Influence of S-Ethyl Dipropylthiocarbamate on Growth, Chlorophyll and Carotenoid Production and Chloroplast Ultrastructure of Germinating Polytrichum commune Spores

Abstract

Germinating P. commune Hedw. spores showed great insensitivity to S-ethyl dipropylthiocarbamate (EPTC) herbicide. At the lowest EPTC concentration (2 ppmw [parts per million by weight] EPTC) the young protonema was usually more developed than the control material, with higher chloroplast pigment content on a basis of milligrams per dish. At 100 ppmw EPTC the young protonema was less developed and production of chlorophylls and carotenoids was decreased by about 30%; dry weight was at the level of the control material. At 200 ppmw EPTC spores either remained ungerminated, stopped germinating at an early stage or developed into sporelings with few tightly-packed short cells containing chloroplasts. At this stage growth processes in general were inhibited more than the chloroplast pigment production. The following changes in ultrastructure of sporelings were noted: cytoplasm was very dense, nucleus large, amount of vacuolization low and chloroplasts were amyloplast-like. At 300 ppmw the spores were usually ungerminated.