PLANT STRUCTURE AND FUNCTION
THE PHYLOGENY OF PLANTS… Charophytes (green algae) Bryophytes (non vascular) Trachoephytes (seedless, vascular) Gymnosperms (“naked seeds”,vascular) Angiosperms (contained seeds, vascular) Monocots / Dicots
Major Parts of a Plant Leaves Seeds Flower Stem Root Where photosynthesis occurs Seeds Method of sexual reproduction Flower Site where reproduction occurs Stem Transports nutrients and supports the plant Root take in nutrients and anchor plant
The Seed Parts of a Seed The first leaves of a plant Cotyledon The first leaves of a plant Seed Coat Outside covering of a seed Endosperm Food storage tissue that nourishes the embryo Embryo New plant developed after fertilization
Types of Seeds Monocots A seed with only one cotyledon All grasses are monocots Flower parts in threes Leaves with parallel primary veins Dicots A seed with two cotyledons Flower parts in fours or fives Leaves with distinct vein network All broadleaf plants are dicots
Seed Parts Fertilizationzygoteseed (embryo) Plumule- is like a leave in its early development becomes the shoot Hypocotyl- develops into the stem Radicle- Becomes roots
Male Parts of the Flower Stamen- Makes up all male parts Pollen- Male sex cell, similar to sperm Anther- Sac-like structure on top of the filament Filament- Short stalk that holds the anther
Female Parts of the Flower Pistil- Makes up all female parts Ovules- Female sex cell, similar to the egg Stigma- Sticky part of the system, catches pollen Style-Tube that leads from the stigma to the ovary Ovary- Place where ovule is fertilized by the pollen, Turns into a fruit or seed coat
Primary Growth Occurs in apical meristems of plant (found at tips of stems and roots)
PROBLEM! IF THE CUTICLE BLOCKS WATER, WHAT ELSE IS PREVENTED FROM ENTERING/EXITING THE PLANT? C O 2 !!
Solution? STOMATA! Tiny pores in epidermis surrounded by two guard cells! Open during the day! Why? PS occurs during the day Transpiration necessary for cooling
VASCULAR TISSUE 2 MAJOR TYPES: XYLEM TISSUE PHLOEM TISSUE Found together in VASCULAR BUNDLES Arise primarily from apical meristem Arise secondarily from vascular cambium
XYLEM TISSUE CONDUCTS WATER PROVIDES MECHANICAL SUPPORT 2 TYPES OF XYLEM CELLS: TRACHEIDS: VESSEL ELEMENTS:
PHLOEM TISSUE CONDUCTS SUGARS COMPOSED OF TWO CELL TYPES: SIEVE-TUBE MEMBERS COMPANION CELLS
Sieve tube members Form sieve tubes to conduct sugars throughout plant Lack nuclei, ribosomes, vacuoles, etc. Vascular bundle
xylem
Stems Transports food, water, and nutrients Supports the leaves and flowers
Parts of the Stem Water and minerals travel up to other plant parts Xylem Water and minerals travel up to other plant parts Phloem Manufactured food travels down to other plant parts Cambium Separates xylem and phloem
Types of Root Systems Short, small, compact roots Fibrous Roots Easier to transplant Short, small, compact roots Tap Root Difficult to transplant, since most of the tap root is cut-off Tap root is primarily used for storage of food In both types, most nutrients and water are absorbed by root hair
Fibrous Roots Monocots Several roots of same size w/ branching
Roots can be adapted for storage of nutrients: Example: Carrot (Taproot) Sweet Potato (Fibrous Root)
Plant Processes Photosynthesis Mixes light, water, and carbon dioxide in the presence of chlorophyll to produce sugar and oxygen Respiration Combines sugars and oxygen to give off water and heat Transpiration Loss of water through the leaves or stems Causes wilting when soil is dry
Animal Water Wind Dispersal of Seeds Gravity Wind Force
Let's have a short Review
Plant Systems There are 3 main plant systems: Reproductive – this is the flower structure Transport – this is the stem and roots and their xylem and phloem Energy – this is the leaf and other areas of photosynthesis.
Leaf Tissue – What happens where?