OBJECTIVETo study the effect of drought stress on the changes of physiological adaptation of Atractylodes lancea seedlings.

METHODInvestigation was carried out on content changes of MDA, soluble protein, and activities of SOD, POD, CAT, APX in A. lancea seedlings under polyethylene glycol (PEG-6000)-simulated drought stress.

RESULTIn A. lancea seedlings treated with 15% and 25% PEG, the content of MDA increased significantly with the stress time, and increased more significantly at a higher concentration of PEG. The content of soluble protein increased significantly after treatment on the day one and day three; activities of SOD, POD, CAT and APX increased at first and decreased later, increasing rates rose at high concentration of PEG moreover, activities of POD, APX reached the maximum after three days, and the time of maximum activities changed with concentration of PEG.

CONCLUSIONA. lancea seedlings adapted to drought stress by increasing the content of soluble protein to decrease water potential, and by improving activities of protective enzymes to enhance anti-oxidative ability under drought stress.

Adaptation, Physiological ; physiology ; Ascorbate Peroxidases ; Atractylodes ; enzymology ; metabolism ; physiology ; Catalase ; metabolism ; Droughts ; Gene Expression Regulation, Plant ; physiology ; Peroxidase ; metabolism ; Peroxidases ; metabolism ; Seedlings ; enzymology ; metabolism ; physiology ; Superoxide Dismutase ; metabolism

Leaf senescence is often caused by water deficit and the chimeric gene P(SAG12)-IPT is an auto-regulated gene delaying leaf senescence. Using in vitro leaf discs culture system, the changes of contents of chlorophylls, carotenoids, soluble protein and thiobarbituric acid reactive substance (TBARS) and antioxidant enzymes activities were investigated during leaf senescence of P(SAGl2)-IPT modified gerbera induced by osmotic stress compared with the control plant (wild type). Leaf discs were incubated in 20%, 40% (w/v) polyethylene glycol (PEG) 6000 nutrient solution for 20 h under continuous light [130 micromol/(m(2) x s)]. The results showed that the contents of chlorophylls, carotenoids and soluble protein were decreased by osmotic stress with the decrease being more pronounced at 40% PEG, but that, at the same PEG concentration the decrease in the transgenic plants was significantly lower than that in the control plant. The activities of superoxide dismutase (SOD), catalases (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and dehydroascorbate reductase (DHAR) were stimulated by PEG treatment. However, the increases were higher in P(SAG12)-IPT transgenic plants than in the control plants, particularly at 40% PEG treatment. Lipid peroxidation (TBARS content) was increased by PEG treatment with the increase being much lower in transgenic plant than in the control plant. It could be concluded that the increases in the activities of antioxidant enzymes including SOD, CAT, APX, GPX and DHAR were responsible for the delay of leaf senescence induced by osmotic stress.
Alkyl and Aryl Transferases ; genetics ; Antioxidants ; metabolism ; Arabidopsis Proteins ; genetics ; Ascorbate Peroxidases ; Asteraceae ; genetics ; metabolism ; Carotenoids ; metabolism ; Catalase ; metabolism ; Chlorophyll ; metabolism ; Cysteine Endopeptidases ; genetics ; Genes, Bacterial ; Genes, Plant ; Lipid Peroxidation ; Osmotic Pressure ; Oxidoreductases ; metabolism ; Peroxidase ; metabolism ; Peroxidases ; metabolism ; Plant Leaves ; metabolism ; Plant Proteins ; metabolism ; Plants, Genetically Modified ; Promoter Regions, Genetic ; Solubility ; Superoxide Dismutase ; metabolism

OBJECTIVETo analysis the effects of water deficit on the transcript level of SOD, APX, DHAR and MDHAR genes in Scutellaria baicalensis.

METHODThree-month-old S. baicalensis was in glasshouse under water deficit stress, and the transcript level of SOD, APX, DHAR and MDHAR genes were analysis utilized semi-quantitative RT-PCR.

RESULTCompared with the control group, a significant decline of the transcriptional level of APX gene was observed at 70 days after water deficit. The transcript level of DHAR gene was reduced at 30 and 50 days after water deficit. And MDHARI gene was significant declined at 50 days.

CONCLUSIONAsA which is an important antioxidant plays a major role in hydrogen peroxide clear system under water deficit, and maybe have an antagonistic effect to the accumulation of baicalein.

Ascorbate Peroxidases ; genetics ; metabolism ; Ascorbic Acid ; metabolism ; Gene Expression Regulation, Enzymologic ; drug effects ; Gene Expression Regulation, Plant ; drug effects ; Hydrogen Peroxide ; metabolism ; NADH, NADPH Oxidoreductases ; genetics ; metabolism ; Oxidoreductases ; genetics ; metabolism ; Plant Proteins ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Scutellaria baicalensis ; enzymology ; genetics ; metabolism ; Superoxide Dismutase ; genetics ; metabolism ; Time Factors ; Water ; metabolism ; pharmacology