22:
1829:
236:. Each of the microsporocytes in the microsporangia undergoes meiosis, producing four haploid microspores. These develop into pollen grains, each consisting of four cells and, in conifers, a pair of external air sacs. The air sacs give the pollen grains added buoyancy that helps with wind dispersal.
311:
Although it is not the usual route of a microspore, this process is the most effective way of yielding haploid and double haploid plants through the use of male sex hormones. Under certain stressors such as heat or starvation, plants select for microspore embryogenesis. It was found that over 250
331:
Microspore embryogenesis is used in biotechnology to produce double haploid plants, which are immediately fixed as homozygous for each locus in only one generation. The haploid microspore is stressed to trigger the embryogenesis pathway and the resulting haploid embryo either doubles its genome
280:
of a flowering plant develops, four patches of tissue differentiate from the main mass of cells. These patches of tissue contain many diploid microsporocyte cells, each of which undergoes meiosis producing a quartet of microspores. Four chambers (pollen sacs) lined with nutritive
227:
grains each containing a reduced, multicellular male gametophyte. The megaspores, in turn, develop into reduced female gametophytes that produce egg cells that, once fertilized, develop into seeds. Pollen cones or
332:
spontaneously or with the help of chromosome doubling agents. Without this double haploid technology, conventional breeding methods would take several generations of selection to produce a homozygous line.
507:
Seguí-Simarro, José M.; Nuez, Fernando (1 September 2008). "How microspores transform into haploid embryos: changes associated with embryogenesis induction and microspore-derived embryogenesis".
232:
usually develop toward the tips of the lower branches in clusters up to 50 or more. The microsporangia of gymnosperms develop in pairs toward the bases of the scales, which are therefore called
1659:
1664:
320:, it can deviate towards embryogenesis and become star-like microspores. The microspore can then go one of four ways: Become an embryogenic microspore, undergo
1797:
57:
develop into female gametophytes. The male gametophyte gives rise to sperm cells, which are used for fertilization of an egg cell to form a
1715:
395:
Bateman, R.M.; Dimichele, W.A. (1994). "Heterospory – the most iterative key innovation in the evolutionary history of the plant kingdom".
293:
producing two cells. The first of the cells (the generative cell) is small and is formed inside the second larger cell (the tube cell).
1531:
141:
within the microspore wall. Either 128 or 256 sperm cells with flagella are produced in each antheridium. The only heterosporous
446:
379:
137:, each producing four microspores. Each microspore may develop into a male gametophyte consisting of a somewhat spherical
233:
130:
126:
229:
552:"Microspore embryogenesis: targeting the determinant factors of stress-induced cell reprogramming for crop improvement"
486:
285:
are visible by the time the microspores are produced. After meiosis, the haploid microspores undergo several changes:
1721:
117:. The perispore is the thickest of the three layers while the exospore and endospore are relatively equal in width.
616:
1055:
1536:
986:
1705:
1292:
807:
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1521:
62:
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life cycles using microspores and megaspores arose independently in several plant groups during the
1809:
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1639:
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These steps occur in sequence and when complete, the microspores have become pollen grains.
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1423:
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609:
1026:
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8:
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The microspore has three different types of wall layers. The outer layer is called the
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328:(haploid/double haploid plant), become a pollen-like structure or die.
74:
70:
43:
187:
35:
whereas the numerous smaller red spores at the bottom are microspores.
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The members of each part of the microspores separate from each other.
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54:
32:
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110:
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In heterosporous seedless vascular plants, modified leaves called
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different species of angiosperms responded this way. In the
1465:
1460:
1112:
952:
927:
922:
906:
765:
299:
A double-layered wall then develops around each microspore.
248:
18:
Small land plant spores that develop into male gametophytes
462:
1385:
947:
594:
397:
Biological
Reviews of the Cambridge Philosophical Society
145:are aquatic or semi-aquatic, including the genera
506:
61:. Megaspores are structures that are part of the
1845:
394:
437:Bidlack, James E.; Jansky, Shelley H. (2011).
610:
436:
133:containing many microsporocytes that undergo
1716:International Association for Plant Taxonomy
120:
617:
603:
549:
575:
476:
1660:International Code of Nomenclature (ICN)
31:. The large three spores at the top are
25:Microscopic photo of spores (in red) of
20:
1846:
598:
369:
502:
500:
498:
481:. New Age International. p. 8.
461:
432:
430:
428:
426:
194:Types of seedless vascular plants:
13:
439:Stern's Introductory Plant Biology
409:10.1111/j.1469-185x.1994.tb01276.x
14:
1865:
1665:ICN for Cultivated Plants (ICNCP)
495:
423:
175:. Heterospory also occurs in the
1828:
1827:
521:10.1111/j.1399-3054.2008.01113.x
306:
316:, after a microspore undergoes
556:Journal of Experimental Botany
543:
470:
455:
388:
363:
271:
214:
1:
441:. New York, NY: McGraw-Hill.
357:
223:the microspores develop into
113:, and the inner layer is the
100:
1706:History of plant systematics
1293:Thorns, spines, and prickles
374:. New York: Peter Marshall.
7:
335:
185:and in the quillwort genus
10:
1870:
1522:Alternation of generations
624:
550:Testillano, Pilar (2019).
289:The microspore divides by
65:in many seedless vascular
63:alternation of generations
1823:
1771:
1735:
1672:Cultivated plant taxonomy
1635:Biological classification
1625:
1498:
1414:
1310:
1260:
985:
915:
858:
820:
794:
730:
650:
632:
1532:Evolutionary development
477:Bhatnagar, S.P. (1996).
121:Seedless vascular plants
89:, and are produced from
85:period. Microspores are
1183:Hypanthium (Floral cup)
179:in the spikemoss genus
49:that develop into male
1798:by author abbreviation
1722:Plant taxonomy systems
1640:Botanical nomenclature
239:Types of Gymnosperms:
36:
1805:Botanical expeditions
509:Physiologia Plantarum
24:
1537:Evolutionary history
1527:Double fertilization
1379:Cellular respiration
756:Non-vascular plants
370:Evert, Ray (2013).
93:microsporocytes by
1854:Plant reproduction
1261:Surface structures
1056:Flower development
568:10.1093/jxb/ery464
464:Feddes Repertorium
109:, the next is the
37:
1841:
1840:
1480:Herbaceous plants
1306:
1305:
562:(11): 2965–2978.
448:978-0-07-304052-3
381:978-1-4292-1961-7
372:Biology of Plants
318:microsporogenesis
1861:
1831:
1830:
1810:Individual trees
1485:Secondary growth
1456:Succulent plants
1444:Prostrate shrubs
1327:Apical dominance
1312:Plant physiology
1273:Epicuticular wax
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802:Plant morphology
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234:microsporophylls
127:microsporophylls
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1788:Botanical terms
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1677:Citrus taxonomy
1655:Author citation
1621:
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1406:Turgor pressure
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1302:
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1071:Floral symmetry
989:
981:
911:
900:Vascular bundle
895:Vascular tissue
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761:Vascular plants
726:
722:Plant pathology
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342:Microsporangium
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1778:Related topics
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1645:Botanical name
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1627:Plant taxonomy
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1622:
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1612:
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1603:Megasporangium
1600:
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1591:Microsporangia
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1429:Cushion plants
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1364:Plant hormones
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1347:Photosynthesis
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1066:Floral formula
1063:
1061:Floral diagram
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1036:
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993:
991:
990:(incl. Flower)
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890:Storage organs
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776:Spermatophytes
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746:Archaeplastida
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652:Subdisciplines
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488:978-8122407921
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403:(3): 345–417.
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131:microsporangia
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77:. Plants with
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1763:Phytochemical
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1401:Transpiration
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1199:
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1189:
1188:Inflorescence
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873:Ground tissue
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833:
831:
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796:Plant anatomy
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660:Archaeobotany
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414:
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366:
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353:
350:
348:
345:
343:
340:
339:
333:
329:
327:
326:organogenesis
323:
319:
315:
307:Embryogenesis
304:
298:
295:
292:
288:
287:
286:
284:
283:tapetal cells
279:
267:
264:
262:
259:
257:
254:
250:
247:
246:
245:
242:
241:
240:
237:
235:
231:
230:microstrobili
226:
222:
210:
207:
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202:
200:
197:
196:
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192:
190:
189:
184:
183:
178:
174:
173:
168:
167:
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156:
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144:
140:
136:
132:
128:
118:
116:
112:
108:
98:
96:
92:
88:
84:
80:
79:heterosporous
76:
72:
68:
64:
60:
56:
52:
48:
45:
41:
34:
30:
29:
23:
16:
1758:Horticulture
1748:Floriculture
1650:Correct name
1595:
1500:Reproduction
1490:Woody plants
1415:Plant growth
1374:Gas Exchange
1359:Phytomelanin
1237:Plant embryo
987:Reproductive
835:Phragmoplast
577:10261/176079
559:
555:
545:
512:
508:
478:
472:
463:
457:
438:
400:
396:
390:
371:
365:
330:
322:callogenesis
310:
302:
275:
238:
218:
193:
186:
180:
170:
164:
158:
154:Regnellidium
152:
146:
124:
104:
51:gametophytes
39:
38:
26:
15:
1574:Pollen tube
1569:Pollinators
1559:Pollination
1554:Germination
1369:Respiration
1352:Chlorophyll
1198:Pedicellate
1132:Gametophyte
1051:Aestivation
1002:Antheridium
997:Archegonium
845:Plasmodesma
822:Plant cells
685:Paleobotany
680:Ethnobotany
665:Astrobotany
515:(1): 1–12.
479:Gymnosperms
272:Angiosperms
266:Gnetophytes
221:seed plants
215:Gymnosperms
204:Spikemosses
199:Water ferns
182:Selaginella
139:antheridium
75:angiosperms
71:gymnosperms
40:Microspores
28:Selaginella
1596:Microspore
1586:Sporangium
1564:Artificial
1252:Sporophyte
1247:Sporophyll
1242:Receptacle
1137:Gynandrium
1007:Androecium
916:Vegetative
786:Angiosperm
781:Gymnosperm
675:Dendrology
358:References
209:Quillworts
101:Morphology
67:cryptogams
55:megaspores
53:, whereas
44:land plant
33:megaspores
1793:Botanists
1711:Herbarium
1608:Megaspore
1506:Evolution
1449:Subshrubs
1417:and habit
1342:Nutrition
1337:Cellulose
1332:Bulk flow
1315:Materials
1278:Epidermis
1142:Gynoecium
1123:Endosperm
1118:Dispersal
1034:Staminode
970:Sessility
958:Cataphyll
878:Mesophyll
830:Cell wall
771:Lycophyte
751:Bryophyte
705:Geobotany
690:Phycology
529:1399-3054
352:Megaspore
160:Pilularia
115:endospore
107:perispore
1848:Category
1833:Category
1753:Forestry
1743:Agronomy
1736:Practice
1687:Cultivar
1682:Cultigen
1542:timeline
1434:Rosettes
1322:Aleurone
1298:Trichome
1215:Perianth
1027:Filament
885:Meristem
808:glossary
670:Bryology
586:30753698
537:18507790
417:29709953
336:See also
244:Conifers
177:lycopods
166:Salvinia
148:Marsilea
111:exospore
83:Devonian
73:and all
1511:Ecology
1268:Cuticle
1098:Capsule
1088:Anatomy
1039:Tapetum
963:Petiole
938:Rhizome
933:Rhizoid
860:Tissues
850:Vacuole
840:Plastid
642:Outline
637:History
291:mitosis
276:As the
256:Ginkgos
188:Isoëtes
135:meiosis
95:meiosis
91:diploid
87:haploid
1815:Plants
1718:(IAPT)
1471:Lianas
1439:Shrubs
1391:Starch
1283:Nectar
1203:Raceme
1169:Stigma
1157:Locule
1147:Carpel
1108:Pyrena
1046:Flower
1022:Anther
1017:Stamen
1012:Pollen
734:groups
626:Botany
584:
535:
527:
485:
445:
415:
378:
314:anther
278:anther
261:Cycads
225:pollen
172:Azolla
169:, and
69:, all
59:zygote
47:spores
1775:Lists
1692:Group
1615:Spore
1549:Flora
1466:Vines
1461:Trees
1424:Habit
1396:Sugar
1288:Stoma
1230:Sepal
1225:Petal
1220:Tepal
1208:Umbel
1193:Bract
1174:Style
1162:Ovule
1152:Ovary
1093:Berry
1083:Fruit
1076:Whorl
943:Shoot
741:Algae
732:Plant
413:S2CID
347:Spore
249:Pines
143:ferns
129:bear
1697:Grex
1579:Self
1113:Seed
975:Stem
953:Leaf
928:Root
923:Bulb
907:Wood
868:Cork
766:Fern
582:PMID
533:PMID
525:ISSN
483:ISBN
443:ISBN
376:ISBN
42:are
1386:Sap
1103:Nut
948:Bud
572:hdl
564:doi
517:doi
513:134
405:doi
324:to
219:In
1850::
580:.
570:.
560:70
558:.
554:.
531:.
523:.
511:.
497:^
425:^
411:.
401:69
399:.
191:.
163:,
157:,
151:,
97:.
810:)
806:(
618:e
611:t
604:v
588:.
574::
566::
539:.
519::
491:.
466:.
451:.
419:.
407::
384:.
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