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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #253649

Title: Functional morphology and seed anatomy of the invasive weed, benghal dayflower (Commelina benghalensis): Implications for dispersal by mourning doves

Author
item Goddard, R.h. - Valdosta State University
item Webster, Theodore
item Carter, R - Valdosta State University
item Grey, T.l. - University Of Georgia

Submitted to: Microscopy Society Meeting Southeastern
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2013
Publication Date: 7/1/2010
Citation: Goddard, R., Webster, T.M., Carter, R., Grey, T. 2010. Functional morphology and seed anatomy of the invasive weed, benghal dayflower (Commelina benghalensis): Implications for dispersal by mourning doves. Microscopy Society Meeting Southeastern. 30:23.

Interpretive Summary: Benghal dayflower (BD) is an exotic weed that reduces yields in many agricultural crops. Potential dispersal of this weed by migratory Mourning doves was investigated in this study. Evidence shows that doves feed on BD seeds, with some birds containing hundreds of seeds. Seeds extracted from harvested birds were examined for changes in their external morphology during digestion by scanning electron microscopy (SEM) and their viability by germination. Control seeds were used to ascertain seed tolerance to acid environments and for their normal structure. BD seeds showed reduced but high germination rates (45%) in seeds extracted from dove gizzards, and very high tolerance to a 2 h treatment in 1.0 M HCl for 2 h (82% germination) as compared to controls (92%). BD seeds germinate by rupturing through the micropyle region and lifting the embryotega, a callus-like covering over the micropyle. Even after imbibition, the seed coat does not rupture relating to its strength. The seed coat itself appears structurally reinforced with an intricate underlying cell layer with a complex of lateral cell walls that form a “honeycomb” pattern with little or no intercellular spaces. The outer “honeycomb” patterned layer is subtended by a continuous thick cell wall layer. The lumen of the outer layer of cells contains many inclusions whose chemistry has not yet been determined.

Technical Abstract: Benghal dayflower (BD) is an exotic weed that reduces yields in many agricultural crops. Potential dispersal of this weed by migratory Mourning doves was investigated in this study. Evidence shows that doves feed on BD seeds, with some birds containing hundreds of seeds. Seeds extracted from harvested birds were examined for changes in their external morphology during digestion by scanning electron microscopy (SEM) and their viability by germination. Control seeds were used to ascertain seed tolerance to acid environments and for their normal structure. BD seeds showed reduced but high germination rates (45%) in seeds extracted from dove gizzards, and very high tolerance to a 2 h treatment in 1.0 M HCl for 2 h (82% germination) as compared to controls (92%). BD seeds germinate by rupturing through the micropyle region and lifting the embryotega, a callus-like covering over the micropyle. Even after imbibition, the seed coat does not rupture relating to its strength. The seed coat itself appears structurally reinforced with an intricate underlying cell layer with a complex of lateral cell walls that form a “honeycomb” pattern with little or no intercellular spaces. The outer “honeycomb” patterned layer is subtended by a continuous thick cell wall layer. The lumen of the outer layer of cells contains many inclusions whose chemistry has not yet been determined.