Plant Reproduction

1. Plant Reproduction Unit 6 – Lecture 6

2. Alternation of Generations • type of reproduction utilizing asexual & sexual means

3. Alternation of Generations • offspring generations alternate between being haploid [1n] in one generation to being diploid [2n] the next.

4. Alternation of Generations • in some plants, the sporophyte is a completely different plant than the gametophyte. • in others, the gametophyteis something we really don’t see.

5. Alternation of Generations • Sporophyte [2n] produces spores [1n]through meiosis • sporophyte is the typical “adult plant” that we see

6. Alternation of Generations • Spores [1n] producegametophytes [1n] throughmitosis

7. Alternation of Generations • Gametophyte [1n]produces gametes [1n]through mitosis

8. Alternation of Generations • Gametes [1n] fuse in fertilization to produce zygote [2n]

9. Alternation of Generations • Zygote [2n] grows to become embryo [2n]

10. Alternation of Generations • Embryo [2n] grows to become sporophyte [2n]… • etc.

11. Alternation of Generations • non-vascular and non-seed plants MUST have water to reproduce. • flagellated sperm must swim to egg • gametophyte can be very small, but visible – 1cm or less.

12. Other Asexual Reprod Methods • vegetative reproduction – new plant forms from existing plant part (roots) • fragmentation – new plant forms from a cutting of the original plant.

13. Seed Plants • are vascular… • two varieties: • gymnosperm – produce cones • angiosperm – produce flowers

14. Angiosperms • produce flowers and seeds inside of a fruit • petals, pistil, stamen, etc. • petals attract pollinators • fruit attracts organisms which can spread seeds

15. Angiosperms

16. Angiosperms

17. Angiosperms • are either monocot or dicot • cotyledon – the seed “leaves” or sides / food supplies • don’t need to know these directly: • have different types of xylem & phloem • have different types of veination • have differences in petal arrangement

19. Seed Production

20. Germination • germination – zygote growing into new plant • requirements: • water • suitable temperature • oxygen • time

21. Germination • germination – zygote growing into new plant • requirements: • light • other: • freezing – apples • soaking in salt water – coconuts • fire – many conifers • cannot be halted