基于遥感光谱的干旱区土地退化评价体系构建

干旱区土地退化(荒漠化)作为全球面临生态环境挑战之一,对粮食安全、环境质量和区域自然资源管理至关重要。土地退化本质是人与自然因素协同作用下土地利用/覆被类型、数量、结构以及功能的改变而引起的生态服务价值降低,核心是土壤和植被的退化。一方面,人与自然共同作用下的土地利用覆被可以表征土地退化状态,另一方面植被-土壤生境时间序列相互作用过程进一步辅助土地退化过程诊断。因此,该文首先从覆被结构、退化类型和退化程度3个层次建立干旱区土地退化状态评价体系。其次,采用GF-1/WFV时间序列遥感影像,基于多端元光谱混合分解模型建立土地利用/覆被精细分类量化表征下垫面质量属性,并进一步利用植被-生境组分互动特征参数进行功能量化,综合评价民勤2015年退化类型和退化程度。最后,结合地面立地景观照片以及采样点实测数据,对土地退化状态评价结果进行绝对定标和交叉验证。结果表明:遥感评价识别土地退化类型和程度的能力分别为87.5%和78.7%。对于民勤旱地系统,沙化过程、沙-盐化过程是主要的土地退化过程,轻度沙化、中度沙化为主导退化程度。该方法为宽波段遥感国产高分1号卫星在旱地系统土地退化状态信息提取和深入应用提供科学依据和实证研究。     

Patterns of SSR variation in bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) seeds under ex situ genebank storage and accelerated ageing

Maintaining seed viability and germplasm integrity is a challenging task in conservation of plant genetic resources, as seeds under storage will lose viability and genetic changes will occur. Attempt was made to analyze the patterns of genetic changes in wheat germplasm under ex situ genebank storage and accelerated ageing treatments. A set of 16 naturally aged wheat accessions under ex situ genebank storage since 1994 were sampled. Four recently regenerated wheat accessions were selected, four random seed samples were chosen from each accession, and three of them were exposed to three different accelerated ageing treatments. These 32 seed samples in two germplasm sets displayed a range of germination rates from 4 to 98 %. Thirty-seven microsatellite markers representing 21 wheat chromosomes were applied to screen 12 seeds of each sample and 449 SSR alleles were scored. Large SSR variation was found in each germplasm set. There was 73.1 % of the total SSR variation present among the naturally aged samples and 78.2 % present among the accelerated ageing samples. Several analyses for genetic association consistently revealed no clear genetic separations among samples of high or low germination rates in both germplasm sets. Samples under different accelerated ageing treatments did not show much genetic differentiations from the original sample of each accession. Mantel tests revealed non-significant associations between SSR variability and sample germination rates for both germplasm sets. These findings are useful for understanding seed deterioration under different ageing conditions and suggest that genome-wide SSR variability may not provide sensitive markers for the monitoring of wheat seed viability.     

HJ-1卫星延寿期的CCD影像质量评价与可用性分析

HJ-1卫星发射升空投入运行以来,已在灾害与环境的快速监测与预报领域发挥了重要作用。HJ-1卫星目前已经成功运行3a多,属于超期服役状态。为了评价延寿期影像质量,该文从影像的几何校正精度、灰度特征和纹理特征3个方面对延寿期HJ-1A-CCD影像进行分析,并与正常寿命运行期的HJ-1ACCD影像、同时期的Landsat7 ETM+影像进行比较,分析结果表明:延寿期HJ-1A-CCD影像质量虽然有一定程度的下降,但其与正常寿命期影像质量接近,仍能较好地描述丰富的地物类型及地物细节信息,可以像正常寿命期影像一样,有效地用于环境监测、灾害监测、国土资源管理、城市规划、农业应用等方面。     

水体太阳能供电增氧系统及其运行效果

为了快速改善水产养殖水体质量,该文分析了国内水体富营养化的现状和存在的问题,提出了以太阳能电池为动力,采用单片机设计了一套水体增氧系统,重点介绍了硬件组成、结构特点和软件实现方法,并应用在公园鱼池净化和鲤鱼养殖生产中。试验结果表明,该系统能够实时控制鱼池中的溶氧量、pH值,使多环境因子稳定在最佳值附近。为增强水体的自净能力,提高水产养殖水平提供了一种切实可行的技术措施。     

稀土元素钕对铜绿微囊藻生长和生理特性的影响

通过模拟培养试验,研究了不同Nd3＋初始浓度条件下铜绿微囊藻（Microcystis aeruginosa）的生长及生理变化。结果表明,相对BG11培养基（Nd3＋初始浓度为0 mg.L-1）,低初始Nd3＋浓度（0.01、0.05、0.1、0.5、1 mg.L-1）条件下,随着Nd3＋浓度的增加,藻细胞中叶绿素a含量、可溶性蛋白含量和过氧化氢酶（CAT）活性均呈增加趋势,促进了铜绿微囊藻生长;在Nd3＋初始浓度为5 mg.L-1和10mg.L-1时,藻细胞丙二醛（MDA）含量急剧增加,CAT活性下降,藻细胞清除活性氧（ROS）能力下降,抗氧化防御体系被破坏,膜脂过氧化严重,严重抑制藻细胞生长,在初始Nd3＋浓度50 mg.L-1胁迫下,铜绿微囊藻无法生长。藻细胞超微结构表明,过量的Nd3＋破坏了藻细胞内的类囊体结构,胞内脂质体含量增加,细胞膜变粗糙甚至变形破碎,对藻细胞造成不可逆伤害。     

Short-term gully retreat rates over rolling hill areas in black soil of Northeast China

Soil loss has become one severe problem in black soil areas of Northeast China after several decades of cultivation. Gully erosion is one of its main components. In this study, short-term gully retreat was monitored from 5 active gullies selected in representative black soil area during April 2002 to June 2004, using differential global positioning system (GPS). With the support of geographic information system (GIS), multitemporal digital elevation models (DEM) were constructed from the data collected by GPS and then used for further analysis. This presents a new method to compute the retreat rate of gully heads and the rate of soil losses caused by gully erosion. The results indicate that the average volumetric retreat rate was 729.1 m³ year^− 1, corresponding with an average linear retreat rate of 6.2 m year^− 1 in gully head and planimetric changes of 323.6 m² year^− 1 during the two monitored years, but more erosion took place during the second and third monitored period compared to the first. The erosion by freeze thawing and snowmelt accounts for a large percent. And this will be emphasized when rainfall is added in spring. If only considering the third monitored period, the conservatively estimated retreat rate by freeze thawing and snowmelt (i.e. before rainy season) may even reach 8.6 m year^− 1 in gully head, with a volumetric rate of 120.9 m³ year^− 1 and planimetric changes of 173.6 m² year^− 1. These results reveal that gully erosion is a great threat in the study area and conservation measures are urgently needed. Based on the analysis of multi-temporal DEM, one conceptual model for gully developing in black soil of Northeast China is proposed, which is supported by the data.     

外源甜菜碱对盐胁迫下大麦幼苗体内多胺和离子含量的影响

外源甜菜碱对200 mmol/L NaCl胁迫下大麦幼苗的伤害有显著的缓解效应,0.5～10.0 mmol/L的甜菜碱均可以有效抑制盐胁迫导致的叶片中MDA含量的上升,增加根系含水量与幼苗鲜重,降低植株体内Na+/K+比,尤以1 mmol/L甜菜碱的效应最明显。甜菜碱可以显著地提高盐胁迫下大麦幼苗根系多胺含量,促进叶片内腐胺与亚精胺向精胺的转化     

氮肥施用对柑橘果园土壤有机碳矿化的影响

土壤有机碳矿化是土壤向大气释放CO2的最大净输出途径,其与植被的净初级生产力的差值是判断生态系统碳“源”或“汇”的关键。采用室内模拟试验,在10、20、30℃ 3个温度条件下,研究施肥施用对柑橘果园土壤有机碳矿化的影响。结果表明：3种温度处理下,各施氮处理土壤有机碳矿化速率都表现为培养前期快速下降,培养后期保持相对稳定的趋势。在整个培养过程中,3种温度条件下各施氮处理的土壤CO2累积排放量为1328.25~2219.42 mg/kg,100 mg/kg（N4）处理土壤有机碳矿化量最大,CK处理最低,100 mg/kg（N4）和80 mg/kg（N3）2个高氮处理显著高于低氮50 mg/kg（N2）、30 mg/kg（N1）处理。土壤有机碳矿化速率随温度升高而增长,不同的土壤施氮条件下土壤有机碳矿化的温度敏感性不同,N2处理土壤有机碳矿化的温度敏感性最低,N4处理最高。柑橘果园土壤有机碳矿化受高施氮量影响较大,低施氮影响不明显。随着施氮量的增加土壤有机碳矿化的温度敏感性增加,氮肥施用和温度的共同作用可能使柑橘林向大气中排放的CO2增加。     

SSR指纹技术在甜、糯玉米区试中的应用

以2009年浙江省甜、糯玉米区试品种为材料,利用SSR指纹技术研究了参试品种的一致性和真实性。结果表明:除T10和T12之外,其他品种一致性均达到国家玉米区试品种纯度标准。真实性检测结果表明,糯玉米区试品种中,N2、N6、N73个品种在40个SSR位点上均无差异,并且这3个品种均与已审定的京科糯2000相似。从检测效果看,应用SSR技术进行参试品种的一致性和真实性检测非常必要,可有效防止雷同及一致性差的品种通过审定,确保品种审定的严肃性。     

新型葡萄埋藤机设计

为解决现有多数葡萄埋藤机埋土量少和埋藤质量差等问题,研制了一种新型冬季葡萄越冬埋藤机。该机采用20～40 kW拖拉机为动力,一次覆土既可完成冬季埋藤作业,还可在覆土前将葡萄藤收拢起来并铺上膜,减少了埋藤前捆藤作业环节,大大降低了冬季埋藤和春季扒藤劳动强度。该机主要由牵引架、传动换向齿轮箱、旋耕取土机构、土壤输送系统、传动链轮、万向行走轮和压藤铺膜机构等部分组成。阐述了其工作原理及关键部件的设计,介绍了机器的工作状态、适用范围和主要技术指标。该机结构设计合理,为我国葡萄种植机械化提供了技术支持。