Endophytic bacteria play crucial roles in plant pathogen protection and growth. Oryza eichingeri is a unique wild rice species rich with genetic resources. Studies have explored beneficial endophytic bacteria and investigated the synergistic interaction between microbes and wild rice. However, the endophytic bacterial community of Oryza eichingeri and their plant growth-promoting (PGP) abilities characteristics remain largely unknown. Here, endophytic bacteria in the root, stem, and leaf tissues of Oryza eichingeri were characterized using metagenomic Illumina 16S rRNA gene sequencing. Additionally, culturable endophytic bacteria were isolated. The metagenomic analysis showed that, compared to those in other tissue compartments, the endophytic bacterial community in the roots had a more complex structure and enhanced functions, and each compartment had its own specific endophytic bacterial biomarkers. A total of 94 endophytic bacteria were isolated from Oryza eichingeri, among which 80 strains possessed PGP traits including increasing phosphate solubilization, siderophore production, IAA production, and nitrogen fixation. These strains displayed good PGP effects on cultivated rice seedlings, promoting the formation of strong root systems, stimulating biomass accumulation, and increasing root length and plant height. These findings provide insights into the composition of the bacterial endosphere of Oryza eichingeri and potential applications of the dominant PGP bacteria in rice cultivation.
As the nominal voltage of power transmission system rising,switching overvoltage has more and more important effect on the insulation of equipments.How to calculate the switching overvoltage accurately has attracted much more attention.At present,the attenuation and distortion of overvoltage caused by switching impulse corona are ignored in the calculations.Switching impulse corona experiments on the conductors of the type that commonly used in China are carried out in the UHV test base.The results show that the switching impulse corona incepts as the voltage exceeds the inception voltage.Long wave front time switching impulses generate more space charge than standard switching impulse.Positive impulses generate stronger corona than the negative impulses.In the end,controllable breaker is suggested to be used in the transmission lines.As a result,only positive switching corona will be generated and the switching overvoltage will be greatly decreased.
In this paper, the experimental results of the quantitative transition condition between streamer and leader are presented for a plane-rod gap. The charge injected into the rod, energy input caused by charge moving in streamer channel before the first leader, and charge injection during leader discharge are measured and calculated. The test gives new results: (1) the charge injected to the rod prior to inception leader point is increased correspondingly from 3.9 /spl mu/C to 11.1 /spl mu/C with the change of the time to peak of switching impulse from 100 /spl mu/s to 250 /spl mu/s; (2) the more charge needed at transition point from streamer to leader discharge, the higher the sparkover voltage, but the smaller the charge injected to the rod during the leader discharge; (3) the relationship of energy input to streamer channel and sparkover voltage is obtained. The more the energy input, the lower the sparkover voltage; and (4) in the U50% breakdown case, with increase time to peak of impulse voltage, the injected charge in the leader up to the point where voltage collapsed tends to decrease, but the instantaneous voltage at this transition point tends to increase.
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