INFRARED MICROSPECTROSCOPY OF HYDRATED BIOLOGICAL-SYSTEMS - DESIGN AND CONSTRUCTION OF A NEW CELL WITH ATMOSPHERIC CONTROL FOR THE STUDY OFPLANT-CELL WALLS

A new hydration cell has been constructed that allows wet biological s amples, or samples of controlled moisture content, to be analysed in s itu using infra-red microspectroscopy, The cell has been used to show that there are minor spectral changes associated with the hydration of pectin and tomato pericarp cell walls and slightly more significant c hanges in onion and carrot epidermal walls. The cell was also used to show that molecular orientations of polymers, previously observed in d ry cell walls, were also to be seen in hydrated walls. For cell walls of onion and carrot epidermis, it was shown that the orientations of c ell wall polymers are not affected by hydration, Furthermore, the poly mer orientations in cell walls of fully elongated onion epidermal cell s are different from those of elongating carrot epidermis, By using th e hydration cell, it is now possible to investigate both fresh samples and wet systems routinely. The applications of this to the study of b iological materials with infra-red microspectroscopy are discussed.