Pathways of Foliar Feeding

Foliar feeding is a technique that involves applying nutrients directly to plant leaves, bypassing root uptake for quicker absorption. This method utilizes two primary pathways: stomatal uptake, where nutrients enter through microscopic leaf pores, and cuticular absorption, which involves penetration through the leaf’s waxy surface. Foliar feeding is especially useful for correcting nutrient deficiencies and supporting plant growth during critical or stressful stages.

Stomatal Uptake

Stomatal uptake plays a role in foliar feeding, as it is one of the main pathways through which nutrients are absorbed when applied directly to plant leaves. 

During foliar feeding, nutrient solutions are sprayed onto the leaf surface, and their uptake primarily occurs through open stomata, tiny pores that control gas exchange and water vapor loss. When the stomata are open, the nutrients can quickly move into the internal leaf tissues. This pathway is particularly effective because it bypasses the slower root absorption process, making it ideal for addressing acute nutrient needs and enhancing plant resilience under stress conditions.

Cuticular Absorption

Cuticular absorption refers to the process by which nutrients penetrate the leaf’s outer waxy layer, known as the cuticle, before entering the underlying plant tissues. 

The leaf cuticle, a waxy layer that covers the epidermis, provides a secondary pathway for nutrient absorption. While the cuticle acts as a barrier to water loss, it also permits the slow penetration of certain dissolved nutrients, especially when surfactants are used to reduce surface tension. This serves as an alternative pathway when stomata are closed which allows for the uptake of applied nutrients even under suboptimal conditions. 

However, this process is typically less efficient and slower compared to stomatal absorption. Factors like the thickness of the cuticle, its chemical composition, and the presence of additives (e.g., surfactants) can influence the rate of nutrient uptake through this route

NutriHydro’s Biostimulants series promotes effective foliar feeding for enhanced plant health and growth. Their focus on nutrient uptake through stomatal and cuticular pathways highlights their commitment to enhancing plant health.

References:

Fu, Z., Wang, Y., Lu, Y., & Yuan, T. (2016). Nitric oxide is involved in stomatal development by modulating the expression of stomatal regulator genes in Arabidopsis. Plant Science, 252, 282–289. https://doi.org/10.1016/j.plantsci.2016.08.005 

Haworth, M., Marino, G., Loreto, F., & Centritto, M. (2021). Integrating stomatal physiology and morphology: evolution of stomatal control and development of future crops. Oecologia, 197(4), 867–883. https://doi.org/10.1007/s00442-021-04857-3

Kannan, S., & Charnel, A. (1986). Foliar absorption and transport of inorganic nutrients. Critical Reviews in Plant Sciences, 4(4), 341–375. https://doi.org/10.1080/07352688609382231