Establishment of Warm- and Cool-Season Native Perennial Grasses on the North-West Slopes of New South Wales. I. Dormancy and Germination

Abstract

The dormancy and germination of two groups of native perennial grasses were investigated in caryopses or dispersal units. The species were the warm-season native perennial grasses Aristida ramosa R.Br., Bothriochloa macra (Steud.) S. T . Blake. Dichanthium sericeum (R.Br.) Camus, Sporobolus elongatus R.Br., Eragrostis leptostachya Steud., Chloris truncata R.Br. and the cool-season species Stipa variabilis Hughes and Danthonia linkii Kunth. Optimum temperatures for germination were 20-35°C for A . ramosa; 15-35° for D. sericeum and C. Truncata; 20-25° for E. leptostachya; 20-30° for B. macra and S. elongatus and 15-25° for D. linkii and S . Variabilis. At 1O° and 40° D. linkii and A. ramosa respectively were the only species that had high germination percentages. Removal of the lemma and palea from freshly harvested units of A. ramosa, B. macra, D. sericeum, C. Truncata and S. variabilis significantly increased germination. In units stored at 12-27°C there was a breakdown in dormancy after 2-3 months in A. ramosa and B. macra and after 9 months in S. elongatus. In the germination of D. sericeum and D. linkii the lemma and palea appeared to have a long-term inhibitory role. Twenty-week-old whole dispersal units of B. macra, S. elongatus and E. leptostachya and 40-week-old units of S. elongatus and E. leptostachya had an obligate light requirement for germination. The ecological implications of these data in the successful germination of natural seed falls and artificial seedings are discussed.