Abstract
In order to obtain baseline data for the development of diagnostic methods for forest decline based on chemical analyses, partitioning of metallic elements into liquid and solid phases (0.1M HCl soluble and insoluble fractions) from needles of Japanese cedar (Cryptomeria japonica) in the Kanto Plain of Japan and the distribution of elements in needles of different ages were examined. The results showed that most of the K, Mg and Mn in needles are present in their liquid phase while the greater parts of Ca, Al and Fe are contained in their solid phase. It was found that the significant proportions of Al and Fe were present in the form of soil particles (0.1M HCl insoluble fraction of solid phase) deposited on the surface of needles which can not be physically separeted for analysis. Also, the selective extracting technique using 0.1M HCl solution proved to be useful for evaluation of the amounts of Al and Fe supplied to needles through transpiration current. K, Mg, P and N were significantly enriched in current year needles, suggesting the occurrence of retranslocation of those elements from old needles. For K and Mg, concentration change by retranslocation from 1-year-old needles to current year needles could be analysed by a simplified mathematical model. On the other hand, higher concentrations of Ca, Al and Fe were observed in older needles, probably because those elements transported to needles through transpiration current were fixated into the tissue and accumulated with increase of needle age.
