Volatile phytotoxins in forest litter.
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Volatile inhibitors in Pinus radiata litter, which may affect the establishment of second generation P. radiata or pasture growth beneath P. radiata trees, were investigated. A bioassay technique was devised to ascertain the effects of vapour from incubated litter samples. Litter vapour caused growth inhibition of clover (Trifolium repens), ryegrass (Lolium perenne) and pine (P. radiata) seedlings. The inhibitor was identified as ethylene by using absorbent and cold traps and confirmed by gas chromatographic analysis. Litter vapour also inhibited seed germination although in some instances clover germination was stimulated. It was found that ethylene and carbon dioxide were responsible for these effects. Under laboratory conditions, litter was shown to produce ethylene but ethylene was not detected in vapour samples from the field. Volatile compounds from P. radiata litter are not thought to affect plant growth under normal field conditions.