RNA editing was a biological process that the RNA molecular occurred base change or modification to result in the change of genetic information at the post-transcriptional level.As one of the most post-transcriptional regulation methods in higher plant,RNA editing played the vital roles in higher plants,such as biological development,stress response,cell organelle biosynthesis,and so on.In order to understand the composition and characteristic of Triticum urartu chloroplast genome RNA editing,we systematically predicted and identified the RNA editing sites in T.urartu chloroplast using bioinformatics analysis combined with RT-PCR.Bioinformatics analysis showed that in the 75 protein coding gene,15 gene occurred RNA editing.A total of 33 sites distributed in 15 genes were predicted,all of which were C to U conversion.Among them,ndhB had the most editing sites.Than we randomly selected 5 genes to validate the editing sites.Furthermore,we predicted the protein's secondary structure and transmembrane domain of these five genes that had occurred gene editing.Results showed that the secondary structures of all these genes were changed,and the transmembrane domains of ndhB were also changed.Finally,we compared the similarities and differences of the chloroplast RNA editing sites of T.urartu and other five Triticum species.It was found that the chloroplast editing site had been highly conserved in wheat crops.Meanwhile we also found specific editing sites of individual species.This study laid a foundation for further study on the biological function of chloroplast RNA editing in T.urartu,which also provided the important information to revealing the origin and evolution of wheat from the perspective of RNA editing.

This study aims to evaluate the relationship between loess soil-based sediment transport capacity and the most well-known and extensively used shear stress and unit stream power for different steep slopes. This study also determined the suitability of shear stress- and unit stream power-based transport capacity functions for rill flow on non-erodible bed.

Sediment transport is an important aspect of soil erosion, and sediment transport capacity (Tc) is a key to establishing process-based erosion models. A lot of studies exist that have determined Tc for overland flow, however, few studies have been conducted to determine Tc for loess sediments on steep slopes. Experimental data for this region are thus needed. The objectives of this study are to formulate new equations to describe Tc and evaluate the suitability of these equations for loess sediments on steep slopes. The slope gradients in this study ranged from 10.51% to 38.39%, and flow discharges per unit width varied from 1.11×10−3m2s−1 to 3.78×10−3m2s−1. Results showed that Tc increased as a power function with flow discharge and slope gradient, with R2=0.99 and Nash–Sutcliffe model efficiency (NSE)=0.99. Tc was more sensitive to flow discharge than slope gradient. Tc increased as a power function with mean flow velocity, which was satisfied to predict Tc with R2=0.99 and NSE=0.99. Shear stress (R2=0.89, NSE=0.88) was also a good predictor of Tc, and stream power (R2=0.96, NSE=0.96) was a better predictor of Tc than shear stress. However, unit stream power was not a good predictor to estimate Tc in our study, with R2=0.63 and NSE=0.62. These findings offer a new approach for predicting Tc for loess sediments on steep slopes.

This study aims to verify the performances of Water Erosion Prediction Project (WEPP) rill erosion equation using loess material by investigating the variations of soil detachment rate with sediment load by rill flow, quantifying the response of soil detachment rate to sediment load, and comprehensively examining WEPP rill erosion equation, so as to provide scientific basis for the application of WEPP model on the loess plateau and to sufficiently understand the response of soil detachment rate to sediment load.

Waste grassland is the main primary land type in the construction area of Banduo hydropower station of the Yellow River. Exploring its erosion process may provide an important basis for the quantitative evaluation of soil and water loss in the area. Based on field scouring experiment, the erosion processes of waste grassland in the Banduo hydropower station project area in the Yellow River are studied and following results are obtained. Both the erosion rates under different slopes and different water supply discharge show overall decrease trend and finally reach relative stability, which can be described through logarithmic equation and power equation, respectively. The main difference between them is that under different slope, the erosion rate falls rapidly after 5 minutes of runoff and then the decrease rate become slower, while under different water supply discharges, it falls rapidly in 15 minutes; the erosion modulus increases with the slope and water supply discharge, an exponential equation can be used to describe the trend. While a dual power equation can be used for the description of combined effects of both factors.

Sheet flow runoff on loess hillslope was studied through simulated rainfall experiments,under the conditions of rainfall intensities of 1.00,1.33,1.67,2.00,2.33 mm min-1 and slopes of 9°,12°,15°,18°,21°.Results show that 1) regardless of rain intensity and slope degree,the runoffs displayed a general trend in rate,that is,increasing first and leveling off late,however,the turning point came 5 min earlier in treatments of rain intensity than in treatments of slope degree,and the variation could be described with a logarithm equation y=aLn(x)+b;2) depth of the sheet flow runoff varied with rainfall intensity and slope gradient as well,which could be described with a power function equation H=aIb and H=aS b respectively;3)the integrated response of the runoffs in depth to rainfall intensity and slope gradient could be described with a dual power function equation H=3.83I1.01S0.490,and the response to rainfall intensity was greater than to slope gradient;and 4)the effect of sheet flow runoffs on sheet erosion was significant,and varied with rainfall intensity and slope gradient,which could be described with a power function equation M=0.0 378 H1.21and a linear equation M=0.235 H-3.48 respectively.

采用具有定流量放水组合小区模拟降雨试验方法,对黄土坡面细沟侵蚀过程进行模拟试验.结果表明:不同坡度和不同降雨强度下,细沟侵蚀率都呈现随径流变化过程的递增而增大的趋势,并且幂函数方程可以较好地模拟出其变化过程,同时在径流变化过程中,不同坡度下细沟侵蚀率随径流过程变化的递增速率总体上大于不同降雨强度下的递增速率；细沟侵蚀模数随坡度及降雨强度的增大皆增大,可分别用对数方程及指数方程很好地描述,坡度及降雨强度对细沟侵蚀模数的综合作用可用二元幂函数方程很好地描述；试验条件下,水流切应力是细沟侵蚀过程发生发展的动力根源.

Water transport capacity is a very important parameter of soil erosion, accurately calculating it which can reveal the mechanism of the process of rill erosion effectively and provide a significant basis for establishing process-based model. In the paper, the variation of rill flow sediment transport capacity was studied by a flume. Results showed that： （1）Rill flow sediment transport capacity increased smoothly with flow discharge at different slope gradients and could be described by power equation; rill flow sediment trans- port capacity increased with slope gradient at different flow discharges and could be described by linear equa- tion; rill flow sediment transport capacity which varied with slope gradients and flow discharge could be de- scribed by a dual binary power function, the effect of flow discharge was greater than slope gradient in the power function; ANSWERS model was not well predicted sediment transport capacity of sheet flow over loess slope.

Flow velocity is one of the most basic and important hydraulic parameters.Clarifying the variation of rill flow velocity is of importance to reveal the mechanisms of dynamic rill erosion processes.Rill flow velocity on loess hillslope is studied through a multi-plot experiment under simulated rainfall with the addition of a steady in-flow at the top of the multi-plot system.The main findings are as follows:(1) Rill flow velocities for different rainfall intensities decrease with runoff duration,which can be well described by an exponential equation.The decrements are great 6 min after runoff generation and then decline.The tendencies are basically consistent for the decrements at different intensities.(2) Rill flow velocities for different slopes also decrease with runoff duration,which can be described by an exponential equation.The tendencies for the decrements on different slopes are consistent.The decrements are basically consistent during the whole runoff process.(3) The mean flow velocity increases with increased rainfall intensity,which can be well described by a logarithmic equation,and increases with increased slope steepness,which can be well described by a power equation.A dual logarithmic equation can be used to describe the variation of the mean flow velocity with rainfall intensity and slope.

As sheet erosion has spatial variations along slope,it is important for the improvement of soil erosion theory to explain soil erosion process on different segments of a hillslope.Sheet erosion characteristics on downslope were analyzed based on experiments of simulated rainfall with multiple plots.The results show that the sheet erosion characteristics on the down slopes differed from those on the whole slopes and upslopes.The sheet erosion on downslopes displayed extremely strong variability.The sheet erosion rates fluctuated with rainfall course,rainfall intensity,and slope gradient.Generally,it increased with the increased time at beginning and then stabilized.The rate increased with slope gradient and rainfall intensity.The variation of sheet erosion modulus with rainfall intensity and slope gradient can be described by a duality linear equation and rainfall intensity affected sheet erosion modulus much greater than slope gradient.The impact of runoff from both upslope and downslope and sediment from upslope on downslope sheet erosion were described by a duality linear equation,with contributions of 56.9% and 25.4%,respectively.Runoff had a greater effect than sediment.It can effectively control sheet erosion on downslope to take measures such as increasing the infiltration and reducing runoff.

Runoff-induced sediment discharge is one of the most important process of erosion and sediment yield.It is important to clarify the relationships of runoff-induced sediment discharge and hydrodynamic parameters of rill flow on loess hillslope.In this paper,the relationships were studied by experiment of simulated rainfall and constant flow using group plots.Results showed that: 1) In single rainfall-runoff event,the response of sediment transport modulus to mean hydrodynamic parameters was given as follows: mean unit energy(R=0.99)>mean stream power(R=0.88)>mean stream shear stress(R=0.82)>mean unit stream power(R=0.76).2) During the rainfall-runoff process,the response of the sediment transport rate to stream shear stress(R=0.88) was greater than stream power(R=0.47),and the correlations of sediment transport rate with unit energy and with unit stream power were weak.The relationship of stream shear stress and the sediment transport rate could be expressed by power functions.