Northeast Institute of Geography and Agroecology, Chinese Academy Of Sciences
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一种快速、无损大豆种子DNA提取方法的建立和应用
No full text基因分型是进行植物基因功能的遗传分析和分子标记辅助育种的重要环节。该研究以大豆(Glycine max)成熟种子为材料, 建立了通过钻孔采集样品、快速提取DNA进行基因型鉴定的方法。用此方法, 一个熟练的工作人员可以在1个小时内完成120个样品的采集和DNA提取; 同时种子钻孔取样后, 不会对大豆种子的萌发造成影响。利用该方法获得的DNA可满足PCR扩增的要求。实验重复性好, 成功率在98%以上。这种快速且无损的大豆种子基因型鉴定方法可以用于鉴定杂交种子、品种纯度以及遗传分析等研究工作
基于多态蚁群算法的高光谱遥感影像最优波段选择
No full text由于传统蚁群算法搜索空间大,算法时间复杂度高等,导致基于传统蚁群算法的高光谱数据波段选择算法(ACA-BS)耗时长,算法效率低下,且易陷入局部最优。而多态蚁群算法能大大缩小算法的搜索空间,降低算法时间复杂度。因此,研究设计了基于多态蚁群算法的高光谱数据波段选择算法(PACA-BS)。从算法运行时间、波段子集的类别可分性及信息量、总体分类精度等方面对算法进行对比分析。用于实验的数据为Hyperion和AVIRIS高光谱影像。实验结果表明: PACA-BS的运行时间较ACA-BS大大减少;对Hyperion影像进行降维时,基于PACA-BS的运行时间约为ACA-BS的一半。两种算法获得的波段子集的类别可分性大小较为接近,但PACA-BS获得的波段子集的信息量和总体分类精度优于ACA-BS。研究表明PACA-BS是一种效率较高的高光谱波段选择算法
双台河口国际重要湿地芦苇地上生物量遥感估算
No full text基于多时相的Landsat8 OLI卫星遥感数据,采用面向对象的分类方法,提取双台河口国际重要湿地芦苇分布信息。通过对归一化植被指数(normalized difference vegetation index,NDVI)等6个植被指数与野外实测芦苇地上生物量数据间的统计分析,比较不同植被指数对芦苇地上生物量的敏感性,构建双台河口国际重要湿地芦苇地上生物量遥感反演模型; 应用该模型对芦苇地上生物量进行遥感反演以及空间格局分析。结果表明: 双台河口国际重要湿地芦苇分布面积为4.39×10~4 hm~2,约占该研究区总面积32.96%; 选取的6个植被指数均与芦苇地上生物量显著相关(p<0.05),其中,以NDVI为变量的幂指数形式的估算模型为芦苇地上生物量遥感估算最优模型,模拟精度为79%,决策系数为0.76; 双台河口国际重要湿地芦苇地上生物量呈东高西低和北高南低的分布格局,其平均地上生物量为4 785.5 g/m~2,总地上生物量为2.06×10~6 t; 本研究结果可为双台河口国际重要湿地生态系统管理和生物多样性保护提供数据支持与科学指导
土壤扰动对寄生真菌代谢物温室防治大豆胞囊线虫的影响
No full text大豆胞囊线虫是影响大豆产量的主要限制性病原。大豆胞囊线虫的自然抑制性是存在的,并且日益受到关注,然而在胞囊线虫生态抑制方面的研究却很少。研究在温室条件下接种真菌后以扰动(土壤过0.5 cm孔筛)为土壤微环境并与无干扰对比,用厚垣轮枝菌(Pochonia chlamydosporium)、镰孢菌(Fusarium spp.)和淡紫拟青霉(Paecilomyces lilacinus)的混合代谢物分别对大豆胞囊线虫进行处理,探讨其对大豆胞囊线虫温室盆栽防效的影响。在接种二龄幼虫(J2)35d后,对大豆胞囊线虫密度调查结果表明:土壤扰动条件下,接种混合代谢物与不接种混合代谢物相比,雌虫数量降低20.0%~35.9%,胞囊数量降低18.3%~35.0%,卵量降低21.5%~ 38.5%,根内J2数量降低14.6%~35.3%,其中以4号混合代谢物扰动对大豆胞囊线虫密度降低作用显著;土壤不扰动下,接种混合代谢物与不接种混合代谢物相比,雌虫密度降低19.5%~32.7%,胞囊密度降低19.5%~35.2%,卵量降低21.1%~37.8%, J2数量降低8.0%~27.6%,仅雌虫和根内J2数量与不接种混合代谢物对照差异显著,菌株之间差异不显著。对大豆植株生长发育调查结果表明:扰动可能会促进植株生长、植株鲜重增加,但与不扰动差异不显著。试验证明:扰动对盆栽大豆胞囊线虫雌虫、胞囊、卵和J2的密度有一定的影响,扰动有增强寄生真菌代谢物对胞囊线虫温室防效效果的趋势,对降低大豆胞囊线虫密度起到积极作用。真菌对大豆胞囊线虫生长发育具有抑制作用,土壤扰动干扰和真菌代谢物的配合应用会降低土壤中胞囊线虫的密度,并影响真菌在土壤中的生防效果
羊草功能性状和地上生物量对氮素添加的响应
No full text植物功能性状对资源变化的适应策略是生态学研究的基本问题之一。本研究在不同氮添加梯度处理下,测定了羊草(Leymus chinensis)的11个功能性状和地上生物量的变化。结果表明,氮添加显著影响羊草的叶片叶绿素a和b含量、叶片类胡萝卜素含量、叶片氮含量、叶片干物质含量和比根长(P 0. 05); 叶绿素a和b含量、类胡萝卜素含量、叶片氮含量、叶片干物质含量、比茎重和比根长之间有显著的相关关系(P 0. 05); 20 g·m~(-2)的氮添加处理下,羊草地上生物量最高; 羊草地上生物量随叶绿素a和b含量、类胡萝卜素含量、叶片氮磷含量、株高的增大而显著升高(P < 0. 05),随叶片干物质含量、比茎重的增大而显著降低(P < 0. 05)
生长季初刈割时间对羊草群落特征的影响
No full text为了研究不同刈割起始时间对羊草种群和群落特征的影响,在我国东北松嫩草地开展了刈割控制实验。刈割起始时间间隔为10d,留茬高度2cm。结果表明:生长季初不同时间刈割对松嫩草地羊草群落特征有显著的影响。5月下旬之前刈割,为家畜提供高品质饲草的同时,对再生羊草种群和群落的产量和质量没有明显的影响,而进入6月后进行刈割不利于羊草再生,降低了羊草在群落中的竞争力和优势地位,群落组成中一年生杂草比例增加,饲草质量降低,不利于草地健康维持。但生长季初不同时间刈割,对群落功能群丰富度都没有显著影响,表明对于羊草占绝对优势的松嫩草地,植物物种丰富度对干扰的响应更敏感,在草地管理中应更关注物种丰富度而非功能群丰富度
农田恢复措施对黑土母质发育的新成土壤团聚体微形态及孔隙结构的影响
No full text土壤结构是土壤肥力的物质基础,水土流失等导致土壤结构退化成为威胁我国粮食安全的重要因素。本文利用8年田间定位试验,通过土壤切片技术,研究不同农田恢复措施(耕作和有机物料投入)对黑土母质发育的新成土壤团聚体微形态的影响,对理解成土过程和肥力快速恢复具有重要意义。结果表明:免耕土壤(自然、人工植被恢复) 、不施肥耕作土壤和仅施化肥耕作土壤均为复合孔洞状微结构,主要孔隙形状均为面状或孔洞状,连通性及数量相当,土壤垒结和微结构类似;但土壤颗粒分布频度和均匀度及粗细粒质接触紧密度与耕作负相关,免耕土壤显著地高于耕作土壤(P < 0.05) 。施肥耕作土壤中,施有机物料的土壤为海绵状微结构,施高量有机物料的土壤微结构发育最好,施低量有机物料的土壤微结构次之,不施有机物料土壤微结构最差;其土壤垒结和微结构发育特征与有机物料的投入正相关
The allometry of reproductive allocation in a Chloris virgata population in response to simulated atmospheric nitrogen deposition
No full textThe quantitative relationship between the size of a plant and its reproductive output is a central aspect of its reproductive strategy. Resource availability influences plant size and the allocation of biomass to different structures. here we investigate how variation in nitrogen (N) addition affects the allocation of biomass to vegetative and reproductive structures in a population of Chloris virgata. We used four levels of N addition to simulate atmospheric N deposition in the field, and evaluated size dependent and size-independent effects on reproductive allocation. Total biomass of C. virgata increased with increasing N levels but decreased at the highest level (20g m(-2) N). Reproductive output (mass of seeds produced) was higher when plants were fertilized with 2.5 g rn(-2) N than in the control treatment (no N addition), but further increases in N did not result in a significant further increase in seed production. The relationship between size and reproduction in C. virgata in response to different N levels was largely allometric (size dependent), but there were also size-independent effects. C. virgata allocated absolutely more, but proportionally less, biomass to reproduction in response to increased N availability, except at the very highest level of N addition, where biomass production was lower. C. virgata is adapted to low nutrient levels, and this limits its ability to utilize high N levels to produce more offspring
Carbon input from C-13-labelled soybean residues in particulate organic carbon fractions in a Mollisol
No full textUnderstanding the decomposition processes of crop residues and the quantity of residue carbon (C) incorporated into soil organic C (SOC) pools in the soil is crucial for optimizing C management in agricultural systems. This study is highly valuable in Mollisols in northeastern China, where SOC is markedly decreasing. Soybean is a major crop in this region; however, the decomposition processes of soybean residues and their contributions to physically separated SOC pools remain unknown. Thus, a 150-day incubation experiment was conducted with different C-13-labelled residues of soybean, i.e., leaf, stalk, and root, incorporated into a Mollisol. The leaves had the highest decomposition rate. At the end of the incubation, cumulative respiration reached 7.76 mg CO2-C g(-1) in the leaf-incorporated soil, but only 5.98 and 5.51 mg CO2-C g(-1) was recorded for the stalk- and root-amended soils. Furthermore, similar trends were found for the microbial biomass C and dissolved organic C. Different residue sources greatly affected the residue-derived C incorporation in the SOC fractions, resulting in a ranking of root > stalk > leaf. The root-derived C incorporation values were 49.5, 17.2, and 5.0 g residue C kg(-1) in the coarse particulate organic C (POC), fine POC, and mineral-associated C (MOC) fractions, respectively, which were significantly higher than those for the stalk- and leaf-derived C. These results indicate that C input from roots can play an important role in C stability in this Mollisol by incorporating more C in the POC and MOC
Diversity of parasitic fungi from soybean cyst nematode associated with long-term continuous cropping of soybean in black soil
No full textThe soybean cyst nematode (SCN) is a major yield-limiting pest of soybean. In this study, experiments were conducted to examine the diversity of parasitic fungi from SCN associated with disease-suppressive soil fields in Northeast China. Soil samples were collected from three fields under different rotation systems that were established in 1991: (1) a continuous long-term cropping field with soybean (SSSS) that had been shown to be SCN-suppressive, (2) cycles of three-year rotation with corn, soybean, and wheat (WCS), and (3) continuous cropping field with three-year cycles of two years soybean and one-year corn (SSC). In the traditional method result, cyst densities of SCN declined as increase of parasitic fungi, and the percentage of parasitic fungi associated with cyst of SCN was higher in SSSS field than other two fields. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) also showed that parasitic fungi of SCN were also increased in SSSS field, compared with the other two fields. Principal component analysis based on PCR-DGGE data revealed that fungal communities on cysts could be divided into three groups: one group occurred in SSSS, and the other two groups were in WCS and SSC fields, respectively. Long-term cropping with soybean monoculture in the black soil field might increase parasitic fungi of SCN. These fungal communities may play an important role in the ecological suppression of SCN in disease-suppressive soil