磷矿周围环境砷污染情况调查

调查磷矿周围环境和畜禽组织砷含量,为掌握磷矿区周围畜禽产品安全提供依据。采用原子吸收光谱法进行测定。结果表明,环境中砷含量从高到低依次为水体、白菜、土壤、大米、玉米、牧草,而辣椒和萝卜未检出砷;鸡内脏及肌肉砷含量从高到低依次为肾脏、肺脏、心脏、肝脏、脾脏、肌肉;鸭内脏及肌肉砷含量从高到低依次为肾脏、肝脏、肺脏、肌肉、脾脏、心脏;猪内脏及肌肉砷含量从高到低依次为肠、肾脏、肝脏、脾脏,而心脏、肺脏和肌肉未检出。说明磷矿周围饲养的畜禽存在砷污染现象。     

Comparison of acid-detergent lignin,alkaline-peroxide lignin,and acid-detergent insoluble ash as internal markers for predicting fecal output and digestibilily by caltie offered bermudagrass hays of varying nutrient composition

Background： The potential for acid-detergent insoluble ash （ADIA）, alkaline-peroxide lignin （APL）, and acid-detergent lignin （ADL） to predict fecal output （FO） and dry matter digestibility （DMD） by cattle offered bermudagrass [Cynodon doctylon （L） Pers.] hays of different qualities was evaluated. Eight ruminally cannulated cows （594 ± 35.5 kg） were allocated randomly to 4 hay diets： low （L）, medium low （ML）, medium high （MH）, and high （H） crude protein （CP） concentration （79, 111,131, and 164 g CP/kg on a DM basis, respectively）. Diets were offered in 3 periods with 2 diet replicates per period and were rotated across cows between periods. Cows were individually fed 20 g DM/kg of body weight in equal feedings at 08：00 and 16：00 h for a 10-d adaptation followed by a 5-d total fecal collection. Actual DM intake （DMI）, DMD, and FO were determined based on hay offered, ort, and feces excreted. These components were then analyzed for ADL, APL, and ADIA concentration to determine marker recovery and marker-based estimates of FO and DMD. Results： Forage DMI was affected by diet （P = 0.02）, and DMI from MH and H was greater （P 〈 0.05） than from L. Apparent DMD tended （P = 0.08） to differ among diets while FO （P = 0.20） was not affected by diet treatments. Average ADL recovery （1.16） was greater （P 〈 0.05） than that of ADIA （1.03） and APL （1.06）, but ADIA and APL did not differ （P = 0.42）. Estimates of FO and DMD derived using APL and ADIA were not different （P≥0.05） from total fecal collection while those using ADL differed （P 〈 0.05）. There was no diet by marker interaction （P≥ 0.22） for either FO or DMD. Conclusion： Acid-detergent insoluble ash and APL accurately predicted FO and DMD of cattle fed bermudagrass hay of varying nutrient composition. These internal markers may facilitate studies involving large numbers of animals and forages. Results from such studies may be used to develop improve     

Comparison of 5′-inosine monophosphate and p-nitrophenyl phosphate degrading activities among red,pink, and white muscle fibers of cultured carp

ABSTRACT:   As part of a study to clarify the differences in the temporal change in K -value among fish species, the temporal change in K -value and the 5'-inosine monophosphate (5'-IMP) and p-nitrophenol phosphate (p-NPP) degrading activities in the red, pink, and white muscle fibers in the dorsal muscle of the carp were compared. The temporal change in K -value was fastest in red, followed by pink, and white muscle fibers, at both 0°C and 32°C. Moreover, the 5'-IMP and p-NPP degrading activities were highest in red, followed by pink, and white muscle fibers at near optimum pH concentrations. The 5'-IMP degrading activity at pH 7.0 had a positive correlation with the increasing rate of K -value at 32°C for all types of muscle fibers. These results suggest that differences in increasing rates of K -values between red, pink, and white muscle fibers corresponded to the 5'-IMP degrading activities.     

甘蔗SPS基因家族成员表达与糖分积累关系解析

以甘蔗高糖品种福农95-1702和低糖品种ROC-5为材料,分析SPS I、Ⅱ、Ⅲ、Ⅳ、Ⅴ在高、低糖这两个品种的幼叶、第三功能叶和不同蔗茎的表达,测定甘蔗糖分积累早期、中期和后期的糖分含量。结果显示,在功能叶和茎第二节中,三个阶段SPS家族成员在高糖品种的含量整体趋势高于低糖品种,结合蔗糖积累特点分析表明其可能在蔗糖合成中扮演着重要的角色。与正三叶相反,在幼叶中,三个阶段SPS家族成员在高糖品种的表达量整体趋势低于低糖品种,表明其可能与嫩叶的生长等其他生理性状相关,在成熟茎中,随着蔗糖积累时间的增加,高糖品种中的优势表达基因减少,而低糖品种中的优势表达基因增加,这可能与低糖品种中、后期大量积累蔗糖相关。     

启动磷肥不同施用方式对玉米养分吸收及生长和产量的影响

为了探索启动磷肥不同施用方式对玉米生长和产量的影响,设置启动磷肥大田滴施(T1)、穴施(T2)和不施启动磷肥(CK)3个施肥处理,其中启动肥磷肥用量为P₂O₅ 30 kg·hm^-2,探究启动磷肥不同施用方式对玉米生长、养分分配和产量构成的影响;设置启动磷肥根箱土壤滴施(P1)、穴施(P2)和不施启动肥(CF)3个处理,其中启动肥磷肥用量为P₂O₅ 0.2 g·kg^-1土,探究启动磷肥施用后土壤中磷素的空间分布与迁移效果。结果表明,玉米四叶期和六叶期,T1和T2处理均显著增加了苗期玉米总根长,根表面积,地上、地下部生物量和N、P、K养分积累量。在六叶期,T1和T2处理玉米总根长较CK分别增加了21.10%和30.35%,根系表面积分别增加了23.48%和29.20%,地上和地下部生物量分别增加了31.24%和52.38%、33.61%和57.81%。与CK相比,T1和T2处理促进了玉米N、P、K养分的积累,同时促进了养分由营养器官向生殖器官的转移。在玉米吐丝期至成熟期,T1和T2处理玉米N、P、K养分转移量较CK分别增加了29.75和44.73 kg·hm^-2、10.76和14.65 kg·hm^-2、2.20和24.67 kg·hm^-2。玉米穗长、行粒数、产量和磷肥偏生产力均表现为T2>T1>CK,玉米穗秃尖长度表现为T2相似文献   

富钾土壤中氮、磷肥不同水平对甘薯生长及产量的影响

试验研究了氮肥、磷肥不同水平对甘薯生长发育动态、产量的影响。结果表明,在氮肥试验中,氮水平为75 kg/hm2处理的薯块鲜质量和茎叶鲜质量都达到最大,鲜薯产量达51 519.25 kg/hm2,单株结薯数达5.0个,商品薯率为89.43%,平均单株薯质量为1084.71g;氮水平小于等于75 kg/hm2处理的薯块鲜质量和茎叶鲜质量均随着施氮水平的提高而提高;氮水平大于等于75 kg/hm2处理薯块鲜质量和茎叶鲜质量随着施氮水平的升高急剧下降。在磷肥试验中,磷用量为135 kg/hm2时,鲜薯产量最大,为46 802.35 kg/hm2,单株结薯数为4.65个,商品薯率为91.0%,平均单株薯质量为978.0 g;磷水平低于135 kg/hm2时,随着磷用量的提高产量逐渐增大,磷水平高于135 kg/hm2时,随着磷用量的提高产量降低。合理施肥是甘薯增产增收栽培的有效措施。     

Bioavailability of ascorbyl phosphate calcium in hybrid catfish,Clarias macrocephalus (Gunther) × Clarias gariepinus (Burchell) feed

A 10-week feeding experiment was performed in hybrid catfish (Clarias macrocephalus (Gunther) × C. gariepinus (Burchell, 1822) with initial average weight of 1.17 g, in glass aquaria of 200-L capacity. The experiment comprised seven treatments with three replicates each. Ascorbyl phosphate calcium (APCa) was included at 30, 75, 150, 300 and 1000 mg kg⁻¹ feed and compared with one with ascorbyl polyphosphate (APP) at 36 mg kg⁻¹ feed and one without vitamin C supplementation. Fish fed APCa-supplemented feed showed better growth, feed conversion ratio, survival rate and protein utilization compared with those without such supplementation. Ascorbate concentrations in liver and head kidneys were correlated closely with dietary APCa levels. Vertebral collagen and hydroxyproline contents were significantly lower in the fish group without ascorbate supplementation. Red blood cell and white blood cell counts showed no correlation with vitamin C supplementation. Serum protein level was lowest in the group fed feed without vitamin C supplementation and this was lower than those fed feed with APCa and APP supplementation. The fish fed APCa- and APP-supplemented feed showed no difference in serum protein levels. External scorbutic symptoms and histopathological changes of gill tissue were noted in fish fed feed without APCa supplementation. The study indicates that 12.6 mg kg⁻¹ of ascorbic acid molar equivalent supplied as APCa (30 mg kg⁻¹) provided maximum growth and no gross signs as well as histological changes resulting from vitamin C deficiency.     

Phosphorus availability of sewage sludge‐based fertilizers determined by the diffusive gradients in thin films (DGT) technique

The plant‐availability of phosphorus (P) in fertilizers and soil can strongly influence the yield of agricultural crops. However, there are no methods to efficiently and satisfactorily analyze the plant‐availability of P in sewage sludge‐based P fertilizers except by undertaking time‐consuming and complex pot or field experiments. We employed the diffusive gradients in thin films (DGT) technique to quantify the plant P availability of various types of P fertilizers with a novel focus on sewage sludge‐based P fertilizers. Mixtures of fertilizer and soil were incubated for 3 weeks at 60% water holding capacity. DGT devices were deployed at the beginning of the incubation and again after 1, 2, and 3 weeks. Two weeks of incubation were sufficient for the formation of plant‐available P in the fertilizer/soil mixtures. In a pot experiment, the DGT technique predicted maize (Zea mays L.) biomass yield and P uptake significantly more accurately than standard chemical extraction tests for P fertilizers (e.g ., water, citric acid, and neutral ammonium citrate). Therefore, the DGT technique can be recommended as a reliable and robust method to screen the performance of different types of sewage sludge‐based P fertilizers for maize cultivation minimizing the need for time‐consuming and costly pot or field experiments.     

Comparative efficiency of phosphate-solubilizing bacteria under greenhouse conditions for promoting growth and aloin-A content of Aloe barbadensis

This study was conducted with Aloe barbadensis in order to investigate the efficacy of four phosphate-solubilizing bacteria (PSB), Pseudomonas synxantha 10223, Burkholderia gladioli 10242, Enterobacter hormaechei 10240 and Serratia marcescens 10241 to solubilize Mussorie rock phosphate (MRP) and to evaluate its effects on growth, soluble P content and P uptake compared with control, i.e. uninoculated plants. Pot experiments were conducted in a greenhouse, in soil supplemented with MRP. Each PSB treatment showed different effects on different plant growth parameters. The maximum increase in leaf length (23.7%), total number of leaves (33.33%) and dry rind weight (69.10%) was observed in plants treated with P. synxantha 10223 compared with control. Whereas, maximum increase in root length (23.43%), fresh leaves weight (79.03%), dry gel weight (113.08%) and total gel volume (112.10%), was observed in plants treated with S. marcescens 10241 compared with uninoculated plants. Maximum increase in aloin-A content [114.92% (per g dry gel weight) and 322.32% (per plant dry gel weight)] was observed in plants treated with P. synxantha 10223 compared with control plants. Root colonization by inoculated PSB as estimated by RAPD technique showed that all PSB were able to survive in the rhizosphere of Aloe plants.