Various word roots relating to decayed matter (detritus, sapro-,
lyso-), to eating and nutrition (
-vore, -phage,
-troph), and to plants or life forms (-phyte,
-obe) produce various terms, such as
detritivore, detritophage, saprotroph,
saprophyte, saprophage, and saprobe; their meanings overlap, although technical distinctions (based on
physiologic mechanisms) narrow the
senses. For example, biologists can make
usage distinctions based on macroscopic swallowing of detritus (as in
earthworms) versus microscopic
lysis of detritus (as with
mushrooms).
Process
As matter decomposes within a medium in which a saprotroph is residing, the saprotroph breaks such matter down into its composites.
Cellulose, a major portion of plant cells, and therefore a major constituent of decaying matter is broken down into
glucose
These products are re-absorbed into the hypha through the cell wall by
endocytosis and passed on throughout the mycelium complex. This facilitates the passage of such materials throughout the organism and allows for growth and, if necessary, repair.[5]
Conditions
In order for a saprotrophic organism to facilitate optimal growth and repair, favourable conditions and nutrients must be present.[7] Optimal conditions refers to several conditions which optimise the growth of saprotrophic organisms, such as;
Presence of water: 80–90% of the mass of the fungi is water, and the fungi require excess water for absorption due to the evaporation of internally retained water.[7]
Presence of
oxygen: Very few saprotrophic organisms can endure anaerobic conditions as evidenced by their growth above media such as water or soil.[7]
Neutral-acidic
pH: The condition of neutral or mildly acidic conditions under pH 7 are required. [7]
Low-medium temperature: The majority of saprotrophic organisms require temperatures between 1 and 35 °C (34 and 95 °F), with optimum growth occurring at 25 °C (77 °F).[7]
The majority of nutrients taken in by such organisms must be able to provide carbon, proteins, vitamins and, in some cases,
ions. Due to the carbon composition of the majority of organisms, dead and organic matter provide rich sources of disaccharides and
polysaccharides such as
maltose and
starch, and of the monosaccharide
glucose.[5]
^
abcClegg & Mackean (2006, p. 296) states the purpose of saprotrophs and their internal nutrition, as well as discussing the main two types of fungi that are most often referred to. It also describes, visually, the process of saprotrophic nutrition through a diagram of hyphae, referring to the
Rhizobium on damp, stale whole-meal bread or on rotting fruit.
^
abcClegg & Mackean (2006, p. 296), fig 14.16—Diagram detailing the re-absorption of substrates within the hypha.
^
abcdeClegg & Mackean (2006, p. 296), fig 14.17—A diagram explaining the optimal conditions needed for successful growth and repair.
Further reading
Clegg, C. J.; Mackean, D. G. (2006). Advanced Biology: Principles and Applications (2nd ed.). Hodder Publishing.
Zmitrovich, I. V.; Wasser, S. P.; Ţura, D. (2014).
"Wood-inhabiting fungi"(PDF). In Misra, J. K.; Tewari, J. P.; Deshmukh, S. K.; Vágvölgyi, C. (eds.). Fungi from Different Substrates. N. Y.: CRC Press, Taylor and Francis group. pp. 17–74.