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Seed germination studies with Heteropogon contortus

1977; Wiley; Volume: 2; Issue: 4 Linguagem: Inglês

10.1111/j.1442-9993.1977.tb01163.x

0307-692X

J. C. Tothill,

Plant and animal studies

Abstract Germination characteristics of Heteropogon contortus were investigated in germination cabinets and in the glasshouse using soil trays. Under the former a dual inhibitory system appeared to operate. On the one hand naked caryopses from seeds which were less than 4 months of age were inhibited from germination by a process apparently analogous to epicotyl dormancy. This could readily be broken by applying 1% gibberellic acid and partly broken by repeated wetting and drying. On the other hand between 4 and 12 months, naked caryopses germinated more readily than intact seeds (caryopsis plus glumes, lemmas, etc.). However, the dormancy factor apparently associated with these structures could not be detected when seed was germinated in soil in the glasshouse and it appeared that they are a necessary protection for the caryopsis under field conditions. The optimal temperature for germination was between 30 and 35°C constant. Alternating diurnal temperatures of less than this appeared to cause reduced germination, and no high‐temperature stimulation was observed. Germination was not directly promoted by the passage of a normal grass fire.