Plant Biology Form and Function

What are we learning today? Benchmark: SC.912.L.14.7 – Relate the structure of each of the major plant organs and tissues to physiological processes. AA Objectives: Identify the major plant organs Discuss the functions of the various plant organs

What is the essential question? Plants are complex multicellular organisms with many organs and structures that allow them to carry out all of life’s processes. How do these organs and structures function?

What are the types of tissues found in plants? Plant tissues are organized into three systems: Dermal tissue is like the “skin” of a plant in that it is the outmost layer of cells. Vascular tissue is like the plant’s “veins,” transporting water and nutrients throughout the plant, and Ground tissue is everything else. Ground tissue is made of cells whose cell walls have different thickness.

What is vascular tissue? Forms transport system that moves H2O and nutrients through the plant Made up of a network of hollow connected cells Xylem, a H2O conducting tissue, Phloem, a food conducting tissue, http://www.bing.com/videos/search?q=plant+tissue&FORM=HDRSC3&adlt=strict#view=detail&mid=B243CDC2669A14264988B243CDC2669A14264988

Organs of the Plant Plants have 3 main organs: Roots Stems Leaves

Root Form and Function Two types of roots systems in plants: Taproots Fibrous roots Roots are made up of a Root cap protects the growth zone of the root Root hairs increase water absorption rate Root Functions Anchor and support the plant Absorb water and dissolved nutrients from the soil Store food and water.

Root Structure

Root Form and Function How is a taproot different from a fibrous root? What are the two main functions of roots? How does a root prevent erosion? How are the roots of most plants adapted to perform the major root functions? How root hairs increases the ability of a plant to absorb water from the soil the plants grows in?

Stem Form and Function Stem shape and growth are adaptations to the environment Stems grow in length and thickness Stems have several functions Transport materials between a plant’s roots and its leaves Support leaves and other structures Store food and water

How do plants grow in length? Meristems are clusters of tissue that are responsible for continuing growth throughout a plant’s lifetime. The new cells produced in meristematic tissue are undifferentiated. An apical meristem is a group of undifferentiated cells that divide to produce increased length of stems and roots. Plants grow as long as they live. Undifferentiated means that they have not yet become specialized for specific functions. All cells originated in meristems look very much alike. Gradually, these cells develop into mature cells with specialized structures and functions, a process called differentiation.

What is primary and secondary growth? Primary growth is a type of plant growth that occurs at the tips of roots and shoots produced by cell divisions in the apical meristem. Increases length Secondary growth is the type of growth that increases the plant’s stem width (makes it thicker). Via the cork cambium and vascular cambium

How do plants transport water? Three processes combined to move water up in a tree Root pressure Capillary action Transpiration Pressure created by water entering the tissues of a root can push water upward in a plant stem. However, root pressure does not exert enough pressure to lift water up into trees. How do plants fight against gravity? To the Teacher: Use the analogy of a very tall building to understand the problems a large tree like General Sherman (Height - 275 feet, Circumference - 102 feet, Maximum Diameter - 36 feet. ) to get water to the top.

How does capillary action work? H2O molecules are attracted to one another by a force called cohesion. H2O molecules can also be attracted to other substances resulting from a force called adhesion. H2O is then attracted to the walls in xylem, and H2O molecules are attracted to one another. The tendency of H2O to rise in a thin tube is called capillary action. Cohesion is the attraction of molecules of the same substance to each other. Adhesion is the attraction between unlike molecules. The thinner the tube, the higher the water will rise inside it.

Stem Form and Function What are the three main functions of stems? How do the functions of a stem relate to the roots and leaves of a plant? Describe how water is transported through a plant? What is the difference between primary and secondary growth?

Leaf Form and Function Main organs that carry out photosynthesis Most leaves are flat to absorb sunlight Leaves have small openings called stomata (stoma) that control gas exchange and water loss. A major limitation of photosynthesis is insufficient water Tiny structures called guard cells control the size of the stomata.

Leaf Form and Function What is the function of the stomata? What is the function of guard cells? What is function of leaf veins? Would a 10 foot tree with no leaves but healthy roots be able to move water to its top? Explain your answer. How does the thin, flat structure of leaf helps increase the efficiency of photosynthesis? How does a leaf structure is an adaptation that allows intake of carbon dioxide with minimal water loss? Vein Leaf cross section Mesophyll CO2 O2 Stomata

Seed Form and Function Seeds are the reproductive structure that contains a plant embryo Seeds store food that the embryo uses for germination Seeds have a protective coat (Cotyledon) Seed may contain one (monocot) or two (dicot) seed coats.

Flower Form and Function Flower: Modified leaves Reproductive structure of angiosperms During pollination, pollen (the male gamete) is transferred from the stamen to the stigma Many attract animals Others are wind pollinated After fertilization it develops into a fruit. Aids in dispersal of seeds Protects the seed

Draw and label the parts of the flower Male parts: -Stamen (anther and Filament) Female parts: -Carpel Stigma Style Ovary

Cone Form and Function Reproductive organ of gymnosperms (“naked seeds”) Male cones produce sperm Female cones produce eggs. Wind pollinated After fertilization, a seed develops Seeds are not enclosed in protective fruit. Most gymnosperms are hermaphrodites (see picture). Why would it bear male cones on the lower branches, below the female cones?

Reproduction Form and Function How are the different part of a flower involved in reproduction? Why is it adaptive for some seeds to remain dormant before they germinate? Why did the development of the seed was a major factor in the success of plants? How do the flowers of wind-pollinated plants differ from the flowers of animal-pollinated plants? How might it be an advantage for a plant to have many flowers together? Why might wind-pollinated plants create more problems for allergy sufferers than animal-pollinated plants?

What is the essential question? Plants are complex multicellular organisms with many organs and structures that allow them to carry out all of life’s processes. How do these organs and structures function?

Independent Practice: EOC workbook Page 78-83