| In order to provide theoretical foundation for exploitation of Weigela in urban park service and afforestation, two old seedling of wild Weigela florida, Weigela florida cv. Red Prince and Weigela ‘Red Prince’+vat were selected as research subject to explore the difference of drought and salt stress between wild and cultivate Weigela. In present study, first, salt concentration of 0(blank control), 0.1%(A), 0.2%(B), 0.3%(C), 0.4%(D), 0.5%(E) were set using potted plant method to study salt tolerance of Weigela. Another, the drought- resistances were researched using sustainable natural dry processing with the control was kept sprinkling normally. Physiological and biochemical indexes, including damage indexes, survival rate, growth, relative growth rate, relative water content of water, relative conductance, free praline content(Pro), soluble sugar content(WSC), malondiald ehyde content, defense enzyme activity, photosynthetic characteristics, Point impedance spectroscopy parameters, chlorophyll fluorescence dynamics were compared under the condition of soil water and salt stress. The main results are summarized as follow: 1.The drought resistance and salt tolerance of the three varieties of Weigela florida(Bunge) are evaluated by the subordinate function value method of fuzzy mathematics, and it is got to know that wild Weigela florida﹥ Weigela florida cv. Red Prince﹥ Weigela ‘Red Prince’+vat。 2. With intensified of soil water deficit and increase of soil salt concentration, the damage indexes of Weigela leaf increased, survival rate, seedling height growth and growth rate of seedling decreased, as well as high growth is blocked. Weigela ‘Red Prince’+vat was the most susceptible, subsequently Weigela florida cv. Red Prince, wild Weigela florida to soil water and salt stress. The damage indexes of Weigela ‘Red Prince’+vat was higher than Weigela florida cv. Red Prince、wild Weigela florida, while survival rate, seedling height growth and relative growth rate of seedling was lower than Weigela florida cv. Red Prince. 3. The relative water content of leaf of three species Weigela were decreased under soil water and salt stress. The relative water content of leaf of was the most susceptible in the three species. The content of proline and soluble sugar also raised to some extent under the soil water and salt stress condition, while SOD of three Weigela were not increased and decreased tendency with increasing drought and salt stress. In addition, the CAT activity shows slightly drought under drought stress and relative increase under the salt stress. 4. Due to inhibition in the water splitting system and the receptor part before QA, OEC, PSⅡside were damaged, Chlorophyll fluorescence yield were increase, and then K point appear under the different soil water content and salt stress. With intensified of soil water deficit and increase of soil salt concentration, the maximal photochemistry efficiency(ΦPo), the probability of capture exciton QA- to pass electrons to other electron acceptor of the electron transport chain downstream were undulant decreased, while ΦEo, RC/CSM, ABS /CSM, TRO/CSM, ETO/CSM and DIO/CSM was diminished, but the ΦDowas increased dramatically. With the decrease of soil water content, PIABS、PICSM and DFCSM of Weigela florida cv. Red Prince, wild Weigela florida and Weigela‘Red Prince’+vat show obvious downward trend. 5. Under soil water and salt stress conditions, the exocellular resistance, internal resistance,relaxation time and distribution factor of relaxation time of leaves of Weigela florida Bunge showed a trend is “lower-rise-lower” with the increase of salt stress and the decrease in soil water. As the drought worsens, three varieties of Weigela florida relaxation time is “rise- lower- rise”. Changes of leaves of Weigela florida Bunge of electrical Impedance spectroscopy parameters were significant,When the salinity is above 0.2 and Sustained drought in 15 days. |
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