Plant Growth and Reproduction

1. Plant Growth and Reproduction

2. Growth Roots and Shoots • Roots grown downward • Shoots grow upward Meristems– • area of actively dividing plant cells • tissue that is growing on the plant Primary Growth increases length or height of plant • Uses Apical meristems which are located at the tips of shoots & roots • tissues that result from primary growth are known as primary tissues Secondary Growth • increases a plant’s stem and root width. Mineral Nutrients Plants need at least 14 mineral nutrients for growth. They also need carbon dioxide and water for and oxygen for cellular respiration.

3. Type of Growth Plant responses to the direction of light, gravity, and touch are called tropisms. Tropisms can be positive or negative. Tropisms include: • phototropism • gravitropism • thigmotropism

4. Environmental Influences on Growth Phototropism - caused by changes in availability of light, also the length of days and nights • http://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/phototropism/corn/cornworship.html

5. Gravitropism- If a plant is knocked over or in a thick forest, it will move back to the vertical position or the leaves will move vertically, in response to gravity http://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/gravitropism/gravi1/gravitrop.html

6. Thigmotropism Response to touch or physical contact of a solid object • Ex: vines growing up lattace work or the side of a house • http://plantsinmotion.bio.indiana.edu/plantmotion/movements/nastic/nastic.html • http://plantsinmotion.bio.indiana.edu/plantmotion/movements/nastic/nastic.html • http://plantsinmotion.bio.indiana.edu/plantmotion/movements/nastic/nastic.html

7. Reproduction Vocabulary • Gamete- a haploid (unpaired chromosome) reproductive cell that unites with another haploid reproductive structure to form a zygote (fused cell) • Gametophyte- the phase in which gametes are formed • Sporophyte- in plants and algae, the diploid (a cell that contains two haploid sets of chromosomes) individual produced haploid spores

8. Spore vs. Seed • Nonvascular plants- • Water needed for fertilization • Reproduces with spores • Vascular seedless plants • Water needed for fertilization • Reproduces with spores • Vascular seeded plants • Gymnosperms- Cones • Angiosperms • Make pollen and ovules (ovaries) • Once fertilized, the ovules produce fruit • Fruit houses/protects seeds

9. Pollen grains contain sperm. • They are produced in the anthers of the flowers in angiosperms. • Ovaries with ovules become fruits with seeds after the ovule (egg) is fertilized by sperm from the pollen

10. Flowers Flowers have four types of parts—petals, sepals, stamens, and pistils. • Sepals- outermost structure that protect a flower from damage • Petals- innermost structure that is colorful to attract pollinators • Stamen- male reproductive structures • Anther produce pollen • Filament holds anther • Pistil- Female reproductive structures • Stigma- top of the style, tacky so pollen sticks • Style- stalk rising from the ovary • Ovary- where ovules develop

12. Parts of a Seed • A seed contains an embryo, which is a new sporophyte, and a supply of nutrients for the embryo. • The cotyledons of an embryo help transfer nutrients to the embryo. • A seed coat covers and protects a seed. http://en.wikipedia.org/wiki/Image:Capsicum0.jpg

13. Seed Dispersal/Pollination by many vectors, including: Wind- some seeds are shaped to be carried by the wind easily Animals- • Some seeds stick to animals that brush past it • When insects drink nectar, they get coated in pollen which will, in turn, be passed on to the next flower the insect gathers nectar from • Water- can easily carry seeds miles away from parent plant