This project from the Citrus Research and Education Center (CREC) will survey citrus groves across the state to assess Hurricane Ian’s impact and how quickly the trees recover from it. We hope the results of these surveys will help you better understand the medium-term impacts of hurricanes based on windspeeds. Other goals for the project include equipping you with knowledge to develop plantings that are more resilient against storms. We hope this information can help with recovery, both now and in the future. Overall, we hope this knowledge will be applicable and useful for growers to protect their groves from storm damage. To do this we will be surveying your groves monthly to measure over time the impact of Hurricane Ian.
A hurricane damaged tree and a tree involved in the study.
This is the first update that will summarize the results of the surveys and share their potential application for grower practices. Results will eventually be published in Citrus Industry Magazine as well. An EDIS document for grower use will also be published in late 2023 outlining how to make plantings more resilient, recover from wind damage, and predict the severity of the damage on their groves based on the storm.
For questions or more information, please contact project leader Christopher Vincent at civince@ufl.edu.
We are excited to share our results with you over the next year. Please share this blog with anyone who also might find this information pertinent!
Fasih Khalid came to CREC from Pakistan for a six-month program to work as a horticulturist focused on stress physiology. He also wanted to learn about physiological techniques and how to use different instruments. In Pakistan, he spent time working on abiotic stresses like water deficits and salinity. In our lab, he worked on experiments dealing with sap flow and hydraulic conductance. He said with the results the lab can determine whether “the sap flow movement is OK in relation to the regular irrigation.” Because of rising prevalence of water deficit problems in the world, it is important to see how irrigation levels in plants can be adjusted to save water and lead to more efficient water practices in the future.
Fasih loves research and learning. After his Master’s he spent about a month working in a farmer’s co-op in Pakistan, which he didn’t enjoy. As soon as an opportunity presented itself, he entered his PhD. He had done research on lychee in his Master’s and had published it, so he decided to go back to school and into the research field. After a couple of months in his PhD, he decided “…there is nothing in the world for me except research. I have to be researching.” He initially was interested in horticulture after going through his required two years of studying it in Pakistan. He thought he wanted to work in floriculture and landscaping but ultimately found pomology to be the most engaging because there are many different opportunities in that field. Plus, “The good thing of fruit is you can research or if you don’t want to research you can eat.”
During his time at CREC, he was also able to participate in several competitions, most of which were academic, though one was a t-shirt design contest for CREC, which he won! The academic competitions allowed Fasih to share the work he did at CREC, as well as help him improve his English. He liked to share that his work is important because it helps growers understand how to adapt to a world with climate change. He believes it is important for all people, not just growers, to care about changing water conditions and how this affects plants because “…we have to save water for the world and for the plants, for the next [plants].” If growers are unable to find solutions for their plants in water scarce conditions, this will cause further problems for the world as demand for fresh water reserves increases, eventually affecting our food supply, which would affect us all. He wants to take the things he’s learned during his time here back to Pakistan. His two big takeaways were time efficiency and the benefits of using hydraulics instrumentation for research. He hopes to apply these lessons as he continues horticulture research in the future.
Mark Keeley turned a lifelong passion for plants into work that hopefully will help us better understand the way HLB affects Florida citrus trees. He worked in citrus research before starting his Master’s, but said he’s always been interested in plants and has been playing around with them for as long as he can remember. He made his way to plant research after trying out several undergrad degrees that didn’t fit quite right. Eventually, to no one’s surprise he told me, he joined the UF Horticultural Sciences Department. From there he had several jobs before landing one at a private agricultural research station. He likes his job because he said it’s, “Me and orange groves 4 or 5 days a week. Me and the plants, it’s quiet. Calming.” Through this job he decided to pursue a Masters in Agronomy. When asked why he’s pursuing his masters and working full-time for the private lab he laughed and said it was mostly for selfish, personal reasons. As a part of his master’s program he’s working with the tree physiology lab on a project that’s attempting to show a relationship between photosynthesis and citrus greening.
At the tree physiology lab, we hope to improve citrus growth based on understanding its environmental physiology. This particular experiment’s goal to describe the effects of HLB on photosynthesis. Part of this experiment also includes looking at the difference between shoot photosynthesis and leaf photosynthesis. This photosynthetic activity can’t be translated between leaf and tree, so we are trying to determine why. Studying photosynthesis on the leaf level can help garner understanding for the effects of photosynthesis on the whole canopy, but we need to understand what causes differences, too. Mark explained, “[We are] specifically looking at impacts of greening on photosynthesis as well as the amount of photosynthesis acquired from the leaf material and the stem material and what those impacts are over time on maturation.” In terms of the importance of this work for management, “It’s no longer preventing the bacteria from being there; it’s more how do we support the tree in [spite] of the bacteria,” he explained. This would be helpful because Mark believes the current approach to managing HLB isn’t working, so this could open the door to try other approaches.
The project uses an infared gas analyzer (affectionately called “IRGA”) called Li-Cor 6800. The machine cycles a known amount of CO2 and water over the leaf and measures how the concentrations change after they pass over to determine how much CO2 is being taken in and how much water is being released by the plant. This allows us to measure photosynthetic activity. Doing this in the lab with a known amount of light allows us to see the direct impacts of disease or other treatments over time without having to contend with clouds, different radiation intensities, etc. Eventually Mark would like to do work like this in the field, but while he’s still developing the methods, inside the lab is the best opt
The project uses an infared gas analyzer (affectionately called “IRGA”) called Li-Cor[RV1] 6800. The machine cycles a known amount of CO2 and water over the leaf and measures how the concentrations change after they pass over to determine how much CO2 is being taken in and how much water is being released by the plant. This allows us to measure photosynthetic activity. Doing this in the lab with a known amount of light allows us to see the direct impacts of disease or other treatments over time without having to contend with clouds, different radiation intensities, etc. Eventually Mark would like to do work like this in the field, but while he’s still developing the methods, inside the lab is the best option.
When I asked why he believes this work is important he said, “Fascination for me. I keep going down the rabbit hole more than anything. I think it will be important if we find some of these relationships with the infection level and the tree. Like I said, it’ll change the way we culturally try to manage the disease [HLB]. Other than that, it’s more of a curiosity.”
Talent Vharachumu was an undergraduate intern who is originally from Zimbabwe and attends university in Costa Rica. She is studying agricultural sciences and has become particularly interested in plant physiology, especially due to her time at the lab. Along with the work Talent did for the physiology lab, as is typical for an intern, she sometimes participated in work with other labs as well. She enjoyed this because it allowed her to learn many different things and meet more people. She hopes to be able to return to the lab to complete her masters.
She enjoyed her work at the lab because she learned more about plant physiology. Our goal at the tree physiology lab is to improve general tree health and make strides in understanding tree physiology better and more completely. To accomplish this goal, we do research with a whole plant approach. One such experiment is on how different plants respond to and are affected by heat.
Talent primarily worked on that experiment. She would collect leaves from a variety of trees in a variety of genotypes and perform a procedure on them to test how they tolerate the different temperatures. To do the experiment she used a machine that punches a piece of the leaf out, then placed the piece on a black disk that went inside a Ziplock bag, which was then placed in a container of water for 30 minutes. Then she’d record the chlorophyll fluorescence (photosynthetic energy conversion) of the leaves, given from a machine called the Fluoremeter. She also worked on another project with an infrared gas analyzer (Li-6800) machine to measure photosynthesis, gas exchange, and chlorophyll fluorescence.
When I asked Talent why she believes this work is important and why she thinks people should care about it she explained that the data she’s gathering helps us better understand the way climate change is affecting the planet, different environments, and plants in general. People who work in agriculture can use the data about which plants tolerate heat better to determine which genotypes to grow, which hopefully will increase plant yield and agricultural efficiency as temperatures warm. Talent also said it “…can help them reduce losses from low production due to high temperatures that are being caused by global warming.” This is useful because it allows growers to make informed decisions about what kinds of crops to plant as the climate and planet continue to change. I asked specifically what she would say to people who think they don’t have a reason to care about plants and she said, “They don’t care about plants, but they care about eating.”
Citrus Tree Physiology Lab 