Effects of NaCl and Na_2CO_3 stresses on seed germination and seedling growth of Quercus variabilis
LI Zhiping;ZHANG Wenhui;CUI Yuchuan;Tianjin Key Laboratory of Animal and Plant Resistance,College of Life Sciences,Tianjin Normal University;
Choosing fresh cork oak seeds and using Petri dish and filter paper germination method,the NaCl and Na2CO3 resistant potential of Quercus variabilis seeds with five different NaCl and Na2CO3concentrations(0,50,100,200 and 400 mmol / L) were examined. During the experimental process,the seed germination,radicle growth,three protective enzyme(SOD,POD,CAT) activities and the organic osmoregulation substances(proline,soluble protein and soluble sugar) were all measured,and the correlation between the seed germination,radicle growth rate under NaCl and Na2CO3 stress were analysed. The results showed that:( 1) NaCl and Na2CO3 stress had no significant impact to seed germination rate and germination index,even under high Na+concentration( 200 mmol / L) stress,seed germination rate was still higher than contrast. With the addition of Na+concentration,radicle length,radicle growth rate and fresh weight of radicle under two kinds of stresses presented the downward trend. The vigor index and salt tolerance index under NaCl stress increased at the lower concentrations(50 mmol / L) and then decreased at the higher concentrations(100,200 and 400 mmol / L),but theyboth declined under Na2CO3 treatment. Relative salt-harmed rate waved under two stresses,they were lower than the contrast under 50 and 200 mmol / L Na+concentration,but were higher under 100 and 400 mmol / L Na+concentration.(2)The regression equation between vigor index,radicle growth rate and different concentrations of NaCl and Na2CO3 stress were found,and they showed that the critical value of the vigor index,fresh weight of radicle,radicle length and radicle growth rate under NaCl stress,were 300. 0,300. 0,333. 6 and 369. 6 mmol / L respectively,they were 69. 0,67. 2,182.0,187. 5 mmol / L respectively under Na2CO3 stress.( 3) Under two kinds of stresses, with the increase of Na+concentration,MDA( malondialdehyde) content increased significantly; SOD( superoxide dismutase) activity decreased after increasing under NaCl treatment, but they were all lower than the contrast under Na2CO3treatment; POD(peroxidase) activity had no significant change,CAT(catalase) activity was down and then rose. Proline,soluble protein and soluble sugar contents were increased in varying degrees with the addition of Na+concentration,they were to the maximum under the largest concentration of NaCl treatment,and they were all higher than the contrast under Na2CO3treatment(4) Under the same Na+concentration stress,the growth indicators such as seed germination rate,germination index,radicle length,radicle growth rate and fresh weight of radicle under NaCl treatment were all higher than that of Na2CO3 treatment,malondialdehyde,protective enzymes( SOD,POD,CAT) activities and osmotic adjustment substances(proline,soluble protein and soluble sugar) contents were all lower than that of Na2CO3 treatment,which showed the effects of Na2CO3 stress on seeds were more significant than that of NaCl stress. Thus it can be seen that cork oak seeds increased protective enzymes activities and contents of osmotic regulation substances in vivo to adapt to the salt-alkali stress,making the inhibition degree of germination and growth to the minimum.
【Fund】： 国家林业局林业公益性行业专项(201104011);; 国家自然科学基金项目(30872018)
【CateGory Index】： Q945.78
【CateGory Index】： Q945.78