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Physical Protection
some plants usage various forms of physics protection:
Hawthorns usage thorns to discourage searching by herbivores such together deer.

You are watching: Thorns and small hairs on plant stems and leaves help to

Thorns on hawthorn
Spines top top cactus
Cactus have spines to protect their succulent stems, and also thus their valuable water supplies.
Hollies be affected by each other spines on the margins of their pipeline as a deterrent come would-be browsers.
Spines on holly
Prickles on rose
Rose prickles (commonly, though inaccurately, referred to as thorns) deter grazing animals, and their bottom curve prevents tiny animals indigenous climbing the stem.

Many plants have actually fuzzy or hairy leaves—the hairs room actually specialized epidermal cells—that safeguard the tree from insect attack. (The fuzzy structure may also discourage grazing.)

Perhaps the simplest instance of physical protection is the bark of trees. Bark is made up of a special layer that dead cell that develops a barrier against water loss and also invasion by insects or disease.

A an essential component the physical protection is quick wound healing. If a plant’s epidermis is injured, water loss and invasion by insects and condition organisms have the right to rapidly threaten the plant. Herbaceous tree respond to any break in the epidermis by collapsing the cells follow me the surface of the wound, effectively sealing it. Waxy substances room then deposit to more seal the wound. Woody organization respond come injury by creating a callus, which consists of a mass of regardless of whether cells emerging from cell division near the wound surface. Gradually cork encroaches from the area surrounding the wound, and may completely cover it. Cork is a an additional tissue, formed by the cork cambium. That is component of the external bark that replaces the epidermis in woody plant parts.


A Prickly Subject.

So what’s the difference in between a thorn and also a prickle?

A thorn is a rigid, sharp-pointed outgrowth indigenous the timber of a stem, and, due to the fact that of its internal structure, is thought about a amendment stem. Due to the fact that they arise in sheet axils in the position of axillary buds, thorns room usually consistently spaced.

Prickles are comparable to thorns, yet they originate from the bark or epidermis of a plant fairly than indigenous the wood. They are usually irregularly spaced, and also can be removed without damaging the stem.

A spine is a modified sheet part. Plenty of cactus have actually spines, and also the points on holly leaves are spines.


Pruning Protocol. once you prune a tree or shrub, friend are creating an open up wound. Though the traditional recommendation offered to it is in to paint over any large cuts v a one-of-a-kind sealer, recent research reflects that this does not speed healing and also may even slow the process.

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However, friend can assist the healing procedure by pruning branches close to the branch collar—the swollen area where the branch meets the trunk—without actually cutting right into the collar. This form of cut will allow the tree to most quickly form protective callus, and also eventually cork, layers.

Don’t leaving a long branch stub; if you do, the cork tissue will certainly not grow over and protect the protruding section.