The polyphenols of fresh green and dried leaves, litter, and superficial humus from mull and mor sites were examined by paper chromatography and paper electrophoresis. The greatest diversity and quantity of phenolic substances obtained in the extract of the fresh beech leaves from the mor site. There was a change in quantity of simple polyphenols grading from a maximum in fresh growing green leaves, falling through senescent leaves to dead leaves to fresh fallen leaves, to a minimum in decayed leaves and humus or stored dry leaves. Tannin stripping and especially hydrolysis and reduction of the decayed leaves and superficial humus released polyphenolic substances. The role of polyphenols in mull and mor formation is discussed.
The role of polyphenols in the stabilization of protein in superficial humus and the relationship of this role to mull and mor formation is discussed.Polyphenols extracted from a variety of plant materials were used to tan gelatin over a wide range of pH. T h e stability of gelatin, tanned with polyphenols extracted from green beech leaves (mor site), against microbial degradation was then estimated. Over the range of p H found in soils, stability was greatest when the p H of the tanning was low.It seems likely that mor-forming plant species contain more efficient tannins and the acid condition of the associated soil is better suited to the tanning process. Quantitative differences in tanning substances between mull and mor sites have already been reported by us (Coulson et al., 1960~).
The leuco-anthocyanin and tannin contents of green leaves of several species collected at mull sites have been compared with those collected at mor sites. Species growing under mor conditions usually contain greater amounts of both than the same species under mull. By growing a number of plants in sand it has been shown that this high content of polyphenolic substances can be associated with lack of nitrogen or of phosphorus.
I Present address:quantity of olyphenolic substances in fresh beech K eaves obtained from a mor site t E an in those from a mull site (Coulson et al., 1960).(Sericea Zespedeza) produced signi L I cant y greater quantities of tannins of trees is affecte B by the soil, though z e makes no reference to the effect culture, F ound that a N-deficient medium gave a high level of anthoinduced in su % terranean clover by lack of symbiotic organisms, was
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