2 Plant Adaptations (21.1, 22.4, & 22.3) State Standard SB4E. Relate plant adaptations, including tropisms, to the ability to survive stressful environmental conditions.
3 Acts as a barrier to invading microorganisms Chapter 21Introduction to PlantsGeneral Plant AdaptationsCuticleFatty coating that helps prevent the evaporation of water from plant tissuesActs as a barrier to invading microorganisms
4 Openings in the outer cell layer of leaves and some stems Chapter 21Introduction to PlantsGeneral Plant AdaptationsStomataOpenings in the outer cell layer of leaves and some stemsAdaptations that enable the exchange of gases even with the presence of a cuticle on a plant
5 Chapter 21Introduction to PlantsGeneral Plant AdaptationsVascular TissuesVascular tissue enables faster movement of substances than by osmosis and diffusion, and over greater distances.Vascular tissue provides support and structure, so vascular plants can grow larger than nonvascular plants.
6 Vascular Tissues – 2 Types Chapter 21Introduction to PlantsGeneral Plant AdaptationsVascular Tissues – 2 TypesXylem – carries water & dissolved minerals from the roots upward to the stem & leavesPhloem – food-carrying tissue. Carries sugars & other organic compounds throughout the plant
7 Chapter 21Introduction to PlantsReproductive AdaptationsFlowersFlowers are the reproductive structures of a group of plants called anthophytes.Flowers contain both male parts (stamens) & a female part (pistil).The movement of pollen from a stamen to the pistil is called pollination.
8 Flowers can be pollinated by wind, insects, birds, & other animals Reproductive Adaptations - FlowersFlowers can be pollinated by wind, insects, birds, & other animalsMany flowers are brightly colored to attract birds & insects that aid in pollination
9 Chapter 21Introduction to PlantsReproductive AdaptationsConesCones are the reproductive structures of a group of plants called conifers (coniferophyta).Conifers produce small male cones & larger female cones.The male cones produce pollen while the female cones remain on the plant until its seeds have matured.MaleFemale
10 Chapter 21Introduction to PlantsReproductive AdaptationsSeedsPlant structures that contain an embryo, nutrients for the embryo, and are covered with a protective coatThese features enableseeds to survive harsh environmental conditions andthen sprout when favorable conditions exist.
11 Reproductive Adaptations Seed DispersionMaple trees produce seeds that are shaped like wings & are carried over long distances by wind.Some plants produce seeds with barbs or hooks that attach to the fur of passing animalsMaple Seed
12 Reproductive Adaptations Seed DispersionCoconuts from palm trees float which allows seeds to travel from one island to another
13 Other Plant Adaptations - Dormancy Many seeds & plants will go dormant (inactive) during unfavorable conditions such as drought or coldSome roots & stems are able to store food for dormant periodsSome trees drop their leaves during dormancyOther trees (such as conifers) have waxy needle-like leaves to conserve water and flexible trunks to bend & not break under the weight of ice & snow
14 A tropism is a plants growth response to an external stimulus. TropismsA tropism is a plants growth response to an external stimulus.If a plant grows toward the stimulus it is called a positive tropismIf the resulting plant growth is away from the stimulus it is called a negative tropism
15 TropismsPhototropism is a plant growth response to light caused by an unequal distribution of auxin.
16 Gravitropism is a plant growth response to gravity (AKA Geotropism) TropismsGravitropism is a plant growth response to gravity (AKA Geotropism)Roots usually show a positive GravitropismStems show a negative Gravitropism
17 TropismsThigmotropism is a growth response to mechanical stimuli such as touch
18 Plant HormonesPlants control their growth in response to environmental stimuli by using chemical messengers known as hormonesA hormone is a chemical produced in one part of an organism that is sent to a different part of the organism to affect activities there
19 Types of Plant Hormones AuxinControls phototropism by elongating cells on the shaded side of the stem to push the plant toward lightPromotes growth of fruit and controls when the fruit falls from the plant
20 Types of Plant Hormones GibberellinsCause plant to grow tallerIncrease rate of seed germination & bud development
21 Types of Plant Hormones Abscisic AcidInhibits plant growth during times of stress, such as cold temperatures or drought