氮磷钾用量对小麦冠层不同层次光截获和干物质分配的影响

为明确不同氮、磷、钾用量对小麦冠层不同层次光截获和干物质分配的影响，以济麦22为供试材料，设置F0（不施肥）、F1（N 180 kg·hm^-2，P₂O₅ 75 kg·hm^-2，K₂O 60 kg·hm^-2）、F2（N 225 kg·hm^-2，P₂O₅ 120 kg·hm^-2，K₂O 105 kg·hm^-2）和F3（N 270 kg·hm^-2，P₂O₅ 165 kg·hm^-2，K₂O 105 kg·hm^-2）4个施肥量处理，比较分析开花后不同氮、磷、钾用量对小麦叶面积指数、冠层不同层次光截获特性和成熟期干物质分配的影响。结果表明，F1处理下叶面积指数显著高于F0处理，而与F2和F3处理间无显著差异；开花后15 d，F1处理下小麦冠层不同层次及总PAR截获率和截获量均显著高于F0处理，而与F2和F3处理间无显著差异。F1处理下成熟期干物质在小麦冠层不同层次营养器官中的分配量、籽粒中的分配量及总干物质积累量显著高于F0处理，而与F2和F3处理间无显著差异。成熟期干物质在小麦冠层不同层次营养器官和籽粒中的分配量以及总干物质积累量与冠层上层（顶部至株高2/3）、中层（株高2/3至株高1/3）和总PAR截获率均呈显著正相关。F1处理（N 180 kg·hm^-2，P₂O₅ 75 kg·hm^-2，K₂O 60 kg·hm^-2）为本试验条件下的最优处理。     

Leaf carbohydrates assimilation and metabolism affect seed yield of rapeseed with different waterlogging tolerance under the interactive effects of nitrogen and waterlogging

Waterlogging is a main factor causing rapeseed (Brassica napus L.) yield loss, and reasonable nitrogen (N) applications can compensate for this loss. To investigate the effects of N rates on seed yield of waterlogged rapeseed, the waterlogging-tolerant rapeseed variety ZS 9 and sensitive variety GH01 were waterlogged for 0 and 10 days with five leaves at the seedling stage under four N rates (0, 90, 180 and 270 kg/ha). Waterlogging significantly decreased seed yield, while N application can alleviate the yield loss. The yield decrease rate of waterlogged GH01 was greater than that of ZS 9 under the same N rate. During the seedling and bolting stage, the leaf photosynthetic rate (Pn) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity increased, while activities of adenosine diphosphate glucose pyrophosphorylase (AGPase), sucrose synthase (SuSy) and sucrose phosphate synthase (SPS) decreased with more N under the same watering conditions. Compared to the plants without waterlogging, the leaf Pn and Rubisco activity, starch and sucrose contents of waterlogged rapeseed decreased at the two stages; activities of AGPase, SuSy and SPS of waterlogged rapeseed decreased at the seedling while increased at the bolting stage for both the two varieties. At the flowering stage, the Pn, the activities of Rubisco, AGPase, SuSy, SPS and contents of sucrose, starch increased with more N application for both ZS 9 and GH01. Compared to the plants without waterlogging, the Pn and Rubisco activity for waterlogged plants of the two varieties increased; the waterlogged plants of tolerant variety had higher activities of AGPase, SuSy and SPS, while those of sensitive variety was significantly lower. However, the decreased starch and sucrose content were found in both tolerant and sensitive varieties. The activities of AGPase, SuSy and SPS at flowering were highly positively correlated with yield under the interactive effects of N and waterlogging. These results suggested that the flowering stage is the most important stage that N had the positive regulation on waterlogged rapeseed growth. The carbohydrates translocation from leaves to seeds of the tolerant variety were enhanced after waterlogging, while that of the sensitive variety was still inhibited. This was the main reason for the difference in yield between the two waterlogged varieties.     

养猪场沼渣制备包膜缓释肥理化性质表征

文章以分散式养猪场沼渣为应用研究对象,以8%聚乙烯醇为包膜材料,改性斜发沸石为肥料载体和缓控释材料调理剂,通过添加不同沸石量制备3种复混包膜缓释肥。利用红外光谱、扫描电镜及三维荧光对3种缓释肥的进行表征。结果表明:添加改性沸石的复混包膜肥除了增加显著的沸石红外特征谱外,其余红外光谱图差异不明显,表明添加沸石对有机质(富里酸和腐殖酸)结构和化学键型并未产生明显的影响,即不影响沼渣理化性质;添加改性沸石可以使聚乙烯醇完整的覆盖在肥料表面,膜壳更加平整光滑,膜层更加致密;三维荧光光谱显示复混包膜肥Ⅰ浸出富里酸和腐殖酸浓度最大,复混包膜肥Ⅲ浓度最低,表明添加沸石有减缓肥料养分释放的效果。该研究对于利用养猪场沼渣制备包膜缓释肥有一定的参考价值。     

Exploiting chemical ecology to manage hyperparasitoids in biological control of arthropod pests

Insect hyperparasitoids are fourth trophic level organisms that commonly occur in terrestrial food webs, yet they are relatively understudied. These top‐carnivores can disrupt biological pest control by suppressing the populations of their parasitoid hosts, leading to pest outbreaks, especially in confined environments such as greenhouses where augmentative biological control is used. There is no effective eco‐friendly strategy that can be used to control hyperparasitoids. Recent advances in the chemical ecology of hyperparasitoid foraging behavior have opened opportunities for manipulating these top‐carnivores in such a way that biological pest control becomes more efficient. We propose various infochemical‐based strategies to manage hyperparasitoids. We suggest that a push‐pull strategy could be a promising approach to ‘push’ hyperparasitoids away from their parasitoid hosts and ‘pull’ them into traps. Additionally, we discuss how infochemicals can be used to develop innovative tools improving biological pest control (i) to restrict accessibility of resources (e.g. sugars and alternative hosts) to primary parasitoid only or (ii) to monitor hyperparasitoid presence in the crop for early detection. We also identify important missing information in order to control hyperparasitoids and outline what research is needed to reach this goal. Testing the efficacy of synthetic infochemicals in confined environments is a crucial step towards the implementation of chemical ecology‐based approaches targeting hyperparasitoids. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Responses of plant community to the linkages in plant-soil C:N:P stoichiometry during secondary succession of abandoned farmlands,China

Succession is one of the central themes of ecology;however,the relationship between aboveground plant communities and underground soils during secondary succession remains unclear.In this study,we investigated the composition of plant community,plant-soil C:N:P stoichiometry and their relationships during secondary succession after the abandonment of farmlands for 0,10,20,30,40 and 50 a in China,2016.Results showed that the composition of plant communities was most diverse in the farmlands after secondary succession for 20 and 50 a.Soil organic carbon and total nitrogen contents slightly decreased after secondary succession for 30 a,but both were significantly higher than those of control farmland(31.21%-139.10%and 24.24%-121.21%,respectively).Moreover,C:N ratios of soil and microbe greatly contributed to the changes in plant community composition during secondary succession of abandoned farmlands,explaining 35.70%of the total variation.Particularly,soil C:N ratio was significantly and positively related with the Shannon-Wiener index.This study provides the evidence of synchronous evolution between plant community and soil during secondary succession and C:N ratio is an important linkage between them.     

施氮量和采收时期对油蔬两用型油菜菜薹维生素合成的影响

为明确施氮量和采收时期对油蔬两用型油菜薹维生素含量的影响,以富硒1号为材料,采用裂区试验设计,设置3个施氮量(120、180和240 kg·hm^-2)和4个采收时期(以株高20、30、40和50 cm表示),分析了油菜薹维生素C、维生素E、维生素B₁和维生素B₆含量的变化;比较了半乳糖内酯脱氢酶(GalLDH)、抗坏血酸氧化酶(AAO)、抗坏血酸过氧化物酶(APX)、脱氢抗坏血酸还原酶(DHAR)和单脱氢抗坏血酸还原酶(MDHAR)活性,并分析了维生素家族基因在菜薹中的表达量。结果表明,随着施氮量的增加,油菜薹还原型维生素C(AsA)含量降低;氧化型维生素C(DHA)含量在株高20 cm采收时增加,但在30 cm及以上株高采收时则降低;维生素E和维生素B₆含量先增加后降低;维生素B₁含量增加;维生素C合成关键酶GalLDH活性先略增加后降低;AAO和DHAR活性增加,APX和MDHAR活性则整体表现为先增加后降低。且施氮量增加后,维生素家族各基因在株高30和40 cm采收的菜薹中主要表现为正向调控,而在株高20和50 cm采收的菜薹中主要表现为负向调控。就采收时期而言,菜薹中的维生素含量在株高30~40 cm时高于其他时期;在同一施氮量下,随着菜薹采收株高的增加,维生素家族基因的表达量主要呈上调模式。综合分析可知,GalLDH活性的降低以及AAO/DHAR和APX/MDHAR代谢平衡是增施氮肥导致菜薹维生素C含量降低的重要原因。本研究结果为油蔬两用型油菜薹优质栽培技术提供了理论依据。     

北方夏玉米滴灌施肥一体化技术应用效果

为有效提高夏玉米水肥利用效率,通过田间试验对滴灌施肥一体化高效调控与利用技术进行系统的探究。结果表明,与常规漫灌(T1)相比,采用滴灌施肥一体化技术(T2和T3)可显著提高夏玉米大喇叭口期至灌浆期的叶面积指数;显著促进吐丝期至成熟期的干物质积累;在产量构成因素方面显著增加穗粗和穗粒数,并在一定程度上降低玉米穗的秃顶长度,进而显著提高夏玉米的产量。与T1相比,T2和T3增产5.32%~6.13%;水分利用效率提高36.10%~39.42%;氮、磷、钾肥利用率分别提高37.56%~35.29%、23.09%~30.30%、106.21%~121.51%。此外,采用滴灌施肥一体化技术可显著提高夏玉米生产经济效益。与T1相比,T2和T3可有效降低投产比,收益率平均提高4.71个百分点。在化肥用量较常规灌溉模式减少20%条件下,采用滴灌施肥一体化技术既能显著提高夏玉米产量,又能提高经济效益,是适宜在潮土区推广的一种高效节本增收的灌溉模式。     

硅钙钾镁肥配施黄腐酸钾对土壤酶活性及桃幼树生长的影响

为探究硅钙钾镁肥配施黄腐酸钾对桃树生长的效应,以盆栽一年生瑞蟠21号毛桃(Amygdalus persica Linn.)为试验材料,设置3种不同施肥方式(T1:硅钙钾镁;T2:硅钙钾镁+黄腐酸钾;CK:空白对照),在桃幼树生长季进行追肥处理,研究硅钙钾镁肥及硅钙钾镁肥配施黄腐酸钾对土壤酶活性、土壤养分状况及桃幼树根系构型和植株生长的影响。结果表明,与CK相比,T1、T2均显著提高了桃幼树生长季各时期土壤酸性磷酸酶、脲酶和过氧化氢酶活性,以及土壤中碱解氮、有效磷、速效钾和有效硅等含量,且配施黄腐酸钾后作用更明显。与CK相比,T1、T2细根比重分别提高了11.2%和26.2%,根系活力分别提高了12.2%和18.1%,根系总长度分别增加了28.1%和61.9%,且有效延缓了根系衰老;T1、T2植株总干重分别提高了1.2倍和2.0倍,根冠比分别提高了9.4%和17.0%,且差异显著。与CK相比,T1、T2各器官中全氮、全磷、全钾含量均显著增加,地上部硅含量分别提高了61.3%和91.9%,地下部硅含量分别提高了62.3%和102.5%,且差异显著。同时,T1、T2桃幼树叶片叶绿素含量和净光合速率均显著提高。综上所述,硅钙钾镁肥可有效提高土壤酶活,促进桃幼树细根的生长,延缓根系衰老进程,增加氮、磷、钾、硅等营养元素积累量,提高叶片光合速率,促进植株生长;硅钙钾镁肥配施黄腐酸钾后,提高了土壤有效硅及植株硅含量,比单施硅钙钾镁肥效果更加显著。本研究结果为桃树合理施用硅钙钾镁肥提供了理论依据。     

稳定碳、氮同位素在牛肉加工过程中的分馏效应

为了探究牛肉及副产物中稳定碳、氮同位素在加工过程中的变化规律,确证稳定碳、氮同位素在牛肉加工制品产地溯源中的稳定性和有效性。本试验通过对牛肉进行不同时间的水煮、烤制和油炸3种处理,其中水煮和烤制加工时间分别为5、10、15、20、25和30 min,油炸加工时间分别为1、2、3、4和5 min;采用元素分析仪-稳定同位素比率质谱仪(EA-IRMS)测定脱脂牛肉、粗脂肪及副产物中δ¹³C和δ¹⁵N值。结果表明,脱脂牛肉中δ¹³C值在水煮、烤制和油炸3种加工方式不同加工时间之间均无显著差异,水煮和烤制后粗脂肪中δ¹³C值无显著变化,油炸后的牛肉粗脂肪δ¹³C值主要受植物油的影响,加工方式及加工时间对其无显著影响;水煮脱脂牛肉δ¹⁵N值在加工25、30 min时与对照组牛肉存在显著差异,但平均差值仅为0.3‰~0.9‰。牛肉稳定碳、氮同位素在不同加工过程中分馏效应较小,可有效用于牛肉加工半成品及成品的原产地溯源。     

基于15N示踪技术的干旱区滴灌葡萄氮素利用分析

为研究水氮调控对干旱区滴灌葡萄氮素吸收利用的影响,以新疆鲜食葡萄弗雷为试验材料,利用¹⁵N 示踪技术,设置2种灌水处理(灌水量为4 950、5 400 m³·hm^-2,分别记作W1、W2),3种施氮处理(施氮量为177、235、292 kg·hm^-2,分别记作F1、F2、F3)进行大田试验。结果表明,各处理土壤全氮含量和¹⁵N丰度差异极显著(P<0.01),并且在0~20 cm土层出现富集现象。各器官征调氮素能力随水氮投入加大极显著增强(P<0.01)。根系、茎秆、叶片器官的生物量随着吸氮量的增加极显著提高(P<0.01),而较高施氮量(F3)不利于果实器官生物量的积累。果树吸收的肥料氮量随水氮投入的加大逐渐增加,受水氮调控影响极显著(P<0.01),果树吸收的土壤氮量大于肥料氮量。W2F1的¹⁵N标记氮肥利用率和¹⁵N标记氮肥偏生产力最高,分别为38.36%和114.20 kg·kg^-1,W2F2的产量最高,为20 253 kg·hm^-2,但与W2F1差异不显著。表明水氮投入过多会引起茎秆和叶片器官徒长且不利于提高¹⁵N标记氮肥利用率。综上所述,灌水量5 400 m³·hm^-2、施氮量177 kg·hm^-2(W2F1)是兼顾经济效益与生态效应的可行水氮运筹模式。本研究结果为干旱区滴灌葡萄高产高效种植提供了参考。