The Physiological Response To Drought Stress Of Different Varieties Of Olea Europaea L. And Drought Resistance Comprehensive Evaluation

Wudu district in Longnan of Gansu province is one of the best suitable areas for growing olive across the country. In the current research, six varieties of biennial olive seedling from Fujiang plantation in Wudu district were selected and they were Leccino, Ascolano Tenera, Frantoio, Ezhi 8, Picholine, and Pendolino. Both the photosynthetic index and the physiological and biochemical index of olive were measured under different drought stress degrees. The membership function method and principal component analysis method were adopted to analyze the collected data.The results were as followed:1)The result showed that in Mild drought(LD), Moderate drought(MD) and Severe drought(SD) condition, the stomatal conductance, intercellular CO2 concentration, transpiration rate and net photosynthetic rate of olive increased,followed by a decline as the degree of drought increased and showed a “S” curve. The peak was achieved at the LD stress condition. As it got to the SD stress condition, the activity of the plant decreased, and the indexes also declined. In the SD stress condition, the highest rate of water utilization was Leccino and Ezhi 8, and the lowest were Frantoio.2)The content of the chlorophyll decreased with an increasing level of drought,and it reached the lowest point under the severe drought stress. The content of proline,malondialdehyde, soluble sugar and soluble protein changed as the drought stress degree increased, and got its maximum at the moderate drought stress. When the condition got to the severe drought, all indexes declined. The chemical activity of superoxide dismutase, catalase and peroxidase reached to their maximums under the moderate drought stress condition, and decreased in the severe drought stress condition.3)The drought resistance degree of the selected varieties of olive were evaluated and sequenced after the research. With the Principal Component Analysis method:Ezhi 8 > Leccino > Ascolano Tenera > Pendolino > Frantoio > Picholine. With the Membership Function method: Leccino > Ezhi 8> Ascolano Tenera > Pendolino >Frantoio > Picholine. Even though the two results were different, Leccino and Ezhi 8 had the highest drought resistance capacity among all the six varieties.