Difference Between Thorns and Spines

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It is difficult to spot the difference between thorns and spines based only on their appearance since they both look almost identical. To know what is the difference between thorns and spines, we must look at how these two are created from different parts of a plant. While thorn is a modified stem, the spine is a modified leaf. At Vedantu, we have created a comprehensive summary of spines, thorns, and pickles along with their differences. 


Spines

Spines are sharp, pointed structures on a plant and are the modified leaf. They protect the plant from predators. An example of spines can be seen in the Opuntia plant where the minute leaves of axillary buds transform into spines. Another example is pineapple where the margin of leaves is modified into spines. 


Thorns 

Thorns are woody, pointed structures in a plant that protect the plant and help in climbing. They are modified axillary leaves and are different from both spines and prickles. Thorns may be branched or non-branched and are always subtended by a leaf.


What is the Difference Between Thorns and Pickles?

The terms prickles and thorns are often mixed and used interchangeably but there is a slight difference between thorns and prickles. 

  • While thorns are formed from internal tissue (endogenous), prickles develop from external tissue ( exogenous). 

  • Prickles develop from the epidermis and cortex of plant stems while thorns are modified branches.

  • Prickles can also occur on leaves and protrude from the main veins of the leaf unlike thorns

  • Prickles can also be seen on adventitious roots and some fruits unlike thorns

 An example of prickles is the rose plant. 

Spines, thorns, and prickles all prevent the animals from eating the plant.

Let’s look at the difference between thorns and spines in detail.


Criteria

Spines

Thorns

Part of the plant

Spines are modified leaves or part of leaves

Thorns are modified branches

Location

They are placed at the same positions as leaves and have a bud in their axil

Thorns develop in the axil of the bud in place of leaves and thus can only be seen at the node of the plant

Connection to vascular tissue

May not be connected to the vascular tissue as they are not placed too deeply

Connected to the vascular tissue as they are placed deeply

Function

Protect the plant and prevent excess transpiration

They protect the plant and act as the climbing part of the plant

Formation

They are formed from external tissues and are exogenous

Thorns are formed from internal tissue and are called endogenous

Examples

Opuntia, Agave, Cactus

Carissa, Duranta

FAQ (Frequently Asked Questions)

Q1. What is the Main Function of the Spines of a Plant?

Ans. The primary function of spines is to protect the plant. During hot weather or dry conditions, spines prevent water loss from the plant. When the leaves are modified into spines, their surface area reduces and this lessens the water loss. Photosynthesis in this case is performed by the stem.

Q2. What is the Main Difference Between Spines, Thorns, and Prickles?

Ans. The main difference between spines, thorns, and prickles is:

  • Thorns are modified stem of a plant

  • Spines are modified leaf or stipule

  • Prickles are an outgrowth from the epidermis of the plant

Q3. Does the Cactus Plant Have Thorns, Prickles, or Spines?

Ans. Most cactus species do not have leaves and are covered with spines that are modified leaves. These spines grow from structures called areoles. They help the plant in conserving water as well as defending against herbivores. The spines on a cactus help in preventing water loss by reducing the airflow close to the plant and giving it some shade.