Unit 7. Lesson 38 (Dicotyledonous Plant Structure)

1. Outline the wide Diversity in the plant kingdom as examplified by the structrual differences between bryophytes, filicinophytes, coniferophytes, and angiospermiphytes.

Bryophytes are moss, liverworts and similar plants. They are the smallest type and are produced in a capsule and do not technicaly have roots.

Filicinophytes are ferns, or vascular plants, that provide support for themselves through many vascular tissues. They vary in size from very small to surprizingly large. This is because they reproduce via spores, not ovum or seeds.

Coniferophytes are shrubs and trees. They have sturdy stems with xylem cells that form tightly in rings of strong wood. They can grow to be very tall and large despite gravity due to the strenth of the 'stem' structure, also called the trunk. Their leaves have a waxy coating of cuticle. They repruduce by developing seeds on or in the female cone of teh structure.

Angiospermiphytes are flowering plants that have full shoot and root system. They can be trees, bushes or short plants. This variety is unfied by the development of seeds within fruits from the ovaries found in flowers.

2. Draw a digram to show the external parts of a named dicotyledonous plant incliding root, stem, leaf, axillary and terminal buds.

3. Draw a plan diagram to show the distribution of tissues in the stem, root, and leaf of a generalized dicotyledonous plant. (Note that plan diagrams do not show individual cells, rather a distribution of tissues)

4. Explain the relationship between the distribution of tissues in the leaf and the functions of these tissues.

The Vascular Tissues: The vasscular tissues are the transport system of the plant. There is the xylem of the plant moves water and minerals upward. and Phloem transport manufactured nutrients from mature leaves to the root system.

The Ground Tissues: The ground tissues are everythign that is not dermal or vascular and lies between them. It caries out most of the metabolic functions of the plant.

The Dermal Tissues: a sinlge layer of cells that covers the entire outer part of the plant, acting as a sort of skin. It has a waxy complextion to both keep extra water out and the nessasary water in.

5.Outline four adaptations of xerophytes.

* Limit water loss by reducing surface area.

* Roots are near surface and spread out over a wide area to gather rainwater.

* Shaped in a long and thin way to limit exposure to sun during hotest part of the day.

* Unsusualy thick cuticle that is almost leathery and protects stroed water within palnt.

6. Outline two structural adaptations of hydrophytes.

* Air pockets in structure provide bouyancy as the plant floats in water.

* Pores in cuticle allow for gas exchange in the otherwise sealed dermal layer.

Photo from a great candid still life photographer:

http://www.art-photograph-gallery.com/still-life-pictures.html