Plant Transport AS Much Knowledge So Application.

Plant Transport AS

Much KnowledgeSo Application

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Overview

Shoots – Leafs & Stems

Roots – Underground

3 Tissue types in the above Dermal, Vascular, & Ground

5 Types of Differentiated Plant Cells Parenchyma Collenchyma Sclerenchyma Xylem Phloem

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Shoots

Plant stuff that is above ground Leaves – main photosynthetic organ Stems – displays the leaves

2 types of buds (growing parts) Terminal (Apical) Bud – located at top end of stem

Growth usually occurs at this bud Axillary Bud – located in the “v” between leaf and stem

Can potentially form a branch

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Questions

What is the advantage to a plant to only grow at the apical and axillary buds?

A tree house was built between the stem and a branch without axillary buds. The growth rate of the apical buds is 2 feet per year, the growth rate of the axillary buds is 3 feet per year, and the tree house was built at a height of 10 feet. What will be the height of the tree house in 10 years?

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Multicellular organ

Anchors plant

Absorbs water & Minerals

May store sugar & starches

Fibrous Roots – mat of thin roots that are spread just below the root’s surface

Taproots – 1 thick, vertical root with many lateral roots that emanate from it

Roots

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Root Hairs

Located at the tips of roots

Dramatically increase the surface area

Efficient absorption of H2O and minerals

Mycorrhizae – Symbiotic relationship Root tips & fungus – assist in

absorption Found in vast majority of plants

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Mycorrhizae

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Questions

Which root type is focused on absorption?

Which root type is focused on storage?

Fibrous roots are not efficient absorbers, so what structure is responsible for absorption?

What is the function of root hairs or mycorrhizae?

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3 Tissue types1. Dermal

Cover entire plant Protect against water loss Nonspecific defense mechanism

2. Vascular Continuous throughout the plant Transports material between roots and shootsa) Xylem – transports water & minerals up

from the rootsb) Phloem – transports food from the

leaves to rest of plant

3. Ground Tissue that is neither dermal nor vascular Pith – ground tissue inside vascular tissue Cortex – ground tissue outside vascular tissue Parenchyma, collenchyma, and sclerenchyma

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3 Cell Types in Ground Tissue

1. Paren(chyma) -- Most abundant cell type-- Present throughout the plant-- perform most of the metabolic functions of the plant (Photosynthesis & Respiration)

2. Collen(chyma)-- Support growing parts of the plant-- Grouped into cylinders

3. Scleren(chyma)-- Occupy NonGrowing parts of plant-- Cell wall makes up to 90% of cell space-- May contain lignin (wood)-- Dead cells at maturity

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Vascular Tissue - Xylem

– Water conducting cells-- 2 types: Tracheids & Vessels-- Both types are dead at functional maturity

-- Tracheids found in ALL vascular plants-- Long thin cells with lignin-- Water moves through the pits

-- Vessels (Vessel Elements) found primarily in angiosperms -- Have pits & perforated end walls for water

movement

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Vascular Tissue - Phloem

-- Transport Sucrose & other organic compounds

2 Types: Sieve-tube elements & Companion Cells-- Both types are alive at functional maturity

Sieve Tubes-- Consist of chains of cells-- Called sieve-tube element-- Highly modified for transport-- Lack nucleus, ribosomes, & vacuoles

Companion Cells-- Provide for the molecular needs of the sieve-tube elements-- Connected to the sieve-tube elements by plasmodesmata

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Questions

Why would there be more vascular tissue in the roots instead of the stem or leaves?

Why is there more dermal tissue in the leaves than stem or roots?

Which part of the plant (leaves, stem, roots) would you expect to have the most parenchymal cells?

Which type of xylem has the larger cross section?

How are sieve-tube elements functionally different than the companion cells?

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Roots – Cross

Section

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Leaves…

Stomata interrupts the underside of the leaf Flanked by guard cells – open/close the stomata

Ground tissue is in between upper & lower epidermis, in the mesophyll

Ground tissue is composed of parenchyma cells Site of photosynthesis are parenchyma cells Palisade mesophyll is elongated to maximize photosynthesis Spongy mesophyll is

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Leaf: Cross-Section

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Questions

Why are there two types of mesophyll?

Why would there be spaces in the spongy mesophyll?

Why would there not be spaces in the palisade mesophyll?

Plant Transport AS Much Knowledge So Application.

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