ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 60 Number 3
Effect of clipping on the carbohydrate composition of different morphological parts of guinea grass (Panicum maximum Jacq.)
The carbohydrate reserves were quantified in five morphological parts of guinea grass (Panicum maximum Jacq.) during regrowth after defoliation. Plants were grown in controlled environment facilities and were defoliated twice before beginning the experiment. At the time of the third defoliation, the roots accounted for 49% of the total plant dry matter (DM). After seven days' regrowth, root DM had declined by 36% of its original weight but subsequently increased. The DM of the stem-base also declined, as DM in crown, stem-sheath and leaf samples increased. Total available carbohydrates (TAC) were primarily stored in roots (39% of TAC in the plant) and stem-base (23%), and declined in both tissues during regrowth. Alcohol-soluble carbohydrates (ASC) comprised at least 50% of TAC and accounted for the majority of the TAC mobilized during regrowth. The polysaccharide fraction increased in all tissues after defoliation, except in the root where the polysaccharides declined by 25%. The root of guinea grass apparently serves as the major carbohydrate storage organ and ASC are its main source of reserve carbohydrates.
Keywords: Carbohydrates; Panicum maximum Jacq.; Clipping