Cell, tissues, organs (2)

Slide 1 en.wikipedia.org Cells, Tissues and Organs Botany LHAP 105 McGraw-Hill Companies, Ltd. en.wikipedia.org www.pinterest.com Slide 2 Gymnosperms vs Angiosperms Conifers vs flowering plants Conifers (spruce, pine, etc.) do not have ‘flowers’. Instead they have cones that bear ‘naked seed’ Angiosperms, or flowering plants, have flowers that develop into fruit. The seed is enclosed in the fruit. Slide 3 Most of what will be presented in this course will be about angiosperms, plants with true flowers Slide 4 Cells Tissues Organs cells that divide (meristematic) Dermal (epidermis) Roots Leaves Stems cells that differentiate Vascular (xylem and phloem) Flowers Fruit Seed Cortex type tissue (parenchyma, collenchyma, sclerenchyma) all of these tissue types are represented in each of the above organs } } vegetative reproductive Slide 5 monocots vs dicots Angiosperms are divided into 2 main groups: monocots these are plants that are grass-like (for example: iris, palm trees and grasses of course!) dicots these include herbaceous plants as well as woody species en.wikipedia.org en.wikipedia.org en.wikipedia.org en.wikipedia.org en.wikipedia.org Slide 6 Tissues tissues are a collection of cells that perform specific functions permanent tissues are cells that have ‘matured’ and developed specialized features to enable them to carry out specific tasks Slide 7 Surface tissues surface tissues protect the plant from the outside environment 1. Epidermis usually only one-cell thick cutin coats the outer surface to form a ‘cuticle’ which helps limit water loss desert plants would have a thick cuticle roots would have a very thin cuticle en.wikipedia.org Slide 8 Surface tissues surface tissues protect the plant from the outside environment 2. Periderm as woody plants increase in diameter (girth) the original epidermis “splits off” as bark is produced bark has meristematic tissue (phellogen; cork cambium) to protect the stem Slide 9 Storage/support tissues 1. Parenchyma Parenchyma tissues are very flexible and do not provide structural support they function mainly as storage tissue - storing sugars produced from photosynthesis roots cannot produce food - so they have abundant parenchyma to store food parenchyma, if required, can become meristematic and can live for decades A.Shigo Slide 10 Storage/support tissues 1. Collenchyma Collenchyma tissues are both flexible and provide structural support they are found just under the epidermis their cells walls are thicker than parenchyma but are still resilient and flexible en.wikipedia.org parenchyma collenchyma epidermis Slide 11 Storage/support tissues 1. Sclerenchyma Sclerenchyma tissues provide structural support they are dead at maturity their cell walls are tough, thick; impregnated with lignin scleroids: randomly distributed among other tissues fibres: occur in specific zones in stems, leaves and fruits wikipedia/commons Slide 12 Vascular tissue 1. xylem xylem vessels are made up of cells that are stacked up one on top of the other to form thin hollow tubes xylem vessels transport water and dissolved minerals upward from the roots to the outmost tips of the plant supplying every living cell xylem itself is dead Slide 13 Vascular tissue 2. phloem phloem tissue transports sugars (products of photosynthesis) throughout the plant to wherever energy is required (in all directions) if there is a surplus of ‘food’ it may be transported to the parenchyma storage cells for future use (food reserves) www.boundless.com Slide 14 Secretory tissues these tissues ‘secrete’ substances that were produced within a cell and moved to the outside of the cells. examples include resin, latex, nectars and oil en.wikipedia.org Slide 15 Plant Organs Vegetative roots stems leaves www.rosenotes.com Slide 16 Plant Organs Reproductive flowers fruit seeds en.wikipedia.org