Download Phylum/Divison Pterophyta

Phylum/Divison Pterophyta
• 
2 types of sporangia
–  eusporangia = multiple initials or parent cells
•  inner layer = irregular mass, gives rise to spore mother cell
•  outer layer = sporangium wall
Phylum/division Pterophyta
–  leptosporangia = one superficial initial
•  stalked sporangium
•  capsule with nutritive tissue (tapetum)
•  tapetum  annulus that contracts to catapult spores
•  inner tissue becomes spore mother cells
alterna'on of diploid sporophy'c genera'on with a haploid gametophy'c genera'on. Sporophy'c genera'on is dominant in the life cycle. Phylum/Division Pterophyta. Equisetales
One genus: Equisetum (horsetails)
Homosporus
Spores with elaters
• Shoot with
terminal
strobilus.
• Photosynthetic shoot
• Nodes and internodes
Perennial rhizomes
• Whorls of
scale-like
leaves
• Low content
of
chlorophylls or
no
chlorophylls
Gymnosperms Evolu'on of the seed All seed plants are heterosporus embryo Microspores  microgametophyte Megaspores  megagametophyte
Mature ovule Evolu'on of the seed Evolu'on of the integuments Lobes of integument ovule Elkinsia polymorpha micropyle Progymnosperms FlaEened lateral branch system Callixylon (logs of Archaeopterix)
permineralized wood; radial sec<on. PiEed tracheids Archaeopteris  Late Paleozoic era  Reproduc<on by spores  Bifacial vascular cambium • Secondary xylem • Secondary phloem  Eustele Ex'nct gymnosperms This is an unnatural mixed group (like the pro<sta) with no taxonomic ranking and not enough specimens to determine phylogenies well. Pteridospermales Cordaitales BenneKtales Five phyla of seed plants s'll exist today. • Coniferophyta -­‐ the conifers • Ginkgophyta -­‐ the ginkgos • Cycadophyta -­‐ the cycads, or sago "palms” • Gnetophyta -­‐ the gnetophytes and ephedras gymnosperms (from the Greek gymnos, meaning "naked" and sperm, meaning "seed") 840 species * Anthophyta -­‐ the flowering plants angiosperms (from the Greek angion, meaning "box"). 300,000 species Living gymnosperms. Conifers Seeds do not develop within an ovary. Seeds are exposed on the surface of sporophylls or other structures. Polyembryony: One megagametophyte = several archegonia more than one egg may be fer<lized Produc<on of pollen grains transferred by wind. Pollina'on and pollen tubes Pollina<on is the transfer of the whole male gametophyte to the female receptacle. Antheridia is absent in Gymnosperms In conifers, gnetophytes and angiosperms the pollen tube conveys the sperm to the egg cell Seed-­‐scale complexes megasporocyte or Ovuliferous scale nucellus • 24 months to complete the cycle of life • The seed coat and the embryo are two different sporophy<c genera<ons • Megaspores are the gametophyte. Steril bract Maturity of the cone Bristlecone Pine cone – first year First, second, and third year cones on the same branch. Pinnus contorta Leaf arrangement Pine Leaves "needles": • Long and thin modified leaves • Borne singly needles clusters or Fascicles scalelike leaves • Whorl around the branches • Photosynthe<c • 2-­‐45 years Fascicles are short shoots without apical meristema<c ac<vity • Determinate • Indeterminate Transfusion <ssue: Conduc<on of materials between the mesophyll and the vascular bundles Tracheids Sieve cells Taxus sp. (Yew) cypress Mature juniper cones California's coulter pine (Pinus coulteri) Sugar Pine (Pinus lamber<ana) Development of the microgametophyte of Ginkgo biloba When it is ready for pollina<on a mucilaginous droplet is exuded from the inside of the ovule to catch the pollen. Haustorium Cycads Zamia roezlii Sperm 0.4 mm long 2 for each microgametophyte 40,000 flagella Mesozoic era. Era of cycads and dinosaurs Neurotoxins Carcinogenic compounds Phylum Gnetophyta Strobili similar to flower clusters in angiosperms Welwitschia • Monophyle<c group Ephedra Gnetum • Group of gymnosperm more related with angiosperms • Ephedra is a s<mulant that constrict blood vassels and increases blood pressure and heart rate.