Growth performance and whole‐body composition of yellow catfish (Pelteobagrus fulvidraco Richardson) under feeding restriction

Fish growth is an important index in aquaculture practice. However, the effect of growth under restricted feeding on quality of fish grown to the same size remains poorly unknown. In this study, yellow catfish were reared by feeding them at three different feeding rates such as low (FR‐L group), medium (FR‐M group) and high (apparent satiation) ration levels for 82, 58 and 34 days to reach the same size, respectively. After this period, the growth performance, whole‐body amino acid composition and fatty acid profile of the fish were evaluated. Feeding restriction led to significant decreases in specific growth rate and feed conversion efficiency. Significant increases in dry matter, protein and energy contents were observed in fish under both restricted feeding treatments. FR‐L‐treated fish had significantly lower whole‐body essential amino acid contents, and significantly higher Ala and non‐essential amino acid contents compared to fish fed to satiation. Fish in restricted feeding treatments had significantly higher n‐3 PUFA and n‐3/n‐6 ratio compared to the fish fed to satiation. The present results indicate that from a quality perspective, there are certain advantages in improvement of whole‐body composition and enrichment of n‐3 PUFA associated with the restricted feeding of yellow catfish at slow growth rate.     

种植方式对水稻产量及根系性状的影响

2011—2012年在湖南长沙以超级杂交稻Y两优1号、杂交稻汕优63和常规稻黄华占为材料的大田定位试验,比较了垄作梯式栽培技术(两种垄规格)和垄厢栽培技术(3种厢规格)对水稻产量和根系性状的影响。与平作栽培(T0)相比,窄垄作梯式栽培(T1)和垄厢栽培(T3)均可提高水稻产量,其中以T1的产量最高,比T0平均增产22.2%(17.1%～27.2%),其次T3平均增产10.4%(5.8%～15.0%),但随着垄宽或厢宽的增加,产量增幅逐渐下降。较高的穗数和每穗粒数、良好的根系特性(根系氧化力、根表面吸收面积、根系孔隙度)以及齐穗后干物质积累量大是上述两种栽培技术增产的重要原因。同时,根解剖结构表明垄作梯式栽培的根皮层减小、中柱和导管面积增大,增强了水分吸收能力。     

煮熟和干燥处理对黄藤笋抗氧化活性的影响

通过测定黄藤熟笋、生笋(鲜切笋)、熟笋干和生笋干的水和4种不同浓度乙醇提取物中的自由基清除能力、总还原能力、总多酚含量和总黄酮含量,研究了煮熟、干燥加工方法对黄藤笋提取物抗氧化活性的影响。结果表明,煮熟处理能保持或提高提取物的抗氧化活性,干燥处理则相反。乙醇提取物比水提取物具有更高的抗氧化活性,以50%~75%的乙醇提取溶剂效果最好。熟笋在所有溶剂中的自由基清除能力、总还原能力、总多酚含量和总黄酮含量均表现出最高水平,表明煮熟是黄藤笋适宜的加工利用方式。     

terraGIS – a web GIS for delivery of digital soil maps in cotton‐growing areas of Australia

Effective management of soil requires the spatial distribution of its various physical, chemical and hydrological properties. This is because properties, for example clay content, determine the ability of soil to hold cations and retain water. However, data acquisition is labour intensive and time‐consuming. To add value to the limited soil data, remote sensing (e.g. airborne gamma‐ray spectrometry) and proximal sensing, such as electromagnetic (EM) induction, are being used as ancillary data. Here, we provide examples of developing Digital Soil Maps (DSM) of soil physical, chemical and hydrological properties, for seven cotton‐growing areas of southeastern Australia, by coupling soil data with remote and proximal sensed ancillary data. A greater challenge is how to get these DSM to a stakeholder in a way that is useful for practical soil use and management. This study describes how we facilitate access to the DSMs, using a simple‐to‐use web GIS platform, called terraGIS. The platform is underpinned by Google Maps API, which is an open‐source development environment for building spatially enabled Internet applications. In conclusion, we consider that terraGIS and the supporting information, available on the sister web page ( http://www.terragis.bees.unsw.edu.au/ ), allow easy access to explanation of DSM of soil properties, which are relevant to cotton growers, farm managers, consultants, extension staff, researchers, state and federal government agency personnel and policy analysts. Future work should be aimed at developing error budget maps to identify where additional soil and/or ancillary data is required to improve the accuracy of the DSMs.     

Stability analysis of seven agronomic traits for soybean [(Glycine max (L.) Merr.] Tokachi nagaha and its derived cultivars using the AMMI model

The stabilities of seven agronomic traits were analyzed and the general stabilities of soybean [Glycine max (L.) Merr.] accessions were evaluated based on the additive main effects and multiplicative interactions (AMMI) model using the founder parent Tokachi nagaha and 137 of its derived cultivars as materials. The objective was to provide a theoretical basis for effectively using germplasm in soybean breeding and production. Analysis of variance (ANOVA) showed that genotype, environment, and genotype by environment interactions were significantly different for each trait. The first three interaction principal components axes (IPCA) were highly significant, accounting for 61.28–70.00% of the total variation. The stability differed for the different traits. 50 cultivars with high general stabilities were identified. The general stability of Tokachi nagaha was moderate, as the stability coefficients (D_i) of its seven traits were relatively high; this must be considered by breeders using this cultivar as a breeding parent. There were significant positive correlations between the phenotypic values and their own D_i values for number of branches per plant, number of pods per plant, number of seeds per plant, and seed weight per plant. This would lead to the expectation that the phenotypic stability would be lower when a cultivar had more branches, pods, seeds, and high per plant yields. Thus, it appears difficult to breed cultivars that simultaneously have high yields and high stability.     

棉花叶枝数与种植密度对单株结铃数的影响

为了探明棉花叶枝数和密度对单株结铃的影响规律，试验设置5种留叶枝方式：不留叶枝（CK）、留1叶枝、留2叶枝、留3叶枝、留全部叶枝；5个种植密度（万株·hm^－2）：2.25，3.00，3.75，4.50，5.25。研究结果表明：在同一密度条件下，随叶枝的增多，单株铃数增加；留1叶枝单株铃数较对照增加10%左右，留2、3叶枝单株铃数较对照增加15%左右，保留全部叶枝较对照增加25%左右。在同一叶枝处理下，随密度的增加，单株铃数减少；密度每增加7500株·hm^－2，5种留叶枝方式的单株结铃分别减少2.60个、3.04个、3.06个、3.44个和3.71个。总铃数随叶枝和密度的增加而增加，当总成铃为88.24万个·hm^－2时产量最高。     

黑龙江省2019年乳品产业现状及未来展望

黑龙江省目前是国内主要乳制品生产地区之一,在对黑龙江省2019年乳制品生产的上游牧场、下游乳品企业及乳制品市场销售情况等全产业链调研的基础上,分析了黑龙江省2019年乳品产业的生产情况变化及乳制品市场价格波动的原因,对2020年乳品产业发展进行了展望,并预测了新冠肺炎疫情对乳品产业的影响,以期为牧场、乳品企业和地方政府部门提供合理化建议。     

不同品种藜麦苗期对海拔变化的生理响应

为研究不同品种藜麦幼苗对海拔梯度变化的生理响应机制,本试验以4个藜麦品种—‘陇藜1号’、‘陇藜2号’、‘陇藜3号’及‘陇藜4号’为材料,选取甘南州临潭县3个不同海拔(2380 m,2580 m,2780 m)分布区为试验地。通过测定幼苗生物量及生理生化指标,分析不同藜麦品种幼苗在不同海拔试验区的生理响应机制,为建立藜麦品种和环境相适宜的评价体系提供参考依据。结果表明,随海拔升高,藜麦叶片叶绿素、可溶性蛋白以及抗坏血酸过氧化物酶(APX)含量逐渐降低,海拔2780 m最低;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)逐渐升高,在海拔2780 m达到最大值;超氧阴离子(O2·-)产生速率呈现先升高后降低的趋势。不同藜麦品种幼苗生物量随着海拔的升高逐渐降低。说明高海拔下太阳辐射强度增大、温度降低,导致藜麦幼苗植株抗氧化酶活性升高以清除多余活性氧(ROS)自由基,使得植株能够适应高海拔环境而正常生长,但生物量较低海拔仍有降低。因此,不同品种藜麦在低海拔地区受到的胁迫较低,虽然在高海拔区域胁迫加剧,但藜麦幼苗可以正常生长并进行干物质的积累。     

晋中盆地典型耕地厚度、土壤养分空间变异

旨在探究旱作区耕地土壤耕层厚度及土壤养分空间格局与变异规律。以晋中盆地典型耕地土壤为研究对象,运用地统计学方法对耕地耕层厚度及土壤养分的空间变异进行分析,土壤养分选取有机质、pH、有效磷、缓效钾4个指标。结果表明：（1）各个指标的空间自相关性都是随着距离的增加而减小;（2）有效磷的半变异函数最优模型为高斯模型,其他指标的最优模型均为指数模型。各指标的块金系数由大到小依次为：有机质>有效磷>pH>耕层厚度>缓效钾;（3）耕层厚度、有效磷均为西北高东南低的空间格局,缓效钾为东北高西南低,有机质为西南高东北低,pH除北洸乡偏低外均偏高。地统计方法能良好地描述土壤性质的空间分布和变异特征,各土壤性质的空间变异过程中随机性与结构性并存,并且随机性均小于50%。