Nitrogen Vertical Distribution and Status Estimation Using Spectral Data in Maize

Nitrogen (N) is often distributed in a vertical gradient and the symptom of N deficiency usually appears earlier in the lower leaves than in the upper ones. As for hyperspectral technology, identifying the sensitive leaves and the effective index are the two key factors for timely N topdressing. The results of this paper showed that the N contents in the lower leaves produced significant difference among different N rate treatments (a = 0.001) and showed an extremely significant relationship with soil nitrate nitrogen at 30 days after emergence. Taking the optimal treat as a reference, Nitrogen Stress Index (NSI) and Nitrogen Spectral Stress Index (NSSI) of the lowest two leaves could indicate plant N deficiency and guide nitrogen topdressing. NSI or NSSI could change regularly with the nitrogen stress degree and indicate the necessary amount of N topdressing. NSSI is relatively a better indicator since it comes from a fast, timely, uncontaminated, and nondestructive method.     

辽宁省水稻主栽品种稻曲病抗性鉴定与评价

为明确辽宁省水稻主栽品种对稻曲病的抗性水平,从而为抗病品种选育、品种合理布局提供科学依据,在2015-2019年对辽宁省200个水稻主栽品种设置3个播期,在田间病圃内采用自然诱发法对稻曲病进行抗性鉴定和评价。结果显示,不同年度间、同年度不同播期间,水稻品种间抗性差异明显,不同穗型水稻稻曲病发生程度不同,且显著差异。随着播期的推迟,稻曲病的发生程度明显下降,并且年度间变化趋势基本一致。200个供试水稻品种中表现高抗（HR）和抗病（R）品种分别为5个（占2.5%）和34个（占17.0%）,中抗（MR）和中感（MS）品种分别为34个（占17.0%）和53个（占26.5%）,感病（S）和高感（HS）品种分别为46个（占23.0%）和28个（占14.0%）。整体上,抗∶中∶感品种数的比值为19.5∶43.5∶37.0,结果表明辽宁水稻主栽品种稻曲病抗性较差。     

Variation of intra‐aggregate organic carbon affects aggregate formation and stability during organic manure fertilization in a fluvo‐aquic soil

The aggregate formation and stability are controlled by the dynamics of soil organic matters (SOM), but how it is related to SOM chemical composition within different‐sized aggregates is largely unknown during manure fertilization. In this study, the variations of intra‐aggregate organic carbon (OC), including intra‐particulate organic matter (iPOM) and mineral‐associated organic matter, were quantitatively and qualitatively analysed, and then, their effects on aggregate formation and stability were assessed under four treatments: control (CK), mineral fertilizer (NPK), reduced manure (30%M) and manure fertilizers (M). Manure application (M) significantly increased macroaggregate proportion, mean weight diameter (MWD), and OC contents within different‐sized aggregates compared to CK, NPK, and 30%M. The OC accumulation of macroaggregate in M was attributed to OC content increase in silt plus clay subfraction rather than iPOM with more labile organic groups; oppositely, in microaggregate it was located in the relatively stable fine iPOM. The macroaggregate formation and stability were controlled by the fine iPOM within macroaggregates, whose abundant polysaccharide‐C and aliphatic‐C after manure fertilization advanced the microbial growth except for Gram‐positive bacteria, which further promoted macroaggregate formation and stability. The free silt plus clay fraction also affected macroaggregate formation and stability, and its polysaccharide‐C derived from microorganisms or decomposing SOM was positively associated with MWD and macroaggregate proportion. Because polysaccharide‐C can be easily associated with mineral particles, further improving micro‐ or macroaggregation. We conclude that continuous manure fertilization could increase labile SOM accumulation within aggregates and then facilitate microbial growth, which collectively are responsible for aggregate formation and stabilization.     

白细胞介素18与有关疾病的研究进展

白细胞介素18(IL-18)是近年来发现的一种多效应细胞因子,除了具有免疫调节作用外,还与肿瘤性疾病、感染性疾病、变态反应性疾病、自身免疫病及肝病等密切相关。在疫苗佐剂、多肽性药物开发等方面具有潜在的应用前景。     

甜菜覆膜栽培高产生理基础的研究

本文介绍了3年的覆膜栽培实验研究,其结果表明:覆膜栽培,可为甜菜生育创造良好的土壤环境。生育前期提高土壤含水量10.7～27.4%;0～25厘米耕层积温增加684.1℃;0～20厘米耕层速效氮提高8.0～26.7%,速效磷提高12.4～18.8%,速效钾提高7.3～27.9%,甜菜提早出苗8天左右,较直播甜菜早11天左右,叶面积指数(LAI)3.0时达郁闭状态,持续期增多25天,LAI最大值达4.9,高于直播0.8。总光合势增加36.7%,光合速率增加CO_20.57毫克/分米~2时以上,生长中心提早5天以上转至根部。在块根增长期,根部干物质积累强度(1.9克/株·日)提高0.36倍,总光能利用率为:1.84%,较直播甜菜高0.45%。在同等栽培条件下,覆膜甜菜平均单产为3439.1公斤/亩,较直播增产31.8%。     

校园网站的建设与应用

学校在硬件建设基础上,投资购进了较先进的网络信息管理平台,使得我校的信息化建设迈上了一个新台阶。通过网络实现教学、政务管理现代化、无纸化、规范化,极大程度地提高了管理效率。     

美洲狼尾草与象草杂交中花期相遇的调节

美洲狼尾草Ｔｉｆｔ２３Ａ（Ｐｅｎｎｉｓｅｔｕｍａｍｅｒｃｕｎｕｍ以下简称２３Ａ）在适宜播期内主茎叶数一般为２５。出叶间隔２～４ｄ。出叶速度总体上依抽出顺序而温慢，其分蘖一期发生在５～７叶龄；拔节则发生在１４叶龄前后，幼穗分化与拔节基本同步，在杂交制种中，当母本２３Ａ拔节前对父本象草Ｎ５１（Ｐ．ｐｕｒｐｕｒｅｕｍ，以下简称Ｎ５１）进行３～４周，每日９ｈ的短日照处理，则父母本花期基本相遇。     

空心件楔横轧参数对轧件壁厚变化的影响

通过对空心件楔横轧变形特点的分析，建立了空心件楔横轧的上限法模型，并利用该模型分析了空心件楔横轧工艺参数对轧件壁厚变化的影响，提出了研究空心件楔横轧壁厚变化预测的新方法，取得了一些重要结果。     

甜菜（Beta vulgaris L）物质生产与碳水化合物代谢的生理生态学研究──第Ⅴ报可溶性糖分的分配动态与蔗糖积累遗传差异的研究

利用１４Ｃ标记研究了不同类型品种甜菜生育期间主要糖分的运转分配动态与蔗糖积累遗传差异．结果表明，在生育期间，叶片中葡萄糖和果糖占叶片和根内３种糖（葡萄糖、果糖和蔗糖）的百分比分别呈先下降后上升趋势，而根中两种糖的百分比呈下降趋势．叶片中蔗糖占叶片和根内３种糖（葡萄糖、果糖和蔗糖）的百分比呈先上升后下降趋势，但根中蔗糖的百分比始终保持上升趋势，甜菜糖分代谢强度随生育期而改变．高糖型品种叶片中葡萄糖、果糖和蔗糖的百分比都分别低于其它类型甜菜３种糖的百分比，而根中３种糖的百分比分别高于其它类型甜菜３种糖的百分比．说明高糖型品种叶片蔗糖合成和运转分配能力强，根部具有优势的蔗糖贮藏能力，最终表现为根中高额蔗糖的积累．