Download Gametophyte Development Objectives

Gametophyte Development
Objectives
• Review alternation of generations
• Review floral morphology
• Examine gametophyte development
– Male
– Female
• Endosperm development
Flower Morphology
Stamen & Anther Morphology
3. Petals…
Corolla
2. Sepals … Calyx
5. Carpel
Stigma
Style
Ovary
Anther
Filament
4. Stamens: Anthers
Filaments
Androecium
1. Pedicel = flower
stalk or peduncle
Anther Lobe = Microsporangium
1
Male Gametophyte development
Early Microsporogenesis
Microsporogenesis
Microsporogenesis: Meiosis
Meiosis I
Meiosis II
Sporogenous Tissue
with microsporocytes
Tapetum
Mature pollen grains
Meiosis I
Anther lobe wall
Pollen grain wall morphology
Pollen grain aperture morphology
1. Pores
2. Fissures
Intine
Exine
Sporopollenin
2
Microgametogenesis
Stigma & Pollen Grain Interaction in Brussel Sprouts
(http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1469-8137.1972.tb01952.x)
Stigma - immature
Pollen grains
(microspores)
Stigma - mature
Stigma-pollen grain
interaction
Pollen Grain
Tube cell
Microgametophyte
Generative Cell
Pollen
Tube
Papers related to pollen tube growth
Pollen Tube Paths
Mascarenhas Joseph P.(1993) Molecular mechanisms of pollen tube growth and
differentiation. Plant Cell. 5(10). 1303-1314.
Heslop-Harrison, J (1987) Pollen Germination and Pollen-Tube Growth,
International Review of Cytology, Vol 107 PP1-77. >From the above review: "pollen
germination and pollen tube growth....are seen from the forgoing to be matters of
daunting complexity-biochemically, physiologically and structurally
Transmitting tissue in style
Malho Rui [a]. Institution [a] Dep. Biol. Vegetal, Fac. Ciencias Lisboa, R, Ernesto
Vasconcelos, Bloco C2, 1780 Lisboa Portugal. Title Pollen tube guidance-the long
and winding road. Source Sexual Plant Reproduction. 11(5). Nov., 1998. 242-244.
Herrero M [a]. Hormaza J I. Institution [a] Unidad Fruticultura, S.I.A.-D.G.A.,
Campus Aula Dei, Apartado 727, E-50080 Zaragoza Spain. Title Pistil strategies
controlling pollen tube growth. Source Sexual Plant Reproduction. 9(6). 1996. 343347.
Cheung Alice Y. Institution Dep. Biology, Yale Univ., P.O. Box 208104, New
Haven, CT 06520, USA. Title The pollen tube growth pathway: Its molecular and
biochemical contributions and responses to pollination. Source Sexual Plant
Reproduction. 9(6). 1996. 330-336. ISSN 0934-0882
1. Calcium gradient
2. Polarized growth
of pollen tube
3. Actin
microfilaments
3
Pollen Development in Angiosperms
Summary: Microspore (Pollen), Microgametophyte &
Sperm Development
Two developmental events
1. Microsporogenesis
Diploid microsporocytes ÷ meiotically
Haploid microspores form
Microspores develop into pollen grains
2 sperm nuclei
Microsporogenesis Æ produces microspores
Microspores Æ produce pollen grains
Pollen grains Æ produce male gametophytes
2. Microgametogenesis
Mitosis of microspore
Production of generative cell and tube cell
Mitosis of generative cell Æ 2 sperm nuclei
(=microgametogenesis)
Male gametophytes Æ produce male gametes
Megasporogenesis, Megagametogenesis &
Ovule Development
5. Carpel
Stigma
Style
Ovary
4