1. Plant Physiology
Unit 3

2. Life Cycle of Plants
Annual – a plant that completes its life cycle in one year
Biennial – a plant that completes its life cycle in two years (usually grows in the first year and flowers in the second year)
Perennial – a plant that lives more than two years (some will grow and bloom in the first year)

3. Leaf Retention of a Plant
Deciduous – plants that lose their leaves during the dormant season
Evergreen – plants that retain their leaves and remain green year round

4. Moisture in Plants
Turgid – a plant that is swollen or filled with moisture
Wilted – a plant that is limp because it does not have enough moisture

5. Plant Growth Dormant – a stage when a plant rests or grows very little
Plants generally go dormant in response to adverse conditions such as extreme heat or cold
Botany – the part of biology that deals with plants

6. Season Crop Type
Cool season plants – relish cool temperatures, growing best in spring or fall (ex – pansy)
Warm season plants – grow best in warm temperatures, growing best in the summer and every fall (ex – zinnia, marigold, vinca)

7. https://youtu.be/p3St51F4kE8
Plant Anatomy

8. Leaves
External Parts
Petiole – the lead stalk or part that connects the leaf to the stem
Midrib – the large center vein
Blade – the large, flat part of the leaf
Veins – the structural framework of the leaf
Margin – the edge of the leaf
Apex – the leaf tip

9. Leaves

10. Leaves
Internal Parts
Upper and lower epidermis – the skin of the leaf that prevents the loss of too much moisture
Stomates – the small openings under the leaf for breathing or transpiration
Guard cells – surround the stomates and regulate the open and close of the stomates
Chloroplasts – small green particles that contain chlorophyll, give leaves their green color, and are necessary for photosynthesis

11. Leaves

12. Leaves Functions of the leaf
Photosynthesis – process by which plants capture sunlight and use it to convert carbon dioxide and water into food (sugar)
Respiration – converts sugars and starches into energy
Transpiration – the release of water vapor from the leaves of plants and it helps cool the plants

13. Leaves

14. Leaves Leaves additional
Sessile describes leaves without a petiole (ex – zinnia)
Bracts are modified leaves (ex – poinsettia)
Needles and scales are modified leaves (ex – pine tree)
Glabrous leaves or stems have a smooth non-hairy feel (ex – southern magnolia)
Pubescent leaves or stems have a hairy feel (ex – African violet)

15. Stems
External parts
Lenticels - breathing pores found on stems and branches
Bud scale scars - indicate where terminal buds have been located
Leaf scars - indicate where leaves were attached
Terminal bud - a bud on end of stem
Axillary bud - the bud located at the axil of the leaf
Lateral buds - buds on side of stem

16. Stems
Internal parts
Xylem – the tissue that transports water and nutrients up from the roots to the stem and leaves
Phloem – the tissue that transports food down from leaves to the roots
Cambium – a thin, green, actively growing tissue located between the bark and wood and produces all new stem cells
Bark – old inactive phloem
Heartwood – old inactive xylem
Sapwood – new active xylem

17. Stems
Phloem
Phloem
Xylem

18. Stem
Bark
Cambium
Sapwood
Heartwood

19. Stems
Cotyledons
Monocots – plant systems that have vascular bundles which contain xylem and phloem; they produce one seed leaf (ex – grass & corn)
Dicots – plant stems that have a phloem layer and xylem layer separated by cambium; they produce two seed leaves (ex – trees & vegetables)

20. Stems
Xylem
Cambium
Phloem
Dicot
Monocot

21. Stems Functions of the stem
Translocation – the movement of water and minerals through the plants; the phloem moves food down from the leaves to the roots
The xylem moves water and nutrients up from the roots to the leaves

22. Roots
External parts
Root cap - located at the tip of the root and is where new cells are produced
Root hairs – absorb moisture (water) and minerals

23. Roots
Internal parts
Phloem – the outer layer of the root and carries food down the root
Xylem – the inner layer and carries water and minerals up to the stem

24. Roots

25. Roots
Types of roots
Fibrous roots have many branched shallow roots; they are easy to transplant
Tap roots are long roots with few branched ones; they are more difficult to transplant

26. Roots Functions of roots Anchorage Absorption Asexual Reproduction
Storage

27. Flowers (develop into seeds & fruits)
External parts
Sepals – the green parts of the flower that cover and protect the flower bud before it opens
Petals – leaves that are modified to attract insects for flower pollination

28. Flowers (develop into seeds & fruit)
Internal parts
Stamens – male flower parts
Anther – a sac like structure that contains pollen and male sex cells
Filament – a short stalk that holds up the anther

29. Flowers (develop into seeds & fruit)
Internal parts
Pistil – female part of the flower
Stigma – sticky pat on top of the style where insects leave pollen
Style – hold up the stigma and connects it to the ovary
Ovary – if fertilized, becomes a fruit
Ovules – the eggs or female sex cells that become seeds if fertilized

30. Flowers

31. Flowers

32. Flowers (develop into seeds & fruit)
Functions of the flower
It attracts insects for pollination
It produces seeds for sexual reproduction
It produces fruit to nourish and protect the seed

33. Flowers Additional flower and fruit information
Complete flowers have both male and female parts
Incomplete flowers have only male or female parts

34. Flowers

35. Flowers Additional flower and fruit information
Fertilization – when pollen travels down the style, joining the sperm and the ovule
Pollination – the transfer of pollen from the anther to the stigma
Cross-pollination – the transfer of pollen from the stamen to the stigma of one flower to a flower on another plant
Self-pollination – the transfer of the pollen to the stigma of a flower on the same plant

36. Flowers Additional flower and fruit information
Corolla – all auxiliary parts of the flower not including reproductive organs; the collective term for all petals of a flower
Calyx – the external usually green or leafy part of a flower; also the collective term for all sepals of a flower
Receptacle – the enlarged tip of a stem on which a flower is born

37. Flowers Additional flower and fruit information
The fruit serves as protection for the seed
The function of the fruit is to help with seed dispersal
The juvenile stage is when a plant first begins growing from a seed