Effects of Saline-alkali Stresses on the Growth and Endogenous Hormone Contents in Leaves of Hybrid Hazelnut Liaozhen 3

Three types of salt-alkaline stress conditions were performed with NaCl and Na2CO3 to study the changes of the growth indexes and endogenous hormone contents in leaves of Ping'ou hybrid hazelnut (Corylus heterophylla × Corylus avellana, Liaozhen 3) under different saline-alkali stresses. The correlations between growth indexes and endogenous hormones were analyzed. The results showed that the net growth of plant height, new shoots length and number of leaves, the shoot biomass, the total biomass of Ping'ou hybrid hazelnut were inhibited apparently under the three salt-alkali stresses with the order of NaCl stress > mixed salt-alkaline stress > Na2CO3 stress, while the root/shoot ratio increased significantly. The stem diameter widened with low salt-alkali stress concentration and the root biomass raised significantly in 50, and 100 mmol·L-1 Na2CO3 stress. Furthermore, NaCl stress resulted in significant decrease of water content in leaves. The ABA contents of leaves increased significantly with the three salt-alkali stresses, and the (GA + IAA +ZR)/ABA ratio also reduced apparently compared with the control. Moreover, the ABA synthesis was more rapid, and it had no relation with the stress concentration in Na2CO3, but the ABA content were directly related with the concentration of NaCl stress. The correlation analysis indicated that significant positive correlation was found between the (GA + IAA +ZR)/ABA ratio and the plant height, new shoots length and leaves, whereas the (GA + IAA +ZR)/ABA ratio and the root/shoot ratio were negatively related. In conclusion, the inhibition on growth indexes imposed by neutral salt were greater than that by alkaline salt and mixed salt-alkaline stress, the difference in response characteristics of endogenous hormones was found under the three salt-alkali stresses, and the Ping'ou hybrid hazelnut showed stronger tolerance to Na2CO3 than to NaCl.