Alleviation of cadmium toxicity and growth promotion of rice by gamma-polyglutamic acid produced from bacillus subtills

Name: Nuchnapa Kotabin

LCSH: Kasetsart University -- Dissertations. Ph.D. (Bioproducts Science) 2017

Classification :.LCCS: QH545.C3

LCSH: Kasetsart University. Department of Science -- Dissertations

LCSH: Cadmium -- Environmental aspects

LCSH: Heavy metals -- Environmental aspects

LCSH: Rice -- Effect of cadmium on

LCSH: Rice -- Growth

LCSH: Glutamic acid polymers

LCSH: Bacillus subtilis

Abstract: The effect of gamma-polyglutamic acid (-PGA or PGA) produced by Bacillus subtilis on cadmium (Cd)-damaged rice was investigated in both laboratory and greenhouse experiments. For laboratory experiment, the result revealed that Cd at a concentration of 500 µM significantly reduced the percentage of germination and the vigor index of rice seedling. The growth of rice seedling was obviously inhibited by Cd resulting to decreases of fresh and dry weights in comparison to the control. Furthermore, Cd caused decreases in the chlorophyll contents, soluble protein contents and amylase activities. However, the addition of PGA can mitigate the adverse effects of Cd. Analysis of Cd in rice seedling tissues exhibited that the addition of PGA at a concentration of 1,000 mg/L noticeably decreased the Cd contents in the tissues. For greenhouse experiment, pots containing soil contaminated with Cd at a concentration of 0-200 mg/kg and PGA at a concentration of 0-500 mg/kg were used. Although Cd reduced the growth and productivity of rice in comparison to the control, the addition of 500 mg/kg of PGA alleviated the effects of Cd toxicity in rice, resulting in increases in shoot and root lengths, the vigor of the rice and the number of healthy seeds per panicle. Micrographs of ultrathin sections of root cells showed that the addition of 500 mg/kg of PGA decreased Cd accumulation in both the epidermis and the intracellular space of cortex, suggesting that PGA reduced Cd transportation into root cells. Based on these results and the metal-binding characteristics of PGA, it is conceivable that the mechanism by which PGA alleviates Cd toxicity is the extracellular formation of Cd-PGA complexes.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Orawan Chunhachart

Role: Thesis Advisor

Name: Kritchaya Issakul

Role: Thesis Co-Advisor

Created: 2017

Modified: 2023-06-21

Issued: 2023-06-21

วิทยานิพนธ์/Thesis

application/pdf

URL: https://kasetsart.idm.oclc.org/login?url=https://www.lib.ku.ac.th/KUthesis/2560/nuchnapa-kot-all.pdf

CallNumber: QH545.C3.N83

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Bioproducts Science

Grantor: Kasetsart University

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