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How Conifers succeed in the North

Ncumisa Mnotoza

2253897@uwc.ac.za

All conifers are seed plants with vascular tissue that All conifers are seed plants with vascular tissue that bear cones. bear cones.

They contain more trees than shrubs. They contain more trees than shrubs. They have monopodial growth form, that is a tall They have monopodial growth form, that is a tall

straight trunk and narrow branches. straight trunk and narrow branches. They are usually found in cool or cold climatic regions. They are usually found in cool or cold climatic regions.

Most have evergreen leaves that are needle-like.Most have evergreen leaves that are needle-like. They are all wind pollinated. They are all wind pollinated. Conifers make up 30% of the world’s forest and are a Conifers make up 30% of the world’s forest and are a

group that consists of the tallest, largest, thickest and group that consists of the tallest, largest, thickest and oldest living thing.oldest living thing.

ConifersConifers

Tallest: 112.83m Tallest: 112.83m Coast Coast RedwoodRedwood

Largest: base trunk Largest: base trunk 31.5m volume 1486.9cm31.5m volume 1486.9cm33 Giant sequoia Giant sequoia

Thickest: trunk diameter Thickest: trunk diameter 11.42m 11.42m Montezuma Montezuma cypresscypress

Oldest: 4.7 million years Oldest: 4.7 million years oldold

SCIENTIFIC CLASSIFICATIONSCIENTIFIC CLASSIFICATION

KingdomKingdom :: PlantaePlantae

DivisionDivision : : PinophytaPinophyta

ClassClass :: PinopsidaPinopsida

OrderOrder :: PinalesPinales

FamilyFamily :: PinaceaePinaceae

GenusGenus :: Pinus L.Pinus L.

GYMNOSPERMS Gymnosperms are plants that produce seeds not Gymnosperms are plants that produce seeds not

spores, the seeds are naked meaning that they are spores, the seeds are naked meaning that they are not covered by an ovary. These are non flowering not covered by an ovary. These are non flowering plants. Usually, the seed is produced inside pine cone plants. Usually, the seed is produced inside pine cone hence the name "conifer." In essence the name word hence the name "conifer." In essence the name word conifer means cone bearing.conifer means cone bearing.

Conifer are trees and shrubs that have cones and Conifer are trees and shrubs that have cones and characteristically have needle-like, scale-like or awl-characteristically have needle-like, scale-like or awl-like leaves. like leaves.

Approximately 600 species are counted as conifers, Approximately 600 species are counted as conifers, and some fall under the family and some fall under the family CONIFERACEAECONIFERACEAE. .

Gymnosperms have been Gymnosperms have been distributed among four distributed among four groups that have been groups that have been given equal ranks in the given equal ranks in the Kingdom Plantae.Kingdom Plantae.

Namely:Namely: Division:Division: Pinophyta Pinophyta – –

ConifersConifers Division:Division: GinkgophtaGinkgophta – –

GinkgoGinkgo Division:Division: CycadophtaCycadophta – –

CycadsCycads Division :Division : GnetophytaGnetophyta - -

Gnetum, EphedraGnetum, EphedraCoast Douglas-fir ConeCoast Douglas-fir Cone

Gymnosperms are not the same thing asGymnosperms are not the same thing as

conifers but merely a division within that conifers but merely a division within that group.group.

In very cold climatic regions conifers are In very cold climatic regions conifers are the only group within the common the only group within the common gymnosperms that will be foundgymnosperms that will be found

PinophytaPinophyta

Pinophyta it has one class, Pinopsida that includesPinophyta it has one class, Pinopsida that includesboth the living and fossil taxa. Conifers have 6 to 8 both the living and fossil taxa. Conifers have 6 to 8 families that contains 65 to 70 genera and 600-650 families that contains 65 to 70 genera and 600-650 species. A phylogenic diagram relates thespecies. A phylogenic diagram relates the seven most distinct families.seven most distinct families.

Phlogeny of molecular data based on cladistic Phlogeny of molecular data based on cladistic analysis of molecular dataanalysis of molecular data

ConiferalesConiferalesThere are six families within this order:PinaceaeTaxodiaceaeCupressaceaeAraucariaceaePodocarpaceaeCephalotaxaceae

PinaceaeLeaves are linear, flat or needle-like Leaves are linear, flat or needle-like and spirally arranged in two or more and spirally arranged in two or more rowsrows

MonoeciousMonoecious

Cones are mostly woody and spirally Cones are mostly woody and spirally arranged scalesarranged scales

The bracts are separate from scales The bracts are separate from scales except at the base. The bracts are except at the base. The bracts are small and narrow sometimes longer small and narrow sometimes longer than scales. The bract and ovuliferous than scales. The bract and ovuliferous scale are distinctscale are distinct

Two pollen sacs and pollen has two Two pollen sacs and pollen has two air bladders. Sporophyll are spirally air bladders. Sporophyll are spirally arranged. Pollen grains are winged arranged. Pollen grains are winged

Juvenile (left) and adult Juvenile (left) and adult

foliage of Stone Pine foliage of Stone Pine

((Pinus pineaPinus pinea). The adult ). The adult

shoot has dark brown shoot has dark brown

scale leaves and needles.scale leaves and needles.

Pinophyte needle-like Pinophyte needle-like leaves (close- upleaves (close- up) ) Picea Picea AbiesAbies

Parts are spirally arrangedParts are spirally arranged

Leaves are opposite or spirally arranged, Leaves are opposite or spirally arranged, narrow, linear or awl- shaped narrow, linear or awl- shaped

MonoeciousMonoecious

Cones have a globose scale that is Cones have a globose scale that is spirally arranged, leathery and woody. The spirally arranged, leathery and woody. The bract and ovuliferous scale are free when bract and ovuliferous scale are free when young then they fuse in the mature coneyoung then they fuse in the mature cone

Each ovuliferous scale has 2 to 9 ovules. Each ovuliferous scale has 2 to 9 ovules. Pollen sacs 2 to 9 on each microsporophyllPollen sacs 2 to 9 on each microsporophyll

Pollen grains without air bladders, pollen Pollen grains without air bladders, pollen is wingless or wingedis wingless or winged

Taxodiaceace

CupressaceaeCupressaceae Parts are oppositely or whorled in Parts are oppositely or whorled in

arrangementarrangement Monoecious or dioeciousMonoecious or dioecious Small adult leaves, scale-like Small adult leaves, scale-like

arranged in opposite pairs or threearranged in opposite pairs or three Cones are small, the scales are Cones are small, the scales are

confluent with bracts and are confluent with bracts and are woody when ripe and contains woody when ripe and contains numerous ovules. Ovules are numerous ovules. Ovules are erect and can be any number from erect and can be any number from 3 to 20 per scale3 to 20 per scale..

FEATURES OF CYPERACEAEMicrosporophylls have 3 to 6 microsporangia and the Microsporophylls have 3 to 6 microsporangia and the pollen sacs range between 3 and 6pollen sacs range between 3 and 6

Cones may overlap e.g Cones may overlap e.g ThunjaThunja

valvate e.g valvate e.g CupressusCupressus

fleshy e.g fleshy e.g JunipersusJunipersus

Pollen grains lack air bladders and Pollen grains lack air bladders and have a good drop mechanismhave a good drop mechanism

.The cones are fleshyThe cones are fleshy and berry-like, theand berry-like, the

seeds are bird seeds are bird disperseddispersed

Araucariacaeae Spiral arranged leaves that are narrow Spiral arranged leaves that are narrow

or broad with parallel veins, the buds or broad with parallel veins, the buds are not scaled are not scaled

Dioecious or monoeciousDioecious or monoecious Cones have a large woody one Cones have a large woody one

seeded scales and no distinct bracts. seeded scales and no distinct bracts. Cones fall when seeds are ripeCones fall when seeds are ripe

Microsporophylls consist of 5 to 20 Microsporophylls consist of 5 to 20 micropsporophylls. The scale of a micropsporophylls. The scale of a seed contains one ovule and is fused seed contains one ovule and is fused with a sterile bract. with a sterile bract.

Ovules are solitary with Ovules are solitary with microsporangia hanging from a peltate microsporangia hanging from a peltate sporophyll. The male strobili is dense, sporophyll. The male strobili is dense, cylindrical with many sporophyllscylindrical with many sporophylls

(Monkey Puzzle Family)

Pordocarparceaeleaves are evergreen, spirally leaves are evergreen, spirally arranged, scale-like or needle-like, arranged, scale-like or needle-like, linear or lanceolate, or linear or lanceolate, or oblanceolateoblanceolate

Monoeciouis or dioeciousMonoeciouis or dioecious

Ovule erect or reflexedOvule erect or reflexed

Commonly the the ovuliferous Commonly the the ovuliferous scale is folded around the single scale is folded around the single ovule to form an added envelop, ovule to form an added envelop, the epimatium, which is fused the epimatium, which is fused completely or partially to the completely or partially to the integument or in some species it is integument or in some species it is fused to the bract scalefused to the bract scale

Podocarparceae conesMale cones have a number of microsporophylls eachMale cones have a number of microsporophylls each

with 2 pollen sacs. The pollen grains have 2 or 3 airwith 2 pollen sacs. The pollen grains have 2 or 3 air

bladders. The pollen is wingedbladders. The pollen is winged

In some species the ovule are borne in cones. In In some species the ovule are borne in cones. In others the female cone is reduced to form a fleshy others the female cone is reduced to form a fleshy receptacle with a single terminal ovule. The outer seed receptacle with a single terminal ovule. The outer seed coat is dry or fleshy, in reduced cones or supported by coat is dry or fleshy, in reduced cones or supported by a fleshy bract and stalka fleshy bract and stalk

CephalotaxaceaeSpirally arranged linear leaves and Spirally arranged linear leaves and opposite or whorled branchingopposite or whorled branching

DioeciousDioecious

The ovules are borne on cones. The ovules are borne on cones. Ovules are in pairs at the base of each Ovules are in pairs at the base of each opposite bracts. One ovule grows into opposite bracts. One ovule grows into a big olive-like seed that has an outer a big olive-like seed that has an outer fleshy layer that surrounds a stony fleshy layer that surrounds a stony layerlayer

The male cone have spirally The male cone have spirally arranged microsporophyll with 2 to 3 arranged microsporophyll with 2 to 3 pollen sacs. The pollen bladders have pollen sacs. The pollen bladders have no air bladders. The pollen is winglessno air bladders. The pollen is wingless

Pollination is a drop mechanismPollination is a drop mechanism

Reproductive CharacteristicsDioecious or monecious plants:Dioecious or monecious plants:The microsporangiate stobili are pollen cones, that The microsporangiate stobili are pollen cones, that makes pollen(microgametophyes. They consist of makes pollen(microgametophyes. They consist of sporophylls where the pollen sacs (microsporangia) sporophylls where the pollen sacs (microsporangia) are borne on the lower surface are borne on the lower surface All species are wind-pollinatedAll species are wind-pollinatedSperm are not flagellated they reach the egg via a Sperm are not flagellated they reach the egg via a pollen tube. pollen tube. Except for the Except for the TaxaceaeTaxaceae, ovules are borne in , ovules are borne in secondarily reduced microsporangiate stobili (seed secondarily reduced microsporangiate stobili (seed cones) with seed scales that have ovules. These are cones) with seed scales that have ovules. These are subtended by a sterile bract, together they are called a subtended by a sterile bract, together they are called a seed scale complex. They are arranged around the seed scale complex. They are arranged around the central axis of the ovulate cone.central axis of the ovulate cone.

A GENERALIZED LIFE CYCLE OF PINESA GENERALIZED LIFE CYCLE OF PINES

The male cone releases pollen to fertilise the ovum. The The male cone releases pollen to fertilise the ovum. The pollen is transported by wind to the female cone. When the pollen is transported by wind to the female cone. When the female gamete is fertilized it is called a zygote that grows into female gamete is fertilized it is called a zygote that grows into an embryo.The embyro has integument cells that surround it an embryo.The embyro has integument cells that surround it and altogether can be found in the seed. When the seed is and altogether can be found in the seed. When the seed is mature it drops onto the ground, and germinates. The mature it drops onto the ground, and germinates. The seedlings grow into a mature plant that produces cones…seedlings grow into a mature plant that produces cones…and and the cycle continuesthe cycle continues

SUCCESS OF CONIFERSSUCCESS OF CONIFERS

MORPHOLOGY:A scale or a needle leaf is very small and thus has A scale or a needle leaf is very small and thus has minimal exposed surface area and they are also minimal exposed surface area and they are also lightweight. lightweight. This would make it impossible for trees and shrubs trap This would make it impossible for trees and shrubs trap any snow on their leaves because it would not be able to any snow on their leaves because it would not be able to support the weight of snow.The minimal surface area support the weight of snow.The minimal surface area exposure ensures that they do lose any water that it exposure ensures that they do lose any water that it retains. retains. The branches are thin, so they cannot trap much snow, The branches are thin, so they cannot trap much snow, or this would result in the branches breaking off the trees.or this would result in the branches breaking off the trees.

Photosynthesis still occurs in extremely lowPhotosynthesis still occurs in extremely low temperatures due to the leaves being temperatures due to the leaves being evergreenevergreen.. These trees take advantage of the short wet andThese trees take advantage of the short wet and the short dry season which is characteristic of the the short dry season which is characteristic of the

northern climates. northern climates.

This mechanism allows tress to ‘save’ nutrients, This mechanism allows tress to ‘save’ nutrients, because they do not have to form new leaves annualy. because they do not have to form new leaves annualy. This is advantageous in soils with low nutrients and This is advantageous in soils with low nutrients and environments with a slow decomposition.environments with a slow decomposition.

TRACHEIDSThey are long, narrow-diameter cells. Their narrownessThey are long, narrow-diameter cells. Their narrowness

prevents bubbles forming during spring when stems prevents bubbles forming during spring when stems

thaw. Air bubbles form as water freezes and air goes thaw. Air bubbles form as water freezes and air goes

out of solution forming a gas. Due to the tracheids beingout of solution forming a gas. Due to the tracheids being

narrow only small bubbles can form which end up narrow only small bubbles can form which end up

redissolving.redissolving.

STOMATAThey help the trees in the case of water loss and toThey help the trees in the case of water loss and toaviod dessicatio form occuring,(aviod dessicatio form occuring,(as the air warms inas the air warms in spring the soil is still frozen and water can't move intospring the soil is still frozen and water can't move into tree freely to make up for the water loss from leavetree freely to make up for the water loss from leave

ECONOMIC IMPORTANCE

Conifers are used to make softwood Conifers are used to make softwood timber.This wood is commonly used in timber.This wood is commonly used in temperate regions for lumber constrution temperate regions for lumber constrution making: polywoods, particleboards, and making: polywoods, particleboards, and chipboards; from processed softwood, chipboards; from processed softwood, paper, plastics, tannins, turpentine. paper, plastics, tannins, turpentine.

Conifers provide food: nuts and berriesConifers provide food: nuts and berries

REFERENCESChamberlain Charles Joseph, 1966. ‘Gymnosperms: Chamberlain Charles Joseph, 1966. ‘Gymnosperms: Structure and Evolution’. General Publishing Structure and Evolution’. General Publishing Company, LTD, Canada.Company, LTD, Canada.

Dallimore W. and Jackson A. B., 1966. ‘A Handbook Dallimore W. and Jackson A. B., 1966. ‘A Handbook of Coniferaceae and Ginkgoaceae, 4of Coniferaceae and Ginkgoaceae, 4thth Edition. Edward Edition. Edward Arnold LTD, LondonArnold LTD, London

Sporne K. R., 1965. ‘The Morphology of Sporne K. R., 1965. ‘The Morphology of Gymnosperms’, Hutchinson & Co LTD, LondonGymnosperms’, Hutchinson & Co LTD, London

http://en.wikipedia.org/wiki/Pinophyta