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Anatomical Study of Seed Shattering in Bahiagrass and Dallisgrass 1
Author(s) -
Burson Byron L.,
Correa Jario,
Potts Howard C.
Publication year - 1978
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1978.0011183x001800010032x
Subject(s) - pedicel , abscission , anthesis , biology , botany , pith , inflorescence , cultivar
Seed shattering is a major problem in ‘Pensacola’ bahiagrass ( Paspalum notatum Flugge) and dallisgrass ( P. dilatatum Poir.) which often reduces availability and quality of seed of these species. An anatomical investigation of the abscission layer formation in the pedicel of Pensacola bahiagrass, common dallisgrass, and yellow‐anthered dallisgrass was conducted to determine the sequential histogenesis of the layer, and to relate its development to different morphological stages of the developing infloresences for each species. The abscission layer was located in the pedicel just below the glumes in both species. In bahiagrass it became distinguishable while the infloresence was in the boot stage, and by anthesis it was fully developed. The layer appeared as a ribbon of thick walled cells, five to seven cells wide, extending across the pedicel. Eight to 10 days after anthesis the abscission cells elongated and collapsed. Small lacunae were initiated adjacent to the vascular strands and continued to increase in size until the crushed vascular and pith cells had completely disintegrated. Spikelets remained attached to the pedicels by the epidermal cells until abscission occurred approximately 13 days after anthesis. In both dallisgrass biotypes the layer became distinguishable when the inflorescence was intermediate between early boot and boot stages, and was fully developed by anthesis. The layer appeared as a slightly wedge‐shaped band of thick walled cells, six cells wide at the epidermal edge and four cells wide at the vascular bundles, extending across the pedicel. Six days after anthesis, abscission layer cells in yellow‐anthered dallisgrass became elongated, and 9 days after anthesis a similar behavior was observed in common dallisgrass. In both biotypes, cells in the layer collapsed, leaving a crushed mass of cells. This and the remaining events were similar to those observed in bahiagrass. Abscission occurred on the 15th day after anthesis in the yellow‐anthered biotype, and on the 18th day in common dallisgrass. It appears that the abscission process in these three grasses is primarily biochemical in nature. These findings are probably indicative of the abscission process in other Paspalum species.