Effect of Aspirin on Flowers

Overview

Aspirin in tablet form has been around for more than 100 years. Also known by its chemical name of acetyl salicylic acid, aspirin is used to reduce pain, inflammation and fever. But aspirin has other uses that are not as commonly known. Aspirin can help plants to grow and an aspirin dissolved in the water of cut flowers will help them last longer.

Origins

Before aspirin was synthesized in the laboratory, it was obtained in the form of salicylic acid from natural sources such as white willow bark, and was used as an herbal remedy for thousands of years. Salicylic acid is a hormone, commonly produced in plants. Plants produce salicylic acid, and a similar chemical called methyl salycilate, especially when a plant is under stress.

Function

When the leaves of a plant are exposed to illness, such as a viral or fungal infection, the plant will respond by developing dead spots at the point of infection to limit its spread. This is referred to as a hypersensitive response. The plant will also boost its immune system in a reaction called systemic acquired resistance to be more able to the fight the infection. They do this in part by producing salicylic acid and methyl salicylate.

Defense Mechanism

The infected plant will make high levels of these chemicals around the dead spots, which will then move through the plant, possibly acting as a warning to the rest of the plant to ramp up defenses. In fact, researchers at the National Center for Atmospheric Research discovered that plants under stress release methyl salycilate into the air, thereby communicating with neighboring plants and warning them of the threat.

Benefits

Because aspirin is so similar chemically to salicylic acid and methyl salycilate, spraying plants with a small amount of dissolved aspirin can actually trigger the same immune response as an infection, thereby intentionally triggering the plant to strengthen itself.

Risks

Giving aspirin to flowers does have a downside, however. If the plant is treated with the aspirin solution too frequently, all of its available energy will be put to responding to the treatment. This reaction can actually inhibit plant from growing and flowering.

Aspirin for Cut Flowers

An aspirin will help cut flowers last longer because salicylic acid is also known to block ethylene production in plants. Even when given sufficient water, cut flowers will eventually wither and die. This process is called senescence and is controlled by the chemical ethylene in the plant, but salicylic acid blocks ethylene production. So, aspirin added to the water for cut flowers will be taken in by the flowers and will significantly slowing senescence, allowing the flowers to last longer.