Improvement of inulin production in Jerusalem artichoke (Helianthus tuberosus L.) through foliar application of certain sugars

Abstract

A field experiment was conducted at the experimental farm of the Agricultural Genetic Engineering Research Institute (AGERI), Agriculture Research Centre (ARC) to investigate the response of Jerusalem artichoke plant to foliar application of Raffinose, Dextrin, and Sucrose at 10, 25, 50, and 100 mM in addition to control (tap water only) using Randomized complete block design with 3 replicates. Tested parameters were: plant fresh weight, dry weight, plant height, number of main branches/plants, number of lateral branches/plants, leaf area, photosynthetic pigment, total carbohydrate, inulin content, Fructan exohydrolase (FEH) activity, SDS-PAGE analysis of protein, soluble sugar content by HPLC, number of tubers produced, the yield per plant, and the overall yield per feddan (tons). Results indicated that spraying plants with Raffinose and Dextrin at 50 mM level enhanced all growth parameters, total carbohydrates, and inulin content. In addition, the dose of Raffinose 50 mM exhibits promising inhibition activity of FEH enzyme, increasing the production of inulin and tuber yield, followed by the same dose from Dextrin and Sucrose treatments. Based on this supposition, the results of this study suggested that the exogenous application of particular sugars, Raffinose and Dextrin, as an eco-friendly material, can improve the plant's overall growth, development, and yield of Jerusalem artichoke plant.