Characterization of rice straw lignin phenolics and evaluation of their role in pollen tube growth in Cucurbita pepo L.

Abstract

Rice straw lignin was extracted via alkaline hydrolysis and structurally characterized using FT-IR and ¹H NMR spectra. Ethyl acetate extract of acid solubilized lignin was found to contain p-coumaric acid, ferulic acid and caffeic acid as major phenolic acids which were isolated and characterized using spectral data. Amides of isolated phenolic acids were synthesized by their reaction with propyl and butyl amines using microwave irradiation and analysed using spectral studies. Phenolic acids and amides were evaluated for their effect on pollen germination and tube growth in pumpkin. Pollen tube length was significantly increased with N-butyl-3-(3, 4-dihydroxyphenyl) acrylamide and N-butyl-3-(4-hydroxyphenyl) acrylamide at 5 ppm concentration than the control. These results could be utilised in increasing pollen tube length of Cucurbita pepo while making interspecific cross between C. moschata and C. pepo in order to transfer hull-less character of C. pepo to virus resistant C. moschata genotypes.

Graphical Abstract

Keywords:

• Rice straw
• lignin
• phenolic acids
• amides
• pollen germination
• pollen tube

Disclosure statement

No potential conflict of interest was reported by the authors.

Scheme 1. Synthesis of phenolic amides from isolated hydroxycinnamic acids.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.