SBI3U1

Plants can reproduce both sexually and asexually

 Sexual reproduction is by sporic reproduction (alternation of generations).  Haploid gametophyte cells (1n) produce gametes  Diploid sporophyte cells (2n) produce spores.  Male and female gametes unite to form the sporophyte that continues the life cycle.

Plant Reproduction SexualSeedless PlantsNon-vascularVascularSeed PlantsGymnospermsAngiospermsAsexual Natural Vegetative Propagation Artificial Propagation OVERVIEW Copy chart on pg. 583 (textbook)

-Fertilization -> the sperm swims from the male gametophyte to the egg in the female gametophyte. -Water must be present & sperm must have a flagellum.

 Ex. gymnosperms and angiosperms  Male gametophytes called a microspore, develop into a pollen grain and sperm.  Female gametophyte, called a macrospore, develops into an egg cell.  In order for pollination to occur; male gametophyte must be transferred to the female reproductive structure.

sepals – protect the flower bud petals – attract pollinators stamens – male reproductive structure pistils – female reproductive structure The reproductive structures are in the flowers. Fertilization & seed development occur within the ovule. Pollination takes place on the stigma. Female gametophytes develop in the ovules, where eggs are formed.

Variations Among Flowers ◦ Complete flowers – Contain all four flower organs ◦ Incomplete – Missing one or more flower organs Grass flowers lack sepals and petals. They are incomplete.

 Self-pollination: Plants pollinate themselves  Cross-pollination: Plants receive pollen from another plant.  Animal Pollination: Insects and other small animals move from flower to flower collecting nectar and moving pollen. Bright, sweet- smelling flowers attract these pollinators.  Wind Pollination: Wind carries pollen and it lands on a receptive reproductive organ.

Self Pollination vs. Cross Pollination

Label your diagram using handout

Seed & Fruit Development Fertilization is one long process that ends with the formation of a seed. A seed is part of a fruit, developed from the ovary

The outside layers of the ovule form a protective cover called the seed coat. Ex:Beans or peas have seed coats that can easily be peeled off

Seed germination  A Seed may remain dormant for a period of time and then resumes growth

 Produces genetically- identical clones from a parent  Vegetative propagation – Involves growing a new individual from only a portion of the original plant

1.Division Splitting2.Grafting

3. Leaf Cutting4. Stem Cutting

5. Root Cutting6 Simple Layering

7. Air Layering8. Cell Culturing

Hormone: chemical compound produced in one part of the plant that controls growth in another part of that plant  act as chemical signals between cells and tissues  Some stimulate growth, others inhibit growth

1. Auxins 2. Cytokinins 3. Gibberellins 4. Ethylene 5. Abscisic acid

 “to increase”  stimulates elongation of plant cells  Produced in developing leaves/seeds and shoot tips  Controls upward growth – apical dominance

 Promotes cell division & differentiation  Stimulates the production of proteins required for mitosis and cytokinesis  delays aging of leaves and fruit

 Stimulates taller, stronger plant growth  Stops dormancy in seeds  Used in commercial crops to increase fruit size or larger cluster size in grapes

 Promotes ripening of fruit  Gaseous hormone  Diffuses through spaces in cells and transported within phloem

 Induces seed dormancy  Inhibits growth of buds in plant stems  Closes stomata & blocks intake of CO 2

Nastic response: a movement of the plant that is reversible, repeatable, and does not include growth. Ex: the opening & closing of flower petals as light conditions change. UNIT 5 Chapter 14: Plants: Reproduction, Growth, and Sustainability Section 14.2

3 main Types:  Growth responses to external stimulation coming from one direction in the environment. 1)Phototropism 2)Gravitropism 3)Thigmotropism

 a growth response to light produced by an unequal distribution of auxin.  More auxin on the side with less light causes those cells to elongate and bend the plant toward the light

 Growth response to gravity  a “positive” growth response of the roots downward or a “negative” growth response of stems upward

 a growth response to mechanical stimuli  Contact with another object  Ie. Ivy growing on a fence or tree

NutrientsSoil pH  Nutrients needed in large amounts are called macronutrients (ie.N, K, Ca, Mg)  Nutrients needed in small amounts are called micronutrients ( ie. Cl, Fe, B, Zn)  Optimal soil pH is slightly acidic ( pH 6-7) or slightly basic ( pH 7-8)  Any extremes in pH will inhibit normal plant growth