Study Points to Importance of Magnesium in Fertilization of HLB-affected Citrus Trees

Jan 17, 2022

By Mike Loizzo

UF/IFAS researchers are trying to extend the life of citrus trees infected with Huanglongbing (HLB), a bacterial disease. New research shows magnesium may play an important role in boosting the productivity of HLB orange trees. Specifically, the researchers looked at the concentrations of the three nutrients in tree leaves and the soil.

Over 18 months, they collected samples from a grove of Valencia orange trees at the UF/IFAS Citrus Research and Education Center. The test plots in the study had varying amounts of nitrogen. Furthermore, they subdivided those and applied different amounts of calcium, magnesium, and a combination of calcium and magnesium.

Results

Dr. Gabriel Maltais-Landry is an assistant professor of sustainable nutrient management systems in the UF/IFAS soil and water sciences department (SWS). He said the different nitrogen rates did not affect leaf nitrogen and soil extractable concentrations. Similarly, the application of calcium did not increase soil calcium extractable concentration relative to the grower standard. It did have a slight effect on leaf calcium, however.

“In contrast, magnesium was effective at increasing both leaf and soil magnesium concentrations,” he said. “Overall, our results suggest a greater impact of magnesium fertilization on soil and nutrient concentrations than nitrogen or calcium fertilization.”

Dr. Davie Kadyampakeni is an assistant professor of citrus water and nutrient management at the UF/IFAS Citrus Research and Education Center and co-author of the research article. He said future studies with a larger sample size and longer duration could help determine the strength of these interactions and their long-term implications. Additionally, measuring nutrient losses through leaching in the future would provide a more thorough understanding of the fate of these nutrient inputs.

“Overall, this study provides insights on the bene?ts of a balanced nutrition approach to ensure the optimal growth of HLB-affected citrus trees in Florida,” he added.

Source : ufl.edu

Video: Can Gene Editing Give Seeds a Stronger Start?

Reagan Reed has a way of describing his research that might make a plant breeder pause.

“I’m the sort of person who likes to break things to understand them,” he says.

What he breaks are genes involved in seed germination. Reed, a Ph.D. candidate at the University of California, Davis, is investigating whether changing those genes can help seeds establish healthy plants under a wider range of conditions.

Reed recently attended the National Association for Plant Breeding meeting in College Station, Texas, as an NAPB Borlaug Scholar. His work speaks to a question that matters well beyond a research lab: what does it take for a seed to get a crop off to a strong start?

A seed that germinates quickly, alongside the others planted with it, spends less time vulnerable to stresses before seedlings become established.

“If you’re able to bridge that gap between germination to stand establishment, then that’s going to give you the highest probability of having a solid yield that year,” Reed says. “There’s a bunch that can go wrong after that, but it maximises your yield from the start, at least.”

Reed works in Dr. Imtiyaz Khanday’s lab at UC Davis, where his research focuses on seed quality in tomatoes and potatoes. He brings an unusual academic background to the work: at Skidmore College, he studied both biology and Latin.

Reed believes that combination prepared him for research. Translating an ancient text means studying each word, weighing its possible meanings and using context to reach the best interpretation. There is rarely a way to know with complete certainty what an author intended. Science, he says, requires a similar willingness to work through uncertainty.

“Attention to detail and comfortability working with uncertainty,” is how he sums up what Latin taught him.

In the lab, uncertainty can produce a surprise. Reed describes changing one gene and seeing little effect. Changing a second gene also appears to do little. Put both changes in the same genetic background, though, and the result can be substantial.

“I break this gene, nothing really happens. I break this other gene, nothing really happens. I combine them into the same genetic background, and now there’s a massive effect,” he says.

Those interactions matter as researchers gain the ability to edit multiple genes at once. They also complicate any simple account of how a trait works: improving a seed may depend on understanding what several genes do together.

For Reed, the question is whether that knowledge could help seeds germinate reliably when conditions are difficult. Some of the genes he studies prevent germination under certain conditions. That response may serve a plant well in one setting while limiting its usefulness in agriculture. He wants to learn what happens when those genes are changed, and whether the result improves establishment.

Yet a discovery that works in a lab still has a long way to travel before it reaches a field. Reed argues that agricultural biotechnology faces an economic challenge as well as a scientific one. New tools can create value for farmers, he says, but developing them requires a way to support the work in an industry where margins can be thin.

His fellowship with Flagship Pioneering gave him a view across AI, agriculture-related work and human health research. It also reinforced the importance of bringing people with different expertise into the same conversation—a benefit of gatherings such as the NAPB meeting.

“You need to have a team of people with different backgrounds who are willing to work together and approach the same problem in different perspectives and different ways,” he says.

That thinking connects the different parts of Reed’s path. Latin taught him to examine details without expecting a perfect answer. Gene editing lets him test what individual genes do—and what happens when their effects combine. Working with people beyond his own field helps him ask what those findings could become.

He came to agriculture because of its reach: the possibility that work by a small group of researchers could eventually make a difference on a much larger scale. His immediate focus is smaller and more precise. He wants to understand what helps a seed get through its first days and become a healthy plant.