Plant Science Plant Science StemsStems

StemsStems StemsStems

The main stem and branches are the scaffolding of The main stem and branches are the scaffolding of the plant

Supports the leaves, flowers and fruits transport water, nutrients, sugars through capillary

action store food

Above ground stem typesAbove ground stem types Woody and HerbaceousWoody and Herbaceous

Woody stemsWoody stems Tough and winter hardy Tough and winter hardy Often have bark around themOften have bark around them

Herbaceous StemsHerbaceous Stems More succulentMore succulent Often green Often green Do not survive in cold climatesDo not survive in cold climates

Modified stemsModified stems Bulbs, corms, Bulbs, corms,

rhizomes and Tubersrhizomes and Tubers BulbsBulbs

Highly compressed Highly compressed underground stemsunderground stems

Have modified leaves Have modified leaves called scalescalled scales

CormsCorms Thickened, compact, fleshly stemsThickened, compact, fleshly stems

RhizomesRhizomes Run just under the surfaceRun just under the surface A new plant will group where each node isA new plant will group where each node is

TubersTubers Thickened underground stems Thickened underground stems

that store carbohydratesthat store carbohydrates

Parts of the stemParts of the stem NodeNode InternodeInternode Axillary BudAxillary Bud AxilAxil LenticelsLenticels Terminal BudTerminal Bud Vegetative BudVegetative Bud Flowering BudFlowering Bud

NodeNode: swollen part of stem where : swollen part of stem where buds form (leaves or stems grow buds form (leaves or stems grow here)here)

InternodeInternode: stem tissue between : stem tissue between nodesnodes

Axillary bud – a bud formed Axillary bud – a bud formed in the axil of a leafin the axil of a leaf

Axil- the angle on the upper Axil- the angle on the upper side of the union of a branch side of the union of a branch and main stem of a leaf and and main stem of a leaf and stemstem

Lenticels – an opening made up of loosely Lenticels – an opening made up of loosely arranged cells in the stem to allow for arranged cells in the stem to allow for passage of gasespassage of gases

Terminal Bud – a Terminal Bud – a bud at the end of the bud at the end of the stemstem

Vegetative Bud – a Vegetative Bud – a terminal plant bud terminal plant bud that produces a stem that produces a stem and leaf growthand leaf growth

Flowering Bud - a Flowering Bud - a terminal plant bud terminal plant bud that produced a that produced a flowerflower

Internal parts of stemInternal parts of stem PhloemPhloem XylemXylem CambiumCambium PithPith CortexCortex

FunctionsFunctions Phloem-Sugar and Phloem-Sugar and

carbohydrates to rootscarbohydrates to roots Xylem- Water and nutrientsXylem- Water and nutrients Cambium- Growing part of Cambium- Growing part of

stemstem

Pith-Occupies the central area Pith-Occupies the central area of the stemof the stem

Cortex- Composed of several Cortex- Composed of several layers of thick-walled cells layers of thick-walled cells