Tech Tuesday

Sensor to Aid Plant Growth Research

Monitoring plant growth in new ways, wild plants get biotech content and helping corn plastic take the heat.

Just how do plants grow? OK, sounds like a simple question, but scientists are hard at work exploring the actual processes going on inside crop plants to better enhance productivity in the future. A key part of the process is a plant hormone called auxin which can regulate root growth and seed development, but how to measure it at work in plants?

Purdue University researchers have developed a biosensor that uses black platinum and carbon nanotubes (tubs a billionth of an inch long) that can detect the movement of auxin along the plant's root surface in real time without damaging plants. Previous work involved cutting into plants to measure the hormone.

According to a Purdue release the nanomaterials at the sensor's tip react with auxin and create an electrical signal that can be measured to determine the auxin concentration at a single point. The sensor oscillates, taking concentration readings at different points around the plant root. An algorithm then determines whether auxin is being released or taken in by surrounding cells.

Auxin is a major plant hormone involved in adaptive growth by plants and research is underway to better understand how the compound regulates root growth in plants on sub-optimal soils. With world pressure to meet the food needs of a growing population, this work can help.

While similar sensors have been used in the past to measure auxin levels, this latest work provides a way to provide both instantaneous and continuous measurement of the compound.

Wild Canola Found with Biotech Genes

University of Arkansas researchers have found populations of wild canola plants containing biotech genes for herbicide tolerance in the United States. In fact, they've found populations of wild plants that contain both glyphosate-tolerance and glufosinate-tolerance genes in the same plant - which doesn't exist in commercial varieties.

According to the researchers, they don't know what the consequences of the gene escapes are, but the news merits some attention. In some parts of the U.S., these plants can be problematic in crops where herbicide options may be limited - such as sugarbeets.

The researchers traveled 3,000 miles of roads to complete their sampling. In some places they found densely packed plants with the biotech material - as many as 1,000 specimens in a 50-meter space. About 83% of the weedy canola they found - in ditches and in road cracks - had biotech content. Given that many roadside ditch sprayings rely on glyphosate, further work on diversifying modes of action may be in order.

Corn Plastic that can Take the Heat

In the food processing industry, the process of "hot-filling" is common. A pasteurized product goes right into the container hot, but current containers made from corn-based plastics can't take that heat. New work by a USDA chemist aims to solve that problem by making corn-based plastics more heat-tolerant.

The team is developing what is called a "heat-deflection temperature modifier" that could be blended with the lactic acid bioplastic - called polylactic acid, or PLA - to make it more heat tolerant. The new modifier is more than 90% corn-based and fully biodegradable. Currently there are no commercial heat-deflection temperature modifiers available for PLA. The researchers have been at work on the issue since 2007.

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