淡水小龙虾头中甲壳素的EDTA法提取工艺研究

以淡水小龙虾头为原料,采用EDTA法提取甲壳素,在单因素试验的基础上,通过正交试验筛选最佳工艺条件。试验结果表明:以13%的EDTA溶液作提取溶剂,在反应温度30℃、pH 12、投料比1∶15、反应25 min的条件下,提取效果最佳,提取率达24.05%,反应前后的脱钙和脱蛋白率分别为100.0%和98.6%。     

辣木

辣木源自印度和非洲,20世纪70年代引入中国云南、海南和广西等地。由于它富含钙质、植物蛋白、重要矿物质、维生素和重要氨基酸等,而受到人们广泛关注。本文研究辣木的起源、植物学、产量、栽培技术、新种质和各种营养物质等,论述其对人体的作用、营养价值、相关疾病的防治及可能的功效等。     

宁杂21号不同种植方式效益比较

以杂交油菜新品种宁杂21号为材料,采用大面积生产上常见的3种移栽种植和2种直播种植方式,在高产栽培条件下研究不同种植方式的产量水平和经济效益,分析比较不同种植方式的用工、农资和农机成本,探索降低生产成本、提高经济效益的途径。结果表明,5种种植方式都能取得高产,平均产量达到3 282.30 kg/hm2,变幅为2 899.50~3 642.00kg/hm2,虽然移栽种植的产量水平和总产值分别高于直播种植429.25和2 189.18元/hm2,但直播种植的生产成本低于移栽种植2 098.81元/hm2,经济效益基本持平。试验结果还表明在油菜生产成本中,人工成本占60%以上,其中收获用工成本又占人工成本的50%左右。因此,在目前生产条件下,应用直播种植、机械收获,可有效降低生产成本,提高油菜经济效益。     

云南农田土壤常量及微量元素含量的测定研究(英文)

为了对云南农田土壤常量与微量元素进行科学有效地管理,并为农作物合理施肥提供依据,利用电感耦合等离子体质谱(ICPMS)法测定云南14个地方农田土壤常量及微量元素(P、K、Ca、Mg、Cu、Fe、Zn、Mn)的含量,并对土壤中常量及微量元素含量的状况与分布进行了研究。结果表明:云南农田土壤中速效P、K元素处于平衡,速效Ca、Mg亏缺,速效Cu、Fe、Zn、Mn等微量元素盈余。在不同地貌下,土壤常量及微量元素分布有明显的差异,滇中红色高原土壤的速效态微量元素(Fe、Zn、Mn)的含量明显高于滇东喀斯特高原和滇西横断山脉;速效P、K、Ca的含量从西至东有逐渐下降的趋势;而速效Cu的含量则从西到东有逐渐上升的趋势。研究结果对于农田土壤元素测定及农业生产具有一定的参考价值。     

Advances in Analytical Techniques for Organochlorine Pesticide Detection in Tea Samples

概述了近年来茶叶中有机氯农药残留分析的前处理技术和测定方法的研究进展,重点包括超声波提取、加速溶剂提取、微波提取、固相萃取、固相微萃取技术及气相色谱、气相色谱质谱联用技术等在茶叶中有机氯农药残留分析中的应用,并指出未来发展方向。     

超声波-反复冻融协同法优化黑木耳菌丝体破壁条件

[目的]研究超声波-反复冻融协同作用对黑木耳菌丝体破壁的影响,并确定最佳破壁组合条件。[方法]利用单因素试验,研究了超声波处理过程中破壁时间、加水量、破壁次数、冷冻时间、冻融次数对多糖得率的影响,并利用正交试验设计确定最佳条件组合。[结果]单因素试验结果表明,破壁时间以20 min为宜,选择15倍为最适加水量,选择2次超声波破壁次数较宜,冷冻时间以30 min为宜,选择3次冻融次数较为合适。正交试验结果表明,各因素的影响效果依次为破壁时间、破壁次数和冻结时间,最佳组合条件为冷冻时间30 min,破壁时间25 min,破壁2次,此时多糖得率可达到57.76 mg/g。[结论]该研究可为指导实际生产提供依据和参考。     

梨斑点病田间病情发生规律及其影响因子分析

采取“四定”跟踪观察方法对梨树新病害梨斑点病田间叶部症状表现、发生规律及相关影响因子进行调查分析,结果表明：梨斑点病田间叶部症状表现斑点小,群体数量大,叶面、叶脉、叶柄均可发生,发病中后期全叶呈黄绿相间黄化脱落;雨量大、雨日多的年份发生重,反之则轻;品种依发病程度不同可明显分为轻、较轻、中等、重等类型,其中‘蜜雪梨’、‘明福’、‘黄花’、‘清香’ 等品种发病轻,发病程度与海拔高度呈显著或极显著负相关,随坡段自下而上呈由重向轻的变化趋势,且位于梨园边行的植株发病较轻;综合管理水平高、树势长势稳健的梨园发病程度相对较轻.     

Effects of Fertilizers with Different Proportions of N,P and K on Citrus Fruit Cracking

[目的]探讨氮磷钾不同配比对柑桔裂果的影响。以期找到最有效的防裂果组合。[方法][结论]通过配施N、P、K不同比例地面复合肥与喷洒不同的矿物营养元素叶面肥处理组合来防止裂果试验。[结果]在春季用肥料配比N：P2O5：K2O=20：10：10。夏秋用肥料配比N：P2O5：K2O=16：8：16。叶面喷施0.5％硝酸钙液的处理组合防裂果效果最好。同时分析不同处理中叶片的N与K比值,N与Ca的比值。Ca与K的比值,发现树体中N与K的比值（N／K）和N与Ca的比值（N／Ca）同裂果呈正相关,即比值越大,裂果越重。树体中Ca与K的比值（Ca／K）与裂果成负相关。其比值越大,裂果越轻。[结论]为避免柑桔裂果,生产中应该根据土壤的墒情、树势的优劣、季节的更替等平衡全面地施肥。     

Nitrogen Removal Improvement by Adding Peat in Deep Soil of Su bsu rface Wastewater Infiltration System

In order to enhance the nitrogen removal, a subsurface wastewater infiltration system （SWIS） was improved by adding peat in deep soil as carbon source for denitrification process. The effects of addition of carbon source in the underpart of the SWIS on nitrogen removal at different influents （with the total nitrogen （TN） concentration 40 and 80 mg L^-1, respectively） were investigated by soil column simulating experiments. When the relatively light pollution influent with 40 mg L^-1 TN was used, the average concentrations of NO3-N and TN in effluents were （4.69±0.235）, （6.18±0.079） mg L^-1, respectively, decreased by 32 and 30.8% than the control; the NO3--N concentration of all effluents was below the maximum contaminant level of 10 mg L^-1; as high as 92.67% of the TN removal efficiency was achieved. When relatively heavy pollution influent with 80 mg LITN was used, the average concentrations of NO3--N and TN in effluents were （10.2±0.265）, （12.5±0.148） mg L^-1 respectively, decreased by 20 and 21.2% than the control; the NO3--N concentration of all effluents met the grade Ⅲ of the national quality standard for ground water of China （GB/T 14848-1993） with the values less than 20 mg L^-1; the TN removal efficiency of 94.1% was achieved. In summary, adding peat in the underpart of the SWIS significantly decreased TN and NO3- -N concentration in effluents and the nitrogen removal efficiency improved significantly.     

Carbon Sequestration in Soil Humic Substances Under Long-Term Fertilization in a Wheat-Maize System from North China

The changes in humic substances （HS） is fundamental in detecting soil carbon sequestration mechanisms in natural and cultivated environments. Based on a long-term trial, the amounts of water dissolved substances （WSS）, humic acid （HA）, fulvic acid （FA） and humin （HU） were determined to explore the impact of long-term fertilization on HS. Increases in the amounts of WSS, HA, FA and HU were significant different among the treatments with manure. A significant correlation was found between the increased soil organic carbon （SOC） and HS （R^2=0.98, P〈0.01）. The change in the E4/E6 ratio was significantly correlated with the increased SOC （R2=0.88, P〈0.01）, HA （R^2=0.91, P〈0.01）, FA （R^2=0.91, P〈0.01） and HU （R^2=0.88, P〈0.01）. The cluster was mainly divided into two parts as manure fertilization and inorganic fertilization, based on the increases in HA, FA and HU. These results suggest that long term fertilization with manure favours carbon sequestration in HS and is mainly stabilized as HU, while the HA becomes more aliphatic. We conclude that increases in SOC can be linked to changes in the molecular characteristics of HS fractions under long term fertilization.