In this paper, a low kilo-volt-ampere rating zigzag connected autotransformer based 36-pulse rectifier system supplying vector controlled induction motor drives (VCIMD) is designed, modeled and simulated. Detailed design procedure and magnetic rating calculation of the proposed autotransformer and interphase reactor is studied. Moreover, the design process of the autotransformer is modified to make it suitable for retrofit applications. Simulation results confirm that the proposed 36-pulse rectifier system is able to suppress less than 35th harmonics in the utility line current. The influence of load variation and load character is also studied to demonstrate the performance and effectiveness of the proposed 36-pulse rectifiers. A set of power quality indices at AC mains and DC link are presented to compare the performance of 6-, 24- and 36-pulse AC-DC converters.
Salt stress inhibited the growth of both tasg1 and wild-type (WT) wheat seedlings, but the inhibition in tasg1 plants was relatively weaker than that of WT. Compared to the WT, the chlorophyll content, thylakoid membrane polypeptides, Hill reaction activity, actual photochemical efficiency of PSII (ΦPSII), and Mg²⁺- and Ca²⁺-ATPase activities were higher in tasg1 under salt stress. At the same time, the photosynthetic activity of the tasg1 was significantly higher than that of WT. In addition, tasg1 plants displayed relatively less accumulation of reactive oxygen species and oxidative damage accompanied by higher activity of some antioxidant enzymes, and the up-regulation of antioxidant genes further demonstrated the improvement of antioxidant activity in tasg1 under salt stress. Furthermore, tasg1 plants also showed relatively weaker Na⁺ fluorescence and lower Na⁺ content, but relatively higher content of K⁺ in their roots and shoots, and then, the roots of tasg1 plants enhanced net outward Na⁺ flux and a correspondingly increased net inward K⁺ flux during salt stress. This might be associated with the relatively higher activity of H⁺-ATPase in tasg1 plants. These results suggest that the improved antioxidant competence and Na⁺/K⁺ ion homeostasis play an important role in the enhanced salinity tolerance of tasg1 plants.
Plant-specific NAM, ATAF1/2, and CUC (NAC) transcription factors serve essential functions in plant development and plant responses to environmental cues. Yet, transcription factors specific to the rose (Rosa hybrida) NAM/CUC3 subfamily are poorly understood. Here, we identify a novel NAM/CUC3-subfamily transcription factor, RhNAC31, that is associated with flower opening and can be induced by increased salt, cold, and dehydration stress treatment. RhNAC31 has a transactivation region in its C-terminal region, and its overexpression is associated with enhanced cold tolerance in Arabidopsis, conferring a higher survival rate and reduced reactive oxygen (H₂O₂ and O₂⁻) levels. Under salt stress conditions, plants overexpressing RhNAC31 displayed increased germination rates and lower levels of H₂O₂, malondiadehyde (MDA), peroxidase (POD), and superoxide dismutase (SOD). Moreover, RhNAC31 conferred enhanced drought resistance by reducing the rate of water loss through leaves. Further characterization revealed a higher sensitivity of RhNAC31 transgenic plants to abscisic acid (ABA) both during and post-germination, causing lower germination and root inhibition rates under ABA treatment. Quantitative PCR experiments showed that numerous abiotic stress-related genes were activated by RhNAC31 overexpression. Our results highlight RhNAC31 as a positive transcriptional regulator of tolerance to multiple abiotic pressures, and we conclude that RhNAC31 has potential for use in the molecular breeding of stress-tolerant crops.
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