[Response of reactive oxygen metabolism in melon chloroplasts to short-term salinity-alkalinity stress regulated by exogenous γ-aminobutyric acid].
The regulatory effect of exogenous γ-aminobutyric acid (GABA) on metabolism of reactive oxygen species (ROS) in melon chloroplasts under short-term salinity-alkalinity stress were investigated in melon variety 'Jinhui No. 1', which was cultured with deep flow hydroponics. The result showed that under salinity-alkalinity stress, the photosynthetic pigment content, MDA content, superoxide anion (O₂·) production rate and hydrogen peroxide (H₂O₂) content in chloroplast increased significantly, the contents of antioxidants ascorbic acid (AsA) and glutathione (GSH) increased, and the activities of H⁺-ATPase and H⁺-PPiase were inhibited obviously. With exogenous GABA application, the accumulations of O₂·, MDA and H₂O₂ induced by salinity-alkalinity stress were inhibited. Exogenous GABA alleviated the increase of photosynthetic pigment content, improved the activity of SOD, enzymes of AsA-GSH cycle, total AsA and total GSH while decreased the AsA/DHA ratio and GSH/GSSH ratio. Foliar GABA could enhance the H⁺-ATPase and H⁺-PPiase activities. Our results suggested that the exogenous GABA could accelerate the ROS metabolism in chloroplast, promote the recycle of AsA-GSH, and maintain the permeability of cell membrane to improve the ability of melon chloroplast against salinity-alkalinity stress.
Li-xia
LX
Xiang
Li-pan
LP
Hu
Xiao-hui
XH
Hu
Xiong-bo
XB
Pan
Wen-qi
WQ
Ren
D000975:Antioxidants / Q000378:metabolism; D001205:Ascorbic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D002462:Cell Membrane; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism*; D019662:Cucurbitaceae / Q000187:drug effects / Q000378:metabolism*; D004281:Docosahexaenoic Acids; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D018527:Hydroponics; D008315:Malondialdehyde / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010539:Permeability; D010788:Photosynthesis; D017382:Reactive Oxygen Species / Q000378:metabolism*; D054712:Salinity; D013312:Stress, Physiological; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D000975:Antioxidants; D017382:Reactive Oxygen Species; C111716:docosahexaenoylascorbic acid; D004281:Docosahexaenoic Acids; D008315:Malondialdehyde; D005680:gamma-Aminobutyric Acid; D006861:Hydrogen Peroxide; D005978:Glutathione; D001205:Ascorbic Acid; D010100:Oxygen