Typically, each lab develops its form of technology and protocols and there is no standardized method. Results vary by lab, but many growers report significant progress in crop improvement when utilizing Sap Analysis technology. Often, the growers who report the most success work with a competent advisor who has learned to use Plant Sap Analysis to make precise recommendations.
From the 1930s to the 1950s Plant Sap Analysis was used in laboratories across the world as a method of common analytics for plants and is well known in research institutions.
Since the late 1970s, it has been used as a quick test for plant nutrient testing. But typically with rapid field tests of a limited number of analytes; tissue analysis gained popularity with its standardized protocols for multiple crops in laboratory environments.
By the early 1980s Sap Analysis began to catch on as an alternative to normal tissue analysis with a few independent researchers in the UK, USA, Africa, and Australia. In the USA, Bruce Tainio began to develop correlations between plant Sap pH and plant health. A handful of research departments in the state university system also performed significant research studies, yet these experiments were never commercialized in laboratories due to complexities in laboratory methods of extraction, preservation, sample preparation, analysis, and data processing. Developing Target Ranges seemed like a laborious task for the independent researcher and university funding was not directed toward the technology.
With the advent of modern spectroscopy and automation, a handful of labs across the world began to commercialize the analysis of plant sap for the benefit of farmers in the early 2000s. Around this same time, Horiba developed a suite of handheld meters for in-field plant sap analysis and introduced the concept to farmers. The analysis of NO3, K, Ca, Brix, pH, and EC was a common toolkit of consultants during the early 2000s. By 2016, brick-and-mortar labs began to become more common offering the sap analysis technology to an increasing number of growers to get better results.
Throughout these years, students of various forms of alternative methods of farming also realized the importance of Brix measurement. Brix represents the percentage of dissolved solids in the sap. However, there was a problem: sometimes, the plants were not healthy when high Brix measurements were observed. After a thorough analysis of why this was the case, certain labs have determined that Brix was skewed by dissolved salts in the plant sap. After careful consideration, total sugars began to be the industry standard, as it is a more consistent method that is not influenced by salt in plant fluids. Total sugars measurement also gives insight into a plant’s resilience similar to Brix, but with greater precision.
A high Brix sap has a lower freezing point and subsequently a greater frost resistance due to lower water activity. As Brix goes up, the freezing point of the crop goes down, leading to greater resilience to frost during the abiotic stress events induced by cold weather.
During heat stress events, higher sugar levels in the plant absorb a greater portion of the intracellular space, thus leaving less room for water. This reduced amount of water produces a higher probability of retaining moisture and preventing the plant from reaching its wilting point. Higher sugar levels also prevent bacterial and fungal infestations and thus increase fruit viability both before and after removal from the plant. As increasing sugar displaces water activity within the fruit, bacteria and fungi will cease to grow. This is why certain fruits and vegetables won’t mold or degrade, but instead dehydrate over time. These are plants that have developed internal resistance to disease pressure via their internal sugar content.
Frontiers in Plant Science featured a journal article on Leaf Testing in their October 15, 2021 edition:
In conclusion, we emphasize again the systemic development of the integrative study of cross-talk between macro-and micro-mineral elements uptake and signaling in land plants will be of great significance and essential for sustainable agricultural and forestry development all around the world.
Cross-Talks Between Macro- and Micronutrient Uptake and Signaling in Plants
Lastly, higher levels of sugar content generally provide an increased flavor profile as well as a greater nutritional content of the food.
As food quality becomes an increasingly desirable characteristic to the grower and consumer, the need for more precise analytics is essential. Working with Apical helps growers increase their yields.
