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1.
This study used two different collectors made of polypropylene (PP) rope and polyethylene (PE) fishing net to determine Mediterranean mussel's settlement, growth, condition index (CI), meat yield (MY) and shell thickness index (STI) during the period spent between June 2017 and November 2018. With this regard, chlorophyll a, water temperature, salinity, pH and particulate matter were defined through water samples that were collected on monthly basis triplicate. The mean chlorophyll a level was recorded as 0.32 ± 0.31 μg/L, while water temperature was 19.73 ± 5.14°C, salinity was 35 ± 2.070‰, pH was 8.12 ± 0.04, and TPM was 14.91 ± 10.48 mg/L. As a result of the cultivation period of 8 months spent following the first intense grip, the length of the mussels is measured as 31.79 ± 6.20 mm. Based on the Pearson correlation analysis results, the most important environmental parameter affecting Mediterranean mussels growth in length on PP rope collectors is the temperature (p < .05). The STI and CI were determined to be related with environmental temperature parameters, while no determinations could be obtained concerning the correlation of MY with environmental parameters. Assessment of Mediterranean mussels’ growth rate in PP rope collectors proved significant differences (p < .05) between March and November 2018. As no Mediterranean mussels are observed on PE fishing nets during the samplings performed throughout the study period, it is determined that PE fishing nets are not suitable collector types for Mediterranean mussel cultivation.  相似文献   
2.
郑贤  李滔滔  李丁  韦雨佳 《农机化研究》2021,(3):119-122,127
目前,我国普遍采用的木薯收获方式为人工收获,劳动生产率低、工作环境差且经济效益低下,而国外的木薯收获机普遍不适应于我国南方的粘性土壤,存在木薯损失率高且土壤分离不彻底的问题。查阅资料得知,挖拔式木薯收获机十分适应我国南方的木薯种植环境,可减少木薯损失,促进木薯与土壤的分离。为此,利用UG设计了一款挖拔式木薯收获机,利用Adams软件对机器进行仿真分析得出多组数据,并使用MatLab对这些数据进行处理,以根据运动关系确定关键零件参数,使其可以与目前市面上的拖拉机匹配,实现高效低能耗收获木薯的目的。  相似文献   
3.
为了减少大豆生产过程中化肥的施用量及对黑土地的保护,开展大豆田间试验,分别施用大豆专用复合肥(CK)、枯草芽孢杆菌+氨基酸型有机肥(T1)、枯草芽孢杆菌+黄腐酸钾肥(T2)、枯草芽孢杆菌+海藻精粉颗粒肥(T3)、枯草芽孢杆菌秸秆腐熟有机肥(T4)、枯草芽孢杆菌鸡粪腐熟有机肥(T_5),综合评价各种肥料对大豆光合作用和土壤酶活的作用效果。结果表明:光合参数方面,T1、T4和T_5处理的净光合速率较CK增加了5.0%、0.7%和8%,但差异不显著;蒸腾速率的最大值为T_5,较CK增加了30%,最小值为T2,较CK降低了43.1%;气孔导度从高到低依次为T_5>T4>T1>CK>T3>T2,其中T2、T3和T_5与CK差异显著;T2处理胞间CO_2浓度最低,较CK显著降低了12.0%,T1、T_5处理较CK分别增加了5%和7%。叶绿素含量中,T4和T_5的叶绿素含量均显著低于CK,T1处理的叶绿素a含量最高,较CK增加了17.3%,T2处理的叶绿素b含量较CK提高了2%,T3处理与CK相比无明显变化。各处理的土壤脲酶活性均显著高于CK T_5处理为最大值,较CK提高17.7%;土壤蔗糖酶从高到低依次为T1> T3>CK>T1>T4>T2,其中T1较CK提高了18.9%,T2较CK降低了27.8%;土壤碱性磷酸酶的最小值为T3处理,酶活仅为8.55 mg·g-1,最大值为T4处理,较CK增加了7%。作为环境友好肥料,枯草芽孢杆菌+氨基酸型有机肥、枯草芽孢杆菌秸秆腐熟有机肥和鸡粪枯草芽孢腐熟有机肥部分代替化肥,具有应用潜力。  相似文献   
4.
郑伟  师筝  龙美  廖允成 《中国农业科学》2021,54(21):4539-4551
【目的】叶色突变体是研究叶绿素合成、叶绿体发育和光合作用的理想材料,探索小麦黄绿叶突变体的光合生理特性,旨在阐明其光合作用调控机理,为小麦黄绿叶突变体的进一步利用奠定基础。【方法】以野生型冀麦5265和突变体冀麦5265yg为试验材料,对叶色表型进行观察,采用分光光度计和试剂盒法测定色素含量和酶活性,并利用Li-6400便携式光合仪和PAM100叶绿素荧光仪进行光合气体交换参数和叶绿素荧光参数测定。【结果】表型观察和色素含量结果表明,突变体苗期叶片表现为黄绿色,抽穗后叶片逐渐转变为淡绿色。遮阴处理可以使叶片颜色部分复绿,但比野生型略浅,属于光诱导转绿型突变体。突变体叶绿素a和叶绿素b含量显著低于野生型,叶绿素a/b的比值升高,为典型的叶绿素缺乏型突变体;光响应曲线和CO2响应曲线显示,突变体的表观量子效率(AQY)、光饱和点(LSP)、最大净光合速率(Pn-max)、光补偿点(LCP)、暗呼吸速率(Rd)、羧化效率(CE)和饱和CO2浓度(I-sat)显著高于野生型,说明突变体叶片的光合机构稳定,强光下光合速率更高;光合气体交换参数和叶绿素荧光动力学参数表明,突变体的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、光化学量子效率(Fv/Fm)、实际光化学效率(ΦPSII)和光化学淬灭系数(qP)显著高于野生型,说明其具有较强的光能转化和CO2固定能力;突变体的超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性均高于野生型,丙二醛(MDA)含量下降,可溶性糖和可溶性蛋白含量升高,说明抗氧化酶系统通过清除氧自由基降低了氧化损伤,突变体叶片细胞膜损害减轻,抗逆性增强;突变体的核酮糖-1,5-二磷酸羧化酶/加氧酶(Rubisco)活性显著低于野生型,磷酸烯醇式丙酮酸羧化酶(PEPC)活性显著高于野生型,推测C4 途径光合酶PEPC活性的升高可能是突变体具有较高净光合速率的原因之一。花后遮阴以及外源喷施抗坏血酸AsA和二硫苏糖醇DTT处理表明,突变体对光强变化更敏感、叶片内AsA含量及叶黄素循环效率更高。【结论】黄绿叶突变体冀麦5265yg叶片气孔导度明显改善、热耗散降低、C4途径光合酶活性升高,是其光合速率提高的主要原因。该结果为小麦叶色突变体高光合特性的分子调控机制研究奠定基础。  相似文献   
5.
The widespread use of sodium p-perfluorous nonenoxybenzene sulfonate(OBS), a typical alternative to perfluorooctane sulfonate, has resulted in potential threats to the environment, but the adsorption behavior of OBS in soils has not yet been reported. In this study, the adsorption behaviors of OBS on five soils with different physicochemical properties were investigated. The rate of OBS adsorption was fast, and most of the OBS uptake was completed within 12 h. The good model fit of OBS adsorption to the pseudo-second-order and Elovich models indicated the occurrence of chemical adsorption. The adsorption isotherms of OBS on the soils were better described by the Freundlich model than by the Langmuir model, suggesting that the OBS adsorption sites on the soils were heterogeneous. This is possibly associated with various adsorption mechanisms including hydrophobic, π-π, hydrogen bonding, and electrostatic interactions,further confirmed by the good model fit to the D-R isotherm. Adsorption of OBS occurred on the soils, and the adsorption process was spontaneous and endothermic. In addition, the soils were more suitable for OBS adsorption at lower pH values due to the stronger electrostatic adsorption. The OBS adsorption on the soils decreased with the increase of soil depth from 0 to 30 cm. Moreover, the presence of organic matter and ammonia nitrogen in the soils was favorable for OBS adsorption, and these parameters decreased with increasing soil depth, making OBS adsorption less prominent in the deeper soil. This study indicates that OBS is easily enriched in surface soils, and that soil organic matter and ammonia nitrogen significantly affect OBS migration in soil.  相似文献   
6.
Five isonitrogenous and isoenergetic diets with soybean oil (SO), linseed oil (LO), algae oil from Schizochytrium sp. (AO), mixed oil (MO, SO:LO:AO = 1:1:1) and fish oil (FO; control group) were selected to feed juvenile Onychostoma macrolepis (initial weight 1.86 ± 0.07 g) for eight weeks. The results showed that in the LO and FO groups fish grew best. There was no significant difference in specific growth rate (SGR) and feed efficiency (FE) between the MO and FO groups (p > .05). The highest contents of 18:2n‐6, 18:3n‐3 and 22:6n‐3 in liver and muscle were found with the SO, LO and AO groups, respectively (p < .05). There appeared the highest malondialdehyde (MDA) content and the lowest superoxide dismutase (SOD) activity in the fish liver of the AO group. There appeared the highest concentrations of serum glucose (GLU), cholesterol (CHOL) and triglycerides (TG) in the SO group. The expressions of lipid anabolism genes were significantly up‐regulated by dietary SO and LO (p < .05). The expressions of lipid catabolism genes were significantly higher with the AO, MO and FO groups (p < .05). This study recommended that LO or MO as a better vegetable oil source for juvenile O. macrolepis.  相似文献   
7.
Homestead ponds may offer an ideal opportunity in contribution to household income, fish consumption through fish culture. Phytoplankton plays a key indicator in pond productivity. However, the phytoplankton communities in the homestead ponds are nearly undetermined in Bangladesh. This study summarizes the phytoplankton diversity, assemblage and ecological parameters of the homestead ponds in central coastal belt, Bangladesh, based on two seasons. The results revealed that significant differences (p < .05) were found in pH, DO, conductivity, TDS, nitrates, phosphates and sulphates except temperature in monsoon, and transparency in both seasons. A total of 34 phytoplankton genera representatives of five major groups were recorded such as Euglenophyceae (41.5%), Chlorophyceae (30.5%), Cyanophyceae (13%), Dinophyceae (10%) and Bacillariophyceae (5%). A significant difference (p < .05) in phytoplankton abundance was found in both seasons with the highest mean of 186.13 ± 129.34 × 104 cells L?1 in monsoon and the lowest mean of 144.40 ± 107.26 × 104 cells L?1 during winter. The diversity (H'), evenness (J'), richness (d) and dominance (D) ranged from 1.62 to 2.47, 0.52 to 0.97, 0.37 to 1.15 and 0.10 to 0.28 respectively. Based on SIMPER, the most dominant (>10%) genera for dissimilation within stations and seasons were Euglena spp., Phacus spp., Chlorella spp., Strombomonas spp. and Peridinium spp. ANOSIM results stated that 12 genera of phytoplankton were significant contributors based on average dissimilarity. Pearson's correlation coefficient and canonical correspondence analysis (CCA) revealed that phytoplankton abundance, diversity and community were mainly governed by transparency, dissolved oxygen and nitrates.  相似文献   
8.
【目的】利用星载激光雷达波形数据对森林类型识别时,受地形、噪声和林层结构等因素影响,针叶林、阔叶林和混交林森林类型识别精度较低,为提高森林类型识别精度,需提取与森林类型相关的波形特征参数。【方法】结合回波仿真原理与林分冠层特征对GLAS回波波形进行理论分析,提出了与森林类型相关的波形特征参数Rcafit1-47、K1-47,并与其他森林类型相关的波形特征参数进行联合,建立多种波形特征参数组合,用于森林类型识别。【结果】1)针叶林和阔叶林森林类型识别时,波形特征参数组合Rcafit1-47、K1-47森林类型总体识别精度为92.86%,优于另外两种波形特征参数组合AGS、MSGS和AGS、SGS森林类型总体识别精度;2)针叶林、阔叶林和混交林森林类型识别时,波形特征参数组合Rcafit1-47、K1-47森林类型总体识别精度为77.03%,低于另外两种波形特征参数组合AGS、MSGS和AGS、SGS森林类型总体识别精度;3)波形特征参数Rcafit1-47、K1-47与其他波形特征参数组合后能够提高森林类型识别精度,其中,Rcafit1-47、K1-47、AGS、MSGS参数组合森林类型识别精度最高,针叶林和阔叶林森林类型识别精度为94.64%,针叶林、阔叶林和混交林林分类型识别精度为89.19%。【结论】提出的波形特征参数Rcafit1-47和K1-47在针叶林和阔叶林森林类型识别方面具有明显优势,而且与其他波形特征参数组合后能够明显提高针叶林、阔叶林和混交林3种森林类型的识别精度。  相似文献   
9.
以10 a生酿酒葡萄‘蛇龙珠’为试验材料,运用水肥一体化滴灌的方式分别在萌芽期(S1)、新梢旺长期(S2)、开花期(S3)、果实第一次膨大期(S4)和副梢生长旺期(S5)一次性施入300 kg·hm-2尿素,对照为整个生育期均不施氮肥(CK),分别于花后50 d(DAF50)、花后85 d(DAF85)和花后120 d(DAF120)进行光合特性指标的测定,并采样分析氮肥施用时期对葡萄叶片光合生理及内源激素水平的影响。结果表明:各生育期施氮均能增加叶片净光合速率(Pn)及PSⅡ最大光化学效率(Fv/Fm),在花前施氮肥叶片Pn和Fv/Fm增加最为显著,最高分别达到18.22 μmol·m-2·s-1和0.854。S1、S2和S3处理显著增大了不同生育期叶片气孔导度(Gs)和蒸腾速率(Tr),且S2处理在DAF85时最显著,Gs和Tr分别比CK高18.5%和10.8%;S3、S4和S5处理显著降低了叶片的胞间CO2浓度(Ci)和非光化学淬灭系数(NPQ),S1处理叶片Ci与CK之间无显著差异。果实第一次膨大期之前施入氮肥能够显著增大各生育期叶片的PSⅡ电子传递量子效率(ФPSⅡ)和光化学淬灭系数(qP),最高分别达到0.889和0.959。可见,不同时期施氮肥,通过改变光合荧光相关参数影响叶片光能的吸收、传递、耗散和分配,从而改善叶片光能利用效率。氮肥的施用时期影响各生育期叶片内源激素的含量,施氮肥均显著提高了DAF85后叶片玉米素(ZT)含量,与CK相比至少提高21.9%;花后施入氮肥叶片中IAA含量在果实采收时保持在34.9 μg·g-1以上,S4和S2处理GA3含量最高,分别为7.11 μg·g-1和6.49 μg·g-1。因此,氮肥施用时期影响葡萄各生育期不同内源激素的积累。  相似文献   
10.
为解析谷子黄叶色突变体高光合特性机理,以野生型豫谷1号为对照,分析了谷子全生育期黄叶色突变体ylm-1和ylm-2的光合色素、光合速率、气孔特性、荧光参数、光合关键酶活性和产量性状。结果表明,突变体光合色素含量为野生型豫谷1号的50%~60%,强光下突变体光合速率(Pn)较野生型显著提高,且无明显的“午休睡眠现象”;ylm-1和ylm-2气孔导度(Gs)显著增加。荧光参数结果显示,与野生型相比,突变体的光能利用效率和转化效率明显增加,光合关键酶1,5二磷酸核酮糖羧化酶(Rubisco)活性明显降低,而ylm-1和ylm-2磷酸烯醇式丙酮酸羧化酶(PEPCase)和苹果酸酶(NADP-ME)活性分别增加了23.3%、24.4%和12.9%、15.5%。产量相关性状分析表明,突变体单穗质量、穗粒质量及千粒质量较野生型显著增加。本研究结果为谷子高光效及分子标记辅助选择育种提供了重要的理论依据。  相似文献   
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