California Ag Network

Tag: University of Florida

  • Building a More Heat Tolerant Plant Starts with Genes

    In a warming world, scientists at the University of Florida are looking for ways to help crops beat the heat.

    A new study identifies genes that may help plants cope with high temperature stress, setting the stage for developing crops bred for enhanced heat tolerance, said Bala Rathinasabapathi, senior author of the study and a professor in the UF/IFAS horticultural sciences department.

    Some plant species are more sensitive to heat than others. But when temperatures rise above what a species can typically withstand, the plants become stressed, often producing smaller yields, Rathinasabapathi explained.

    “Our program has been studying how plants respond to high temperature stress and designing new ways to improve the tolerance levels of crops. When we placed plants under controlled conditions and increased the temperatures, we noticed that young leaves were affected much less than older leaves,” Rathinasabapathi said.

    “This observation prompted us to question the cause of such a difference,” he added. “We rationalized that if we could identify the genes that are involved in young leaves’ tolerance to high temperature stress, it will provide testable ideas to improve heat stress tolerance of crops.”

    In the experiment, study co-author Qingyuan Xiang, a Ph.D. student in Rathinasabapathi’s lab during the study, tested how the plant Arabidopsis thaliana changes its gene expression in response to extreme heat. Arabidopsis is often used in the plant sciences because it grows relatively quickly and its genetics are well understood, making it a good candidate for experiments aiming to understand plants’ genetic response to different environmental conditions.

    In the tests, the scientists exposed some Arabidopsis plants to high heat — 107.6 degrees Fahrenheit — while others were placed in more typical non-stress conditions. After one hour under high heat, the researchers took samples of the plants’ young and old leaves and repeated the process again after 10 hours. The scientists then analyzed gene expression patterns in young and old leaves.

    By sampling at different times, the researchers were able to see how gene expression progressed in the young leaves compared with older leaves. They also compared those patterns to those in plants not exposed to heat.

    Gene expression occurs when a specific portion of DNA is activated in a specific part of that organism under specific conditions, Rathinasabapathi said. Plant breeders look to gene expression for clues about which genes play a role in different scenarios — such as extreme heat — in the hopes of developing plants with genetic traits that allow them to perform better in those scenarios.

    “The current study provided us lists of specific genes that may have functions in heat stress tolerance in plants. In the future, we will aim to test those genes for their potential connections to heat stress tolerance in plants and even use them in breeding strategies,” Rathinasabapathi said. — By Samantha Murray, University of Florida 

  • What Effects do Forest Fires have on the Storage of Carbon?

    The other day I was enjoying a nice breakfast, when I saw a man sitting next to me with his bicycle. Of course, my wife started talking with him! It turns out that he is a professor from Columbia, NY who, as far as I could understood, teaches something related to climate change. I couldn’t help asking him, do we still have time to fix the global warming problem and mitigate climate change? His tone of voice changed and his gazed off and said, “Save yourself, there is nothing we can do about it.” Still, a week after that conversation I am thinking about his comment! I consider myself an optimist, but it worries me when I see what is happening with the fires on the West Coast, and recently the floods in Belgium, Germany, and other places.

    According to the National Interagency Fire Center as of August 26, 88 large fires are burning in the US across 13 States. They have destroyed nearly 2.4 million acres of forest. We know that trees are our best friends, they can store and sequester carbon. We know that a healthy forest reduces carbon dioxide in the atmosphere, but what happens when a forest catches fire?

    The answer is not very simple because the carbon cycle is very complicated, with many variables involve. When carbohydrates are burned, they oxidize, creating carbon dioxide (CO2). Photosynthesis on the other hand, removes CO2 from the atmosphere and simultaneously stores carbon in the form of wood. According to NOAA, a very big and hot wildfire could emit the same amount of CO2 as six large coal power plants in one year.

    To better understand the role that a forest ecosystem has on the storage of carbon, a study was conducted by the NASA Institute on Climate and Planets. They studied what happens in unburned and burned sites in the Black Rock Forest, NY. The hypothesis for the study stated that the unburned site will significantly store more carbon than the burned site.

    The results, as we expected, showed that more carbon was stored in the unburned plot than in the burned plot, which means that the fire diminishes the carbon that was originally store in the wood. On the other hand, some of the vegetation is not consumed by burning, instead it is transformed to charcoal which has the advantage that it resists degradation so it can store carbon in soils over long periods of time. As it was mentioned before, the carbon cycle is very complicated, and fire has other consequences like emissions from decomposing dead wood which can surpass the direct emissions from the fire itself. But at the same time, new growth in the burned areas starts once again to take CO2 from the atmosphere and store it. This topic is very complicated, but fortunately, it looks like the effects of wildfires on climate change are smaller than the effects of coal, oil, and gas. — By Henry Mayer, University of Florida, Institute of Food & Agricultural Sciences

  • Effects of Heat Stress on Dry Cows & Their Next Lactation

    New research out of the University of Florida shows that cows subject to heat stress during their dry period will produce 8-10 lbs/day less milk on their next lactation. Other health impacts were also explored. Watch this brief interview with Geoffrey Dahl, professor at the University of Florida for more details, and read more about mitigating heat stress in California Dairy Magazine.