Allelopathic potential of 'Hyparrhenia hirta' (L.) Stapf. on native grass

Abstract

'Hyparrhenia hirta' (L.) Stapf. (Coolatai grass, Tambookie grass) is an invasive, perennial grass from Africa and the Middle East that has infested large areas of northern New South Wales, Australia, and also occurs in other Australian states. Invasive perennial grasses can be aggressive colonisers and a major threat to the biodiversity of native ecosystems. There are many possible mechanisms by which invasive plants may affect native species such as resource competition, habitat modification and altered ecosystem processes. The present investigation studied the allelopathic potential of 'H. hirta' on germination and seedling vigour of the Australian native grass species, 'Bothriochloa macra' (red grass) and 'Dichanthium sericeum' (Queensland blue grass). In an incubator experiment, aqueous extracts derived from root and shoot of 'H. hirta' were applied to the target species. The full strength extracts (1:10 w/v plant material in water) of H. hirta were used to make the following dilutions: control (deionized water only), 0.1, 1, 10,50,75, and 100 % (v/v).