Effects of GA3 on Plant Physiological Properties, Extraction, Subcellular Distribution and Chemical Forms of Pb in Lolium perenne
The effects of growth-promoting hormone gibberellic acid 3 (GA3) on physiology, Pb phytoextraction, and metal detoxification mechanisms in Lolium perenne were studied. Results showed that addition of GA3 alone at lower doses (1 or 10 μM) facilitated
antioxidant defense of L. perenne under Pb stress, decreased the toxicity of Pb in plant shoot by increasing the proportion of Pb in cell wall, hence significantly enhanced photosynthesis and plant growth, as well as Pb uptake and accumulation in L. perenne (P < 0.05). However, these
indicators showed the opposite changes when treated with GA3 at a higher dose (100 μM). Of the total Pb in plant shoot, 36–51% was associated with cell wall, and 31–40% was soluble fraction, while 41.4–49.7% was NaCl extractable, 24.6–35.4% HAc extractable
followed by other fractions. These findings suggest that Pb fixation by pectates and proteins in cell wall and sequestration in vacuole are responsible for Pb detoxification in plant, and the GA3 at 1 μM appears to be optimal for enhancing Pb phytoextraction by L. perenne
from Pb polluted soils.
Keywords: GA3; L. perenne; Pb; detoxification mechanism; phytoextraction
Document Type: Research Article
Affiliations: 1: College of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University, Hangzhou, Zhejiang, China 2: Indian River Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Fort Pierce, Florida, USA 3: Environmental Protection Agency, Zhejiang Qingyuan, China
Publication date: 02 December 2015
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