Promotion of stipe elongation in Flammulina velutipes by a diffusate from excised lamellae supplied with nutrients

Abstract

Flammulina velutipes fruit bodies were grown on partly decayed Populus tremuloides sawdust supplemented with wheat bran and malt extract. In each culture there was a gradation in fruit body size, which served to select test specimens at an early stage of growth. Diffusates collected in agar blocks were applied on the apex of decapitated stipes. Plain agar and dilute potato dextrose agar (PDA/2) alone had the same slight effect on growth. Lamellae placed on plain agar caused limited growth promotion. Lamellae on PDA/2 gave 100–150% more growth promotion than on plain agar during early development, but the activity decreased to zero during the middle of the stage of rapid elongation. Lamellae of that age had no effect on young stipes and the older stipes were insensitive to diffusate from young lamellae. Very small amounts of lamellae promoted stipe elongation. Potato extract alone did not stimulate production of the lamellar diffusate and glucose was less effective than the two nutrients combined. A delay of 2 h in applying lamellar diffusate reduced stipe elongation, and there was no response after 12 h delay. Pilear trama did not produce growth-promoting diffusate.