Relationships between Drought Resistance and Electrical Parameters in Desert Plant Reaumuria soongorica

Electrical parameters such as resistance in high frequency (r), resistance in low frequency (r_l), specific extracellular resistance (r_e), specific intracellular resistance (r_i), value of conductance (G), susceptance (B) and relative permeability of plasma (RPP) and content of proline (Pro) in the stems of desert plant Reaumuria soongorica under drought stress from four provenances (Lanzhou, Zhangye, Jiuquan and Wuwei) were measured. The relationships between these electrical parameters and RPP and Pro were analyzed. Results showed that with increasing drought stress, stem RPP and Pro increased gradually or increased and then decreased. Significant differences existed among the four provenances (P < 0.05) for RPP in the order Lanzhou > Zhangye > Jiuquan > Wuwei and for Pro in the order Wuwei > Jiuquan > Zhangye > Lanzhou. The r of stem decreased gradually, r_e, r_i and G increased at first and then decreased, while r_l decreased at first and then increased. The variation of B was complex. The six electrical parameters differed significantly between provenance and drought stress treatments (P < 0.05). Correlation analysis and path analysis showed a significant correlation among r_i, r_e, r, B and RPP, and a significant correlation among r_i, r_e, r, G and Pro. However, RPP and Pro showed significant effects on r_i, with path coefficients of 0.938_RPP and 0.897_Pro, respectively. These results indicated that r_i was the best parameter for evaluating the drought resistance of R. soongorica stems and is an effective method for studying adversity stress in desert plants.