Nitrogen (N), the major forms of which are nitrate (NO₃^–) and ammonium (NH₄⁺), plays an important role in plant growth and mediation of root development.  However, the role of auxin in root growth in response to different NH₄⁺/NO₃^– ratios remains unclear.  Two tobacco cultivars (Nicotiana tabacum L.) were adopted in this study, which displayed variant growth features under the situations with sole NO₃^– nutrition ratio (NH₄⁺/NO₃^– ratio: 0/100), low NO₃^– nutrition ratio (NH₄⁺/NO₃^– ratio: 97/3), and optimal NH₄⁺/NO₃^– ratio (50/50).  We investigated the effects of the different NH₄⁺/NO₃^– ratios on the formation and elongation of lateral roots (LRs), auxin concentration, DR5::GUS expression, 3H-labeled indole acetic acid ([3H]IAA) transport, and the expression of six PIN genes in tobacco roots.  We also examined the effects of exogenous auxin and a transport inhibitor on LRs growth.  The results are shown as follows, compared to optimal N nutrition conditions, the biomass and nitrogen (N) accumulation were largely reduced by sole and low NO₃^– nutrition treatment in NC89, but no difference was observed in Zhongyan 100.  In most cases, sole and low NO₃^– nutrition impaired the elongation and formation of first-order lateral roots (1° LRs), only in NC89, thus reducing the root growth.  IAA concentration and DR5::GUS expression levels decreased in roots when NC89 was subjected to sole and low NO₃^– nutrition media, suggesting that different NH₄⁺/NO₃^– ratios affect the transport of auxin from leaves to roots.  Results were similar following exogenous NAA application to low NO₃^– nutrition treated seedlings.  Based on direct [3H]IAA transport measurement, the transport of polar auxin from shoots to roots decreased due to low NO₃^– nutrition.  PIN4 expression levels were markedly decreased in roots of NC89 by sole and low NO₃^– nutrition, while they were unaffected in Zhongyan 100 roots.  Overall, our findings suggest that LRs formation in tobacco seedlings is regulated by NH₄⁺/NO₃^– ratios via modifying polar transport of auxin.

This study was carried out to evaluate the effects of graded levels of fiber from rice hull and the caecectomy on metabolizable energy (ME) and amino acid digestibility (AAD) in 42 Wuzong geese (21 intact and 21 caecectomized). The experiment was a 3×2 factorial randomized design with 3 fiber levels and 2 treatments of geese (caecectomized and intact). Each of the 3 diets was tube-fed (60 g) to 7 caecectomized and 7 intact adult Wuzong geese that had been fasted for 24 h. Excreta were collected for the next 48 h. The same geese were also fasted for estimation of endogenous losses of amino acids (AA) and energy after short period recovery. AA content and metabolizable energy value were determined in the excreta. In general, significant effects were found for fiber levels on apparent digestibility of Thr, Leu, Pro, Glu,Val, Ala and total AA (P<0.05). Apparent metabolizable energy (AME) and true metabolizable energy (TME) were both significantly influenced by increased fiber levels (P<0.01). Compared with caecectomized geese, markedly increases of AME and TME were found in intact geese (P<0.01 for AME and P<0.05 for TME), but no difference in the AAD were found between intact and caecectomized geese (P>0.05), except for Lys and Try (P<0.05). These observations suggested that dietary fiber level played an important role in digestibility of AAD and ME. Intact geese should be chosen for the nutrient evaluation of feedstuffs in practice, resulting from the significant difference between caecectomized and intact geese.

Careful soil management is important for the soil quality and productivity improvement of the reclaimed coastal tidal flat saline land in northern Jiangsu Province, China. Farmyard manure (FYM) and mulch applications, which affect soil characteristics and plant significantly, are regard as an effective pattern of saline land improvement. As a conventional management in the study region, FYM and mulch are used for the amendment of the new reclaimed tidal flat regularly, but little is known about their effects on soil physical properties functioning. A study was conducted on a typical coastal tidal flat saline land, which was reclaimed in 2005, to evaluate the effects of FYM, polyethylene film mulch (PM), straw mulch (SM), FYM combined with PM (FYM+PM), FYM combined with SM (FYM+SM), on soil hydraulic properties and soil mechanical impedance. CK represented conventional cultivation in study area without FYM and mulch application and served as a control. The experiment, laid out in a randomized complete block design with three replications, was studied in Huanghaiyuan Farm, which specialized in the agricultural utilization for coastal tidal flat. Result showed that capillary water holding capacity (CHC), saturated water content (SWC), saturated hydraulic conductivity (Ks) and bulk density (BD), cone index (CI) were affected significantly by the FYM and mulch application, especially in the 0-10 cm soil layer. FYM and mulch management increased CHC, SWC and Ks over all soil depth in the order of FYM+SM>FYM+PM>FYM>SM>PM>CK. With the contrary sequence, BD and CI decreased significantly; however, FYM and mulch application affected BD and CI only in the upper soil layers. CHC, SWC and Ks decreased significantly with the increasing of soil depth, BD and CI, and a significant liner equation was found between CHC, SWC, Ks and BD, CI. With the highest CHC (38.15%), SWC (39.55%), Ks (6.00 mm h-1) and the lowest BD (1.26 g cm-3) and CI (2.71 MPa), the combined management of FYM and SM was recommend to be an effective method for the melioration of reclaimed coastal tidal flat saline soil.

RNAi trigged by dsRNA not only facilitates the development of molecular biology, but also initiates a new way for pest control by silence of fatal genes. However, one of the key limitations in pest control is lack of the convenient and efficient method for dsRNA delivery. In this study, different dsRNA delivery methods at their own optimum conditions were evaluated comparatively for their efficiency with Helicoverpa armigera as test animal. It was found that the popular one- time injection of larvae with dsRNA could reduce the pupation rate by 43.0% and enhance larva mortality by 11.7%. One- time ingestion of dsRNA did not result in any significant effect on phenotype. Continuous ingestion of in vitro synthesized dsRNA by refreshing the bait diet every day caused 40.4% decrease in successful pupation and 10.0% increase in larval mortality, which was similar as one-time injection. The most efficient method was found to be the continuous ingestion of the bacteria containing dsRNA expressed, which reduced the rate of pupation by 68.7% and enhanced the larval mortality by 34.1%. Further analysis found that dsRNA was degraded faster in midgut juice than in hemolymph. However, the cell of bacteria could protect dsRNA and delay the degradation in the midgut juice of H. armigera. These results throw light on the application of dsRNA in pest management with proper ways.

The combined effects of salinity with low root zone temperature (RZT) on plant growth and photosynthesis were studied in tomato (Solanum lycopersicum) plants. The plants were exposed to two different root zone temperatures (28/20°C, 12/8°C, day/night temperature) in combination with two NaCl levels (0 and 100 mmol L-1). After 2 wk of treatment, K+ and Na+ concentration, leaf photosynthetic gas exchange, chlorophyll fluorescence and leaf antioxidant enzyme activities were measured. Salinity significantly decreased plant biomass, net photosynthesis rate, actual quantum yield of photosynthesis and concentration of K+, but remarkably increased the concentration of Na+. These effects were more pronounced when the salinity treatments were combined with the treatment of low RZT conditions. Either salinity or low RZT individually did not affect maximal efficiency of PSII photochemistry (Fv/Fm), while a combination of these two stresses decreased Fv/Fm considerably, indicating that the photo-damage occurred under such conditions. Non-photochemical quenching was increased by salt stress in accompany with the enhancement of the de-epoxidation state of the xanthophyll cycle, in contrast, this was not the case with low RZT applied individually. Salinity stress individually increased the activities of SOD, APX, GPOD and GR, and decreased the activities of DHAR. Due to the interactive effects of salinity with low RZT, these five enzyme activities increased sharply in the combined stressed plants. These results indicate that low RZT exacerbates the ion imbalance, PSII damage and photosynthesis inhibition in tomato plants under salinity. In response to the oxidative stress under salinity in combination with low RZT, the activities of antioxidant enzymes SOD, APX, GPOD, DHAR and GR were clearly enhanced in tomato plants.

Land use practice significantly affects soil properties. Soil is a major sink for atmospheric carbon, and soil organic carbon (SOC) is considered as an essential indicator of soil quality. The objective of this study was to assess the effects of N and P applied to Suaeda salsa on biomass production, SOC concentration, labile organic carbon (LOC) concentration, SOC pool and carbon management index (CMI) as well as the effect of the land use practice on soil quality of coastal tidal lands in east coastal region of China. The study provided relevant references for coastal exploitation, tidal land management and related study in other countries and regions. The field experiment was laid out in a randomized complete block design, consisting of four N-fertilization rates (0 (N0), 60 (N1), 120 (N2) and 180 kg ha-1 (N3)), three P-fertilization rates (0 (P0), 70 (P1) and 105 kg ha-1 (P2)) and bare land without vegetation. N and P applied to S. salsa on coastal tidal lands significantly affected biomass production (above-ground biomass and roots), bulk density (ρb), available N and P, SOC, LOC, SOC pool and CMI. Using statistical analysis, significantly interactions in N and P were observed for biomass production and the dominant factor for S. salsa production was N in continuous 2-yr experiments. There were no significant interactions between N and P for SOC concentration, LOC concentration and SOC pool. However, significant interaction was obtained for CMI at the 0-20 cm depth and N played a dominant role in the variation of CMI. There were significant improvements for soil measured attributes and parameters, which suggested that increasing the rates of N and P significantly decreased ρb at the 0-20 cm depth and increased available N and P, SOC, LOC, SOC pool as well as CMI at both the 0-20 and 20-40 cm depth, respectively. By correlation analysis, there were significantly positive correlations between biomass (aboveground biomass and roots) and SOC as well as LOC in 2010 and 2011 across all soil depth, respectively. The treatment with N at 180 kg ha-1 and P at 105 kg ha-1 was superior to the other treatments. The results from the 2-yr continuous experiments indicated that, in short-term, there were a few accumulation of SOC and LOC concentrations by means of N and P application to S. salsa, whereas in the long run, S. salsa with N and P application was recommended for coastal tidal lands because of its great potential of carbon sequestration, improvements of soil nutrition status and promotion of soil quality.

To better understand soil moisture dynamics in the Yangtze River Estuary (YRE) and predict its variation in a simple way, a field monitoring experiment was carried out along the north branch of the Yangtze River, where seawater intrusion was strong and salt-water variation is one of the limiting factors of local agriculture. In present paper, relation between antecedent precipitation index (API) and soil water content is studied, and effects of groundwater depth on soil water content was analyzed. A relatively accurate prediction result of soil water content was reached using a neural network model. The impact analysis result showed that the variation of the API was consistent with soil water content and it displayed significant correlations with soil water content in both 20 and 50 cm soil layer, and higher correlation was observed in the layer of 20 cm. Groundwater impact analysis suggested that soil moisture was affected by the depth of groundwater, and was affected more greatly by groundwater at depth of 50 cm than that at 20 cm layer. By introducing API, groundwater depth and temperature together, a BP artificial network model was established to predict soil water content and an acceptable agreement was achieved. The model can be used for supplementing monitoring data of soil water content and predicting soil water content in shallow groundwater areas, and can provide favorable support for the research of water and salt transport in estuary area.

The effects of different levels of CaCl2 on photosynthesis under low night temperature (8°C) stress in peanuts were studied in order to find out the appropriate concentration of Ca2+ through the artificial climate chamber potted culture test. The results indicated that Ca2+, by means of improving the stomatal conductivity of peanut leaves under low night temperature stress, may mitigate the decline of photosynthetic rate in the peanut leaves. The regulation with 15 mmol L-1 CaCl2 (Ca15) was the most effective, compared with other treatments. Subsequently, the improvement of Ca2+ on peanut photosynthesis under low night temperature stress was validated further through spraying with Ca15, Ca2+ chelator (ethylene glycol bis(2-aminoethyl) tetraacetic acid; EGTA) and calmodulin antagonists (trifluonerazine; TFP). And CaM (Ca2+-modulin) played an important role in the nutritional signal transduction for Ca2+ mitigating photosynthesis limitations in peanuts under low night temperature stress.

The aim of this paper was to research the spatio-temporal changes in total soluble salt content (TS) in a typical arid region of South Xinjiang, China, where the climate is arid and soil salinization happens easily. The total soluble salt content was interpreted by measurements made in the horizontal mode with EM38 and EM31. The electromagnetic induction (EM) surveys were made three times with the apparent soil electrical conductivity (ECa) measurements taken at 3 873 locations in Nov. 2008, 4807 locations in Apr. 2009 and 6 324 locations in Nov. 2009, respectively. For interpreting the ECa measurements into total soluble salt content, calibtion sites were needed for EM survey of each time, e.g., 66 sites were selected in Nov. 2008 to measure ECa, and soils-core samples were taken by different depth layers of 0-10, 10-20 and 20-40 cm at the same time. On every time duplicate samples were taken at five sites to allevaite the local-scale variability, and soil temperatures in different layers through the profiles were also measured. Factors including TS, pH, water content, bulk density were analyzed by lab experiments. ECa calibration equations were obtained by linear regression analysis, which indicated that soil salinity was one primary concern to ECa with a determination coefficient of 0.792 in 0-10 cm layer, 0.711 in 10-20 cm layer and 0.544 in 20-40 cm layer, respectively. The maps of spatial distribution were predicted by Kriging interpolation, which showed that the high soil salinity was located near the drainage canal, which validated the trend effect caused by the irrigation canal and the drainage canal. And by comparing the soil salinity in different layers, the soluble salt accumulated to the top soil surface only in the area where the soil salinization was serious, and in the other areas, the soil salinity trended to increase from the top soil surface to 40 cm depth. Temporal changes showed that the soil salinity in November was higher than that in April, and the soil salinization trended to aggravate, especially in the top soil layer of 0- 10 cm.

Crop models can be useful tools for optimizing fertilizer management for a targeted crop yield while minimizing nutrient losses. In this paper, the parameters of the decision support system for agrotechnology transfer (DSSAT)-CERES-Maize were optimized using a new method to provide a better simulation of maize (Zea mays L.) growth and N uptake in response to different nitrogen application rates. Field data were collected from a 5 yr field experiment (2006-2010) on a Black soil (Typic hapludoll) in Gongzhuling, Jilin Province, Northeast China. After cultivar calibration, the CERES-Maize model was able to simulate aboveground biomass and crop yield of in the evaluation data set (n-RMSE=5.0-14.6%), but the model still over-estimated aboveground N uptake (i.e., with E values from -4.4 to -21.3 kg N ha-1). By analyzing DSSAT equation, N stress coefficient for changes in concentration with growth stage (CTCNP2) is related to N uptake. Further sensitivity analysis of the CTCNP2 showed that the DSSAT model simulated maize nitrogen uptake more precisely after the CTCNP2 coefficient was adjusted to the field site condition. The results indicated that in addition to calibrating 6 coefficients of maize cultivars, radiation use efficiency (RUE), growing degree days for emergence (GDDE), N stress coefficient, CTCNP2, and soil fertility factor (SLPF) also need to be calibrated in order to simulate aboveground biomass, yield and N uptake correctly. Independent validation was conducted using 2008-2010 experiments and the good agreement between the simulated and the measured results indicates that the DSSAT CERES-Maize model could be a useful tool for predicting maize production in Northeast China.

To evaluate the month-wise prevalence of subclinical mastitis (SM) and its relations with climatic temperature and humidity, and to provide references for control and prevention of mastitis in dairy cows in Guangdong, China, California mastitis test method was used to determine the monthly prevalence of SM (MPSM, %) of lactating Holstein cows from 11 dairy farms in Guangdong Province, China, including about 516 cows per monthly examination. The average MPSM on a cow and a quarter basis were 30 and 13% respectively, and there was a positive linear correlation between monthly mean air temperature (MT, °C) and MPSM on a cow basis (r=0.763, P=0.004) or a quarter basis (r=0.577, P=0.049), but there were no correlations between MT and MPSM on a cow or a quarter basis (P>0.05). There was a shift in MPSM trend that the highest MPSM (38.4%) was not for the hottest July with MT at 30.8°C, but for the later September at 27.9°C. The farms need to develop new housing conditions to control cowshed temperatures in the hot season to reduce the mastitis prevalences in the posthot months.

The objective of the present study was to evaluate potential adverse effects of diacylglycerol microemulsion (DAGM) inrats/mice. Acute safety evaluation was carried out by giving intragastrically with 20 mL 25% DAG kg-1 body weight ofDAGM or water with two groups of mice. Chronic safety evaluation with 40 male and 40 female Sprague-Dawley rats wascarried out by setting a control group and 3 different dose groups (n=10 male+10 female) administered with DAGM with6.7, 10 and 20 mL kg-1 body weight per day. Relevant parameters of liver and kidney function and biochemistry weredetermined by standard methods at end point. Acute toxicity study revealed the maximum tolerated dose (MTD) ofDAGM was 20 mL kg-1 body weight in mice. No death was observed at the dose of 20 mL kg-1 body weight per day. Chronicsafety evaluation did not show significant changes on hematological, histopathologic, clinical, and biochemical testswhen administered at levels of 6.7, 10 and 20 mL kg-1 body weight per day to rats for 30 d. No significant body weightchanges were observed in different dosages in both male and female rats. Our results suggested that acute and chronicadverse effects were not observed in histology and clinical parameters in both mice and rats. The results suggested thatDAGM is safe at the experimental levels.

To investigate the effects of dietary supplementation with hydrolyzed wheat gluten (HWG) on growth performance, cell immunity and serum biochemical indices of weaned piglets, 160 crossed (Large White x Landrace) and weaned piglets were randomly divided into 4 treatments with 4 replicates of 10 piglets each. The piglets in each treatment were fed an experimental diet containing either 0 g kg^-1 HWG (control group), 30 g kg^-1 HWG (3% HWG group), 50 g kg^-1 HWG (5% HWG group), or 2.5 g kg^-1 glycyl-L-glutamine (0.25% Gly-Gln group). The results showed that the diarrhea rates in 3% HWG and 5% HWG groups were significantly lower than in control group from d 1 to 14 (P<0.05). When compared with control group, dietary supplementation with 3% HWG increased the ratio of CD₄ ⁺:CD₈ ⁺ and the ratio of serum albumin and globulin concentrations (A:G) on d 14 and 28, as well as the proliferation of T- and B-lymphocytes (P>0.05) on d 28. In addition, on d 14 and 28, the A:G ratio in 5% HWG group was significantly higher than in control group (P0.05). Interestingly, 0.25% Gly-Gln group had higher proportion of CD₃ ⁺ (P>0.05) and CD₄ ⁺ (P<0.05) on d 14 than control group, but growth performances of 0.25% Gly-Gln group were negatively affected at all experiment stages. These results suggested that HWG might improve the growth performance of piglets by strengthening cell immunity and decreasing the occurrence of diarrhea during the prophase after weaning.