Going Dotty: The Distribution and Effects of Rust on Highbush Cranberry
Purpose Every fall, I collect highbush cranberries (Viburnum edule) to make jelly. In 2012, for the first time, I observed highbush cranberry leaves covered in striking patterns of raised purple dots (telia) caused by the pathogenic rust fungus Puccinia linkii. I investigated the distribution and effects of this rust for several reasons: little is known about P. linkii, highbush cranberries are an important food source for wildlife and people, and foliar pathogens may increase with climate change in sub-boreal forests. First, I investigated the patterns of telia within plants. Second, I compared the variation in infection severity among plants, hypothesising that younger plants, those in dense populations, and those in low-elevation riparian areas would be most infected. Finally, I studied the effects of P. linkii on its host, hypothesising that highly infected plants would produce fewer berries and produce berries with less sugar, and that infected leaves would die sooner. Procedures This study investigated P. linkii in mixed coniferous-deciduous forest sites near Smithers, British Columbia. I marked a total of 41 randomly-selected focal V. edule plants in four sites. To examine within-plant patterns of infection, I photographed four leaves of each plant and used a graphic analysis program to examine the size, density and coverage of telia. To assess among-plant patterns, I compared infection severity (5 classes of telia coverage), to three ecological variables: host density within 5m, position on a moisture gradient, and plant maturity. To investigate the effects of P. linkii on its host, I compared infection severity to the number of berries produced, the proportion of malformed and infected berries, and the sugar content of mature berries as measured with a handheld refractometer. I measured leaf mortality in fall. Results P. linkii produced a characteristic pattern within each plant: higher leaves consistently had fewer but bigger telia than lower leaves. Across sites, plants were significantly more infected in areas of high host density. Within sites, young plants and plants and in moister ecosystems were significantly more infected (increases of 1.1 ± 0.2; F1,128=44.8, P
Development of a Method for Measuring the Ozone Concentration in the Atmosphere Using Passive Method
1. Introduction Passive method is widely used for measuring air pollutant for one day to several weeks. This method can be used easily and doesn’t need electricity, but expensive devices are needed for measuring substances, so this is not suitable for high school students for measuring or investigating. Then, we focused on the reaction, in which Indigo, the blue pigment, is discolored by ozone, and we built up a hypothesis, that indigo is suitable for measuring ozone concentration. 2. Experimental Section We soaked a 10 mm×20 mm filter paper in an indigo solution, including hosphoric acid. Then, they were dried in an automatic oven. 5.5 cm×10 cm PTFE sheet was fold in two and five sheets of indigo filters were fixed inside (passive sampler). The passive samplers were fixed on a stand and exposed to ozone in the atmosphere. After a few days, we collected the samplers and put each indigo filter and 4.0 mL of ion-exchange water into sample tubes. Then we shook this and extracted the color pigment. We had the average value of 600 nm from the five sheets as a measure value. 3. Results and Discussion The total amount of ozone for one to seven days measured in the experiment was directly proportional to the amount of ozone measured by Osaka Prefecture. We found that we can measure ozone in atmosphere using our method. Passive method has an advantage: it can be carried out easily. We employed this trait and measured ozone concentration at 23 points simultaneously in the north of Osaka for 48 hours. We made the map of ozone concentration by marking on a blank map. The map we made was just like the map published by Osaka Prefecture. We expect that this method will be useful in measuring ozone, where measuring devices are not available. 4. Conclusion We succeeded developing new method for measuring ozone in the atmosphere by passive method using indigo, the blue pigment.