Seed structure and germination of Dichrostachys cinerea

Abstract

Dichrostachys cinerea (L.) Wight et Arn. (Legume: Mimosoideae) is a major contributor to the bush encroachment problem in Mkuzi Game Reserve. Seed characteristics were examined so that ecological and managerial concepts could be evaluated. Dormancy is imposed by the smooth, hard and impermeable testa. Scarification or cracks in the testa allow imbibition through the lens, which is followed by germination. The percentage germination of Dichrostachys cinerea is higher in light than in dark and there is a loss of temperature sensitivity with time. The behaviour of Dichrostachys cinerea seeds is not as that typically reported for mimosoid seeds, since germination improved with storage, and light enhanced germination of scarified seeds. This has important ecological implications, since seeds would germinate easier where the canopy has been removed or the soil has been disturbed. Dichrostachys cinerea (L.) Wight et Arn. (Legume: Mimosoideae) is ‘n belangrike bydraer tot die bos- indringerprobleem in die Mkuzi Wildreservaat. Saadkaraktertrekke is bestudeer sodat ekologiese en bestuurskonsepte geëvalueer kon word. Saadrus word veroorsaak deur die gladde, harde en waterdigte testa. Skarifikasie en barste in die testa laat imbibisie deur die lens toe sodat ontkieming kan plaasvind. Die persentasie ontkieming van Dichrostachys cinerea is hoër in die lig as in die donker en daar is ‘n verlies van temperatuursensitiwiteit met tyd. Dichrostachys cinerea sade reageer nie soos verwag word van mimosoidsade nie, aangesien ontkieming met opberging verbeter het, en lig die ontkieming van geskarifiseerde sade verhoog het. Hierdie aspek het belangrik ekologiese implikasies omdat sade beter sal ontkiem waar die plantegroei verwyder of die grond versteur is.