不同氮（N）水平下玉米的生理和代谢差异是田间合理氮素营养管理的基础，对提高氮肥利用率和减少环境污染具有重要作用。本文在明确长期不同氮肥处理下玉米氮效率和产量响应的前提下，利用非靶代谢组学方法分析了相应的差异代谢物及其代谢途径的差异。结果表明，氮胁迫（包括缺乏和过量），通过调节碳代谢产物（包括糖醇和TCA循环中间体）和氮代谢产物（包含各种氨基酸及其衍生物）影响碳氮代谢的平衡。缺氮胁迫时，L-丙氨酸、L-苯丙氨酸、L-组氨酸和L-谷氨酰胺显著下调，而过量氮时，L-缬氨酸、脯氨酸和L-组氨酸显著上调。除了上述碳氮代谢中的糖醇和氨基酸外，在该实验条件下，一些次生代谢物如黄酮类化合物（包括山奈酚、木犀草素、芸香素和香叶木素）和激素类（包括吲哚乙酸、反式玉米素和茉莉酸）可以初步被筛选作为氮胁迫诊断的指标。本研究还表明，N2处理（120 kg·ha^-1 N）和N3处理（180 kg·ha^-1 N）的叶片代谢水平相似，这与12年试验中两处理之间生理指标和产量的变化趋势一致。本研究在代谢水平上验证了氮肥减施即施用量从180 kg·ha^-1（当地推荐）减少到120 kg·ha^-1的可行性，为不降低产量条件下减少氮肥施用，进而提高氮肥利用率和保护生态环境提供了理论基础。

气候变化对农业产生了重大影响。但大多数研究基于历史气象数据的分析，缺乏与作物生长发育和土壤水分相关联的长期监测。本研究收集了甘肃省农业科学院镇原试验站1957-2020年气象数据和1981-2019年作物生育期数据，并在陇东和宁南开展了相关田间长期试验。研究结果表明，60年来，每10年平均气温增加0.36°C和降水减少11.2mm；1981-2019年的39年间旱地冬小麦田间耗水量平均362.1mm，呈现出每10年减少22.1mm的趋势，但1985-2019年的35年间春玉米耗水量平均405.5mm，保持基本稳定。气候干暖化导致旱地作物生育期发生了明显变化，每10年冬小麦和春玉米生育期缩短5.19天和6.47天，播前推迟3.56天和1.8天，成熟期提前1.76天和5.51天。全膜双垄沟集雨种植使小雨量在垄沟集雨效率达到65.7-92.7%，水分向土壤深层入渗，作物根域水分成倍增加，作物水分满足率提高110-160%，连续15年全膜双垄沟较半膜平作覆盖旱地玉米增产19.87%。旱地玉米群体大小是影响产量和水分利用效率的关键因素，种植密度从3000提高到4500株/亩，玉米产量和水分利用效率增加20.6%和17.4%，从4500提高到6000株/亩再增加12.0%和12.7%。然而，不同降水量地区旱地玉米产量与种植密度均呈现二次曲线关系，曲线性状、最高产量对应的最大密度在地区之间差异很大。在300-500mm年降水量地区，种植密度随降水量的增加而增加，适水种植密度为每1mm降水可种植玉米12株/亩，但超过500mm时种植密度随降水量变化不大。因此，旱地农田抗旱节水应集中在压夏扩秋适水型种植结构建立、垄沟覆盖集雨种植、以水定密适水种植等，以减少气候变化引起的负面影响，增强旱地玉米生产的可持续。

红火蚁Solenopsis invicta是一种严重威胁入侵地生物多样性、农林业生产和公共安全的危险性害虫。目前，红火蚁的防治药剂主要分为毒饵和触杀性粉剂两种类型。毒饵对红火蚁的防控效果虽然较彻底，但是见效慢，一般2周左右才能达到理想的防效。触杀性粉剂见效快，施药后3-5天即可达到理想效果，适合应用于红火蚁的紧急扑灭。为筛选出更多可用作触杀性粉剂的有效成分，本文开展了联苯菊酯和四氟甲醚菊酯对红火蚁的毒力、水平传递毒性及其触杀性粉剂的田间防效研究。研究显示，联苯菊酯和四氟甲醚菊酯对红火蚁工蚁的致死中量LD₅₀分别为3.40 ng/头和1.57 ng/头。20 μg mL^-1联苯菊酯对红火蚁工蚁的击倒中时KT₅₀和95%击倒时间KT₉₅分别为7.179 min和16.611 min。20 μg mL^-1四氟甲醚菊酯对红火蚁工蚁的击倒中时KT₅₀和95%击倒时间KT₉₅分别为1.538 min和2.825 min。联苯菊酯触杀性粉剂和四氟甲醚菊酯触杀性粉剂在蚁群间具有良好的水平传递毒性。0.25、0.50 和1.00% 联苯菊酯触杀性粉剂处理48小时后，第一次继发传递毒性的受药蚁的死亡率（二级死亡率）和第二次继发传递毒性的受药蚁的死亡率（三级死亡率）均超过了80%。0.25、0.50 和1.00% 四氟甲醚菊酯触杀性粉剂处理48小时后，第一次继发传递毒性的受药蚁的死亡率超过了99%，但是第二次继发传递毒性的受药蚁的死亡率则低于20%。野外结果显示，1.00%联苯菊酯触杀性粉剂和1.00%四氟甲醚菊酯触杀性粉剂处理14天后，对红火蚁蚁群的综合防效分别为95.87%和85.70%，防治效果较好。

磷（P）是一种不可再生资源，也是植物生长的关键营养元素，对作物产量的提高起着重要作用。磷肥的过量施用在农业生产中很普遍，这不仅浪费了磷肥资源，还造成了磷的积累和地下水污染。为了获得较高的产量和磷素利用效率（PUE），我们假设农业系统的表观磷平衡可以作为确定磷投入阈值的关键指标。因此，我们进行了长达12年的定位田间试验，包括6个施磷处理，施磷量分别为0、45、90、135、180和225 kg P₂O₅ ha^–1，以明确作物产量、PUE和土壤Olsen-P对磷平衡的反应并优化磷投入。结果表明，当磷肥施用量超过某一水平时，周年产量不再增加，当周年磷肥施用量为90–135 kg P₂O₅ ha^–1时可以实现较高的产量和PUE。当磷平衡阈值为2.15–4.45 kg P ha^–1时可以实现最佳产量和最小的环境风险。基于磷平衡阈值估算的磷投入为95.7–101 kg P₂O₅ ha^–1，施磷量在此阈值内时可以协同提高产量与PUE（90.0–94.9%）。此外，本研究发现磷投入-产出平衡框架的建立有助于评估土壤Olsen-P在未来的变化，其中土壤磷平衡每增加100 kg P ha^–1，有效磷含量上升4.07 mg kg^–1。总之，磷平衡可以作为农业生产中磷管理的一个重要指标，为限制磷过剩和制定更高产、高效和环保的磷肥管理策略提供有力参考。

增加种植密度是提高玉米产量的有效手段，但密植会加重雌穗顶端籽粒败育引发秃尖，进而导致减产。前期已有报道，对干旱逆境下玉米雌穗顶端籽粒败育的调控机制进行了研究，但对密植条件下玉米雌穗发生秃尖的调控机制知之甚少。本研究旨在探讨玉米应答密植环境、导致籽粒败育的潜在机制。选用两个自交系郑58和PH4CV，及分别由郑58和PH4CV做母本和父本组配的两个生产常用杂交种郑单958和先玉335为研究对象，观察了4个材料在四种不同种植密度（60,000 株/公顷 (60 k)、90,000株/公顷 (90 k)、120,000株/公顷 (120 k) 和 150,000株/公顷 (150 k)条件下，株型、秃尖情况、开花时间和花丝发育等表型的变化趋势。结果表明，随着种植密度增加，株高变化不明显，但茎粗、叶绿素含量和生物量的变化则呈现明显负相关。同时，散粉-吐丝期(ASI)延长，且苞叶中吐出花丝的数量也随之减少，说明密植条件下花丝生长减缓。进一步对花丝细胞形态的观察也发现，随着种植密度的增加，花丝细胞呈现减小趋势。转录组学数据分析表明，差异表达基因主要是花丝伸长相关基因，而非与碳代谢相关基因。以上研究证实，密植影响玉米花丝生长、使吐丝延迟、ASI加长，进而引起花期不遇，导致顶端胚珠授粉不良发生败育而产生秃尖表型。该研究加深了对密植条件下玉米花丝生长规律的认识，为进一步解析玉米应答密植条件，调控花丝生长的分子机制提供理论依据。

甜樱桃是世界最受欢迎的水果之一。早先，我们发现了一种黑色暗格真菌S16，它能够促进樱桃砧木吉塞拉5号的生长。然而，关于它们之间作用的分子机制还不甚了解。在本次研究中，我们分析了与S16共生的樱桃根部的生理指标以及转录组本，初步阐释了S16促樱桃生长的分子机制。与S16共生后，樱桃幼苗的活力更强。而且，与对照相比，S16共生根部共鉴定到4249个差异表达基因。这些基因涉及到与植物代谢、激素相关的生长过程。而且，与氮调控相关的基因高度富集。生理指标测定表明，S16能够促进樱桃幼苗利用NO₃^-转运蛋白来吸收氮源。因此，此次RNA测序数据库可以更加深入了从分子机制层面解析黑色暗格真菌促樱桃的生长过程。

本研究深入分析了在不同氮依赖黄瓜品种的叶片中CsGS1相对表达模式，并对CsGS1蛋白进行亚细胞定位。结果表明，低氮依赖品种D0328在叶片中特异性地高表达CsGS1，而高氮依赖品种D0422的叶片、茎和根中CsGS1的表达量没有明显差异。GS1蛋白定位于细胞质上，为细胞质蛋白。进一步将CsGS1转化到两个黄瓜品种D0328和D0422中，过量表达CsGS1可显著提高黄瓜植株的光合参数、植株鲜重、株高、根长、叶绿素b含量、植株总氮量以及GS活性等指标，反义表达CsGS1使这些指标水平显著降低。黄瓜CsGS1能够响应低氮胁迫，提高黄瓜植株对低氮的耐受性，因此CsGS1的高效表达可以作为提高黄瓜氮素利用效率的潜在育种目标。

The wild hawthorn species, Crataegus songorica K. Koch., is an important wild germplasm resource in Xinjiang, China that has been endangered in recent years.  The genetic diversity of C. songorica K. Koch. germplasm in five populations from Daxigou, Xinjiang, China were evaluated based on phenotypic traits and ISSR molecular markers to provide basic information on resource protection, rational utilization and genetic improvement.  The F-value for the phenotypic differentiation coefficient of the 33 traits measured ranged from 0.266 to 15.128, and mean value was 13.85%.  The variation among populations was found to be lower than that within population.  A total of 303 loci were detected within the five populations by 12 primers.  Within 298 polymorphic loci, the polymorphism was 98.35%, showing a high genetic diversity in C. songorica K. Koch.  The gene diversity within population, total population genetic diversity, genetic differentiation coefficient and gene flow were 0.2779, 0.3235, 0.1408, and 3.0511, respectively.  Our results showed that C. songorica K. Koch. from Xinjiang has a high level of genetic diversity at both the phenotypic and molecular levels.  Significant genetic differentiation existed within population and the differentiation trend showed a regional association.  And in this study, in situ and ex situ conservation approaches were raised for wild hawthorn protection utilization.

    The structural characteristics of protein body accumulation in different endosperm regions of hard wheat cultivar (XM33) and soft wheat cultivar (NM13) under drought stress were investigated. Drought stress treatment was implemented from plant regreening to the caryopsis mature stage. Microscope images of endosperm cells were obtained using resin semi-thin slice technology to observe the distribution and relative area of protein body (PB). Compared with NM13, relative PB area of XM33 was significantly higher in sub-aleurone endosperm region. The amount of accumulation, including the size and relative area of PB, in two wheat cultivars was higher in sub-aleurone region than that in central region at 18 days post anthesis (DPA). Drought stress significantly enhanced the sizes and relative areas of PBs in the dorsal and abdominal endosperms in two wheat cultivars. Particularly for dorsal endosperm, drought stress enhanced the relative PB area at 18 DPA and NM13 (5.0% vs. 6.73%) showed less enhancement than XM33 (5.49% vs. 8.96%). However, NM13 (9.58% vs. 12.02%) showed greater enhancement than XM33 (10.25% vs. 11.7%) at 28 DPA. The protein content in the dorsal and abdominal endosperms of the two wheat cultivars decreased at 12 DPA and then increased until 38 DPA. Drought stress significantly increased the protein contents in the two main regions. From 12 to 38 DPA, the amount of PB accumulation and the protein content were higher in XM33 than those in NM13. The results revealed that PB distribution varied in different endosperm tissues and that the amount of PB accumulation was remarkably augmented by drought stress.

      The microscopic investigation of the floral development of sweet cherry (Prunus avium L. cv. Hongdeng) from a warm winter climate (Shanghai) and cold winter climate (Tai’an, Shandong Province, China) was conducted to explore the reason of low fruit set. The effect of hydrogen cyanamide (HCN) on floral development under warm winter conditions was also investigated. Trees grown in Shanghai with insufficient chilling accumulation exhibited little difference in the progression of microspore development compared to trees in Tai’an that accumulated adequate chilling, but showed substantial delays in ovule and embryo sac development. The growth of nucelli did not proceed beyond the macrospore mother cell and macrospore stages with abortion rates of 13, 15 and 45% by 6, 3 and 0 d before full bloom, respectively. These abnormalities in the ovule and embryo sac in the Shanghai-grown trees were eliminated by HCN application. These results suggest that chilling regulates the development of female floral organs in winter dormancy; therefore, insufficient chilling accumulation, causing abnormality of the female floral organs, restricts the cultivation of sweet cherry in warm winter regions. Interestingly, HCN application, which decreased the chilling requirements for Hongdeng, may be a potential strategy for sweet cherry cultivation in warm winter regions.

The physical and chemical heterogeneities of soils make the soil spectral different and complicated, and it is valuable to increase the accuracy of prediction models for soil organic matter (SOM) based on pre-classification. This experiment was conducted under a controllable environment, and different soil samples from northeast of China were measured using ASD2500 hyperspectral instrument. The results showed that there are different reflectances in different soil types. There are statistically significant correlation between SOM and reflectence at 0.05 and 0.01 levels in 550–850 nm, and all soil types get significant at 0.01 level in 650–750 nm. The results indicated that soil types of the northeast can be divided into three categories: The first category shows relatively flat and low reflectance in the entire band; the second shows that the spectral reflectance curve raises fastest in 460–610 nm band, the sharp increase in the slope, but uneven slope changes; the third category slowly uplifts in the visible band, and its slope in the visible band is obviously higher than the first category. Except for the classification by curve shapes of reflectance, principal component analysis is one more effective method to classify soil types. The first principal component includes 62.13–97.19% of spectral information and it mainly relates to the information in 560–600, 630–690 and 690–760 nm. The second mainly represents spectral information in 1 640–1 740, 2 050–2 120 and 2 200–2 300 nm. The samples with high OM are often in the left, and the others with low OM are in the right of the scatter plot (the first principal component is the horizontal axis and the second is the longitudinal axis). Soil types in northeast of China can be classified effectively by those two principles; it is also a valuable reference to other soil in other areas.

The effect of long-term straw return on crop yield, soil potassium (K) content, soil organic matter, and crop response to K from both straw and chemical K fertilizer (K2SO4) were investigated in a fixed site field experiment for winter wheat-summer maize rotation in 6 years for 12 seasons. The field experiment was located in northern part of North China Plain with a sandy soil in relatively low yield potential. Two factors, straw return and chemical K fertilizer, were studied with two levels in each factor. Field split design was employed, with two straw treatments, full straw return of previous crop (St) and no straw return, in main plots, and two chemical K fertilizer treatments, 0 and 60 kg K2O ha–1, as sub-plots. The results showed that straw return significantly increased yields of winter wheat and summer maize by 16.5 and 13.2% in average, respectively, and the positive effect of straw return to crop yield showed more effective in lower yield season. Straw return significantly increased K absorption by the crops, with significant increase in straw part. In treatment with straw return, the K content in crop straw increased by 15.9 and 21.8% in wheat and maize, respectively, compared with no straw return treatment. But, straw return had little effect on K content in grain of the crops. Straw return had significant influences on total K uptake by wheat and maize plants, with an increase of 32.7 and 30.9%, respectively. There was a significant correlation between crop yield and K uptake by the plant. To produce 100 kg grain, the wheat and maize plants absorbed 3.26 and 2.24 kg K2O, respectively. The contents of soil available K and soil organic matter were significantly affected by the straw return with an increase of 6.07 and 23.0%, respectively, compared to no straw return treatment. K2SO4 application in rate of 60 kg K2O ha–1 showed no significant effect on wheat and maize yield, K content in crop straw, total K uptake by the crops, soil available K content, and soil organic matter. The apparent K utilization rate (percentage of applied K absorbed by the crop in the season) showed difference for wheat and maize with different K sources. In wheat season, the K utilization rate from K2SO4 was higher than that from straw, while in maize season, the K utilization rate from straw was higher than that from chemical fertilizer. In the whole wheat-maize rotation system, the K absorption efficiency by the two crops from straw was higher than that from K2SO4.

To decipher the relationship between the inhibited shoot growth and expression pattern of key enzymes in nitrogen metabolism under root restriction, the effects of root restriction on diurnal variation of expression of nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS1-1, GS1-2, GS2) and glutamate synthase (Fd-GOGAT, NADH-GOGAT) genes and nitrogen levels were evaluated in two-year-old Jumeigui grapevines (Vitis vinifera L.×Vitis labrusca L.) when significant differences in shoot growth were observed between treatments at expansion stage (22 days after anthesis). Grapevines were planted in root-restricting pits as root restriction and in an unrestricted field as the control. Results showed that root restriction significantly reduced shoot growth, but promoted the growth of white roots and fibrous brown roots and improved the fruit quality. (NO3 –+NO2 –)-N concentration in all plant parts, NH4 +-N concentration in white roots and total N concentration in leaves and brown roots were significantly reduced under root restriction. Gene expression analysis revealed that mRNA levels of genes related to the GS1/NADH-GOGAT pathway were lower in root-restricted than in control petioles, whereas genes involved in the GS2/Fd-GOGAT pathway were up-regulated under root restriction. Root restriction also resulted in downregulation of genes involved in nitrogen metabolism in leaves, especially at 10:00, while transcript levels of all these genes were enhanced in root-restricted white and brown roots at most time points. This organ-dependent response contributed to the alteration in NO3 – reduction and NH4 + assimilation under root restriction, leading to less NO3 – transported from roots and then assimilated in root-restricted leaves. Therefore, this study implied that shoot growth inhibition in grapevines under root restriction is closely associated with down-regulation of gene expression in nitrogen metabolism in leaves.

Rapid and mass rearing of Locusta migratoria manilensis is an urgent need to meet the increasing demand for food of people. In this study, the effects of four artificial feeds on the development, reproduction and the activities of detoxification and protective enzymes of L. migratoria manilensis in three successive generations were investigated. The results showed that sucrose and monosodium glutamate (MSG) significantly increased the net reproductive rate (R0) and the intrinsic growth rate (rm) of L. migratoria manilensis, but sodium chloride (0.17%) suppressed this increase. Furthermore, the artificial feed with sucrose and monosodium glutamate increased the activities of esterase (EST), acetylcholinesterase (AChE), glutathione-Stransferase (GST), multi-function oxidase (MFO), phenol oxidase (PO), catalase (CAT) and peroxidase (POD), but inhibited the activity of superoxide dismutase (SOD). However, sodium chloride (0.17%) increased the activities of EST, AChE, CAT and SOD, and inhibited the activities of MFO, GST, PO and POD. Correlation analysis found that the increasing of PO activity and the decreasing of SOD activities were significantly related with the increasing of the intrinsic growth rate (rm). The above results indicated that sucrose and monosodium glutamate could promote the development and reproduction of L. migratoria manilensis, but Na+ inhibit such promotion with the concentration above 0.2%. The activities of PO and SOD can be used as biochemical standard to assess the effect of artificial feed.