透光抚育对“栽针保阔”红松林中红松生长过程的影响

[目的]通过研究长白山地区不同透光抚育强度下"栽针保阔"阔叶红松林中红松的生长情况,揭示透光抚育对"栽针保阔"红松林中红松生长过程的影响规律,旨在为阔叶红松林的恢复、经营提供有力的科学依据。[方法]研究5种透光抚育(未采伐对照、低度择伐、中度择伐、强度择伐及上层皆伐)对红松生长的影响。[结果]红松在群落中的地位随着透光抚育强度的增大逐步得到提升,同时透光抚育能够显著提高"栽针保阔"红松林内红松优势木(63.4%~146.5%、64.6%~158.6%)、平均木(57.9%~271.1%、42.5%~261.7%)和被压木(56.5%~182.6%、95.5%~245.5%)的树高和胸径,且呈现出随透光抚育强度的增大而递增的规律性。[结论]透光抚育能显著提高红松树高和胸径生长。     

湘桂走廊白背飞虱早期虫源及灾变大气背景

为阐明湘桂走廊白背飞虱早期虫源及大气背景在其北迁过程中的影响,利用HYSPLIT软件模拟白背飞虱灾变性迁入高峰期、始见期后向轨迹,分别从个性及共性角度,分析湘桂走廊白背飞虱主要虫源地及其灾变大气背景。结果表明：（1）1991—2014年湘桂走廊白背飞虱的迁入始见期、首次迁入高峰期分别为0.9 d/10 a、1.6 d/10 a;（2）西南路径是湘桂走廊白背飞虱初始虫源迁入的主要路径,永福站、兴安站和全州站虫源西南路径占比分别为54%、50%、72%;（3）中南半岛白背飞虱借助微弱上升气流完成起飞,850 hPa高度上的强劲的西南气流、丰富的水汽条件有利于其北迁,降水是白背飞虱降落的重要大气动力机制。研究结果为白背飞虱的异地监测及科学防治提供科学依据。     

刺嫩芽喜光特性试验研究

刺嫩芽是重要的食用和药用植物,由于刺嫩芽的食用和药用价值很高而备受国内外市场的青睐,其自然资源遭受人为超负荷的采摘利用和挖掘,生态遭到严重破坏,资源濒临枯竭.人工种植面积正在逐年增加,但受其高密度种植的影响,产量降低,品质变差,经济价值受到影响.为此,研究刺嫩芽喜光特性,为后续确定科学的种植密度,增加刺嫩芽产量,提高质...     

A data transfer method for improving seed identification of maize (Zea mays) haploid breeding based on genetic similarity

Maize haploid breeding technology is able to identify haploid seeds non‐destructively, rapidly and at low cost with the help of Near‐infrared (NIR) spectral analysis. However, due to the hybridization of numerous parents and the low production rate of haploid, the haploid data collection becomes a burden for engineering this technology. Biologically, there are considerable similarities between the progeny of the same female parent and different male parents. Based on this advantage, similar spectral data can be transferred when the NIR technology is employed. A revised method of Transfer adaptive boost (TrAdaBoost) is proposed to improve identifying for the backpropagation neural network (BPNN) classifier. To avoid the negative transfer, a screening thresh is used to select out similar data, and the amount of these data are limited to join current training. The results show that the identification performances are improved significantly when the data amount is small. This method shows a high ability to make the seed identification more convenient for engineering maize haploid breeding.     

江苏省空中云水资源评估

研究旨在定量化评估江苏省空中云水资源可开发量及基本特征。根据云水收支方程,将参与大气云水循环且未降落到地面的资源定义为空中云水资源。利用1981—2010年EAR-Interim高分辨率再分析资料的风场及云含水量,计算江苏上空云水资源年均总量、时空特征及变化趋势。结果表明,资源年均总量353.1亿t,春夏季偏多,秋冬季偏少,开发潜力巨大。旱期(缺水期)沿淮淮北最多,达70.8亿t,沿海垦区、苏南环太湖次之;非旱期总量约占全年58.3%。近30年,云水资源呈下降趋势,平均每10年减少18亿t。建议加大开发力度,实现常态化开发利用,率先建立淮北、沿海、环太湖开发利用重点作业区,加强开发利用技术研究,提高开发效率。     

Heat,wheat and CO2: The relevance of timing and the mode of temperature stress on biomass and yield

Atmospheric CO₂ enrichment affects C3 crops both directly via increased carbon gain and improved water use efficiency and indirectly via higher temperatures and more frequent climatic extremes. Here we investigated the response of spring wheat (Triticum aestivum L. cv. Triso) to CO₂ enrichment (550 vs. 380 µmol/mol) and heat, applied as a constant +4°C increase or a typical heat wave either before or after anthesis, or as two typical heat waves before and after anthesis. We applied a climate chamber approach closely mimicking ambient conditions. CO₂ enrichment increased above‐ground biomass and yield by c. 7 and 10%, but was not able to compensate for adverse heat stress effects, neither before nor after anthesis, with few exceptions only. Yield depression due to heat stress was most severe when two heat waves were applied (?19%). This adverse effect was, however, compensated by CO₂ enrichment. Applying heat stress before or after anthesis did not exert different effects on yield for both +4°C warming and heat wave application. However, +4°C depressed yield more than a heat wave at ambient CO₂, but not so at elevated CO₂. Thus, the interactive effects were complex and prediction of future wheat yield under CO₂ enrichment and climate extremes deserves more attention.     

2013年夏季内蒙古干旱-半干旱区两次极端降水事件对比

2013年夏季,内蒙古中西部干旱-半干旱区多次出现极端降水事件,引发气象灾害.为探寻其特征及成因,选择“6·30”、“7·14”两次典型极端降水事件,从天气尺度系统、中尺度对流系统、热力动力条件、水汽来源等方面进行对比分析,得到以下结论:①“6 · 30”暴雨是华北小高压前的切变线产生;“7·14”暴雨是“北槽南涡”与台风北上共同作用的结果.②两次暴雨都是中尺度对流复合体(MCS)发展的结果.“6·30”暴雨突发性强,具有局地特点;“7·14”暴雨具有列车效应,持续时间长.③两次暴雨水汽来源不同.“6·30”暴雨水汽来源于南海;“7.14”暴雨是“北槽南涡”加上远距离台风输送的结果.④“6·30”暴雨是高压切变线西侧干、东侧湿,在锋区附近产生上升运动促发不稳定能量释放;高空“干侵入”是“7·14”暴雨的促发机制.⑤东亚夏季风偏强,西北太平洋副热带高压脊线位置偏北,是内蒙古中西部干旱-半干旱区极端降水事件的重要原因.     

港口原油装船VOCs大气环境影响探讨

收集了原油装船VOCs的估算方法，认为原油装船时VOCs排放量为0.012％，VOCs浓度为0.1kg／m3。采用SCREEN3对其环境影响进行分了析，结果表明：下风向最大浓度出现在400m 处，浓度值7.99mg／m3，直到2700m处，浓度值才小于1mg／m3，直到10000m处，浓度值仍为0.14mg／m3，原油装船VOCs的大气环境影响较大。     

北方森林细根对氮沉降和二氧化碳浓度升高的响应

北方森林是全球第二大生物群区,约占全球森林面积的30%,尽管其细根生物量仅占森林生态系统很小的一部分,但其周转率更快,更易分解,因此,其对土壤碳循环和大气CO_2通量贡献很大。笔者综述了氮沉降和CO_2浓度升高的背景数据,总结了细根对二者变化的响应,主要从细根的形态特征、解剖结构和生理功能方面入手,探讨了其对氮沉降和CO_2浓度升高的响应。结论如下:(1)大气氮沉降量一直处于上升状态,与人类活动密切相关的有机氮量所占比例逐渐加大,而无机氮中NH_4~-N和NO_3~-N的变化趋势表现不同;(2)大气CO_2浓度一直呈上升趋势,细根形态特征、解剖结构和生理功能对其表现出明显的响应;(3)树种、年龄、土壤类型等都会改变细根形态、解剖结构和生理功能对氮沉降和CO_2浓度升高的响应结果,但改变的程度不同。研究结果可为北方森林乃至温带森林生态系统功能对氮沉降和CO_2浓度升高的响应提供参考依据和数据支持。     

大气压等离子体处理对结球白菜种子萌发特性及后期生长的影响

用大气压等离子体对2个品种的结球白菜种子进行处理,研究不同电压等离子体处理对白菜种子萌发及后期生长的影响.结果表明:等离子体处理后在萌发前期对种子有一定影响,但对种子的发芽势、发芽率等基本没有影响;处理种子在室温放置10个月后仍然在萌发前期表现与对照种子有差异;用育苗盘和田间小区种植2种方法均没有发现处理和对照种子之间在苗期生长特性方面存在差异.