National Railroad Contractors Association

Plant Biology

Plant growth stages

Plant life cycles

Plant types

Plant construction

Plant growth factors

Seedling – Small succulent – Stage

most easily controlled

Vegetative – Rapid growth

Reproductive – Flowers and seeds

Mature – Post reproductive

Annual

Biennial

Perennial

Annuals complete their life cycle in

one year.

Winter annuals

Summer annuals

Seeds germinate late summer to

early fall,

Flower and produce seed in mid-to

late spring, and

Die the next summer.

Seeds germinate in the spring,

Flower, produce seeds mid-to late

summer, and

Die in the fall.

Ex-most everything

Live for two growing seasons. Seeds germinate in spring, summer, or fall

of first year. Plants over winter as basal rosette with

storage root. After exposure to cold, plants flower and

produce seeds in summer of second year. Die in the fall.

Produce vegetative structure that

allows them to live more than two

years.

•Overwinters by a perennial root

•Reproduce entirely by seed

Overwinters

Produces new plants from

reproductive structures

Most also reproduce from seed

Stolons horizontal aboveground stems

Creeping roots Underground root

modified for food storage,

vegetative reproduction

Grows deep in soilResistant to control

Soil line

Rhizomes

horizontal

underground

stems

http://www.wildlifeanalysis.org/movabletype/archives/rhizome.jpg

Tubers

thick underground

stems on the ends of

rhizomes

Bulbs

modified underground leaf tissue

Reproducing parts

Grasses/Sedges

Broadleaves (forbs)

Vines

Trees

Ferns

• One leaf at germination

• Fibrous root system

•Growing point at soil surface

•Narrow upright leaves

•Parallel veins running length of leaf

•2 leaves at germination2 leaves at germination

•Broadleaves

•Netted veins

•Growing points all over

•Tap root system

Plant with a weak stem that needs support from

climbing, twining, or creeping along a surface

Trees - perennial, single main stem

or trunk

Shrubs - perennial, more than one

principal stem, shorter than trees

Largest group of seedless, vascular plants

Grow in moist places

New fronds (leaf) form from rhizome

Xylem – moves herbicide, water, nutrients up from roots

Phloem – moves herbicide from foliage down to roots

Grasses have vascular bundles that contain xylem and phloem in one unit

Water Transports nutrients and herbicides

from root to leaf Moves sugars and foliar applied

herbicides from leaf to roots

Water is key in photosynthesis Rain carries herbicide to root zone

Soil Soil texture depends on percentages of sand, silt, clay

Soil

Coarse or light soil

is high in sand

Soil

Fine or heavy soils

are high in clay

Soil

Dark soils are high in organic matter

(OM), decaying plants and animals.

  As Clay As OM As Sand

Adsorption Adsorption Adsorption

Leaching Leaching Leaching

Herbicide Use Herbicide Use Herbicide Use

Application Rate Application Rate Application Rate

Temperature

As Temperature

Plant activity

Speed of herbicide effect

Warm soils

Persistence of herbicide