Scientific study of plant life and development?

STUDY OF THE EXTERNAL STRUCTURE OF PLANTS?

STUDY OF THE INTERNAL STRUCTURE OF PLANTS?

 Annual - a plant that completes its life cycle in one season and dies (e.g. wheat, subclover, peas, beans)  Biennial - a plant that requires two seasons to complete its life cycle. Vegetative phase and flowering phase (e.g. carrot, onion)  Perennial - a plant that lives from year to year (e.g. apple, citrus, tea bush)  Ephemeral - very short lived plants (e.g. desert and tundra plants)

 Single seed leaf or cotyledon  embryo contains:  coleoptile -- a sheath in which the true leaves and plumule grow  plumule: origin of young leaves --> growing point, crown or node  radicle ---> initial seminal roots  coleorhiza -- protective sheath for the radicle  Tillers - axillary shoots that grow later from the growing point  Secondary roots form later, often with tillering

Adventitious roots grow from the shoot axis just at or above the soil surface.

 seed has 2 seed leaves /cotyledons  cotyledons either hypogeal (below ground) or epigeal (above ground)  embryo  radicle ---> primary root  hypocotyl - lifts the cotyledons above the soil  epicotyl - main stem and growing point  apical and axillary growing points  secondary roots branch from the primary root to form a structured deep root system

Bean

Dicotyledonous plants tend to have a dominant tap root, which develops downward, together with limited lateral root growth. Monocotyledonous plants tend not to have a dominant tap root, instead, the roots branch in many directions creating a fibrous root system.