Physiology of Adonis amurensis as Affected by Drought

  Objective  Physiological characteristics of Adonis amurensis in response to varying degrees of drought stress and subsequent rewatering were studied prior to the introduction for commercial cultivation and applications of the cultivar.

  Method  Potting with controlled watering was applied to study the effects of varied drought stress and subsequent rewatering on the physiological characteristics of A. amurensis.

  Result  The depleting water supply to the A. amurensis plants decreased the biomass, plant height, relative moisture content in leaf, total chlorophyll, and soluble protein, increased the contents of soluble sugar and malondialdehyde as well as the relative electrical conductivity of the leaves, and rose but followed by a decline on the contents of proline, peroxidase, and superoxide dismutase activities of the plants. Meanwhile, the indicators such as P_n, G_s, T_r, and C_i decreased, F_m, F_v/F_o, F_v/F_m, q_P, ETR, and Ф_PSⅡgradually decreased, and F_o and NPQ gradually increased. Upon rewatering the soil to a moisture content no less than 29.9% in the early stage of drought treatment (0-8 d), the physiological indices fully returned to the control levels. However, the recovery slowed down when the rewatering took place in the mid stage (8-12 d), and the indices shifted significantly from control if the rewatering was implemented during 12-16 d after the draught stress began.

  Conclusion   A. amurensis plants seemed to be capable of withstanding continuous water depletion up to 8 d and maintaining normal growth with a minimum 29.9% of soil relative moisture content. After the threshold points, prolonged drought stress with less than the minimum water requirement in the soil would irreversibly damage the plant physiology.Therefore, water supplement for A. amurensis should not exceed 8 days under drought condition.