蔬菜幼苗叶面积快速测定方法筛选与优化

为得到一种快速且准确测定蔬菜幼苗叶面积的方法,以番茄幼苗为试材,以方格法为对照,研究扫描分析法、叶面积仪法、打孔称重法测定叶面积的准确性、精确性与测定速度,然后采用黄瓜、辣椒叶片及纸片的面积对测定结果进行验证,最后基于不同扫描分辨率对筛选出的方法进行优化。结果表明,相比叶面积仪法和打孔称重法,扫描分析法测定结果更接近真实值,且精度更高,用时更短。扫描分析法不同分辨率下测定结果无显著差异,且扫描分辨率越低所需测定时间越短。扫描分辨率50 dpi下的扫描分析法可作为一种快速准确测定蔬菜幼苗叶面积的方法。     

The effects of density and artificial substrate on intensive shrimp Litopenaeus vannamei nursery production

Recirculating aquaculture systems (RAS) can be installed indoors, allowing year-round production of tropical animals in nearly any climate. A nursery phase is commonly used in Litopenaeus vannamei production since it allows for enhanced biosecurity and better quantification of animals while reducing space requirements. However, it is unclear whether animal density and inclusion of artificial substrate may improve shrimp performance during the nursery phase. In this experiment, we compared shrimp production parameters in two stocking densities with or without the use of an artificial substrate by creating four treatments: low-density LD; 1500 PL/m⁻³, low-density with substrate LDS, high-density HD; 3000 PL/m⁻³), and high-density with substrate (HDS). The LDS and HDS treatments included 0.46-m² of high-density polyethylene 2.5-cm mesh as a substrate, which increased the tank surface area by 21 %. Each treatment was randomly assigned to four 160-l culture tanks, each with a biofilter. The shrimp had an initial weight of 4 mg and were grown for 50 days. The low-density treatments had significantly higher dissolved oxygen (DO) and pH than the high-density treatments (P ≤ 0.001). Specifically, LDS had the highest DO and pH followed by the LD, HD, and HDS treatments, respectively. High-density treatments had significantly higher NO₂-N levels than low-density treatments during week 2 of the experiment when an unusually high concentration of nitrite was observed. FCR was significantly lower in both low-density treatments than in high-density treatments. At harvest, the total biomass (kg m⁻³) was significantly higher in high-density treatments than in low-density treatments (P ≤ 0.001), and the HDS treatment had a significantly greater biomass output than HD. Producers should consider artificial substrate and higher densities during nursery production to maximize shrimp production; however, the effects on water quality should also be taken into account.     

滑菇优良品种筛选试验初报

本试验对 6个不同滑菇品种进行了菌丝体生长和制种观察 ;在栽培试验过程中进行了多点小试和中试 ,初选出Ph0 8号和Ph0 6号两个品种。Ph0 8的单盘产量比CK1高出 2 5 8% ,比CK2 高出 35 3% ;Ph0 6的单盘产量比CK1高出 2 1 5 % ,比CK2 高出 30 6 %。它们均属早生品种 ,适合辽宁地区的气候特点 ,在幼菇期菌盖呈半球形、桔红色、附着的粘液多 ,菌柄比对照短 ,菇体健壮 ,符合商品收购和产品加工的要求     

木耳漆酶高产菌株筛选及其发酵条件的研究

通过运用不同检测方法对木耳属中的三个种的 2 7个菌株的产过氧化物酶、漆酶能力的检测 ,筛选得到一漆酶高产菌株毛木耳 (Auriculariapolytricha)AP4。并且对AP4的产漆酶的发酵条件进行了初步研究。摇瓶实验产漆酶的最佳培养基的成分为 :碳源羧甲基纤维素(CMC) 5g/L ,氮源NH4NO3 L -天冬酰胺 (L -As paragine) 2 4mmol/L ,培养基的初始pH4 0 ,培养温度2 5℃。     

普通钢架大棚甜瓜嫁接砧木品种筛选试验

在普通钢架大棚内,以实生苗为对照,对引进的5个甜瓜砧木品种进行甜瓜嫁接比较试验。试验结果表明,5个砧木品种嫁接苗成活率均在90%以上,其植株和瓜的生长特性、产量和品质均没有显著差异,与实生苗之间亦无显著差异,综合性状表现较好的砧木品种为日本青秀和亮丽王。     

Soil organic carbon stock variability in the Northern Gangetic Plains of India: interaction between agro‐ecological characteristics and cropping systems

Soil organic carbon (SOC) content and its spatial distribution in the Northern Gangetic Plain (NGP) Zone of India were determined to establish the cause–effect relationship between agro‐ecological characteristics, prevailing crop management practices and SOC stock. Area Spread Index (ASI) approach was used to collect soil samples from the NGP areas supporting predominant cropping systems. Exponential ordinary kriging was found most suitable geo‐statistical model for developing SOC surface maps of the NGP. Predicted surface maps indicated that 43.7% area of NGP had 0.5–0.6% SOC, while the rest of the area was equally distributed with high (0.61–0.75%) and low (< 0.5%) SOC content levels. Averaged across cropping systems, maximum SOC content was recorded in Bhabar and Tarai Zone (BTZ), followed by Central Plain Zone (CPZ), Mid‐Western Plain Zone (MWPZ), Western Plain Zone (WPZ) and South‐Western Plain Zone (SWPZ) of the NGP. The SOC stock was above the optimum threshold (> 12.5 Mg/ha) in 97.8, 57.6 and 46.4% areas of BTZ, CPZ and MWPZ, respectively. Only 9.8 and 0.4% area of WPZ and SWPZ, respectively, had SOC stock above the threshold value. The variation in SOC stock was attributed largely to carbon addition through recycling of organic sources, cropping systems, tillage intensity, crop or residue cover and land‐use efficiency, nutrient‐use pattern, soil texture and prevailing ecosystem. Adoption of conservation agriculture, balanced use of nutrients, inclusion of legumes in cropping systems and agro‐forestry were suggested for enhancing SOC stock in the region.     

关于苗木栽培技术的初步探讨

随着人民群众对生活环境和绿化水平要求的不断提升,苗木行业的市场发展可谓越来越蓬勃,行业前景也是越来越光明。因此与之相关的苗木栽培技术也受到越来越多人的关注。但目前我国苗木行业在栽培技术方面仍存在一定程度的欠缺和不足。基于此,着重对苗木栽培前期的选地、选苗等环节及栽植过程中的技术问题进行分析,希望对今后的工作有所借鉴。     

一种纤维素酶产生菌的筛选方法

[目的]获得一种简单高效的纤维素酶产生菌的筛选方法。[方法]基于扩散原理,采用滤纸条扩散试验筛选纤维素酶产生菌。[结果]获得2株纤维素酶产生菌菌株X1和X2。经DNS法检验,菌株X1的FPA酶和CMC酶活力分别为12.3和8.3 U,菌株X2的FPA酶和CMC酶活力分别为8.8和7.8 U。[结论]滤纸条扩散试验可作为一种便捷高效的筛选高质量纤维素酶产生菌的方法。