Lecture 7

Question 1

What are the characteristics of angiosperms (flowering plants)

Answer 1

• largest plant group
  
  • Flower: aggregation of reproductive organs
  • Stamen: modified microsporophylls bearing microsporangia; mostly composed of filament and anther
  • Male gametophyte reduced to 3-celled pollen grains
  • Female gametophyte reduced to 7-celled embryo sac with 8 nuclei
  • Carpels (modified megasporophyll bearing 2 rows of ovules) and fruit formation (fruit: mature ovaries)
  • Ovules with 2 integuments (bitegmic ovules) – secondary loss in some monocots and most asterids
  • Formation of endosperm (triploid endosperm due to double fertilization)
  • Sieve tube members in addition to sieve cells (conductive elements)

Question 2

describe the principle flower parts

Answer 2

• Pistil: composed of ovary, style and stigma
• Stamens: composed of filament and anther
• Perianth: composed of either undifferentiated tepals or differentiated rings of corolla (composed of petals or corolla lobes) and calyx (composed of sepals or calyx lobes)

Question 3

Difference between gymnosperm and angiosperm gametogenesis

Answer 3

Gymnosperms: multinucleate male gametophyte and sometimes motile sperm cells

Angiosperms: 3-celled male gametophyte producing 2 non-motile sperm cells

Question 4

Difference between gymnosperm and angiosperm fertilization

Answer 4

• *Gymnosperm**: delayed and simple fertilization
• *Angiosperms**: immediate double fertilization (1 sperm cell fusing with egg cell, the other with polar nuclei) after pollination

Question 5

Difference between gymnosperm and angiosperm post-fertilization development

Answer 5

Gymnosperms: haploid female gametophyte nurturing the embryo

Angiosperms: triploid endosperm nurturing the embryo

Question 6

What do angiosperms contain in their conductive tissue

Answer 6

Sieve tubes in conductive tissues are in addition to non-fused sieve cells.

Their pores are larger at end walls and differentated -> sieve plates (simple, compound).

Sieve tubes are associated with companion cells and more efficient sugar conduction

Question 7

What are conductive elements?

Answer 7

• are vessels with perforation plates (Except for angiosperms – vessels aroseprobable independently in several lineages).
• They are more efficient in solute conduction x commoner cavitation under low water potential or freezing.

Question 8

What do angiosperms posess in their xylem?

Answer 8

they mostly possess vessels in addition to tracheids

Question 9

What are basal lineages of angiosperms

Answer 9

Dicots (incl. magnoliids)
o Typically shrubs or trees with broad net-veined leaves, distributed mostly palaeotropically
o Amborella, water lillies, Schisandra (star-anise) are considered the basal-most lineages

Question 10

What are Magnoliids

Answer 10

• Large group of basal angiosperms
• Characterized by trimerous flowers, spirally arranged tepals and often laminar stamens

Question 11

What are represenatives of magnoliids

Answer 11

Representatives:

magnolias, many trees commonly used as spices (nutmeg, bay laurel, cinnamon, camphor, pepper) or fruits (annonas, avocado)

(Magnoliales – annonaceae, nutmeg; Laurales – bay laurel, cinnamon, camphor, avocado; Piperales – pepper)