| Gentiana macrophylla, which had the effect of treatment of rheumatism and rheumatoid, was oneof key protection wild herbs in our country, but the seeds had low germination rate and emergence ofirregular under natural conditions, and seed dormancy and mechanism of salt tolerance of seedlingwere not clearly. The effect of soaking Gentiana straminea Maxim seeds, the crude extract activity andthe germination with potassium permanganate, gibberellic acid, penicillin, sulfuric acid, hydrogenperoxide and soaking of live water were studied, and the seeds dormancy and the methods for breakingdormancy were discussed. And on this basis by using pot culture methodology and physiological andbiochemical methods, studies on physiological and biochemical changes of seedling under salt stressand the effect of salt tolerance in plants by exogenous nitric oxide and glutathione inducing. Andsimultaneously study the antioxidant capacity by using the DPPH method, the flavonoids content byusing AlCl3colorimetry method and the total phenol content by using Folin-C method of different partsof different growth years of G.crassicaulis Duthie ex Burk under different extraction solvents. Theresearch results are as follows:1. The soaking fitted a Logistic curve, and the seed capsule was unimpeded. The treatment ofsulfuric acid and potassium permanganate improved the germination rate of seeds, and that means itwas mechanical forces hinder of seeds. The crude extract which had a strong inhibitory activity at aconcentration of0.02-0.2g/mL were inhibition effect on germination and growth of wheat, cabbage andG.straminea Maxim seeds, and soaking by flowing water could improve germination rate ofG.straminea Maxim seeds, so the intrinsic inhibitors was one of factor of seed dormancy. The differenttreatment could significantly improve germination quality of G.straminea Maxim seeds. germinationrate, germination potential, germination index and vigor index of seeds soaking10by min1.5%potassium permanganate at light culture were significantly higher than other treatments, and comparedwith the control germination rate increased106.90%(p <0.01) very significant difference. Inhibitoryactivity of crude extracts of G.straminea Maxim seeds soaking10min by potassium permanganate ongermination of cabbage seeds was lower than the unhandled, especially significantly lower at aconcentration of0.02-0.04g/mL, and potassium permanganate treatment could clear intrinsic inhibitorsof seeds. In summary, the main causes of G.straminea Maxim seeds dormancy was combinationaldormancy.2. At the low concentrations of NaCl(≤50mmol/L) seed germination of G.straminea Maxim was improved. In high concentrations (≥100mmol/L) seed germination was inhibited very significantly(P<0.01), and germination rate, germination index and vigor index of seeds were very significantlylower than the control (P <0.01), which germination rate was reduced by44.29%,67.15%,88.58%(P<0.01). Appropriate value of seeds germination was88.61mmol/L, the critical value was194.94mmol/L, and limits was301.28mmol/L by the regression equation (y=95.823-0.2351x).3. Seedlings of G.straminea Maxim were object to oxidative damage by the treamnet of100,200,400mmol/L NaCl. Salt stress early the proline and soluble sugar content of seedlings growing150dincreased, and at the second day(2d), the activity of SOD and POD were significantly increased, so theoxidative damage of leaves was alleviated under salt stress. With the increase of NaCl concentrationand stress time, leaves relative conductivity and MDA concent by treatment of400mmol/L NaClreached maximum at6d, which was significantly higher than the control (P <0.01). Antioxidantcapacity of seedling leaves reduced significantly lower (P <0.01). SOD, POD and CAT activity reducedsignificantly lower at4d, and at6d reached minimum. the activity of antioxidant enzymes by treatmentof400mmol/LNaCl was minimum, compared with the control which reduced46.04%,40.65%,68.03%(P <0.01). Though the seedlings show a certain salt tolerance, with the increase of NaCl concentrationand stress time the seedling oxidative damage was the greater and the treatment of400mmol/LNaClwas the most significant.4. Using different concentrations of SNP and GSH could improve the activity of antioxidantenzymes of G.straminea Maxim seedlings under salt stress, which the effect of the treatment of20mg/LGSH and0.1mmol/L SNP were significantly. Compared with0.1mmol/L SNP, the main performanceby the treatment of20mg/L GSH been on scavenging reactive oxygen species(ROS), improvingantioxidant capacity and decreasing MDA content was significantly higher. The treatment of0.1mmol/L SNP been on improving the Pro content of seedlings and reduceing the rate of chlorophylldegradation was better than the treatment of20mg/L GSH. And both on improving the antioxidantenzymes activity were no significant difference. The results indicated that there were protectivefunction to G.straminea Maxim seedling leaves from NaCl oxidative damage when applications ofSNP(0.1mmol/L), GSH(20mg/L) and their mix solutions(0.1mmol/L SNP+20mg/LGSH). However,their mix solutions showed a much better protective impact than the treatments of SNP and GSH as itcould significantly increase activities of antioxidant enzymes, antioxidant capacity of seedling andcontent of proline，while decrease the chlorophyll content decreased rate, the concent of H2O2, andlargely MDA content and O2.-production speed in G.straminea Maxim seedling leaves under salt stress.The mix solution of SNP and GSH could have a big potential for reduction of oxidative damage to G.straminea Maxim seedling leaves under salt stress.5. The antioxidant capacity of the extract liquor of wild G.crassicaulis Duthie ex Burk rootsextracting by the ethanol was maximum, which antiradical efficiency (AE) of DPPH was25%; Theflavonoids content of the extract liquor of wild G.crassicaulis Duthie ex Burk roots extracting by theethanol was maximum, which it was456.28mg/L; The total phenol content of the extract liquor of wildG.crassicaulis Duthie ex Burk roots extracting by the ethanol was maximum, which it was425.17mg/L. |
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