Complex Biopolymeric Systems at Stalk/Epicuticular Wax Plant Interfaces: A Near Infrared Spectroscopy Study of the Sugarcane Example

摘要

Naturally occurring macro molecules present at the epicuticular wax/stalk tissue interface of sugarcane were investigated using near infrared spectroscopy (NIRS). Investigations of water, cellulose, and wax-cellulose interrelationships were possible using NIRS methods, where in the past many different techniques have been required. The sugarcane complex interface was used as an example of typical phenomena found at plant leaf/stalk interfaces. This detailed study showed that sugarcane cultivars exhibit spectral differences in the CHm water OH, and cellulose OH regions, reflecting the presence of epicuticular wax, epidermis, and ground tissue. Spectrally complex water bands (5276 cm(-1) and 7500-6000 cm(-1)) were investigated via freeze-drying experiments which revealed sequentially a complex band substructure (7500-6000 cm(-1)), a developing weak H-bonding system (similar to 7301 cm(-1)), and strong H-bonding (similar to 7062 cm(-1)) assigned to water-cellu lose interactions. Principal component analysis techniques clarified complex band trends that developed during the desorption experiment. Bands from wax-free stalk were minimized in the 4327-4080 cm(-1) region (C-H-n vibrational modes associated with long chain fatty compounds), while bands from the stalk tissue (particularly lignin and moisture) became more pronounced. This work is a comprehensive guide to similar studies by scientists involved in a variety of plant and fiber research fields.