THE SIGNIFICANCE OF ROOT STARCH IN POSTFIRE SHOOT RECOVERY OF THE RESPROUTER STIRLINGIA-LATIFOLIA R BR (PROTEACEAE)

Stirlingia latifolia, a common shrub of Banksia woodlands of SW Australia, is a highly successful resprouter species recovering from fire by multiple sprouting of new shoots from its upper root stock. in comparison with the congeneric fire-sensitive (obligate seeder) species Stirlingia tenuifolia it exhibits a low shoot:root dry weight ratio and high concentrations of stored starch in the cortical tissue of its roots. The relationship between root reserves of starch and development of newly sprouting shoot material following fire is examined in S. latifolia after spring and summer burns. During the initial 2-5 month period after fire, levels of stored starch in the roots fall by 50-75%, followed by a slow increase as plants reproduce and the attainment of pre-fire starch levels by 1·5-2 years after the fire. Starch reserves of roots can be further reduced by shading the regenerating shoots to limit their input of photosynthates and almost totally eliminated by monthly removal of successive flushes of new shoots over a 10-12 month period. New shoots continue to sprout until all the starch is eliminated. The data are discussed in relation to the fire-induced reproduction of S. latifolia and its ability to thrive in very frequently burnt habitats.