|Inflorescence Production in Purple Loosestrife (Lythrum salicaria) Across a Fertility Gradient
Lake Superior State University
Sault Ste. Marie, Michigan
Purple loosestrife is considered an invasive plant species, which thrives in moist soils. It is a highly competitive plant, and can displace native vegetation, leaving poor quality habitat for wetland animals. The purpose of this study is to determine if purple loosestrife, if presented with an increasing amount of fertilizer, will allocate this resource to produce higher quality inflorescences. Purple loosestrife plants were grown in a range of complete fertilization with 0 ppm Nitrogen, 10 ppm Nitrogen, 20 ppm Nitrogen, and 30 ppm Nitrogen over a period of six weeks. Plants were grown in 12” pots filled with play sand and set in standing water in a randomized complete block design. After six weeks, the plants were harvested, inflorescences were separated and dried. Dry mass and inflorescence lengths were measured and mass per unit length was then computed. Caloric content per gram was obtained through bomb calorimeter on the low nitrogen level and high nitrogen level treatments. Analysis of variance showed that fertilization increased total inflorescence length and mass. Mass per unit length also increased, suggesting increased quality of inflorescences with increased nutrient availability. Caloric content showed no difference between the low and high nitrogen level treaments.