:
603:
601:
600:
599:
580:
579:
578:
572:
553:
530:
504:
490:Bold, Harold C.
482:
447:
442:
441:
433:
429:
421:
414:
406:
402:
394:
390:
382:
373:
365:
361:
353:
349:
341:
337:
329:
325:
317:
313:
305:
301:
293:
289:
281:
277:
272:
264:Vascular bundle
259:Vascular tissue
255:
161:
98:vascular plants
86:
37:vascular tissue
17:
12:
11:
5:
608:
598:
597:
592:
577:
576:
570:
557:
551:
534:
528:
508:
502:
486:
480:
463:
448:
446:
443:
440:
439:
427:
425:, p. 322.
412:
408:Beentje (2010)
400:
396:Beentje (2010)
388:
386:, p. 109.
384:Beentje (2010)
371:
367:Beentje (2010)
359:
355:Beentje (2010)
347:
335:
323:
311:
309:, p. 320.
299:
287:
274:
273:
271:
268:
267:
266:
261:
254:
251:
160:
157:
156:
155:
149:
133:
85:
82:
21:vascular plant
15:
9:
6:
4:
3:
2:
607:
596:
593:
591:
590:Plant anatomy
588:
587:
585:
573:
571:0-521-38294-7
567:
563:
558:
554:
552:0-7167-1946-0
548:
544:
540:
535:
531:
525:
520:
519:
513:
512:Foster, A. S.
509:
505:
503:0-06-040839-1
499:
495:
491:
487:
483:
477:
473:
469:
464:
460:
459:
454:
450:
449:
437:, p. 45.
436:
431:
424:
419:
417:
410:, p. 71.
409:
404:
398:, p. 39.
397:
392:
385:
380:
378:
376:
369:, p. 89.
368:
363:
356:
351:
344:
343:Arnold (1947)
339:
333:, p. 44.
332:
327:
320:
315:
308:
303:
297:, p. 42.
296:
291:
285:, p. 58.
284:
279:
275:
265:
262:
260:
257:
256:
250:
248:
244:
240:
235:
233:
229:
225:
221:
217:
212:
210:
205:
201:
197:
192:
190:
186:
182:
177:
175:
165:
153:
150:
147:
143:
142:
137:
134:
131:
130:
125:
121:
118:
117:
116:
113:
111:
107:
103:
99:
96:The earliest
90:
81:
79:
75:
71:
67:
63:
60:
57:
52:
50:
46:
42:
38:
34:
30:
26:
22:
561:
542:
517:
493:
467:
457:
430:
403:
391:
362:
357:, p. 7.
350:
338:
326:
314:
302:
290:
278:
246:
236:
215:
213:
208:
203:
195:
193:
184:
180:
178:
171:
159:Siphonostele
151:
139:
135:
127:
119:
114:
95:
53:
24:
18:
247:atactostele
204:dictyostele
196:solenostele
185:amphiphloic
152:plectostele
136:actinostele
66:H. Doultion
584:Categories
445:References
181:ectophloic
141:Lycopodium
120:haplostele
110:endodermis
84:Protostele
49:endodermis
270:Citations
209:meristele
124:centrarch
59:botanists
45:pericycle
541:(1988).
455:(1947).
253:See also
43:) and a
232:monocot
216:eustele
189:Asterid
568:
549:
526:
500:
478:
168:xylem.
146:exarch
129:Rhynia
106:phloem
56:French
23:, the
239:maize
228:roots
102:xylem
70:shoot
25:stele
19:In a
566:ISBN
547:ISBN
524:ISBN
498:ISBN
476:ISBN
241:and
224:pith
200:fern
174:pith
74:root
72:and
64:and
41:pith
33:stem
29:root
243:rye
230:of
31:or
586::
474:.
415:^
374:^
574:.
555:.
532:.
506:.
484:.
132:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
