1. Topic 9.1.1 – Plant Structure and Growth

2. Kingdom Plantae Filicophytes Spermatophytes Flowers! This is where we will be spending most of our time

3. Monocots vs. Dicots

4. Key Differences Monocots – Floral organs in multiples of 3 – Parallel veins in leaves – Random distribution of vascular tissue in the stem – One cotyledon after germination – Adventitious root system Dicots Floral organs in multiples of 4 or 5 Branched veins in leaves Vascular bundles arranged in rings in the stem Two cotyledons after germination Branching root system

5. Drawing Time! Monocots

6. Dicots

7. How do the stems look? Which is monocot vs. dicot?

8. Tissue Drawing Diagram - Monocot

9. Tissue Diagram Drawing – Dicot

10. Tissue Diagram – Dicot Leaf Cuticle – prevents water loss Palisade mesophyll – cells contain extra chloroplast, which assists with photosynthesis Vascular bundles – transport water to the leaf (xylem) and starch away (phloem) Spongy mesophyll – loosely packed, surfaces for gas exchange Lower epidermis – controlling water loss, contain guard cells Guard cells – open and close to allow water in/out through transpiration, or gas exchange

11. Modified Roots, stems and leaves Roots – primarily function in anchorage and water uptake Stems – function in support and transport of materials Leaves – function in gas exchange and photosynthesis for the plant

12. Bignonia Tendril – Modified leaves Tendrils grow outward from leaves until they make contact with a solid surface This allows plants to climb upwards to attain sunlight

13. Bulbs Bulbs are simply a collection of thick leaf bases that store food for a growing plant. The stem at this point is just too small to see! Little baby stem! http://www.gardenculture.net/grow-your- own/growing-onions-from-scraps- pieceswaste-1925

14. Modified Stems and Roots - Tubers Stem tubers are modified stems that allow the plant to continue to grow every year These tubers provide the nutrients for the plant to grow the following year after a long winter Root tubers are modified roots that perform the same function, but are made of modified roots, rather than stem

15. Plant Growth: Meristems Plants only grow where they have undifferentiated cells – meristems. These meristems act like pockets of stem cells do in humans These can either be apical (meaning at the root or stem tip) or lateral (thickening layers of the cambium)

16. Apical Meristems These areas of growth are found at the terminal bud of the plant. This portion will continue to grow indiscriminately lengthwise and size wise for the plant Each time the plant adds an additional section of growth, it leaves behind an axillary bud. This bud is temporarily inactive until it needs to be used. A hormone inhibitor prevents growth before the plant needs it

17. Lateral Meristems As plants grow up, they also need to grow wider to support their height. Lateral Meristem growth results in secondary growth (xylem growth) in a ring inside the cambium along with secondary phloem growth If you have ever wondered where the rings in a tree come from, this is where! The outermost layer of this is called cork, which is produced by cork cambium. This is the bark of a tree!

18. Tropisms – plant responses to external stimuli Can either be in the direction of the stimulus (positive) or away from the stimulus (negative) This movement is regulated by hormones called auxins. – Auxins promote growth by lengthening the cells in which they are introduced – Auxins are produced by the coleoptile, which is a protective sheath that comes around the emerging plant – Normally auxins are produced evenly throughout the plant, which causes the plant to grow normally If the plant’s photoreceptors detect light, auxin will move in the opposite direction of the light, causing cells on that side of the plant to lengthen themselves. This leads to the plant growing unevenly, but growing in the direction of the light.

19. Kidney Bean Anatomy Kidney beans are a great example organism for a dicot The diagram to the right should give you an idea of where to look for some of the structures mentioned in the lab handout

20. Corn Seed A corn seed is a model monocot organism. Use the diagram below to compare the two types of seeds and