Important Survival Structures and Adaptations in Plants

Vascular Tissue- Nutrition Vascular Tissue  move fluids through the plant body – 1. Xylem– carries water from the root to the other parts of the plant – 2. Phloem – transports nutrients and carbohydrates made by photosynthesis

Vascular Tissue Chart-Nutrition

Leaves-Nutrition Designed for absorbing light and carrying out photosynthesis Two types of leaves: – 1. Simple (one leaf) – 2. Compound (many leaflets)

Leaf Functions-Nutrition Carries out photosynthesis Transpiration- evaporation of water through leaves Gas Exchange – Stomata remains open enough just to allow photosynthesis to take place

Layers of Leaf- Nutrition&Respiration – Cuticle- outer waxy surface of the leaf that prevents drying out – Mesophyll spongy layer is composed of many chloroplasts – Palisade mesophyll – absorb the light – Spongy mesophyll – air spaces that connect the stomata with outside – Stomata – pore-like openings on the underside of a leaf to absorb carbon dioxide – Cuticle- outer waxy surface of the leaf that prevents drying out

Stomata On Surface of Leaf- Respiration Swollen Guard Cells Flaccid (weak) guard cells Small stoma opening  little gas exchange Large stoma opening  ample gas exchange

How the stomata helps to maintain homeostasis? The stomata allows for the plant to REGULATE the exchange of gases  MAINTAIN HOMEOSTASIS – Dependent on the availability of water When water is plentiful  plant can accept more water  guard cells swell  stomata opens  gas exchange can occur readily When water is NOT plentiful OR wants to conserve the water it has  guard cells shrink  stomata closes  gas exchange slows down

Cones in Conifer Plants- Reproduction Cones and pollen are used as the reproductive structures found in gymnosperms Exhibit alternation of generations sporophyte and gametophyte phases. t/chp30/30020.html t/chp30/30020.html

Reproduction in Angiosperms- Reproduction Also exhibit sporophyte and gametophyte generations mations/content/angiosperm.html mations/content/angiosperm.html

Flower Parts-Reproduction Flowers are the reproductive structure in angiosperms. Stamen-> men=male Male: anther+filament Contains pollen Pistil (carpel)-> female – Stigma,style,ovary – Ovary holds the ovules.

Seeds-Reproduction Seeds in plants play an important role in – Protection of the plant embryo – Prevention of drying out of moisture within the seed – Provides nutrients as it develops

Monocot vs Dicot Seeds

Summary Tutorial 838/858365/ch03anim/3_1_6_1a.swf 838/858365/ch03anim/3_1_6_1a.swf

How Do Plants Respond to the Environment? 1-Tropism= response by a plant to an external stimulus – Phototropism  response to light – Gravitropism  response to gravity – Hydrotropism  response to water – Thigmotropism  response to touch (surfaces like vines wrapping around) 2-Hormones= auxins – cytokinins, gibberlins, ethylene

Plant Auxins- Response to Environment Auxins  substances that regulate cell growth at the tip of plant by stimulating cell elongation. – Cytokinins  Stimulate cell division, and cause dormant seeds to sprout. – Gibberillins  dramatic increase in size (stems and fruits) – Ethylene  Stimulate fruits to ripen

Other Environmental Adaptations- Response to Environment Aquatic Plants  Tissues with large air filled spaces for oxygen diffusion Epiphytes-Grow directly on other plants to obtain their nutrients Ex. Spanish Moss Desert Plants (Xerophytes)-Extensive roots, reduced leaves, & thick stems stores water. Nutrition Specialists-Live in areas with low concentrations of nutrients in the soil. – Ex. Carnivorous plants (Venus Fly Trap) – Parasites (Mistletoe)