Event Title

Carbon and Nutrient Cycling in an Agricultural Landscape as a Function of Lignin

Location

CSU Ballroom

Start Date

20-4-2015 10:00 AM

End Date

20-4-2015 11:30 AM

Student's Major

Biological Sciences

Student's College

Science, Engineering and Technology

Mentor's Name

Christopher Ruhland

Mentor's Email Address

christopher.ruhland@mnsu.edu

Mentor's Department

Biological Sciences

Mentor's College

Science, Engineering and Technology

Description

As temperatures warm and rain fall decreases, farmers in Southern Minnesota have started replacing corn with sorghum (Sorghum bicolor). Sorghum has a high water-use efficiency but is hard for animals to digest due to high lignin concentrations. The brown-midrib (BMR) varieties of sorghum have reduced and altered lignin content. Lignin reduction in these varieties is caused by lowered expressions of the enzymes cinnamyl alcohol dehydrogenase (bmr-6) and caffeic acid-Omethyltransferase (bmr-12). Also a “stacked” variety containing both mutations has been developed (bmr-6-12). After a crop is harvested, remnant remaining on the field are recycled into the soil via decomposition. These remnants are important for biogeochemical cycling, and readily decomposable plant matter should be preferable to more recalcitrant material. The purpose of this study is to test how fast bmr sorghum remnants decompose relative to wild-type counterparts. Four varieties of sorghum, wild-type, bmr-6, bmr-12, and bmr-6-12, were grown until 75% of flag leaves were fully expanded and then dried. Samples were weighed into plastic mesh bags and placed into an agronomic field east of Morristown, MN. Samples were placed 15-cm into the ground for six collection dates over the spring and summer. After the samples are collected, they will be analyzed for cellulose, hemicellulose and lignin content using a ANKOM fiber analyzer. The anticipated outcome is that plant litter with the lowest lignin content should decompose the quickest. Our results should help determine carbon fluxes in agronomic settings and help farmers make decisions about till and no-till practices.

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Apr 20th, 10:00 AM Apr 20th, 11:30 AM

Carbon and Nutrient Cycling in an Agricultural Landscape as a Function of Lignin

CSU Ballroom

As temperatures warm and rain fall decreases, farmers in Southern Minnesota have started replacing corn with sorghum (Sorghum bicolor). Sorghum has a high water-use efficiency but is hard for animals to digest due to high lignin concentrations. The brown-midrib (BMR) varieties of sorghum have reduced and altered lignin content. Lignin reduction in these varieties is caused by lowered expressions of the enzymes cinnamyl alcohol dehydrogenase (bmr-6) and caffeic acid-Omethyltransferase (bmr-12). Also a “stacked” variety containing both mutations has been developed (bmr-6-12). After a crop is harvested, remnant remaining on the field are recycled into the soil via decomposition. These remnants are important for biogeochemical cycling, and readily decomposable plant matter should be preferable to more recalcitrant material. The purpose of this study is to test how fast bmr sorghum remnants decompose relative to wild-type counterparts. Four varieties of sorghum, wild-type, bmr-6, bmr-12, and bmr-6-12, were grown until 75% of flag leaves were fully expanded and then dried. Samples were weighed into plastic mesh bags and placed into an agronomic field east of Morristown, MN. Samples were placed 15-cm into the ground for six collection dates over the spring and summer. After the samples are collected, they will be analyzed for cellulose, hemicellulose and lignin content using a ANKOM fiber analyzer. The anticipated outcome is that plant litter with the lowest lignin content should decompose the quickest. Our results should help determine carbon fluxes in agronomic settings and help farmers make decisions about till and no-till practices.

Recommended Citation

Rector, Amanda. "Carbon and Nutrient Cycling in an Agricultural Landscape as a Function of Lignin." Undergraduate Research Symposium, Mankato, MN, April 20, 2015.
http://cornerstone.lib.mnsu.edu/urs/2015/poster_session_A/10