岩石-土壤-四川牡丹元素迁移体系中的微生物效应

[目的]研究四川牡丹岩土环境背景以及微生物在元素迁移过程中的作用,为了解营养元素的表生地球化学行为规律及微生物在元素迁移体系中的作用提供理论依据。[方法]利用ICP-OES测定四川牡丹生境母岩、土壤以及种子的大量(P,S,K,Ca,Na,Mg,Al)、微量(Fe,Mn,Cu)营养元素含量,同时利用Illumina高通量测序技术测定根际土壤中细菌、真菌的组成和结构。[结果](1)四川牡丹生长土壤以弱碱富钙为主要特征,元素组成基本保留了母岩特征;(2)元素从母岩到土壤中的迁移富集系数排序为:CaNaSPMgKAlFeMnCu,植物吸收系数排序为:PSKCuMgCaNaMnFeAl;(3)碱土金属淋溶率和铝铁率对土壤细菌的多样性(Alpha)影响显著,但对真菌的影响不显著;(4)P,Mn的迁移主要受母岩控制,而Ca,Mg,Fe,S等元素的迁移富集受到了微生物的影响。[结论]细菌和真菌在元素迁移体系中的作用相似,主要参与Fe,S,Mg,Ca的相关反应过程。     

1966-2017年贵州省降雨侵蚀力的时空分布特征

[目的] 分析贵州省1966—2017年降雨侵蚀力R值的时空演变规律，为评估该地区降雨对土壤侵蚀的防治、制定水土保持措施及农业生产规划提供参考。[方法] 基于贵州省33个气象站点1966—2017年的日降雨资料，利用克里金插值法、经验正交函数（EOF）方法、Mann-Kendall检验、Morlet小波分析法等，对贵州省52 a的降雨侵蚀力R值的时空特征进行了分析。[结果] ①EOF分析方法可以较好地解释降水侵蚀力的时空分布特征，其前两个特征向量累计贡献率达52%，揭示了贵州省降雨侵蚀力全局型和东西反向型两种典型的分布模态。分析特征向量所对应的时间系数可得，贵州省的降水侵蚀力主要表现为全省全年偏大、全省全年偏小、东大西小、东小西大4种类型；②贵州省降雨侵蚀力R值年内主要受汛期降雨影响，全省各县市汛期降雨侵蚀力R值均占全年总量的60%以上；③在年际变化上，降雨侵蚀力R值存在多突变的现象，1971—1981年突变频率最为频繁。通过周期检验发现其变化主周期为28 a，次周期分别为12 a和6 a。[结论] 贵州省降雨侵蚀力的时空分布与降雨量的时空分布趋势近似，整体呈现南部大北部小，夏季大冬季小的趋势，在未来几年内降雨侵蚀力R值有上升的趋势。     

宁夏玉米营养成分近红外分析模型建立与应用

研究采集宁夏区内各市县(固原、海原、同心、中卫、中宁、永宁、平罗)抽取玉米样品120批,用近红外分析仪扫描定标样品集获得玉米近红外光谱图,利用偏最小二乘法建立模型,并分别经过无预处理、均值中心化、标准正态变量转换、一阶导数、标准正态变量转换结合去趋势校正(SNV+D)预处理光谱,获得水分、粗蛋白、粗脂肪、粗纤维预测模型,分别是经过MC、SNV+D、SNV+D、SNV+D光谱预处理后效果最好。预测决定系数R² _p分别为0.951、0.976、0.728、0.897,相对分析误差RPD除粗脂肪为2.62外,其他均大于3的近红外预测模型,通过预测模型验证集验证后,并对模型预测值与实测值进行U检验,结果为差异不显著(P>0.05)。该近红外预测模型对玉米中水分、粗蛋白、粗纤维具有较佳预测效果,粗脂肪的预测精度有待进一步提高。     

Remediation of saline-sodic soil using organic and inorganic amendments: physical,chemical, and enzyme activity properties

Purpose

Crops grow poorly in saline-sodic soils, and the productivity of these soils can be dramatically improved with proper amendments. Current research mainly focuses on either organic or inorganic soil amendments, whereas few studies address options of combining organic and inorganic amendments. The objective of this study was to develop new organic and inorganic soil amendments which can lower the soil pH, replace sodium, and improve soil structure.

Materials and methods

Polyhalite (PL), microporous potassium-silicon-calcium mineral fertilizer (MF), furfural residue (FR), and fulvic acid (FA) were mixed with four different ratios to produce organic and inorganic soil amendments: PLFR, PLFA, MFFR, and MFFA. And their optimum mixing ratios were determined by comparing the potassium, calcium concentrations, and pH of filtrate after dissolution. Then, a leaching experiment was conducted by packing mixtures (mass ratio of soil to amendment = 219:1, equivalent to 13 t/hm²) of the saline-sodic soil with each one of these amendments plus two contrasts, gypsum (GP), and no amendment (CK). And the remediation effect was compared by pH, EC, ESP, texture, organic recombination degree of clay, saturated hydraulic conductivity, water-stable aggregates fraction, and enzyme (urease, alkaline phosphatase, and catalase) activities of soil.

Results and discussion

After four times leaching experiment, soil treated with PLFR had lower pH and 25.86% lower exchangeable sodium than untreated soils. The water-stable small macroaggregate fractions and saturated hydraulic conductivity of the MFFR-treated soils were significantly increased by 133% and 31%, respectively. Also, the total soil and heavy fraction organic carbons of the soils treated with MFFR in addition to its alkaline phosphatase activity were all significantly higher than the other treatments.

Conclusions

The results revealed that MFFR has more potential as a soil amendment to improve soil structure and quality and thus help in the development and use of saline-sodic lands for agriculture.

     

新型脱叶剂欣噻利在赣北棉花上的应用效果初报

为考察新型脱叶剂欣噻利在赣北的使用效果，以中棉所425为试验材料，进行脱叶剂处理试验。结果表明: 喷施欣噻利1800～2700 mL·hm^－2有较好的脱叶催熟效果，在此范围内其剂量越大，脱叶催熟的效果越好；喷施欣噻利对棉花铃重、铃壳质量、衣分以及纤维品质没有显著影响。     

Effect of substitution of dietary fish meal by soybean meal on different sizes of gibel carp (Carassius auratus gibelio): digestive enzyme gene expressions and activities,and intestinal and hepatic histology

A 7‐week growth trial was conducted to evaluate the effects of dietary soybean meal (SBM) on digestive enzyme activity of intestinal mucosa, mRNA levels of digestive enzymes in hepatopancreas, and the mid‐intestinal and hepatopancreas histology of gibel carp CAS III (Carassius auratus gibelio). Four different growth phases of gibel carp (initial body weight: fry, 0.8 g; juvenile, 5.0 g; 1‐year‐old, 62.7 g; and broodstock, 135.6 g) were tested. Seven isonitrogenous and iso‐energetic diets were formulated to contain different SBM replacement levels (0%, 20%, 40%, 60%, 80% and 100% of dietary fish meal protein), and another diet (SBMAA) contained all SBM protein and supplied crystalline amino acids. The results showed that the activities of mid‐intestine trypsin, α‐amylase and gamma glutamyl transpeptidase reduced with increased dietary SBM, while the chymotrypsin activity increased first and then decreased. The ultrastructures of intestinal epithelial cells and hepatopancreas cells in fry and broodstock fish were distinctly affected by 200 g kg^‐1 dietary SBM. Supplementation of dietary amino acid to the highest replacement groups was not sufficient to improve digestive and absorptive capacities and growth performance. Gibel carp may be adapted to dietary SBM through increase in gene expression of hepatopancreas digestive enzymes and has potential to utilize proceeded SBM as feedstuffs.     

The effect of dietary folic acid on biochemical parameters and gene expression of three heat shock proteins (HSPs) of blunt snout bream (<Emphasis Type="Italic">Megalobrama amblycephala)</Emphasis> fingerling under acute high temperature stress

The effects of dietary folic acid on biochemical parameters and gene expression of three heat shock proteins (HSPs) of blunt snout bream (Megalobrama amblycephala) fingerling under acute high temperature stress. Six dietary folic acid groups (0.0, 0.5, 1.0, 2.0, 5.0, and 10.0) mg/kg diets were designed and assigned into 18 tanks in three replicates each (300 l/tank) and were administered for 10 weeks in a re-circulated water system. The fingerlings with an initial weight of 27.0 ± 0.03 g were fed with their respective diets four times daily. At the end of the experiment, samples were collected before challenge, 0, 24, 72 h, and 7 days. Serum total protein (TP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), cortisol, glucose, complement C3 (C3), complement C4 (C4, immunoglobulin M (IgM) hepatic superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and the expression of heat shock protein 60 (HSP60), 70 (HSP70), and 90 (HSP90) were studied. The results showed that fish fed with dietary folic acid between 1.0, 2.0, and 5.0 mg/kg significantly (P < 0.05) increased serum TP, C3, C4 hepatic SOD, CAT, and the expression of HSP60, HSP70, and HSP90 before and after temperature challenge of 32 °C. Also, serum ALP, cortisol, glucose, and hepatic MDA were significantly (P < 0.05) reduced by supplementation of dietary folic acid level 1.0, 2.0, and 5.0 mg/kg before and after the same temperature challenge of 32 °C. Before stress, 0, 24, 72 h, and 7 days significantly (P < 0.05) affects serum biochemical parameters, immune and antioxidant capacities, and expression level of three HSPs. Furthermore, there was no statistical evidence to show that dietary folic acid inclusion level and temperature duration have significant interactive effect on serum biochemical parameters, antioxidant parameters, and gene expression level (P > 0.05) of the three HSPs. However, there were statistical significant interactive effect between dietary folic acid inclusion level and temperature duration on serum C3 and C4 (P < 0.05) except IgM (P > 0.05). The present results indicate that supplementation of basal diet from 1.0 mg/kg; 2.0 and 5.0 mg/kg can enhance acute high temperature resistance ability in M. amblycephala fingerling to some degree and improve physiological response, immune and antioxidant capacities, and expression level of three HSPs.     

Effect of l‐ascorbyl‐2‐polyphosphate supplementation on growth performance,body composition,antioxidative capacity and salinity stress tolerance of juvenile Pacific white shrimp,Litopenaeus vannamei

An 8‐week feeding trial was conducted to evaluate the effects of ascorbic acid (AsA), in the form of l ‐ascorbyl‐2‐polyphosphate (LAPP) on growth performance, body composition, antioxidative capacity and salinity stress tolerance of juvenile Pacific white shrimp, Litopenaeus vannamei. Five practical diets (46% crude protein and 7.6% lipid) supplemented with graded levels of AsA (14.64, 48.55, 84.98, 308.36 and 639.27 mg kg^?1 diet) were fed to five replicate groups of L. vannamei (mean initial wet weight 0.57 g). No significant differences were found on growth performance among all treatments. However, whole body lipid content significantly decreased with dietary AsA levels increasing. Activities of total antioxidant capacity, glutathione reductase and glutathione peroxidase were significantly affected by dietary AsA levels. Shrimp fed LAPP‐free diet had higher malondialdehyde content than those fed the diets supplemented with LAPP. Dietary AsA levels higher than 308.36 mg kg^?1 diet increased the survival of shrimps after 1, 2 and 3 h of acute salinity change. Broken‐line regression analysis on survival after 3 h of salinity stress and second‐degree polynomial regression analysis on glutathione reductase data indicated that the optimal dietary AsA requirement of L. vannamei was estimated to be 306.39, 319.75 mg kg^?1 diet respectively.     

A novel combined recirculating treatment system for intensive marine aquaculture

This study established a pilot‐scale recirculating treatment system that coupled an ecological process with a biological process to achieve adequate water quality and to minimize the water consumption for intensive marine culture. The recirculating treatment system consisted of a settling cell, a biofilter tank, a bivalve tank and gravel beds. The toxic pollutants, threatening the growth of bivalves, were reduced by the settling cell and the biofilter tank, so that the polyculture of shrimp and bivalves could be achieved. The living bivalve tank could function well as a remover of remaining small suspended solids (SS), and other pollutants. As the SS was reduced to a very low level by bivalve tank before the water flowing into the gravel beds, the risk of clogging was prevented. The studies suggested that the system maintained high removal efficiencies of SS, ammonium nitrogen () and nitrite nitrogen () and could contribute to the increase in shrimp yield.     

Effect of N-acetyl cysteine and glycine supplementation on growth performance,glutathione synthesis,and antioxidative ability of grass carp, <Emphasis Type="Italic">Ctenopharyngodon idella</Emphasis>

An 8-week feeding trial was conducted to evaluate the effect of N-acetyl cysteine (NAC) and glycine supplementation on growth performance, glutathione (GSH) synthesis, and antioxidative ability of grass carp, Ctenopharyngodon idella. Four practical diets were formulated: control, control + 0.2% NAC, control + 0.5% glycine, and control + 0.2% NAC + 0.5% glycine. Each diet was randomly assigned to quadruplicate groups of 30 fish (approximately 8.8 g). Weight gain and specific growth rate were significantly increased with the supplementation of NAC. Supplementation of NAC plus glycine significantly increased the feed efficiency. Glutathione peroxidase (GPx) and γ-glutamine cysteine synthase (γ-GCS) in plasma were significantly increased with the supplementation of NAC plus glycine. GSH in plasma increased and malondialdehyde (MDA) decreased in fish fed diets supplemented with NAC. Respiratory burst, superoxide dismutase (SOD), and catalase (CAT) activity were not affected by NAC or glycine. These results clearly indicated that NAC improved the growth performance and restored GSH of grass carp, supplemented NAC together with glycine enhanced GSH synthesis, and improved the antioxidative ability of grass carp.