Lecture 3 Plant anatomy and physiology by Edgar Moctezuma Ph D Today Announcements Plant Anatomy Cells Tissues Organs Plant Physiology Water sugar transport Plant hormones Announcements Labs start this week get your lab manual BSCI 125 students if you have the following sections 1109 1110 Tues 3 30 5 30 or 1113 1114 Wed 12 2 or 1115 1116 Wed 3 5 or 1123 1124 Thurs 3 30 5 30 and you can switch to an open section Monday or Wed 9 00 11 00 please try to do so Thanks Taking care of your plant Do not overwater it Water only when soil is dry to the touch Place near a sunny window From smallest to largest plants What is plant anatomy ANATOMY study of the structure of organisms looking at cells tissues Morphology Study of form What is plant physiology PHYSIOLOGY study of the function of cells tissues organs of living things and the physics chemistry of these functions Always keep in mind that in plant anatomy morphology physiology Structure correlates to function How can water move from the ground all the way to the top of a 100 m tall redwood tree Plant Anatomy Cells Plant cells are basic building blocks Can specialize in form and function By working together forming tissues they can support each other and survive Levels of organization atoms molecules cells tissues organs whole plant pop Plant Tissues Types All plant organs roots stems leaves are composed of the same tissue types There are three types of tissue 1 Dermal outermost layer 2 Vascular conducting tissue transport 3 Ground bulk of inner layers 1 Dermal tissue Epidermis is the outermost layer of cells Like the skin of animals In stems and leaves epidermis has cuticle a waxy layer that prevents water loss Some have trichomes hairs Root epidermis has root hairs for water and nutrient absorption 2 Vascular tissue Transports water and organic materials sugars throughout the plant Xylem transports water and dissolved ions from the root to the stem and leaves Phloem carries dissolved sugars from leaves to rest of the plant Xylem Transports water and dissolved minerals Tracheids long thin tube like structures without perforations at the ends Vessel elements short wide tubes perforated at the ends together form a pipe called vessel Both cells have pits thin sections on the walls Tracheids Vessel elements Xylem cells Xylem cells are dead They are hollow cells and consist only of cell wall Phloem Cells that transport organic materials sugars Phloem cells are ALIVE unlike xylem However they lack nucleus and organelles Phloem transports sugars Phloem composed of cells called sieve tube members STM Companion cells join sieve tube members are related and help to load materials into STM End walls of STM have large pores called sieve plates Companion cells Sieve tube member Sieve plates 3 Ground tissue Makes up the bulk of plant organs Functions Metabolism storage and support Root Stem Leaf Plant Organs Organs tissues that act together to serve a specific function Roots Dermal Vascular Ground Stems Dermal Vascular Ground Leaves Dermal Vascular Ground Functions of plant organs ROOTS Anchorage water nutrient absorption from soil storage water nutrient transport STEMS Support water nutrient transport LEAVES Photosynthesis food production ROOTS ROOTS the hidden half Functions of roots Ancorage Absorption of water dissolved minerals Storage surplus sugars starch Conduction water nutrients Anatomy of a root epidermis cortex vascular Root Epidermis Outermost single layer of cells that Protects from diseases Absorbs water and nutrients ROOT HAIRS tubular extensions of epidermal cells Increase surface area of root for better water nutrient absorption Root Hairs water and mineral absorption Root hairs increase surface area for better absorption Root Cortex Stores starch sugars and other substances Root Ground tissue In roots ground tissue a k a cortex provides support and often stores sugars and starch for example yams sweet potato etc You re not a yam you re a sweetpotato cortex Hey I yam what I yam man Root Cortex Endodermis Endodermis the innermost layer of the cortex Root cortex Casparian strip The Casparian strip is a water impermeable strip of waxy material found in the endodermis innermost layer of the cortex The Casparian strip helps to control the uptake of minerals into the xylem they have to go through the cytoplasm of the cell STEMS Above ground organs usually Support leaves and fruits Conduct water and sugars throughout plant xylem and phloem Stem anatomy Dermal ground and vascular tissues epidermis cortex pith Vascular bundles Types of Stems Monocot stem Dicot stem Root Types of stems Herbaceous vs Woody stems Tissues of stems Epidermis Dermal tissue type Provides protection Has cuticle wax prevents water loss Trichomes hairs for protection to release scents oils etc Stem Vascular tissue Vascular bundles composed of both xylem and phloem Xylem Conducts water Support Phloem Conducts food Support Vascular cambium Vascular cambium Occurs in woody stems Vascular cambium located in the middle of the vascular bundle between xylem and phloem Vascular tissue Trees Vascular tissue is located on the outer layers of the tree bark phloem Vascular cambium xylem wood Girdling cutting around a tree Damages the phloem and xylem eventually killing the tree Vascular tissue forms rings in trees Annual rings xylem formed by the vascular cambium during one growing season One ring one year History of the tree annual rings Dendrochronology tree time keeping 1492 Columbus lands in the Americas 1489 Tree is planted by Native American 1776 Declaration of US independence 1620 Pilgrims land in Plymouth Mass 1917 1945 Tree Survives two World Wars 1969 Man lands on Moon 1861 Start of Civil War 1971 Birth Year of the IDIOT who cut down this tree Ground tissue Cortex pith Stores food e g potato Site of Photosynthesis when green Support cells cortex pith LEAVES Photosynthetic factories of the plant Function Photosynthesis food production for the whole plant Blade Flat expanded area Petiole stalk that connects leaf blade to stem and transports materials BLADE Leaf Anatomy Leaf anatomy is correlated to photosynthesis Carbon dioxide Water sugars oxygen dermal ground vascular dermal Leaf epidermis Is transparent so that sun light can go through Waxy cuticle protects against drying out Lower epidermis stomata with guard cells for gas exchange CO2 H2O in O2 out Leaf epidermis Trichomes give fuzzy texture Panda plant Leaf vascular tissue VEINS vascular tissue of leaves Veins