Sex-specific Responses Of Populus Deltoids To Winter Waterlogging Stress

Three Gorges Reservoir (TGR) forms 30 m water-level fluctuation zone(WLFZ), causing a sharp drop in the plant diversity and a series of ecological problems. WLFZ is very important in maintaining stability of bank, reducing soil erosion, keeping ecological landscape and water purification. Thus, it’s significant to build ecological shelter. Poplar trees could survive in the upper section of WLFZ and were used for both forest restoration and protection in TGR. They are usually used as pioneer species in extreme environment. Previous studies showed that Populus deltoids have a strong ability to waterlogging stress and have gender differences in response to abiotic stress. Specific response to waterlogging stress between male and female trees was compared in this study through simulating winter flooding condition. The results indicated that male Populus was more tolerant to waterlogging stress than female through regulation of ROS pathway and extensive proteomic reprogramming.1 Comparative analyses of universal extraction buffers for assay of stress related biochemical and physiological parametersTo reduce costs of materials and labor, it’s necessary to develop a universal extraction solution for most physiological parameter assay. The extraction efficiency of commonly used sodium phosphate buffer and Tris-HCl buffer were compared and the results showed that 100 mmol/L universal sodium phosphate buffer was suitable for extracting GR, GPx, CAT, SOD, O2-, soluble protein and free proline.2 Different physiological and biochemical responses between male and female of Populus deltoids under waterloggingBoth male and female were survived after 130 days waterlogging stress. It showed Populus deltoides had a strong ability to waterlogging stress. However, they performed different in plant growth and development, physiological and biochemical aspects. Under normal water condition, the female showed better growth than male plants and accumulated higher amount reduced sugar accumulation, O2-,. OH, APx, CAT, A and WUEi. However, in waterlogged condition, the female had more negative impacts than male plants in its Ci, H2O2, MDA, resulted in decreased height and stem diameter; Moreover, the male plants showed increased GSH, SOD and POD than female plants. In addition, male and female plants had no significant differences in terms of chlorophyll fluorescence before and after the waterlogging stress.3 Proteomics analysis between male and female of Populus deltoids under waterloggingProteomic changes of male and female plant leaves were analyzed using iTRAQ technology. In total 757 proteins were identified by at least one comparison with 2-fold changes. Among them,25 proteins were female specific and induced by waterlogging treatment in female. These proteins were constitutively highly expressed in male plants. Another 80 proteins showed decreased expression in male in relative to females, and waterlogging treatment repressed the expression levels in females. These 105 proteins might be directly involved in Populus response to waterlogging. Pathway enrichment analysis indicated that the functions of these proteins were mainly involved in Transcription, Replication, Recombination and Repair, Post Modification, Protein Turnover, Chaperones, Coenzyme Transport, Metabolism and other pathways.In conclusion,100 mmol/L universal sodium phosphate buffer can be used in extraction GR, GPx, CAT, SOD, O2-, soluble protein and proline. Under waterlogged conditions for 130 days, Populus deltoids showed a strong adaption to waterlogging. However, there are differences between morphology, physiology, biochemical and protein. The male Populus was comparatively tolerant to waterlogging when compared to female through regulation of ROS and protein metabolism.