四川省不同天然种群珙桐叶片解剖结构与其耐热性的关系

以四川省15个珙桐种群为试材,采用石蜡切片法、NaClO法观察叶片16项解剖结构,应用变异系数、聚类分析、相关性分析对叶片解剖结构进行筛选,利用隶属函数法对不同种群的耐热性进行综合评价,以期了解珙桐应对热胁迫的生理变化机制,为野生珙桐资源的保护及园林应用提供参考。结果表明：珙桐叶片为异面叶,气孔主要分布于下表皮。16项解剖结构指标在不同种群间达到极显著差异水平;栅海比、栅栏组织厚度、气孔密度、下表皮角质厚度、主脉凸起度、上表皮角质层厚度、下表皮细胞厚度是影响珙桐耐热性的主要解剖结构指标,叶厚度、海绵组织厚度、主脉厚度、上表皮细胞厚度、主脉维管束厚度、气孔长度、气孔宽度、叶片结构紧密度、叶片结构疏松度与耐热性关系不大;15个珙桐种群耐热性存在一定差异,其强弱顺序为：汉源 > 筠连 > 雷波 > 沐川 > 屏山 > 荥经 > 天全 > 美姑 > 平武 > 碧峰峡 > 北川 > 洪雅 > 宝兴 > 大邑 > 邛崃;15个种群耐热性大致分为4类：汉源种群为耐热型,筠连、雷波、沐川等3个种群为中度耐热型,屏山、荥经、天全、美姑、平武、碧峰峡、北川为低耐热型,洪雅、宝兴、雷波、邛崃等4个种群为不耐热型。     

火灾恢复年限对大兴安岭森林乔灌草多样性及优势种影响

林火是大兴安岭地区森林生态系统的重要影响因子,研究火灾对植物多样性和优势种多度长期影响,有助于火灾区域森林生态系统重建与管理。本研究以大兴安岭不同火烧年限（1~5、5~10、10~20、20~30、30~40和40~50年）48对配对样地（火烧样地与邻近未火烧对照样地）为研究对象,利用二者差值变化来探讨森林恢复年限对植物多样性指数影响,通过对乔灌草相对多度变化确认火灾恢复对优势种的影响。研究结果表明：（1）火烧与对照间乔木多样性和丰富度差值先降后升趋势,在10年左右最低,而恢复30~40年后与对照样地相当或更高。灌木与乔木变化趋势相似,但是变化趋势多达到统计学显著（P<0.05）,灌木Shannon-wiener多样性指数和丰富度差值随年限增加而线性上升。草本Simpson多样性指数随火烧年限增加而直线下降,但是均匀度与丰富度没有出现线性变化。（2）乔灌草优势种变化趋势为：乔木层白桦（Betula platyphylla）在火烧5~30年占比均超过30%,在30年后占比不超过15%,同时兴安落叶松（Larix gmelinii）在30~40年占比超过50%;灌木层在0~30年均是越桔（Vaccinium vitis-idaea）占比最大,30年之后变为榛子（Corylus heterophylla）,草本层5~30年均是小叶章（Deyeuxia angustifolia）占比最大,30年之后变为其他物种。对照样地乔木层主要是兴安落叶松,占比超过50%,灌木层主要是越桔（Vaccinium vitis-idaea）,草本层主要是小叶章（Deyeuxia angustifolia）。整体来看,乔木火后恢复需要更长的时间,而灌木和草本火后恢复更快。植物多样性及优势种变化是研究其对生态服务功能（如碳汇）影响的基础,我们研究结果为天保工程后续实施及科学管理大兴安岭森林生态系统提供数据支撑。     

Prospects for seascape repair: Three case studies from eastern Australia

Three case studies spanning tropical, subtropical and temperate environments highlight the minimum potential benefits of investing in repair of coastal seascapes. Fisheries, a market benefit indicator readily understood by a range of stakeholders from policymakers to community advocates, were used as a surrogate for ecosystem services generated through seascape habitat restoration. For each case study, while recognising that biological information will always remain imperfect, the prospects for seascape repair are compelling.     

Sowing of margin strips rich in floral resources improves herbivore control in adjacent crop fields

相似文献   

Characterization of human natural killer cells for therapeutic use

As a part of the innate immune system, natural killer (NK) cells are cytotoxic lymphocytes that can exert cytotoxic activity against infected or transformed cells. Furthermore, due to their expression of a functional Fc receptor, they have also been eluded as a major effector fraction in antibody-dependent cellular cytotoxicity. These characteristics have led to multiple efforts to use them for adoptive immunotherapy against various malignancies.  There are now at least 70 clinical trials testing the safety and efficacy of NK cell products around the world in early-phase clinical trials. NK cells are also being tested in the context of tumor retargeting via chimeric antigen receptors, other genetic modification strategies, as well as tumor-specific activation strategies such as bispecific engagers with or without cytokine stimulations. One advantage of the use of NK cells for adoptive immunotherapy is their potential to overcome HLA barriers. This has led to a plethora of sources, such as cord blood hematopoietic stem cells and induced pluripotent stem cells, which can generate comparatively high cytotoxic NK cells to peripheral blood counterparts. However, the variety of the sources has led to a heterogeneity in the characterization of the final infusion product. Therefore, in this review, we will discuss a comparative assessment strategy, from characterization of NK cells at collection to final product release by various phenotypic and functional assays, in an effort to predict potency of the cellular product.     

水稻耐储藏特性三年动态鉴定与QTL分析

种子耐储藏特性是粮食作物的特殊农艺性状之一, 耐储藏性能对种子生产和种质资源保存有重要意义。以粳型超级稻龙稻5 (LD5)和高产籼稻中优早8 (ZYZ8)杂交衍生的重组自交系(RILs)群体(共180个株系)为实验材料, 自然高温高湿条件下放置1年、2年和3年后, 对不同储藏时段种子发芽率进行比较, 并利用223个分子标记的遗传图谱进行动态QTL鉴定。结果表明, 不同储藏时段龙稻5的发芽率均显著低于中优早8, 株系间耐储性存在较大差异; 不同储藏时段发芽率显著相关, 相邻存储时段发芽率关系紧密。共检测到17个耐储性相关的QTLs, 3个老化时段分别检测到5、4和3个, 检测到5个动态条件QTLs, 单一QTL解释5.60%-32.76%的表型变异, 加性效应在-16.78%-16.95%范围内。主效QTL簇qSSC2、qSSC6、qSSC7和qSSC8能调控不同储藏时段的发芽率, qSSC6具有明显降低发芽率的效应。共检测到26对上位性互作位点, 主效QTL qSS1和qSS4参与上位性互作, 这表明上位性互作是调控耐储藏性状的重要遗传组成。研究结果为水稻(Oryza sativa)耐储性相关QTL的精细定位奠定基础, 同时丰富了耐储性分子标记辅助选择育种的基因资源。     

Responses of plant 15N natural abundance and isotopic fractionation to N addition reflect the N status of a temperate steppe in China

Aims Elevated anthropogenic nitrogen (N) deposition could alter N status in temperate steppe. However, threshold observations of N status change from N limit to N saturation by far are not conclusive in these ecosystems. Research on the natural abundance of¹⁵N (δ¹⁵N) could greatly help provide integrated information about ecosystem N status. The goal of this study was to investigate the suitability of measurements of δ¹⁵N of major ecosystem N pools and several key species, plant¹⁵N fractionation, together with key vegetation and soil indicators in response to N fertilization as a tool to identify the N status in a temperate steppe in Inner Mongolia.     

Effects of wildfire on soil respiration and its heterotrophic and autotrophic components in a montane coniferous forest

Aims Episodic wildfires are expected to occur more frequently under future climate change scenarios, with substantial effects on CO₂exchange between terrestrial ecosystems and the atmosphere. This study examined the effects of wildfire on soil respiration (R_S) and its heterotrophic (R_H) and autotrophic (R_A) components, as well as their temperature responses (temperature sensitivity,Q₁₀).