CREDITS OBJECTIVES

Water Conservation in Plants

M3 U8 Lesson 7

CREDITS OBJECTIVES

ObjectivesYou should be able to:

1. list and discuss adaptations in plants to conserve water.

2. state the importance to plants of conserving/storing water.

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A hot, dry sandy desert habitat

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Cactus-thorn Scrubland along the Palisadoes Strip

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Why Conserve and Store water?Habitat is dry, hot and desert-like.Sandy/rocky soil does not hold much

water.Rainfall is scarce or only at certain

times.Drought is frequent.Adequate water is not available for

photosynthesis and hydration of the cell contents.Without water – the plant dies!

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Some Water-conservation MethodsStorage of Water

Succulent leaves (Leaf of Life or Bryophyllum sp., Batis sp.)

Succulent plant stem (Cactus)

Storage tank from leaf bases (Bromeliads)

Fleshy tuber (Raphionacme)

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Some Water-conservation MethodsLimit Water Loss

Waxy cuticle (Aloe)Sunken stomata (Pine trees)

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Some Water-conservation Methods

Absorbing moisture from leaf hairs or trichomes (Old Man’s Beard or Tillandsia sp.)

Absorbing Moisture

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Cactus - succulent storage stem with spines (modified leaves)

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Sesuvium: growing in dry sandy soil, has water-storing leaves and thick cuticle.

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Sesuvium - Swollen leaves and stems

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Batis sp. – has succulent storage leaves

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Seaside crab grass

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Leaves are rolled lengthwise

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Swollen, storage leaves of Aloe

Aloe leaf sliced with liquid running out

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Tank EpiphytesThis Bromeliad, a tank epiphyte, collects water at the center of the plant in a pool formed by the leaf bases; the water can be absorbed through the surface of the leaf with the aid of special plant hairs called (trichomes).

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Shaded areas show where water collection and storage occurs between leaves in Bromeliad Tank Epiphytes

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Did You Know?Caudiciform plants can store water and survive many months without rain in hot, arid desert regions. These plants generally have an enlarged basal caudex or stem axis from which the stems and roots arise. The caudex may extend below the ground, is typically non-photosynthetic and often gives rise to slender twining stems.

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SummaryThe protoplasm of living organisms

has a high percentage of water, so without water, living organisms would die.

Plants living in arid conditions where water is not readily available all the time, must adapt their structure and/or their various functions to ensure conservation of needed water.

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CREDITS OBJECTIVES

Credits Slide 1 http://scienceray.com/biology/botany/the-desert-saguaro/ Slide 3 www.ngfans.com/upload/pictures/0401/desert-la... Slide 4 http://www.cbd.int/doc/world/jm/jm-nbsap-01-p4-en.pdf Slide 6: Leaf of life

http://farm4.static.flickr.com/3347/3590825138_0b9ef757b8.jpg?v=0 Slides 6 & 9: Cactus http://scienceray.com/biology/botany/the-desert-saguaro/ Slide 7: Aloe:

http://keetsa.com/blog/wp-content/uploads/2009/06/aloe-vera-plant.jpg Slide 7: Sunken stomata:

http://dangthatscool.files.wordpress.com/2009/09/sunkenstomata.jpg Slide 8: Old Man’s Beard:

http://upload.wikimedia.org/wikipedia/commons/4/4c/Usnea_2_(2005_07_19).jpg Slide s 10-11: Sesuvium sp. http://dspace.mona.uwi.edu Slide 12: Batis sp. http://dspace.mona.uwi.edu Slide 14: Aloe vera http://waterconservationwise.com.au/water-efficient-plants/ Slide 15: Bromeliad http://rainforests.mongabay.com/0405.htm Slide 16: Bromeliad diagram http://aob.oxfordjournals.org/cgi/reprint/83/2/183.pdf Slide 17 Caudiciform http://waynesword.palomar.edu/indxwayn.htm

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