Morphology of stem and bark

morphology stem and bark

Ø Stem – stem is a organ which function both as supportive and as conductive organs. as supportive organ ,it’s supports and elevates the leaves and as conductive organ stem conducts water ,mineral and sugar in vascular tissue between leaves , roots .

or

stem is the main axis of the plant that consist of nodes and internodes.

 

Ø Shoot –shoot is the above ground part of plant ,that consist of leaves ,buds, flowering stem ,flowering bud and the main stem.

Ø Leaf primordium – Formation of immature leaves.

Ø Node – Point of attachment of leaf to stem.

Ø Internode- A slender part between two nodes or joints.

Ø Axil – The angle between the upper side of the stem & a leaf ,branch or leaf petiole.

v Underground stem

Ø Notstocks –some perennial & biennial plants growing under harsh conditions of cold or drought have underground stem.

Ø Bulbs –Shoot consist of a small amount of vertical stem tissue & a massive quantity of thick fleshy storage leaves. Example- Garlic,onion.

Ø Bulbils –it is small bulb like structure that are formed within arial shoots or inflorescence of plant.

Ø Corm – a rounded underground stem storage organ present in plants such as crocuses, gladioli & cyclamens consisting of a swollen base covered by small scale leaves .

Ø Cormel- A small propogative corm growing at the side  of mature corm.

Ø Coudex- the thickened usally underground base of the stem of many perennial herbaceous plants , from which new leaves & flowering stem arise . Example- palm plant.

Ø Rhizome- It is found under the soil and grow horizantlly with short internodes with some scale leaves. Example- ginger,turmeric etc.

Ø Tuber- it is thick underground storage stem, which bears outer buds, its  have lack of protective scale leaves. Example- Potato ; in some plants the tuber are formed arial parts of plant. Example- dioscorea

Ø Stolen or runner – it is a stem with long internode that runs just bellow the surface of the ground forming a new plantlet . when come into the contact of soil . Example- strawberry.

v Arial stem

Ø Cladode – a flattened photosynthetic branch or portion of stem that functions as or resembles as leaf .Eg –cactus.

Ø Succulent stem – this type stem contains high percentage of water. It have high percentage of parenchyma tissue that may store. High quantities of water , and the stored water use in drought periods. Example- aloevera.

Ø Caudiciform stem- it is a fat, swellen perennial storage stem which appears at or ground level. It is a non photosynthetic shoots. Example- Elephant Foot,ming aralia.

Ø Pachycaul- “Pachy is a greek word means Large, and caul are derived from latin word cauli means Trunk”,it is large woody trunk like stem which swellen basally. The swellen region function in storage of water . Example- bottle tree.

v Protective stem

Ø Thorn- A stiff, sharp-pointed woody projection on the stem or other part of plant, that are modification of auxillary shoot system . Example-karonda.

Ø Spines- it is sharp-pointed projection on stem. It is modification of leaf or other part of leaves, auxillary buds. Example- pineapple, agave.

Ø Pricle- a short pointed outgrowth on the bark or epidermis of a plant, it’s looks like a thorn. Example-Rose, ber.

Ø Areole- it is modified, reduced, non-elongating shoot, apical meristem bearing leaf spines. It’s mainly found in cactus.

v Reproductive stem

Ø Scape-  a scape is a long internode(non-woody leafless segment between two leaf bearing region)that forms  from the basal part or the whole of the penducle,it is destined to bear one or more fowers or fruits. Example- onion, garlic.

Ø Culm- Culm word are derived from latin word “culmus” means “stalk”. It is a arial stem of grass of sedge. It is originally refers to the stem of any plant. Example-bamboo tree,sugarcane.

Ø Tiller- a tiller is a stem produced by grass plant, and refers to all shoots that grow after the initial parent shoot grows from a seed, tiller are segmented, each segment processing it’s own two part leaf. They are involved in vegetative propagation and also production of seed . Example- Kentucky bluegrass.

v Other type stem

Ø Burl or lignotuber- lignotuber is swellen woody stem, at slightly bellow ground level & just above the root system. It is a protective & regenerative stem which emerges from following fire hazards. Example- jarran, snappygum.

Ø Pseudobulb- pseudobulb is a storage organ found in many epiphytic & terrestrial sympodial orchids . it may be egg shaped, spherical or flat. Pseudobulbs store water and nutrients during dormat season. Example- dendrobiaum catteya etc.

Ø Spur/dwarf- it is a modified shoot with every shoot internodes- over which flower or leaves are borne. Example- Apple.

Ø Tendril- it is long slender coiling branch which adapted for climbing . it is found on weak stemmed vine & functions as support organ . Example-melon, cucumber etc.

v Stem habbit

Ø Caulescent – a plant with an above ground stem. Example- pineapple,lettuce,carrot etc.

Ø Acaulescent – a plant that lacks of an above ground stem, other than the infloroscence axis, acaulescent plant is biennial herbs. Example- garlic ,onion ,chives.

Ø Arborescent – plant with tree like appearance and size. Example-microcycas  calocoma,  macrozamia moorei etc.

Ø Frutescent- plant having habbit of a shurbs with numerous, woody ,arial trunk.

Ø Suffrutescent- plant having the habbit basally woody,apically herbaceous and perennial in nature. Example- butterfly bush.

Ø Clambering or scadent- stem sprawling a cross objects without specialized climbing structure.

Ø Climbing- stem growing upwards by means of tendrils, petioles or adventitious roots . Example- cucumber,grapevine,moneyplant etc.

Ø Prostrate – stem trailing or laying flat ,but rooting not occurs at nodes. It’s also called

Ø Repent- stem reaping or laying flat, but rooting occurs at nodes. Example- burmuda grass.

Ø Decumbent- laying basally flat on ground, but apically growing upwards. Example- basella, portulaca etc.

v Branching pattern

Ø Indeterminate branching- this type shoot have ability for unlimited growth. It’s apical meristem is continues active & resultant growth is inderterminate. Example- apple , white birch etc.

Ø Determinate- this type shoot have not potential for unlimited growth. it’s apical meristem is terminate in flower ,inflorescence or thorn,tendril etc. Example- potato,cucumber etc.

Ø Hepaxanthic- a determinate shoot that completely terminate into flower or inflorescence. Hepaxanthic plants bears flowers only once in their life cycle. Example- banana bamboo etc.

Ø Pleonanthic- an indeterminate shoot that bears lateral flowers but continues vegetative growth occurs in terminal shoot. It’s type branching pattern mainly sean in palmae or arecaceae family plant .

Ø Monopodial- when stem axis is derived from growth of single meristem, is called monopodial 

Or

When the terminal bud continues grow as a central plant grow from a single point . Example- fagus.

Ø Sympodial- if a stem axis are derived from multiple apical meristem.

Ø Dichtomous- it is a rare type of branching in which a single meristem divides equally into branches. Example-mango,congress grass.

Ø Trunk- undivided stem of a palnt is termed as stem.

Ø Twing- recent growth of branches of trees or shurbs as termed as twings.

Ø Buds- immature shoot system that develops from meristem regions.

·        mined type bud- which develop both vegetative & floral growth .

·        collateral buds- usally one bud are forms per node, but in some plant more than one auxillary bud oriented sideways . they are known as collateral buds.

·        Superposed buds- if 2 or more auxillary buds oriented vertically they are known as superposed buds.

·        Pseudoterminal buds –  some times the apical meristem of a shoot aborts. Then auxillary bud near shoot apex may continue  extension growth & assumes the function of a terminal bud known as pseudoterminal bud.

Ø Bud scale-it is the outer most leaves of the bud, which act as a protective bracts. It is also known as scale leaves.

Ø Bark-it is the outer most layer of the stem,which is composed of the tissue outside the vascular cambium of plant . it is also known as periderm.

v Type of bark

·        Exfoliating leaves- it is a bark that cracks or splits into large sheets. Example- terminalia arjuna, lipistic.

·        Fissured – this type of bark are splits or cracked into vertical or horizontal grooves.

·        Plated- bark which splits or crack with flat plated between the fissures. Example- persimmon.

·        Shreddy – the bark which are coarsely fibrous. Example- yellow birch.

·        Smooth- a non fibrous bark without fissures, firbres, plates or exfoliating sheets . it’s bark are smooth and free from any cracks .

 

Take a test free

You might also like to read

• important Terminology
• Famous name of some crops
• Root morphology
• Chilli
• Capsicum
• Okra
• BrinjaL
• Tomato
• Cauliflower
• Cabbage
• Broccoli
• Knol Khol
• All vegetables
• Fundamentals of horticulture

 

any doubt please comment

If anyone wants to download agriculture books and JRF horticulture old paper pdf free

         Join my telegram channel SpHorticulture   Telegram

&

Group SPhorticulture