Sensors for Plant Water Use Measurements
I am always fascinated by advances in technology, especially those that have the potential to enhance measurement of plant processes. A case in point is the information provided in a Jan. 3, 2018 post in Iowa State University’s (ISU) online News Service publication.
The article’s title “Engineers make wearable sensors for plants, enabling measurements of water use in crops” naturally caught my attention. The article summarizes the content of a journal paper authored by Seval Oren, Halil Ceylan, Patrick S. Schnable, and Liang Dong that appears in the Dec. 2017 issue of “Advanced Materials Technologies”. The following excerpt is from the abstract of that paper.
“This paper reports on a simple and versatile method for patterning and transferring graphene-based nanomaterials onto various types of tape to realize flexible microscale sensors. This technology will open a new route for low-cost, scalable, and roll-to-roll production of graphene-based sensors on tape.”
Thankfully, the content of the ISU News Service publication summarized the technical findings given in the paper in easy-to-understand verbage. Important points from that article are presented below.
• The technology will allow the use of new, low-cost, easily produced, graphene-based, sensors-on-tape that can be attached to plants and provide data to researchers and farmers. The cited case is Dr. Schnable’s measurement of the time it takes corn plants to move water from their roots into the lower and upper leaves.
• The tool making the above water measurements possible is a tiny graphene sensor that can be taped to plants. Graphene is a nanomaterial that consists of one-atom-thick sheets of carbon atoms that are arranged in a honeycomb lattice structure. The material is ideal for conducting electricity and heat, and is strong and stable. [A nanomaterial is any material that has an average particle size of 1-100 nanometers (10-9 meter)].
• Dr. Dong, the developer of the technology, said “We’re trying to make sensors that are cheaper and still high performing”. To do that, they have developed a process for fabricating intricate graphene patterns on tape, thus creating a sensor on the tape.
• The process can produce precise patterns as small as 5 millionths of a meter wide, which is just one twentieth the diameter of the average human hair. The small size of the patterns increases the sensitivity of the sensors.
• According to Dr. Dong, the fabrication process is simple and cheap–just use tape to manufacture the sensors, and the cost is just cents.
• For plant studies, the sensors are made of graphene oxide, which is sensitive to water vapor. The changes in the conductivity of the material in the presence of water vapor can be quantified to accurately measure transpiration from a leaf.
• The tape-based sensors for plants (or “wearable electronic sensors”) are so tiny they can detect transpiration from plants, but they won’t affect plant growth.
• A patent has been applied for on the sensor technology, and an option to commercialize the technology has been granted.
In my 7+ years of blogging on this website, I have reported on numerous new technologies that have the potential to improve our knowledge of plant processes or that will enhance the processes and genetics of agricultural crops, especially soybean (e.g. click here, here, and here). Regrettably, it is very difficult to follow up on these discoveries to determine if they in fact provide the touted result. But it is heartening to know that such new discoveries are coming forward and that at least some of them will likely be applied to produce products or measure processes that will allow for improved crop production and agricultural sustainability.
Composed by Larry G. Heatherly, Jan. 2018, larryheatherly@bellsouth.net