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1.
In the present study, the location, histology and number of corpuscles of Stannius (Sc), which are endocrine glands associated with the kidneys of teleost fish, were investigated for the first time in Lake Van fish (Alburnus tarichi), an anadromous and endemic inhabiting Turkey's Lake Van Basin. The Sc, which were ovoid or spheroid and white or cream in colour, were found to vary in number between three and five among the examined fish. The glands were located in the caudal part of the kidney, and either partially or completely embedded, and found to be present on both the ventral and dorsal surface of either side of the caudal part of the kidney. The Sc were surrounded by a connective tissue capsule that penetrated and divided the gland into incomplete lobules. Two types of cells were determined in the parenchyma of the gland. Type-I cells were predominant throughout the parenchyma and larger than the second (type-II). In the type-I cells, the cytoplasm was observed as weakly or moderately eosinophilic with haematoxylin and eosin staining and weakly or moderately acidophilic with Mallory's triple staining. In the type-I cells, the cytoplasm exhibited weak to moderate periodic acid-Schiff staining and slight or uniform staining with aldehyde fuchsin. The type-II cells were round, had a darkly stained spherical nucleus and were dispersed among the type-I cells. They displayed no cytoplasmic staining with the abovementioned stains.  相似文献   
2.
季节性干旱是限制菠萝增产提质增效的重要原因,发展“以水促肥,以肥促产,水肥高效耦合”的现代灌溉施肥技术,是应对季节性干旱,促进菠萝增产提质增效的重要途径。本文从华南地区季节性干旱时空分布特征、干旱胁迫对菠萝生长发育的影响、我国菠萝水肥管理现状、灌溉施肥技术对菠萝生长发育的影响等4个方面简要阐述了我国菠萝灌溉施肥技术发展的必要性,重点从现代灌溉施肥方式、耗水规律和养分吸收规律等3方面总结了菠萝灌溉施肥技术研究进展,并结合研究进展提出我国菠萝灌溉施肥技术目前存在的问题,探讨未来可能的研究重点和发展方向,为菠萝灌溉施肥技术的研究与应用提供参考。  相似文献   
3.
探讨2种种植方式对水稻生育进程、光合特性及产量的影响,为辽宁省水稻直播栽培提供技术指导。以辽宁省中早熟水稻品种辽星21、旱稻品种旱403和旱9710为试验材料,采用移栽和直播2种种植方式,对水稻生育进程、茎蘖动态、光合特性和产量进行比较分析。结果表明,2种种植方式下,不同品种水稻产量均表现为移栽高于直播,辽星21直播种植产量高于移栽种植的旱403和旱9710;与移栽种植相比,直播种植水稻株高降低,水稻主茎叶片减少约2片,剑叶和倒二叶的净光合速率(Pn)下降,单位面积茎蘖数增加。水稻直播种植宜以主茎成穗为主,优化群体结构,提高光合特性,进而实现产量的增加。  相似文献   
4.
为研究浙江红花油茶高接换冠成活率影响因素,解决嫁接成活率低的问题,2013年6月从中国林业科学研究院亚热带林业研究所引进浙江红花油茶优树穗条,在青田县大垟山林场开展浙江红花油茶高接换冠试验,分析砧木林郁闭度、坡位、砧木生长势及接穗保存时间等因素对嫁接成活率的影响。结果表明,林分郁闭度在0.3~0.7之间,随着郁闭度增加嫁接平均成活率提高;郁闭度在0.7~0.9之间,随着郁闭度增加,嫁接成活率降低;当郁闭度为0.7时,嫁接成活率最高为88.8%。山腰的嫁接成活率高达86%,显著高于山顶和山脚。浙江红花油茶砧木生长势越强嫁接成活率越高。接穗于采集当天嫁接效果最好成活率达89.1%,接穗保存1、2、3、4、5、6天嫁接,成活率分别为85.2%、75.2%、51.6%、28.1%、12.2%、9.3%。偏相关分析表明,各因素对嫁接成活率影响由大到小依次为接穗保存时间(-0.97)、郁闭度(0.85)、生长势(0.81)、坡位(-0.65)。  相似文献   
5.
The potential risk of pesticides to cause harm to humans and other organisms even at trace levels calls for sensitive and accurate analytical techniques for their simultaneous qualitative and quantitative determinations. In this study, a sensitive binary dispersive liquid-liquid microextraction (B-DLLME) strategy was developed for the simultaneous determination of phorate and oxyfluorfen by gas chromatography mass spectrometry after extraction/preconcentration from aqueous solution. An experimental design was used to optimize parameters of the B-DLLME method to obtain maximum outcome. Under the optimum conditions of B-DLLME, the limit of detection (LOD) for phorate and oxyfluorfen were found to be 0.41 μg L?1 and 0.54 μg L?1, respectively. The detection limits correlate to about 37 and 73 folds enhancement in detection powers when compared to direct GC-MS determination of phorate and oxyfluorfen, respectively. In order to find out the applicability of developed method to real samples, recovery tests were performed for 20 μg L?1 of phorate and oxyfluorfen spiked in well water samples. Percent recovery values were found to be 94.5% for phorate and 101.9% for oxyfluorfen.  相似文献   
6.
为了研究机采种植模式下不同水平减施氮肥后增施叶面肥对棉花花铃期冠层光分布、叶面积指数及与产量的影响,旱碱地条件下,设置0(CK)、60(N1)、90(N2)、120(N3)、150(N4)、180(N5,当地常规施氮量)、225 kg·hm-2 (N6)7个施氮水平,其中N1~N4喷施叶面肥4次,测定花铃期群体叶面积指数(Leaf area index, LAI)、冠层光分布和籽棉产量。结果表明:与当地常规施氮量相比,减施(60~150 kg·hm-2)氮肥后,棉花花铃期叶面积指数降低0.7%~5.5%,冠层光总截获率降低0.2~1.7百分点,冠层光透射率升高0.2~0.8百分点;各减施氮肥处理群体叶面积指数与冠层上层叶片的光截获率均呈显著正相关,与下层叶片的光截获率则呈负相关;籽棉产量随施氮量的减少而降低,二者有较高的相关性(R2=0.990 5)。减氮(90~150 kg·hm-2)增施叶面肥处理的LAI、冠层光总截获率、光透射率、冠层上下层叶片光截获率以及籽棉产量与当地常规施氮量180 kg·hm-2处理差异均不显著。综上,旱碱地机采模式棉田增施叶面肥,对减施氮肥棉花花铃期冠层光分布、叶面积指数及籽棉产量有一定补偿作用。  相似文献   
7.
旨在解决传统农产品营销模式中的种植计划粗放、营销市场针对性不足、无法充分挖掘市场等问题,实现猕猴桃电商精准营销。通过互联网等途径采集历年猕猴桃电商营销情况相关数据并建立猕猴桃地理信息数据库,结合GIS的地理数据空间分析与可视化技术,对猕猴桃营销大数据进行智能分析与深度挖掘。可以实现详细的数据统计、分析与总览等,对各地区市场的供需情况精准预测。将相关信息及时反馈给种植者,帮助其进行合理的种植方案决策,同时及时调整猕猴桃种植方案。针对不同季节、地区、需求量、品种等制定精准营销策略,以满足市场多样化需求,有效预防产品滞销等现象发生,切实提高种植户经济效益。  相似文献   
8.
近红外光谱是一种快速光谱分析的新方法,伴随着光谱技术与化学计量法的发展,近红外光谱已广泛应用于农业、食品、医药、石油化工等行业,极大地提高了各行业信息化水平。基于近红外光谱在家禽养殖领域的应用现状,本文总结了近红外光谱技术的发展及其在饲料成分检测和禽肉检测中的应用。在饲料检测和家禽肉类检测方面,通过将禽肉样品的光谱信息与质量指标的参考值相关联,建立了预测饲料和待测肉类高精度、高稳定性的数学模型。与传统方法相比,近红外光谱技术具有信息量大、数据计算速度快等优点。本文还归纳了近红外光谱技术在饲料品质检测和肉类品质检测的应用现状,指出了近红外光谱在家禽养殖领域的大规模应用推广的可能性。同时指出近红外光谱技术存在的问题和未来发展方向,结果表明近红外光谱技术在饲料和畜产品检测领域具有良好的发展前景和应用价值。  相似文献   
9.

Purpose

Riparian zone contamination is a growing problem for several European catchments due to high anthropogenic pressures. This study investigates As, Cd, Cr, Cu, Ni, Pb, and Zn concentrations in the Sava River riparian zone, characterized by wide agricultural areas, various geological substrates, and different types of industrial pollution. The accumulation and mobility of these elements were studied because they are listed as priority substances in the Water Framework Directive and environmental objectives for surface waters.

Materials and methods

Sampling was performed during the sampling campaign of the EU 7th FW-funded GLOBAQUA project in September 2015 during a low-water event. Soil samples were collected along the Sava River at 12 selected sampling sites, from a depth of 0–30 cm, at a distance of 10–15 m from the river bank. The extent of pollution was estimated by determining total and readily soluble element concentrations in the soils. Potential ecological risk and the source of the selected elements in the soils was determined using the enrichment factor (EF), potential ecological risk index (RI), and statistical methods such as the principal component analysis (PCA) and multiple linear regression analysis (MLRA).

Results and discussion

This study showed that concentrations of the selected elements increase along the Sava. In terms of origin, PCA and MLRA indicated that Cr and Ni in soils are predominantly lithogenic, while As, Cd, Pb, and Zn are both lithogenic and anthropogenic (ore deposits, industry, and agriculture). PCA singled out Cu since its origin in soil is most probably from specific point-source pollution. EF was generally minor to moderate for most of the examined elements, apart from Cu, for which the EF was significant at one sampling site. Overall ecological risk (RI) fell within the low-risk category for most sites, apart from Belgrade sampling site (BEO), where high total Cd content affected individual and overall ecological risk indicators, indicating Cd could represent a considerable ecological risk for the downstream riparian zone.

Conclusions

At downstream sites, there was a noticeable increase in PTE content, with Cd, Cr, Ni, and Zn exceeding the proposed threshold values for European soils, indicating rising contamination in riparian soils. In terms of the ecological risk, only Cd could pose a potential ecological threat for the downstream riparian zone.
  相似文献   
10.
In this study, the arterial distributions of the aortic arches of three deer species (Axis axis, Ozotoceros bezoarticus and Mazama gouazoubira) were described. The animals were dissected immediately after being found dead. Latex injection method was used to observe the vascularization of the thorax. The branching pattern of the arteries of the thoracic aorta in O. bezoarticus was similar to domestic ruminants. In the M. gouazoubira and A. axis, there were no bicarotid trunk. Interestingly, the first branch of the brachiocephalic trunk was the left costocervical trunk in A. axis. Then, brachiocephalic trunk was divided into right and left subclavian arteries. M. gouazoubira and A. axis in contrast to O. bezoarticus were different when compared with other ruminants, and the absence of bicarotid trunk was more striking than previous reports.  相似文献   
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