Question

Centaurea maculosa is a noxious weed across most of western North America. Experiments were undertaken in 2001 to understand the role of competition of Centarea with native bunchgrass species such as Festuca idahoensis. Centaurea are thought to produce root exudates that may inhibit neighbors. Experiments were undertaken to determine if Centaurea root exudates affected the growth of neighbor species by planting all species with and without activated carbon (which absorbs allelopathic compounds). Below are some of their results. Fig. 3 Fig. 4 Centaurea, carbon Centaurea, no carbon Festuca, carbon Festuca, no carbon O Active Festuca Roots (%) Festuca Mass (g) 0.0 carbon no carbon carbon no carbon Centaurea Festuca Root Shoot Total b. Based on Fig. 4, does Centaurea utilize interference or exploitative competition (or both) with Festuca? (10 pts) How can you tell? (15 pts)

this is all the information given.

Answer 1

Centaurea maculosa, invasive weeds shows negative mpact on the wot elongatims of Festuca idahoensis testuca cover decreased by more than 75% with moderate Centaurea invasion , and was absent in heavily e invaded area. Thus Centaurea performs Interference competition with Festuca. An experiment was done in which festuca test roof survival was high when grown into its particu - lar enviroment il festuca target shizosphere, and a did not differ, directly or significantly between Carbon a and no carbon treatments while when grown into a Centaurea rhizospheses, festuca rooto test survival was hige in Carbon treatments only and was significantly reduced in no-carbon treatments. This provide stronge endence for allelopathic effects of centaurea roots exudation on Festuca and that these effects could be opeduced by activated Carbon special chemical substance present in Centausee roots ie Cricin, a sesquitespene lactone Callelopathy a substance employed by centaurea since 1987) exudates gesponsible for its inhibitory effect on Festuca. In this case of Interference competitias, individuals al interact directly with one another by physiological as 0 Ics Scanned with CamScanner