Plant Tissues and Organs

Fig. 38.6

Fig. 38.4

Figure 35.21  Modular construction of a shoot

Basic Plant Morphology

• TISSUES- a group of cells functioning together in some specialized activity

• MERISTEMS- a mass of self-perpetuating cells, which are not yet committed to developing into a specialized cell type – Terminal meristems- ends of stems, branches

and roots– Axillary meristems- base of leaves, branches– Lateral meristems are parallel to sides of plant

parts and increase girth.

Meristem types

• Primary– Apical Meristems

• Secondary– Vascular cambium

– Cork Cambium

Flowering plants have 3 basic tissue types

• Dermal– Cover surface of plant– Protection

• Ground

• Vascular– Conducting tissue

Dermal

• Epidermis– epidermal cells

• Periderm– cork cells

Fig. 38.12a

Fig. 38.12b

Fig. 38.12c

Vascular Tissue

• Xylem– Mostly to conduct water and nutrients– E.g., roots to shoots

• Phloem– Mostly to conduct sugars, amino acids, etc.– E.g., leaves to roots or flowers

Fig. 38.13a

Fig. 4.6

Fig. 4.9

Fig. 38.13b

Fig. 38.14a

Fig. 38.14b

Vegetative Organs

• Roots

• Stems

• Leaves

Function of roots

• Anchor the plant

• Absorb water and minerals from soil

• Storage

Longitudinal section of roots

• Root cap• Zone of cell division• Zone of cell

elongation• Zone of maturation

Cross section of root• Vascular bundle (Stele) = contains xylem and phloem• Cortex• Epidermis• Root hairs

– Absorb water and minerals

Fig. 38.15

Fig. 38.21

Function of Stems

• support leaves to maximize light absorption

• part of conduit for transport of water, minerals, and organic solutes

• storage

Fig. 38.25a

Fig. 38.25b

Woody dicots

• Discrete vascular bundles replaced by continuous rings of xylem

• Each ring is xylem produced during one growing season

• Vascular cambium

Fig. 38.7a

Fig. 38.7b

Stems: Secondary growth•Vascular tissue, (xylem) makes up the bulk of the stem•Form tree rings

Fig. 38.23

Fig. 38.28a

Fig. 38.28b

Fig. 38.28c

Function of leaves

• Main photosynthetic structure

Leaf parts

• Blade• Petiole• Pair of stipules

Fig. 38.34

Fig. 38.8

Fig. 38.33

Fig. 38.30

Fig. 38.35

Fig. 39.1

Fig. 39.5

Figure 35.8a  Modified leaves: Tendrils of pea plant

Figure 35.8b  Modified leaves: Cacti spines

Figure 35.8c  Modified leaves: Succulent leaves for storing water

Figure 35.8d  Modified leaves: Brightly-colored leaves to attract pollinators

Figure 35.x1 Lithops

Comparison of monocots & dicots

• Monocotyledon– grasses

– lilies, tulips

– trees: palm

• dicotyledon – roses, asters

– grapes, beans

– trees: oak, maple,

http://www.emeraldashborer.info/index.cfm

                                                                                                                                        

                                                                                   

Emerald Ash BorerEmerald ash borer (EAB), Agrilus planipennis Fairmaire, is an exotic beetle that was discovered in southeastern Michigan near Detroit in the summer of 2002. The adult beetles nibble on ash foliage but cause little damage. The larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients. Emerald ash borer probably arrived in the United States on solid wood packing material carried in cargo ships or airplanes originating in its native Asia. Emerald ash borer is also established in Windsor, Ontario, was found in Ohio in 2003 and northern Indiana in 2004. Since its discovery, EAB has:

*killed more than 10 million trees*cost 10s of millions of $

What to know about EAB:

• It attacks only ash trees (Fraxinus spp.).

• Adult Beetles are metallic green and about ½-inch long.

• Adults leave a D-shaped exit hole in the bark when they emerge in spring.

• Woodpeckers like EAB larvae; heavy woodpecker damage on ash trees may be a sign of infestation.

• Firewood

cannot be moved in many areas of Michigan, Ohio and Indiana because of the EAB quarantine ( Ohio, Indiana, Michigan)

• It probably came from Asia in wood packing material.