Effects of poly-γ-glutamic acid (γ-PGA) on plant growth and its distribution in a controlled plant-soil system

• Published in: Scientific reports 2017-07, Vol.7 (1), p.6090-13, Article 6090
• Main Authors: Zhang, Lei, Yang, Xueming, Gao, Decai, Wang, Lingli, Li, Jie, Wei, Zhanbo, Shi, Yuanliang
• Format: Article
• Language: English
• Subjects: 631/45/47/4112; 704/47/4112; Acidic soils; Amino acids; Biomass; Carbon - metabolism; Glutamic acid; Humanities and Social Sciences; Metabolism; multidisciplinary; Nitrogen - metabolism; Nutrient availability; Nutrient uptake; Phosphorus; Plant biomass; Plant Development; Plant growth; Plant metabolism; Plant nutrition; Plant Roots - metabolism; Plants - metabolism; poly-γ-Glutamic acid; Polyglutamic Acid - analogs & derivatives; Polyglutamic Acid - metabolism; Science; Science (multidisciplinary); Soil - chemistry; Soil Microbiology; Soil nutrients; Soils; Sugar
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-06248-2

To demonstrate the responses of plant (Pakchoi) and soil to poly-γ-glutamic acid (γ-PGA) is essential to better understand the pathways of the promotional effect of γ-PGA on plant growth. In this study, the effects of γ-PGA on soil nutrient availability, plant nutrient uptake ability, plant metabolism and its distribution in a plant-soil system were tested using labeled γ-PGA synthesized from 13 C 1 - 15 N-L-glutamic acid (L-Glu). γ-PGA significantly improved plant uptake of nitrogen (N), phosphorus (P), and potassium (K) and hence increased plant biomass. γ-PGA greatly strengthened the plant nutrient uptake capacity through enhancing both root biomass and activity. γ-PGA affected carbon (C) and N metabolism in plant which was evidenced with increased soluble sugar contents and decreased nitrate and free amino acids contents. About 26.5% of the γ-PGA-N uptake during the first 24 h, after γ-PGA application, was in the form of intact organic molecular. At plant harvest, 29.7% and 59.4% of γ-PGA- 15 N was recovered in plant and soil, respectively, with a 5.64% of plant N nutrition being derived from γ-PGA-N. The improved plant nutrient uptake capacity and soil nutrient availability by γ-PGA may partly explain the promotional effect of γ-PGA, however, the underlying reason may be closely related to L-Glu.