Dry weight loss and changes in chemical composition of pine (Pinus kesiya Royle) needles and teak (Tectona grandis L.) leaves during processing in a freshwater lake

Abstract

The dry weight loss and chemical changes during the process of decomposition of two types of litters viz . ; pine (Pinus kesiya Royle) needles and teak (Tectona grandis L .) leaves have been studied in a small freshwater lake using plastic net (1 mm pore size) bags . The results reveal that type of litter and depth of water were the most important factors regulating the rate of decomposition . The percentage composition of cellulose and hemicellulose showed little variation and only a minor fall was noted in their values towards the end of the study period . The lignin percentage increased steadily at all the stations except the deepest station . The sugar and amino acid concentration dropped appreciably during the initial phase and stabilised during later periods. The general trend of change in nitrogen percentage was initial fall -increase -fall -stabilisation at a near original value . The rate of decomposition was faster when compared with similar studies in Canada and Europe .

Changes in the chemical composition of alder, poplar and willow leaves during decomposition in a river

“…showed the existence of nitrogenous compounds in the 'lignin' fraction during decomposition. This net accumulation of 'lignin' has also been demonstrated for soils by King & Heath (1967) and for waters by Tiwari & Mishra (1983).…”

“…This fact, already reported by Reice (1974Reice ( , 1977, Meyer (1980) and Tiwari & Mishra (1983), suggests that large amounts of trapped sediments reduce the development of microorganisms and slow down decomposition.…”

“…However, disappearance of the soluble sugars was less rapid than that observed by Krumholz (1972) and by for white oak and hickory leaves, in which 70 to 80% of the sugars are leached during the first two weeks. On the other hand, Tiwari & Mishra (1983) have noticed slower kinetics for soluble sugars in teak leaves in India. Not only the quality of plant material but also the environmental factors (e.g.…”

“…These percentages observed before decomposition are slightly higher than those given by Triska et al (1975) and for deciduous leaves. However, King & Heath (1967) and Tiwari & Mishra (1983) have found contents of the same magnitude or higher for other deciduous species. Mangenot & Toutain (1980) explained this variability by the different determination techniques used by the various authors (most of these techniques tend to overestimate lignin concentrations).…”

Vegetative succession and decomposition in reservoirs

“…has a low C:N ratio) generally loses nitrogen to the surrounding water for the duration of exposure. Tissues that contain little nitrogen (high C:N) lose readily soluble (non-cell wall) nitrogen during the beginning of decomposition, then accumulate nitrogen for a relative long period, and then when only the most resistant tissues remain, lose nitrogen again (Kaushik & Hynes, 1971;Godshalk & Wetzel, 1978b;Sardana & Mehrotra, 1981;Tiwari & Mishra, 1983;Marinucci et al, 1983).…”