Laboratory Report

By: Ann Northrup

Ann Northrup spent her undergraduate years at the University of Michigan, where she earned a Bachelor of Science in microbiology….

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Seedless ‘Tango’ Mandarins

Before this spring, the only way to get a seedless mandarin fruit, was to get one where the flower had not been cross pollinated by another seed-bearing citrus, such as lemon, grapefruit, or another mandarin. Bees are some of the best pollinators of citrus and are often responsible for creating seediness in mandarins. Recently, a new variety of mandarin (Citrus xnobilis ‘Tango’) was introduced to the trade from the University of California Citrus Clonal Protection Program in Riverside, California. ‘Tango’ was developed by inducing a mutation into the ‘Murcott’ mandarin, creating a “sport,” which has proven reliably seedless regardless of where it is grown. Through March of 2010, 1.6 million trees had been sold to California growers. The fruit should begin appearing soon in markets, perhaps under the already familiar brand names of “Cuties” or “Delites” or perhaps with the ‘Tango’ name. Trees will likely be available to home gardeners in the future.

University of California Riverside News, January 2010

An Unusual Laboratory, and a Fragrant Audience?

The giant cable television and online shopping entity QVC (“quality, value, convenience”), in an advertising spectacle, commissioned the London Philharmonic Orchestra to play beautiful music to more than one hundred plants at Cadogan Hall in central London. Although the “research” was mostly in fun, there is now available a downloadable selection of Mozart’s music that you can play to your own plants to see if classical music really does help them grow better. The YouTube video can be viewed using the following link: www.youtube.com/watch?v=E2mezHthquk.

Watching Evolution in the Process

A husband and wife team of researchers at the University of Florida became interested in a plant known to be a relatively newly formed species in the Pacific Northwest, where the couple had formerly lived. The new species (Tragopogon miscellus) is a naturally formed hybrid, generated about eighty years ago from two exotic species introduced to the Northwest in the 1920s from Europe. The hybrid plant was larger than either of its parents and spread rapidly in the environment. The hybridization occurred as a result of chromosome doubling, a common means by which new species are developed. The hybrid has been regenerated by the researchers and studied in the laboratory over many generations. The big surprise is that the initial offspring did not show the expected intermediate expression of genes from both parents. It was as if all of the genes from both parents were “turned on,” and the new species was going to find out, in subsequent generations, which genes were needed and which could be “turned off.” In other words, gene expression was relaxed in the beginning, the new species experimenting with what would, in later generations, become a more stabilized gene expression pattern. The research provides insight into the origin of major taxonomic groups of plants.

Current Biology, 21 (7) 551-556

Snails Aiding Robot Research

It’s an interesting challenge. Snails need to stick to surfaces and they need to move. Research at Stanford University, UC San Diego, and University of Madrid has shown that snails do not require slime to propel themselves forward. Though slime works like a glue to adhere snails to a surface when traveling upside down, pressure applied from their muscular foot changes the property of the slime to be more fluid. It was this feature of the mucus that was previously believed to allow forward movement. However, researchers have observed that a thin film of water was sufficient for snail movement on horizontal surfaces; the mucus is, perhaps, not required. A key feature of the wavelike muscular movement of the snail’s foot is that part of it lifts from the surface during forward motion, reducing friction-much like the way a caterpillar moves. Researchers in Japan are already working on a robotic endoscope for human diagnostics that would move like a snail does.

Journal of Experimental Biology, 213 (22): 3920-3933

Success or Not for Green Roof Plants

Substrate type and depth are two important variables in both the suitability for growing plants and in roof weight tolerances for the buildings on which they are placed. Five different types of rooftop plants were used in a Pennsylvania study to determine the influences of substrate type and depth on plant establishment and success. The five plants were two Sedum species, a Dianthus, a Delosperma, and a Petrorhagia. The two substrates included in the study were expanded shale and expanded clay. The substrate depths tested were 30, 50 and 120 mm. With certain exceptions, the plants in the study were most affected by substrate depth. Early drought conditions were hardest on the herbaceous perennials (Dianthus and Petrorhagia). The sedums preferred the expanded clay over the shale substrate.

HortTechnology 20: 395-401 (2010)

Not Just an “Animal-only” Pigment

Expanding on a previous discovery, Professor Cary Pirone from Florida International University has found the pigment bilirubin in the intensely orange-colored seeds of the popular bird-of-paradise (Strelitzia reginae). In animals, this pigment is responsible for the yellowish color of bruises and jaundiced skin. The orange color of bird-of-paradise seeds can remain unchanged for decades.

HortScience 45: 1411-1415 (2010)