Location: Northern Great Plains Research Laboratory
Title: Impact of defoliation on axillary bud activity in smooth brome (Bromus inermis Leyss.)Author
HENDRICKSON, JOHN | |
Yeoman, Vanessa | |
FIELD, AARON - Chadron State College | |
CARRLSON, ANDREW |
Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 12/12/2019 Publication Date: 2/16/2020 Citation: Hendrickson, J.R., Yeoman, V.L., Field, A., Carrlson, A.J. 2020. Impact of defoliation on axillary bud activity in smooth brome (Bromus inermis Leyss.). Meeting Abstract. 1. Interpretive Summary: Technical Abstract: Smooth brome (Bromus inermis Leyss.) is an introduced cool-season perennial grass that invades rangelands in the Northern and Central Great Plains. Anecdotal data suggests smooth brome may be less abundant when grazed. However, the morphological stage at which grazing can have the greatest impact on smooth brome abundance is unknown. Therefore, we designed a study to determine the impact of defoliation on specific morphological stages of smooth brome. Treatments were 1) defoliated at the 1 or 3 leaf vegetative stage once (V1); 2) defoliated at the 1 or 3 leaf vegetative stage twice (V2); 3) defoliation in the elongation stage (E); 4) defoliation in the reproductive stage (R ) and 5) a non-defoliated control (C ). Ten smooth brome plants were randomly located and permanently marked in each of 4 non-grazed exclosures at the Northern Great Plains Research Laboratory (USDA-ARS) near Mandan, North Dakota in May 2018. In September, each of the tillers were dug up and taken to a laboratory at Chadron State College, Chadron, Nebraska. Each tiller was dissected, all crown positions were identified as 1) axillary bud, 2) tiller, 3) rhizome, 4) leaf scar or 5) missing. Tillers were placed in stains to determine activity. Active meristematic tissue would stain red in 0.1% TTC, dead meristematic tissue would stain blue and if meristematic tissue did not stain in either solution, they were considered dormant. There were fewer active rhizomes per tillers in the V2 treatment than in the C, E and R treatments (0.33 vs 0.96, 0.94 and 0.96 respectively). Total outgrowth (rhizomes and daughter tillers) per tiller was less in the V2 (1.3) than in the R (1.9) treatment. Additional data is being collected but defoliating smooth brome tillers twice in the vegetative stage appears to best strategy to reduce potential recruitment in this invasive grass. |