LED补光对水稻秧苗素质及其生理特征和产量的影响

采用发光二极管(light-emitting diode,LED)精确调制光谱能量,研究不同光质对水稻秧苗素质(株高、根长和鲜干重)和生理特征(内源激素、抗氧化酶、可溶性蛋白和丙二醛)的影响,探讨生理特征与秧苗素质和补光移栽后产量的耦合关系。水稻秧苗分别在5种光质下进行补光照射:R (100%红光),B (100%蓝光),RB (80%红光+20%蓝光)RBG_12.5(62.5%红光+25%蓝光+12.5%绿光),RBG₂₅(50%红光+25%蓝光+25%绿光),光量子通量均为1 000μmol·m^-2·s^-1,照射30 d (6 h/d)后采样,并插秧至稻田,以无补光作为对照(CK)。与CK相比,LED补充光源显著(P<0.05)影响水稻秧苗的株高、根长和鲜干重。株高和地上部分干重最大值分别出现在R和RBG_12.5处理,而根长和地下部分干重的最大值均出现在RBG_12.5处理。LED补充光源对内源激素、抗氧化酶、可溶性蛋白和丙二醛的影响程度因光质和植物部位而异。与CK相比,RBG_12.5二显著(P<0.05)提高地上部生长素(IAA)含量和可溶性蛋白含量,B显著(P<0.05)提高地上部超氧化歧化酶(SOD)活性、过氧化物酶(POD)活性和丙二醛(MDA)含量;RBG_12.5和RBG₂₅显著(P<0.05)提高地下部IAA含量,RBC₂₅显著(P<0.05)提高地下部可溶性蛋白含量和MDA含量。补光移栽后水稻产量的变化趋势与光质对水稻秧苗壮苗指数的影响趋势一致:RBG_12.5> RBG25> RB> B> R> CK。逐步回归分析发现,壮苗指数与地上部赤霉素(GA_3)含量和IAA含量及地下部IAA含量和SOD活性显著正相关;补光移栽后产量与秧苗地上部IAA含量及地下部IAA含量和过氧化氢酶(CAT)活性显著正相关。LED补充光源通过调节水稻秧苗生理特征影响其素质,且影响效应延续至水稻成熟期。RBG_12.5光源更利于培育水稻壮苗和水稻增产,适宜用作工厂化育秧的补充光源。     

28种防火林带树种树叶抗火性能研究

为探究树种的防火能力,科学选择防火林带树种,提高生物防火林带的树种多样性,对28种防火林带树种的理化指标进行测定,应用因子分析和聚类分析方法对其抗火性能进行综合排序与分类。结果表明,树叶热值与灰分、挥发分与固定碳之间呈极显著相关关系,热值与挥发分之间、灰分与挥发分之间呈显著相关关系;综合排序表明鸭脚木、夹竹桃、米老排、大叶相思、深山含笑、黧蒴、木荷、红花油茶、铁冬青、台湾相思、醉香含笑、凤凰木为抗火性较好的12个树种。聚类分析结果表明,抗火性强的树种有4种,夹竹桃、鸭脚木、大叶相思、铁冬青;抗火性较强的树种有7种,黧蒴、米老排、醉香含笑、台湾相思、深山含笑、木荷、山杜英;抗火性中等的树种有6种,西南木荷、乌桕、凤凰木、红花油茶、土沉香、樟树;抗火性较弱的树种有8种,枫香、柠檬桉、黄葛榕、马占相思、观光木、红苞木、红锥、山乌桕;抗火性弱的树种有3种,多花山竹子、蝴蝶果、假苹婆。     

渭南市种植业面源污染现状、防治难点及对策建议

掌握面源污染现状是进行污染防治的前提。本研究概述了渭南市种植业面源污染的现状,指出化肥施用高量低效并存、农药包装物污染、残膜污染持续以及秸秆综合利用衍生问题突出,是当前种植业面源污染亟待解决的问题,然后结合防治难点,从宣传普及、强化监测、健全法规、资金保障以及做好技术研发和推广等角度提出了较系统的防治对策和建议。     

土壤不同形态碳氮含量和酶活性对培养时间及外源碳投入的响应

在绿色农业科技的推动下,有机物料资源化利用备受青睐,但有机物料种类不同对土壤肥力的提升效果不同,为探究有机物料施用对潮土不同形态碳氮含量及酶活性的动态影响,通过为期1年的培养试验,设置添加10 g/kg的秸秆菌渣(S)、树枝菌渣(B)、小麦秸秆(W)、黑麦草秸秆(R)和蚕豆秸秆(BB),并以空白处理作为对照(CK)。结果表明:与CK相比,有机物料施用显著增加土壤不同形态碳氮含量及酶活性,随培养时间的延长,有机碳及全氮含量呈增加的趋势,增幅分别为25.4%～42.9%和35%～60%,易氧化有机碳和碱解氮含量呈先上升后下降的趋势,最大值分别为2.80,43.26 mg/kg,水溶性有机碳、微生物量碳氮和酶活性则呈下降的趋势,最大值分别为346 mg/kg,293μg/g和23.08μg/g。有机物料施用会增加土壤酶活性提高土壤呼吸速率,通过对3个取样期7种水解酶的分析发现,酶活性表现为:LAPPHOSNAGBGCBAGXYL,即参与氮循环酶活性参与磷循环酶活性参与碳循环酶活性,绿肥秸秆主要增加氮循环酶活性,且以BB处理酶活性最高,菌菇渣主要增加碳循环酶活性,B处理酶活性高于S处理。有机物料施用会影响土壤酶活性,增加不同形态碳氮含量,但增幅因有机物料种类不同而有所差异,且碳氮组分对培养时间的响应不一。总体而言,小麦秸秆和蚕豆秸秆腐殖化系数最高,对不同组分碳氮含量增加效果最优。     

辽河干流河岸带植物及微生物多样性研究

为明确辽河保护区河岸带生物多样性恢复现状以促进河岸带生态系统的健康管理,本研究通过植被现场调查和土壤微生物高通量测序分析,对辽河干流23个采样点的植物多样性和微生物多样性进行测定,结果表明:辽河干流23个采样点的植被Shannon-Weiner多样性指数平均为1.227,平均植被覆盖率达到74.19%;河岸带土壤微生物Shannon-Weiner多样性指数平均为9.55;其优势度大于1%的细菌属于11个门、32个纲、40个属;人类活动干扰、放牧情况以及土地利用类型是影响河岸带植物和微生物多样性的关键因子。目前辽河保护区河岸带生物多样性恢复状态较好,但日渐增多的人类活动对河岸带生物多样性的恢复产生不利影响,因此建议尽量减少封育区内的人类活动、放牧情况等,以加快辽河保护区河岸带植物及土壤微生物多样性的恢复进程。     

基于无人机高光谱遥感的柑橘患病植株分类与特征波段提取

目的 结合传统与现代农业病虫害监测的优缺点，探索通过无人机高光谱遥感技术检测出患病的柑橘植株、通过人工田间调查方式判断其患病种类及患病程度的病虫害监测方法。方法 使用无人机获取原始高光谱图像，经过光谱预处理和特征工程后，采用连续投影算法提取对柑橘患病植株分类贡献值最大的特征波长组合，基于全波段使用BP神经网络和XgBoost算法、基于特征波段使用逻辑回归和支持向量机算法，建立分类模型。结果 基于全波段的BP神经网络和XgBoost算法的ROC曲线下面积(Area under curve，AUC)分别为0.883 0和0.912 0，分类准确率均超过95%；提取出698和762 nm的特征波长组合，基于特征波长使用逻辑回归和支持向量机算法建立的分类模型召回率分别达到了93.00%和96.00%。结论 基于特征波长建模在患病样本分类中表现出很高的准确率，证明了特征波长组合的有效性。本研究结果可为柑橘种植园的病虫害监测提供一定的数据和理论支撑。     

A型流感病毒分型基因芯片在流感病毒各亚型监测中的应用

为验证自行研制的A型流感病毒分型基因芯片方法在实际中的应用效果,了解A型流感病毒各亚型在我国不同地区和不同宿主中的分布情况,对我国20个地区、不同宿主源(鸡、鸭、鹌鹑、鸽子、猪、人等)拭子和组织样品共16 852份进行了检测。利用自行研制的A型流感病毒分型基因芯片方法,对样品进行RNA提取、多重不对称RT-PCR扩增、芯片杂交、洗涤和扫描分析;同时将基因芯片检测阳性的样品,用普通RT-PCR扩增后进行序列测定。结果显示:利用该方法检出阳性样品2 582份,总检出率为15.32%(2 582/16 852),共检测到H1N1、H2N9、H3N2、H4N6、H5N1、H7N1、H7N9、H9N2、H10N5、H16N3等10个亚型,且均与阳性样品测序结果一致。结果表明,该方法可准确检测不同地区、不同宿主中的A型流感病毒不同亚型。同时,该方法能在同一张芯片上准确鉴定A型流感病毒的多种亚型,解决了其他常规方法无法检测已发现和可能发生变异的所有亚型的棘手问题,从而为A型流感诊断和分子流行病学监测提供了一种新技术。     

Survival and serum biochemical responses of spotted sea bass Lateolabrax maculatus during simulated waterless live transportation

Waterless live fish transportation is an alternative and promising transport strategy, which may reduce shipping costs, increase stocking density and improve survival of some species. Spotted sea bass is one of the most economically important marine fish in China. However, waterless transportation has not yet been studied on spotted sea bass. To explore the possibility of waterless transportation of spotted sea bass and its sublethal stress responses, the survival rate and dynamics of blood biochemical parameters were evaluated in the present study by preserving it under no water, less water and water (control) conditions for 9 hr. The serum biochemical parameters including total protein, cortisol, glucose, lactate, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total carbon dioxide (TCO₂), creatinine, blood urea nitrogen (BUN), ammonia, superoxide dismutase (SOD) activity and malonaldehyde (MDA) were investigated. Results showed that the survival rates of fish in all groups gradually declined with time increasing. At the end of transportation, the survival rates in the control group, less‐water group and no‐water group decreased to 49.11%, 15.60% and 23.96% respectively. Significant changes were observed in several selected serum biochemical parameters, including glucose, lactate, ALT, TCO₂, BUN and ammonia during simulated waterless transportation, which might negatively affect the physiological homeostasis of fish, leading to the high mortality in present study. In general, waterless transportation of spotted sea bass was possible, but it might be rather suitable for short time than long time.     

Evolution of marine fisheries management in China from 1949 to 2019: How did China get here and where does China go next?

China is the world’s biggest fishing nation and a major player in the global seafood trade. Its fisheries development can decisively influence the global seafood trade, food security and marine conservation. In recent years, significant changes have taken place in China’s fisheries management priorities, policies and regulations. In this paper, we review the evolving fisheries management practices in China to delineate changes in the management policies, methods and their performances from 1949 to 2019. We determined that the following issues impede the development, implementation and enforcement of fisheries policies and regulations, namely the large size of the fishing fleet, large and poorly organized fisheries population, the “hidden” fishing capacity, uniform management approaches that sometimes fail to account for local conditions, lack of clearly defined and allocated fishing rights, limited data quality and availability, insufficient fisheries monitoring programmes, absence of a robust scientific input framework and insufficient stakeholder involvement. Combining those problems with China’s current management initiatives, we propose recommendations for China’s future fisheries reforms. We hope this paper can inform China’s marine fisheries policies and provide valuable references for further researches related to China’s sustainable fisheries management.     

Occurrence of prophage and historical perspectives associated with the dissemination of huanglongbing in mainland China

Huanglongbing (HLB), associated with a non-culturable bacterium ‘Candidatus Liberibacter asiaticus’ (CLas), is a highly destructive citrus disease with a long but poorly documented history in China. No effective treatment for HLB is available. The identification of new prophages in abundant CLas genomic sequence data provides new insights into both the diversity of CLas strains and HLB management. In this study, CLas populations from nine provinces were surveyed for the presence of prophage. Two major prophage typing groups (PTGs) were discovered to be associated with two different altitude regions: strains of CLas in PTG1 from high altitude regions (HAR) mainly contained prophage Type 1 only or Types 1 and 3, whereas strains of CLas in PTG2 from low altitude regions (LAR) mainly contained prophage Type 2. The discovery of these CLas population patterns provides evidence for independent origins of HLB in HAR and LAR. Guangdong province is the generally recognized domestic region of origin for HLB and is primarily responsible for the dissemination of HLB in LAR through transport of seedlings. Both Yunnan and Sichuan provinces are the probable regions of origin for HLB in HAR. PTG2 was further divided into two subgroups: PTG2-1, found in Guangdong, Fujian and Guangxi and PTG2-2, found in Jiangxi, Zhejiang and Hunan. These regions and prophage types are correlated with early and late introductions of HLB in LAR. These molecular analyses were supported by studying the history of the dissemination of HLB in historical documents.