Systemic Aquired Resistance | A Plant's Internal Defence

Plant’s get sick – typically due to infection brought on by pathogens, such as viruses, bacteria and fungi. But plants can defend themselves against these disease-causing organisms. Individual plant cells have receptors that recognize pathogen molecules and then trigger defense responses. This defense response is call Systemic Acquired Resistance or SAR.

To activate SAR, a plant must generate a signal in the pathogen-inoculated tissue that travels to the uninoculated portions of the plant, in which it signals defense responses. Salicylic Acid (SA) is the endogenous signal responsible for the activation of SAR, which ultimately provides for a healthier plant with thicker cell walls and a more robust root foundation, improving the plant’s ability to recognize and defend against these invaders. SAR in this sense, is much like the immune system found in animals and humans whose white blood cells attack foreign bodies. But, because plants don't have a circulatory system, each cell in the plant must respond independently.

Salicylic Acid (SA)

Salicylic acid is important as it is an intrinsic signal that is required to activate SAR, increasing the plant’s tolerance and resistance to various diseases. Salicylic acid also acts as a stimulant or transmitter of the cell to withstand environmental stress conditions such as dryness, coldness, heat and increases the plant’s ability to withstand salt stress.

Additional SA Benefits:

• Stimulates flowering
• Ion absorption
• Nutrient transfer

In Conclusion

A quick online search will tell you that SAR is a mechanism of induced defense that gives long-lasting protection against a broad spectrum of pathogens.Salicylic Acid is needed to trigger the plant’s SAR. Including SA as a supplemental bio-stimulant to your feeding regimen may significantly provide for a more fortified immune system with innately better resistance, which will ultimately enhance plant productivity and greater yields. There are several popular products in the marketplace that provide these benefits. Compare their ingredients, percentages and cost and choose the product that best meets your needs.