Plant Transport AS Much Knowledge So Application

Slide 2 of 20 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

Slide 3 of 20 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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Slide 5 of 20 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?

Slide 6 of 20  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

Slide 7 of 20 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

Slide 8 of 20 Mycorrhizae

Slide 9 of 20 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?

Slide 10 of 20 3 Tissue types 1. Dermal  Cover entire plant  Protect against water loss  Nonspecific defense mechanism 2. Vascular  Continuous throughout the plant  Transports material between roots and shoots a) Xylem – transports water & minerals up from the roots b) 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

Slide 11 of 20 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

Slide 12 of 20 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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Slide 14 of 20 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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Slide 16 of 20 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?

Slide 17 of 20 Roots – Cross Section

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Slide 19 of 20 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

Slide 20 of 20 Leaf: Cross-Section

Slide 21 of 20 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?