LONG EXAM 1 FINALS BOTANY ( ROOTs )

LEAVES

LEAVES

functions in terminal bud both photosynthesis and transpiration

STEMS

position leaves for maximum photosynthesis

ROOTS

anchors the plant and absorb water and mineral

Gravity

Roots generally grow downward, i n t h e

direction of ____.

Taproot and fibrous root

What are the two types of roots sytem?

Embryonic root - radicle

Where does taproot and fibrous root develop?

TAPROOT SYSTEM

• consists of one main root (formed from the enlarging radicle)

with many smaller lateral (branch) roots coming out of it.

• are characteristic of many eudicots and gymnosperms.

• often extend down into the soil to obtain water deep under- ground

FIBROUS SYSTEM

• has several to many roots of the same size that

develop from the end of the stem, with smaller lateral roots branching

off these roots.

• form in plants in which the embryonic root is short- lived.

• » The roots originate initially from the

• base of the embryonic root and later from stem tissue.

Anchorage

roots take part in the fixation of plants and supporting the aerial shoot system.

Biennals

Storage tap roots are usually _____ that, as part of thestrategy to survive winter, store their food reserves in the rootduring the first year's growth and use these reserves to reproduce during the second year's growth.

ROOT TIP

This is the part of the root that is made up of meristermatic tissue

and is covered by root caps. This increase the surface area in contact with soil.

Root cap

Each root tip is covered by a ____a protective thimble-like layer many cells thick that covers the delicate root apical meristem.

ROOT CAP

protective thimble-like layer that protects the delicate meristematic tissue in the root apical meristem

ROOT HAIRS

are short-lived, unicellular extensions of epidermal cells near the growing root tip.

Meristematic, elongation, maturation

What are the three overlapping regions?

Meristematic zone

consist of the root apical meristem

Zone of elongation

where the derivatives stop dividing while other grow in length

Zone of maturation

where cells begin specializing in structure and function into different cell type, such as epidermal cells and conducting cells.

Epidermis

a single layer of protective tissue that covers its roots.

Cortex

is composed primarily of loosely arranged parenchyma cells with large intercellular (between-cells) spaces, makes up the bulk of the root.,

Storage

s The primary function of the root cortex is ___

Cortex

These reserves provide energy for such activities as growth following winter or cell replacement following an injury.

Endodermis

The innermost layer of the cortex of the root that prevents water and dissolved materials from entering the xylem by passing between cells.

Symplast and apoplast

2 solution pathways where the water and dissolved minerals enter the root cortex from epidermis

Symplast

The ____ is a continuum of living cytoplasm, which is connected from one cell to the next bycytoplasmic connections called plasmodesmata.

Apoplast

The _____ consists of the interconnected porous cell walls of a plant, along which water and inorganic mineral ions move freely.

Osmosis

Water enters endodermal cells by___

Carrier proteins

whereas inorganic minerals enter by passing through ____ in their plasma membranes.

Stele

At the center of a primary eudicot root is a cylinder of vascular tissues known as a stele.

Pericycle

The outermost layer of the stele is a single layer of cells called the ____ which is just inside the endodermis.

Xylem

the centermost tissue of the stele

• Conduct water and dissolved minerals

Phloem

---

is located in patches between the xylem arms.

• conduct carbohydrates (sucrose).

Pith

The central tissue in s o m e monocot roots is ___

Adventitious roots

• often arise from stem nodes (regions of the stem where leaves are attached)

• Or in unusual areas

Prop roots

_____ are adventitious roots that develop from branches or from a vertical stem and grow downward into the soil to help support the plant in an upright position.

Buttress roots

Swollen bases or braces called ____ hold the

trees upright and aid in the extensive distribution of the

shallow roots.

Pneumatophores

A flooded soil is depleted of oxygen, so these aerial

"breathing" roots, known as _____, may assist in getting oxygen to the submerged roots.

Epiphytes

Examples: Ivy Plant, Money Plant, Betel Plant

Climbed and attached to other plants

Contractile roots

Plants that produce corms or bulbs (underground stems or buds specialized for asexual reproduction) often have wiry __

Graft

so as roots of certain trees grow through the soil, they sometimes encounter roots of other trees of the same or different species. When this occurs, the two types of roots may grow together by secondary growth to form a natural ____

Mycorrhizae

mutualistic association between roots and soil fungi.

Endomycorrhizae

-the fungus penetrates root cells

Ectomycorrhizae

the fungal mycelium (nonreproductive body) encircles the root like a sheath

Rhizobia

Certain nitrogen-fixing bacteria, collectively called ___form associations with the roots of Leguminous plants-clover, peas, and soybeans, for example.

Nodules

Swellings called ___ develop on the roots and house millions of the rhizobia

Ammonia or nh3

The bacteria receive the products of photosynthesis from the plants while helping the plant meet its nitrogen requirements by producing ____ from atmospheric nitrogen.