Exam 1 Vocab - BIOL 1450

Homeostasis

ability for an organism to maintain internal conditions with in a specific range

apical bud

A bud at the tip of a plant stem; also called a terminal bud.

lateral bud

Buds along the sides of a stem that give rise to new branches.

vascular tissue

tubing system throughout plant; like our blood - not being pumped, but pulled through capillary action

indeterminate growth

open-ended growth; can be life long

- important for plants since they're stationary; can't run away, can only grow into and adapt to environment

determinate growth

growth that stops at adult stage

- most animal growth

pathogen

A disease causing agent

systemic acquired resistance (SAR)

A defensive response in infected plants that helps protect healthy tissue from pathogenic invasion.

response occurs in multiple parts of plant

apical dominance

Tendency for growth to be concentrated at the tip of a plant shoot, because the apical bud partially inhibits axillary bud growth.

negative tropism

growth away from a stimulus

positive tropism

Growth towards a stimulus

phototropism

Growth of a plant shoot toward or away from light.

gravitropism

response of a plant to the force of gravity

photoperiod

relative length of day vs night in a 24 hour cycle

photoperiodism

A plant's response to seasonal changes in length of night and day

critical period

number of consecutive hours of darkness that determines flowering for a particular species of plant

short day (long-night): minimum hours of darkness needed to flower

long day (short night): maximum hours of darkness it can flower in

phytochromes

A type of light receptor in plants that mostly absorbs red light and regulates many plant responses, such as seed germination and shade avoidance.

locally induced defense

only act at the site of infection

systemic induced defenses

response occurs in multiple parts of a plant