|Tuesday, April 19th|
2:00 PM - 2:15 PM
Sumak Allpa, a small island in the Ecuadorian Amazon rainforest, was the site of study for a baseline biodiversity survey of macrofungi. Sampling from three main forest types (secondary forest, primary forest, and varzea), a total of 140 morphological species were identified from 468 collected specimens, and statistical analysis was used to predict true species richness. Comparisons of the forest types revealed distinct micro-communities with intriguing trends, such as a lower biodiversity of the varzea, and a significantly higher percentage of soil-inhabiting species in primary forest. The significance of these findings is discussed, but more specific research is necessary to better understand this unique tropical ecosystem. The results of the study support and expound upon previous research that emphasizes the dire need for more biodiversity studies of fungal communities and longer-term research, especially in the understudied tropical rainforests of South America.
2:15 PM - 2:30 PM
Plants and fungi are known to form many types of symbiotic interactions. Emerging evidence suggests that the most common plant-fungal interactions likely involve fungal endophytes. These fungi live within plant tissues without causing any apparent symptoms. Data have shown that fungal endophytes are extremely common and diverse in the tropical forests. However, little is known regarding their prevalence and diversity in deserts. I investigated the diversity and community structures of fungal endophytes in leaf, stem, and root tissues of three herbaceous plant species found in Tucson, Arizona: Solanum elaeagnifolium (Solanaceae), Nicotiana obtusifolia (Solanaceae), and Verbesina encelioides(Asteraceae).
2:30 PM - 2:45 PM
Arabidopsis thaliana is a small flowering plant native to Eurasia that is used by geneticists to study plants. Geneticists often study groups of genes or “gene families.” The PIRL family is made up of nine related genes which all share certain characteristics that are unusual in plants. Functional genomics attempts to determine the function of genes, and one approach is to create an over-expression construct. An over-expression construct is a piece of DNA inserted into the plant’s genome to create many extra copies of a gene product, in this case, protein. This approach has proved successful in the study of the the PIRL9 gene. In Arabdiopis extra PIRL9 protein creates a stunting or dwarf-like effect in the plants which contain the construct. This effect has been quantitatively measured in both the roots and leaves of experimental plants, indicating an important role for PIRL9 in plant development.
2:45 PM - 3:00 PM
Invasive alien plants are often thought to cause detrimental effects to ecosystems, destroying native plant life and altering ecosystem function. Not all interactions between native and invasive plant species are detrimental, however. The native arid grasslands of Ngorongoro Crater, in Tanzania, were surveyed to determine the effects of recent plant invasion. I recorded the color and dryness of the grasses both with and without the presence of invasive shrubs. After analyzing the relationship between presence of invasive shrubs and grass color and dryness, I found something quite unexpected. The presence of the invasive shrubs is not detrimental to the grasses but actually results in greener, less dry grass. This change in greenness may be attributed to a type of symbiotic relationship between the shrub and grasses that is seen in other arid systems. Shrubs may shade grasses, reducing evaporation, or concentrate nutrients in the soil for the grasses to utilize.
3:00 PM - 3:15 PM
Bluebunch wheatgrass (Pseudoroegneria spicata), a local native bunchgrass species, has experienced significant decline over the past century. Historic overgrazing, competition with invasive species such as cheatgrass, and increasingly dry soil conditions may be responsible for this major decline. I created integral projection models of a bluebunch population in the Wallula Gap to analyze the long term behavior of this population and identify demographic patterns in bluebunch wheatgrass that can lead to the population’s survival or decline. Through the analysis of these models, conservation can efficiently target precise size stages of the bluebunch wheatgrass life cycle to maximize survival and reduce the cost of bluebunch wheatgrass restoration efforts.