The objective of this research is to develop an innovative plant root microsystem with a superior capability of monitoring interactions between the plant roots and the immediate root zone environment. The approach is based on novel three-dimensional microsensor arrays. Vertical microarrays of electrochemical electrodes and optical waveguides are developed by new dryfilm photoresist lamination and electroplating processes. The microsensor arrays are integrated with a miniature plant growth system to monitor root zone oxygen distribution.
Intellecyual merit: The interactions between the plant roots and the surrounding media are the least understood and most challenging aspect of plant research. The new microsystem is expected to provide a novel tool for nearly all aspects of root research including metabolic engineering, plant stress physiology, and plant pathology. An unprecedented use of the new microsystem to root zone monitoring will provide a major technological breakthrough for future root research efforts, thus expanding the application area of the microsystem technology to plant and agricultural science and engineering.
Broader Impact: Expanding farming area without improvements of agricultural technology results in low crop yields and land pollution. Solutions to this challenge can only come from a better understanding of the plant root system, which can be expedited through the use of microsystem technology. This project involves a collaboration activity with a minority serving institution to develop root monitoring microsystems to expedite the participation of diversity. This microsystem education effort with an emphasis on plant and agricultural applications will create a new generation of workforce, proficient both in microsystems and agricultural engineering.
The growth of global population requires a substantial increase in agricultural production. Absence of new technology may result in serious impacts on global food security and environmental pollutions. The total yield loss of field crops is related mostly to nutrient deficiency, contaminated soil and drought. Fertilizer and water application still remains the most effective way to increase crop productivity, but the availability of minerals and water may not be sufficient in the near future at current rates of use. Moving into marginal producing areas causes an expansion of farming area into less productive land without technical improvements, while causing serious environmental degradation. Highly productive, yet sustainable and precise, agricultural and environmental technologies must be developed to solve this problem. The research outcome from this grant may help develop this advanced technology. The major goal of this research is to demonstrate miniaturized plant growth systems by adopting microsystem concepts to investigate interactions between small plant roots and the immediate root zone environment. The interactions between plant roots and the surrounding media are the least understood and very challenging aspect of plant research. The root system has been referred to as the "hidden half" because of a lack of convenient, analytical techniques to study that portion of the plant. The root research has not benefited from the miniaturization technology that may provide superior capabilities of spatial and temporal control and monitoring. Miniaturized plant growth systems (rhizobox) were developed utilizing microsystem concepts. The system mainly consisted of two modules. Fluidic channel structure creates two dimensional gradients of humidity around the small plant roots, while embedded humidity sensing sheets based on colorimetry monitor two-dimensional profiles of humidity environment surrounding the roots. The system performance was characterized to investigate preferential growth of small plant roots (tropic responses) toward the favorable environment. Two meso-scale fluidic systems, one with a simple Y-junction fluidic design and the other with embedded air-flow channels, were demonstrated with the actively growing corn seedling roots that show the tropic responses to humidity. We anticipate that this new concept of minizturization technology for root zone control and monitoring may expand the application area of the microsystem to plant and agricultural science and engineering. The research outcome is expected to provide a novel tool for many aspects of plant research including metabolic engineering, stress physiology, plant pathology and plant genetics.
