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Rhamnolipid Effects on Water Imbibition, Germination, and Initial Root and Shoot Growth of Soybeans
Author(s) -
Sancheti Ashwin,
Ju LuKwang
Publication year - 2020
Publication title -
journal of surfactants and detergents
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.349
H-Index - 48
eISSN - 1558-9293
pISSN - 1097-3958
DOI - 10.1002/jsde.12383
Subject(s) - rhamnolipid , germination , imbibition , chemistry , shoot , horticulture , food science , biology , genetics , bacteria , pseudomonas aeruginosa
Rhamnolipid is a nontoxic and biodegradable bioproduct that offers sustainable solutions in agricultural, pharmaceutical, cosmetic, and refinery applications. Its imminent uses in agriculture warrant thorough investigations of rhamnolipid interactions with plants. In this work, the effects of rhamnolipid on soybeans during imbibition and germination under different conditions were studied. Seed coat was determined to serve as the main barrier that regulates water imbibition, and rhamnolipid at 2 g L −1 was found to increase the imbibition rate to 16.1 (% dry bean weight)/h from 12.6% h −1 at 0 g L −1 rhamnolipid in intact soybeans for 0.5–5 h, when the soybean weight increased almost linearly due to the constant permeation rate through hydrated seed coat. Rhamnolipid, however, did not transport freely into beans; only about 50% of the rhamnolipid carried in the volume of water imbibed was absorbed by beans. Two different studies showed that absorbed rhamnolipid, from up to 1.5 g L −1 solutions, did not affect the germination percentages in wet cloths and soil pots. However, an additional study with constant (7‐day) exposure of germinating beans to more concentrated rhamnolipid solutions indicated a slight decrease of germination percentage, down to ~85% at 20 g L −1 rhamnolipid. Rhamnolipid had far more pronounced effects on root development. At high concentrations (5–20 g L −1 ), rhamnolipid severely stunted the root growth, causing reduced root and shoot weights and visible browning and damages of roots; however, low (0.5–1 g L −1 ) concentrations of rhamnolipid stimulated higher lateral root development while reducing the primary root extension, causing no change in the overall root or shoot weight. The findings indicated complex rhamnolipid interactions with soybeans and warranted further study while developing agricultural applications of rhamnolipid.