Succession of fungi on decaying cocksfoot culms: III. A comparison of the sporulation and growth of some primary saprophytes on stem, leaf blade and leaf sheath

Abstract

The frequency of fruiting colonies of some primary saprophytic fungi on decaying stems, leaf blades and leaf sheaths of Dactylis glomerata is compared for standing and uprooted culms. Comparative studies of spore germination on glass slides and mycelial growth on ground sterilized grass at various relative humidity values have shown that the primary colonizers often show more rapid spore germination, more rapid growth and a better ability to grow at lower relative humidity values than secondary colonizers with which they were compared. Nutritional differences between grass tissues collected from upper and lower internodes throughout the year have been compared by testing the growth rate of the primary colonizers on a medium composed of 3 % dried grass in 2 % tap-water agar. Evidence is presented that upper internodes may attain a higher nutritional status than lower internodes during the early period of colonization, but this situation may be reversed later. These findings are discussed in relation to the senescence of host tissues and a hypothesis is presented to explain the observed pattern of fruiting of primary saprophytes on decaying grass stems.