247:
132:
36:
77:
358:
Heterosporous plants that produced microspores in microsporangia and megaspores in separate megasporangia evolved independently in several plant groups during the
Devonian period. Fossils of these plants show that they produced endosporic gametophytes, meaning that their gametophytes were not
95:
386:. Each anther lobe develops two pollen sacs, so each anther has four pollen sacs. Development of pollen sacs begins with the differentiation of
387:
403:
464:
Bateman, R.M.; Dimichele, W.A. (1994). "Heterospory - the most iterative key innovation in the evolutionary history of the plant kingdom".
196:
168:
175:
508:
233:
215:
113:
63:
246:
149:
49:
182:
153:
17:
164:
530:
359:
free-living as in bryophytes but developed within the spores, as in modern heterosporic vascular plants.
446:. The cells of the primary sporogenous layer divide further and give rise to diploid sporogenous tissue.
535:
142:
251:
431:
One to three middle layers. Cells of these layers generally disintegrate in the mature anther
399:
394:
region below epidermis at four corners of the young anther. The archesporial cells divide by
189:
55:
8:
425:
91:
481:
477:
418:
504:
485:
473:
435:
406:
layer. The cells of the primary parietal layer divide by successive periclinal and
407:
255:
383:
340:
316:
283:
524:
439:
348:
291:
375:
363:
295:
287:
279:
395:
391:
332:
324:
309:
305:
275:
271:
443:
379:
315:, the microsporangia produce microsporocytes, the microspore mother
131:
352:
344:
336:
320:
312:
27:
Sporangia that produce spores that give rise to male gametophytes
371:
367:
328:
300:
319:, which then produce four microspores through the process of
466:
Biological
Reviews of the Cambridge Philosophical Society
410:
divisions to form concentric layers of pollen sac wall.
374:
that contains the pollen) consists of actively dividing
323:. Microsporocytes are produced in the microsporangia of
421:, which becomes stretched and shrivels off at maturity
413:
The wall layers from periphery to center consist of:
499:
Stewart, W.N.; Rothwell, Gar W. (26 February 1993).
428:. The cells of endothecium have fibrous thickenings.
156:. Unsourced material may be challenged and removed.
86:
may be too technical for most readers to understand
343:, which then produce four haploid microspores by
282:when they germinate. Microsporangia occur in all
522:
463:
498:
351:, within which the microspores divide twice by
492:
64:Learn how and when to remove these messages
503:(2 ed.). Cambridge University Press.
234:Learn how and when to remove this message
216:Learn how and when to remove this message
114:Learn how and when to remove this message
98:, without removing the technical details.
438:. The tapetal cells may be uni-, bi- or
398:division to give a subepidermal primary
245:
501:Paleobotany and the evolution of plants
14:
523:
457:
355:to produce a very simple gametophyte.
96:make it understandable to non-experts
154:adding citations to reliable sources
125:
70:
29:
267:
24:
478:10.1111/j.1469-185X.1994.tb01276.x
25:
547:
45:This article has multiple issues.
130:
75:
34:
378:cells surrounded by a layer of
141:needs additional citations for
53:or discuss these issues on the
13:
1:
450:
7:
298:and the aquatic fern genus
270: microsporangia) is a
10:
552:
278:that give rise to male
382:. It then becomes two-
259:
252:Encephalartos villosus
290:life cycles, such as
249:
402:layer and a primary
150:improve this article
258:with microsporangia
531:Plant reproduction
442:and possess dense
434:A single layer of
424:A single layer of
417:A single layer of
339:microspore mother-
260:
370:(the part of the
244:
243:
236:
226:
225:
218:
200:
165:"Microsporangium"
124:
123:
116:
68:
16:(Redirected from
543:
515:
514:
496:
490:
489:
472:(3–4): 315–417.
461:
269:
256:microsporophylls
239:
232:
221:
214:
210:
207:
201:
199:
158:
134:
126:
119:
112:
108:
105:
99:
79:
78:
71:
60:
38:
37:
30:
21:
551:
550:
546:
545:
544:
542:
541:
540:
536:Plant sexuality
521:
520:
519:
518:
511:
497:
493:
462:
458:
453:
366:, a very young
347:. These become
284:vascular plants
264:microsporangium
240:
229:
228:
227:
222:
211:
205:
202:
159:
157:
147:
135:
120:
109:
103:
100:
92:help improve it
89:
80:
76:
39:
35:
28:
23:
22:
15:
12:
11:
5:
549:
539:
538:
533:
517:
516:
509:
491:
455:
454:
452:
449:
448:
447:
432:
429:
422:
327:cones and the
274:that produces
242:
241:
224:
223:
138:
136:
129:
122:
121:
83:
81:
74:
69:
43:
42:
40:
33:
26:
18:Microsporangia
9:
6:
4:
3:
2:
548:
537:
534:
532:
529:
528:
526:
512:
510:0-521-38294-7
506:
502:
495:
487:
483:
479:
475:
471:
467:
460:
456:
445:
441:
440:multinucleate
437:
433:
430:
427:
423:
420:
416:
415:
414:
411:
409:
405:
401:
397:
393:
390:cells in the
389:
385:
381:
377:
373:
369:
365:
360:
356:
354:
350:
349:pollen grains
346:
342:
338:
334:
330:
326:
322:
318:
314:
311:
307:
303:
302:
297:
293:
289:
285:
281:
277:
273:
265:
257:
254:
253:
248:
238:
235:
220:
217:
209:
206:December 2017
198:
195:
191:
188:
184:
181:
177:
174:
170:
167: –
166:
162:
161:Find sources:
155:
151:
145:
144:
139:This article
137:
133:
128:
127:
118:
115:
107:
104:November 2017
97:
93:
87:
84:This article
82:
73:
72:
67:
65:
58:
57:
52:
51:
46:
41:
32:
31:
19:
500:
494:
469:
465:
459:
412:
388:archesporial
376:meristematic
361:
357:
299:
296:spike mosses
288:heterosporic
280:gametophytes
263:
261:
250:
230:
212:
203:
193:
186:
179:
172:
160:
148:Please help
143:verification
140:
110:
101:
85:
61:
54:
48:
47:Please help
44:
426:endothecium
404:sporogenous
364:angiosperms
335:. They are
333:angiosperms
306:gymnosperms
292:seed plants
276:microspores
525:Categories
451:References
408:anticlinal
396:periclinal
392:hypodermal
325:gymnosperm
310:angiosperm
286:that have
272:sporangium
176:newspapers
50:improve it
444:cytoplasm
419:epidermis
380:epidermis
56:talk page
486:29709953
400:parietal
436:tapetum
353:mitosis
345:meiosis
337:diploid
329:anthers
321:meiosis
313:anthers
190:scholar
90:Please
507:
484:
372:stamen
368:anther
301:Azolla
192:
185:
178:
171:
163:
482:S2CID
384:lobed
341:cells
317:cells
304:. In
197:JSTOR
183:books
505:ISBN
308:and
169:news
474:doi
362:In
331:of
268:pl.
152:by
94:to
527::
480:.
470:69
468:.
294:,
262:A
59:.
513:.
488:.
476::
266:(
237:)
231:(
219:)
213:(
208:)
204:(
194:·
187:·
180:·
173:·
146:.
117:)
111:(
106:)
102:(
88:.
66:)
62:(
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.