Ethylene turn-over in soil, litter and sediment

Turn-over (i.e. production and consumption) of ethylene was examined in con trasting soil types to evaluate the effect of environmental changes on C2H4 dynamics. Three general responses to batch incubation with C2H4 (generally 12-16 mul l(-1)) were observed: (i) arable soil and lake sediment required prolonged acclimation (1-4 weeks) for C2H4 consumption and showed no C2H4 production; (ii) coniferous and deciduous forest soil showed an inherent ca pacity for C2H4 consumption (21-85 pmol C2H4 g(-1) dry wt h(-1)) and a subs equent C2H4 production (4-26 pmol C2H4 g(-1) dry wt h(-1)), which coincided with a depletion of O-2 to below similar to1%; (iii) coniferous litter sam ples showed a slight C2H4 consumption (0-30 pmol C2H4 g(-1) dry wt h(-1)) f ollowed by a large C2H4 production (32-120 pmol C2H4 g(-1) dry wt h(-1)), a gain coinciding with depletion of the O-2 pool. The results for forest samp les indicated that C2H4 was produced and consumed simultaneously under aero bic conditions, while it was only produced under sub-oxic conditions. Simil ar patterns of C2H4 turn-over were found in samples collected in different years and both C2H4-consuming and -producing microorganisms survived during storage at 2 degreesC for 22 months. Notably in coniferous soil, changes i n C2H4 dynamics apparently could have the potential to adversely influence plant growth. (C) 2001 Elsevier Science Ltd. All rights reserved.