| The growth and development of plants always are influenced by numerous environmental factors, such as low temperature, drought, floods and so on. Meanwhile, with the rapid development of industry and agriculture in our country and the frequent activities of human beings, the deterioration of the ecological environment is accelerated. The heavy metal pollution in soil affects the growth of plants. The experiment was a completely randomized design with the control (75% FC)、drought (25% FC)、Cd (3 mg/kg) and their interactions (25% FC and 3 mg/kg). A controlled pot-culture experiment was conducted to detect effects of drought stress and Cd on growth and photosynthetic pigments, accumulation and partitioning of biomass, physiological-biochemical characteristics, Cd accumulation and allocation of Puelia sinese Roxb. The main results are as follows:In this study, compared with control, drought, Cd stress and their interaction have caused membrane lipid peroxidation, increased accumulation of reactive oxygen plant, and inhibited the normal growth of plants. Under drought conditions, the plant reduced its gas exchange rates and net photosynthetic rate to make better use of limited water resources. In addition, the activity of peroxidase (POD) superoxide dismutase (SOD) and catalase (CAT) significantly increased to clear reactive oxygen species induced by drought stress, and to maintain the balance of the generation and elimination of reactive oxygen species. Plant tolerance coefficient reached 0.72, All these indicate that P. sinese has strong drought resistance Under the Cd stress, plants changed its growth characteristics and adapted the stress by increasing plants’carotenoids, proline and activity of CAT. In the interaction, both Cd and water deficit upset the balance of reactive oxygen species. In addition, the increase in activity of CAT, POD, and APX suggested that modulation in antioxidant enzymes is an important way to control the accumulation of reactive oxygen species, and maintain the balance between ROS production and scavenging, when exposed to the interaction treatment. As a result, although the interaction treatment induced a decrease in growth, nutrient accumulation and biomass of P. sinese, when compared to a single stress, the decrease extent was not significant, which indicated that there was not a synergistic effect induced by the interaction treatment.When comes to the capacity of Cd extraction, plants could accumulated more amount of Cd when there is adequate water in the soil, when compared to drought stress conditions. Our results showed that under the stress of cadmium stress and the interaction of P. sinese cadmium content were:5.41 mg/kg and 4.60 mg/kg, According to projections of the P. sinese’s average fresh yield was 213,900 kg/hm2 and the dry matter yield of about 150,000 kg/hm2,P. sinese can extract 0.82 kg/hm2 and 0.69 kg/hm2 of cadmium. Based on the repair characteristics of cadmium and drought resistance of P. sinese, indicating it might be applied in extreme environments, simultaneous exposure to multiple environmental stresses for agricultural production and environmental restoration. |
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