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Summary: Journal ofArid Environments(1995) 29:15-23
Seed dormancy and persistence of Acacia berlandieri and
Leucaena pulverulenta in a semi-arid environment
M. K. Owens*, R. B. Wallacet & S. Archer~:
* Texas Agricultural Experiment Station, Uvalde, Texas
The Nature Conservancy, Santa Fe and S Department ofRangeland Ecology
and Management, Texas A & M University, CollegeStation, Texas, U.S.A.
(Received 12 April 1993, accepted 9June 1993)
Seed longevity of the leguminous shrubs Acacia berlandieri and Leucaena
pulverulenta was evaluated under field conditions at the soil surface and at 3-5 cm
depth. Abiotic influences on seed longevity and dormancy were investigated by
comparing seeds maintained at 5°C with seeds experiencing fluctuating day/night
temperatures (40°C/20°C vs. 50°C/30°C) under dry and moist conditions. Acacia
seed demonstrated no dormancy and initial germinability was > 82% in the
laboratory. Viability of Leucaena seed was >97%, but seed coat dormancy
limited germination to < 7%.
Persistence of Acacia seeds in the soil seed bank varied with depth. After
42 days the viable seed population of Acacia was reduced by 10 and 80% for
surface and buried seeds, respectively, and no viable seeds were present after
3"5 months of burial. In contrast, Leucaena seeds on the soil surface exhibited no
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