of parent plant material in the dried wood the selection of 65 u00b0 c as the preheating temperature is primarily based on two facts i it is a common practice to use molten paraffin melting at 60 to 65 u00b0 c in histological studies ref u201c histochemistry theoretical and applied u201d by g everson pearse vol i amp ii 4 th edition 1985 churchil livingstone ii plant cell nuclear materials are stable up to 65 to 70 u00b0 c ref u201c plant biochemistry u201d ed by james bonner and j e verner academic press 1965 pp 49 50 in both the cases retention of cellular structure is achieved with high precision the preheating is continued for a period of 24 to 48 hours for completion to obtain constant weight of the preheated product thermogravimetry of dry or preheated powdered monocotyledonous caudex woody specimen indicates that pyrolytic weight loss is practically completed by 600 u00b0 c slow heating at a rate up to 5 u00b0 c per minute up to 750 to 800 u00b0 c of preheated monocotyledonous caudex stem specimen is done under self generated ambient environment at near normal pressure without vacuum or flow of inert gases nitrogen or argon so that ensuring that the biological structural features of the parent plant are preserved in the resulting shape of porous carbonaceous residue u2014 the biopreform heating at lower temperatures results in incomplete pyrolysis heating at higher temperatures causes partial.