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Transport in Xylem

Transport in Xylem. SBI3UP. Transport of Water - Xylem. There are three main properties that enable water to travel from the roots to the leaves in the xylem. These properties must occur in order for water to move against gravity. Properties: Root pressure Transpiration Cohesion/Adhesion.

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Transport in Xylem

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  1. Transport in Xylem SBI3UP

  2. Transport of Water - Xylem • There are three main properties that enable water to travel from the roots to the leaves in the xylem. These properties must occur in order for water to move against gravity. • Properties: • Root pressure • Transpiration • Cohesion/Adhesion

  3. Property 1 - Root Pressure • Root pressure: the mechanism that creates positive pressure in the roots and helps to move water upwards the plant. • Water moves into the roots through the process of osmosis. • Osmosis: movement of water from an area of high concentration to an area of low concentration. • When the water accumulates in the roots, it causes an increase in pressure that helps to push the water upwards.

  4. Property 1 - Root Pressure There is a large concentration of solutes in the roots in comparison to the soil. As a result, there is a lower water concentration in the roots in comparison to the soil. Thus water will more from an area of high concentration (soil) to an area of low concentration (roots).

  5. Property 2 – Transpiration • Water must transpire from the stomata in the leaves to cause a negative pressure at the top of the plant. Water tends to move from an area of high pressure to low pressure. The process of transpiration is dependent on the opening/closing of the stomata. This can be affected by environmental cues.

  6. Property 3 – Cohesion/Adhesion • Cohesion: • Water molecules are polar molecules that have an affinity for one another due to the dipoles. Hydrogen bonds form between the water molecules causing them to pull each other up the xylem.

  7. Property 3 – Cohesion/Adhesion • Adhesion: • The molecules on the xylem walls are also polar. This causes the water molecules to adhere to the xylem wall and ‘climb’ up the xylem wall to the leaves.

  8. AP Lab: Transpiration

  9. AP Lab: Transpiration • Description: Test the effects of environmental factors on rate of transpiration • temperature • humidity • air flow (wind) • light intensity

  10. AP Lab: Transpiration • Concepts • transpiration • stomates • guard cells • xylem • adhesion • cohesion • H bonding

  11. Section 14.1 SBI3UP

  12. Types of Plants This ppt will only focus on angiosperms (flower producing plants).

  13. Sexual Reproduction in Angiosperms Functions: Anther: Pollen: Filament stalk: Stigma: Style: Ovary: Ovules:

  14. Pollination Mechanisms • The process of pollination involves the transfer of pollen from the male anther to the female stigma. • There are three forms of pollination mechanisms: • 1) Self-pollination and Cross-pollination • 2) Animal Pollination • 3) Wind Pollination

  15. 1) Self-Pollination and Cross-Pollination • Self-Pollinating plants will pollinate themselves or other flowers of the same plant. There is very little genetic variation. • Cross-Pollinating plants can receive pollen from other plants and increase genetic diversity. Most angiosperms are cross-pollinators.

  16. 2) Animal Pollination • Animal-pollinated flowers have adaptations that enable them to attract animals so that they can undergo pollination. • Examples of adaptations: scents, sweet nectar, bright colours, etc.

  17. 3) Wind Pollination • The wind may also help to transport pollen and help with fertilization. Plants that use this method of pollination, tend to lack colour or scents. Wind pollinating plants need to produce a large volume of pollen to ensure that they are propagating enough pollen for fertilization. These flowers have a lot of genetic diversity.

  18. The Life Cycle of Flowering Plants Plants reproduce asexually through alterations of generations. Both spores and gametophytes are produced so that sporophytes can be formed.

  19. The Life Cycle of Flowering Plants Only one of the four megaspores produced in the ovule develops into an egg. A pollen tube is formed in the stigma that enables the sperm (pollen) to enter and reach the egg. Two fertilizations occurs. One sperm fertilizes the egg the other fertilizes the nuclei to form an endosperm.

  20. Results of Reproduction • The seed that is formed becomes the part of the fruits that develops in the ovary. These seeds can either develop into monocotsor dicots.

  21. Results of Reproduction • The endosperm is absorbed and it provides most of the nourishment for the embryo. • The endosperm makes up a large portion of the seed.

  22. Results of Reproduction Other portions of the flower may contribute to the fleshy portion of the fruit.

  23. Homework Textbook: p. 592 # 4, 5, 6 & 8

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