Land Plants vs. Aquatic Plants

Land Plants

• Vascular– They have “veins” that transport nutrients

between leaves, roots, stems– The veins are actually vascular tissue called

xylem and phloem

Veins that carry water/nutrients

• Xylem: carries water from roots to other parts of the plant

• Phloem: carries sugar and nutrients from leaves to the rest of the plant– Why would sugar come from leaves?

• Photosynthesis takes place mostly in leaves• (Photosynthesis uses sun and CO2 to make sugar

and O2)

carbon dioxide water sugar oxygen

Parts of a Plantleaf

flowerfruit

stem

seed

roots

Leaves

• Main photosynthetic organ (why?)– Collects the most sunlight

cuticleupper epidermis

palisade cells

ligninxylemphloem

lower epidermisspongy cells

stoma

guard cell

Flowers/Fruits/Seeds

• reproductive organs

• flower petals are modified leaves that attract pollinators

• hold seeds

• dispersed to help the plant grow in new places

Stem/Roots

• the stem holds up and support the plant; it also has vascular bundles of xylem and phloem

• roots anchor the plant in the ground and absorb water and nutrients from the ground

• What is the most important thing for a plant?

• Where would be the best place in the ocean for plants and other photosynthetic organisms to be?

light

near the surface

Zones

• Because light is so important to life, the ocean is separated in zones based on the amount of light that penetrates to that depth

• photic means light• eu means good• dis means poor• a means no

Aquatic Plants

• What do you think are some advantages and disadvantages to living in or near freshwater and saltwater?

Seagrasses

• evolved from land plants

• horizontal stems called rhizomes

• very small flowers because…

• they don’t need to attract pollinators

• why not?

Salt Marsh

• A salt marsh is an area that is partially flooded at high tide

Salt-Marsh Plants• Cordgrasses (halophytes- salt tolerant plants)

– actually in grass family unlike seagrasses– not marine; just tolerant of salt– help protect

areas from erosion

– provide habitat and breedinggrounds

– only get covered by salt water at high tides

– salt glands in leaves excrete salt

salt excreting from leaves

Mangroves• trees and shrubs that live on shores

• land plants tolerant of salt

• create mangrove forests

• thick leaves to reduce water loss; also excrete salt

•seeds grow for a little while on parent then drop into the sediment below

Pneumatophores

• specialized root extensions to help mangroves get extra oxygen because the mud they grow in doesn’t have enough

• mangrove roots beneath water provide shelter for many types of organisms