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.
a College of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University , Hangzhou , Zhejiang , China.
Shanying
S
He
b Indian River Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida , Fort Pierce , Florida , USA.
Zhenli
Z
He
a College of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University , Hangzhou , Zhejiang , China.|c Environmental Protection Agency , Zhejiang Qingyuan , China.
Qiuling
Q
Wu
a College of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University , Hangzhou , Zhejiang , China.
Lei
L
Wang
a College of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University , Hangzhou , Zhejiang , China.
Xi
X
Zhang
D000975:Antioxidants / Q000378:metabolism; D001673:Biodegradation, Environmental; D052918:Environmental Restoration and Remediation / Q000379:methods*; D005875:Gibberellins / Q000494:pharmacology*; D007854:Lead / Q000378:metabolism*; D008129:Lolium / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D010937:Plant Growth Regulators / Q000494:pharmacology*; D012989:Soil Pollutants / Q000378:metabolism*
D000975:Antioxidants; D005875:Gibberellins; D010937:Plant Growth Regulators; D012989:Soil Pollutants; D007854:Lead; C007842:gibberellic acid
GA3; L. perenne; Pb; detoxification mechanism; phytoextraction