Phenotypic plasticity of two invasive alien plant species inside a deciduous forest in a strict nature reserve in Italy

ABSTRACT

Invasive alien plant species (IAPs) represent one of the main biological threats to biodiversity worldwide. Information about their phenotypic plasticity are needed to increase awareness about their future invasive potential. A study about phenotypic plasticity in response to contrasting light regimes and its quantification by a plasticity index (PI) of two IAPs (Ailanthus altissima and Robinia pseudoacacia) inside a Strict Nature Reserve was conducted. R. pseudoacacia showed a 70% higher PI, with a strongly greater value at morphological leaf level, associated with a greater ability to survive and grow in forest understory, explaining its greater widespread. Otherwise, A. altissima showed its highest PI at physiological level, which was associated with the ability to colonize and grow in environments with high-light regimes. Based on these results, the conservative management has limited the presence of A. altissima by its lower ability to grow in forest understory. In fact, the small-scale gaps in the forest infrastructure, that could allow its recruitment, are originated only from the death of a single tree or small group of trees. Regarding R. pseudoacacia, it is critical to maintain this type of management because any disturbances resulting in large openings could further promote its presence inside the Reserve.     

黄条鰤仔稚幼鱼消化酶活性变化研究

为了解黄条鰤(Seriola aureovittata)早期发育阶段的消化生理特性，测定了黄条鰤胚胎、仔稚幼鱼阶段脂肪酶、淀粉酶、胰蛋白酶和碱性磷酸酶活性变化。结果显示，在黄条鰤仔鱼出膜前胚胎阶段，即能检测到脂肪酶、淀粉酶和碱性磷酸酶活性；初孵仔鱼体内(1 d)初次检测出胰蛋白酶的活性。脂肪酶和碱性磷酸酶比活力在仔鱼孵化后迅速增强(P<0.05)，在4 d开口时，2种酶比活力达最高值；淀粉酶比活力在7 d时达最大值；胰蛋白酶比活力在仔鱼阶段缓慢上升，15 d时比活力最大。稚鱼阶段内脏团中脂肪酶、碱性磷酸酶和胰蛋白酶活性基本维持稳定，幼鱼阶段内脏团脂肪酶、碱性磷酸酶和胰蛋白酶活性都呈现上升趋势；稚鱼和幼鱼阶段内脏团中淀粉酶活性下降并基本稳定于较低水平。研究表明，黄条鰤仔稚幼鱼发育过程中，各种消化酶活性变化明显，且与其发育阶段和食性密切相关。在尚未摄食饵料的早期仔鱼体内已存在消化酶，认为其是母源传递而来，不是由外源性饵料所致；幼鱼阶段内脏团脂肪酶、碱性磷酸酶和胰蛋白酶比活力明显提高，这反映出随苗种生长发育，其肠道结构和消化机能逐渐完善，并且对脂肪、蛋白质的需求逐渐增强。     

Insights into the differences in leaf functional traits of heterophyllous Syringa oblata under different light intensities

Many plants exhibit heterophylly; the spatially and temporally remarkable ontogenetic differences in leaf morphology may play an adaptative role in their success under diverse habitats. Thus, this stud...     

宁国市特色农业成功发展的政府作用分析

宁国的特色农业发展是非常成功的,目前已成为全省乃至全国特色农业发展的典范。该文从宣传引导、壮大农业产业化企业、建设和完善基础设施3个方面分析了政府在其中所起的重要作用,并据此对我国特色农业的发展提出了要因地制宜地发展、创造良好的政策环境、加大基础设施投入等建议。     

广元市主要农作物单产风险评估及区划

对广元市7县（区）1954~2007年主要农作物单产进行分析,计算水稻、玉米单产风险指标和综合风险指数,并依据气象产量的减产率界定灾年,分析各县区不同灾害年型减产率和综合风险指数的地域分布规律,并以总体变异系数为依据,参考历年平均减产率和欠年减产率,采用逐步聚类法对不同作物进行风险分区,为调整种植结构、趋利避害等提供了参考。     

Density responses and spatial distribution of cotton yield and yield components in jujube (Zizyphus jujube)/cotton (Gossypium hirsutum) agroforestry

Trees are the dominant species in agroforestry systems, profoundly affecting the performance of understory crops. Proximity to trees is a key factor in crop performance, but rather little information is available on the spatial distribution of yield and yield components of crop species under the influence of trees in agroforestry systems. Also, little information is available on how crop density may be exploited to optimize the yield in such systems. Here we studied the performance of cotton in jujube/cotton agroforestry. Field experiments were conducted in 2012 and 2013 in Hetian, Xinjiang, China. Cotton was grown at a row distance of 60 cm in three densities, 13.5, 18.0 and 22.5 plants m⁻² in six m wide paths between tree lines in a jujube plantation. Plant density affected both cotton aboveground dry matter and yield significantly. The highest yield was attained at the intermediate density of 18.0 plants m⁻² (20.0 plants m⁻² corresponding in sole cotton), lower than the optimal density in sole cotton (25.0 plants m⁻²). Yield at the lower density was constrained by the low number of bolls per m² as a direct consequence of the low density, whereas at the high plant density yield was constrained by a lower allocation of assimilates to cotton seed and lint, as a consequence of intraspecific and interspecific competitions. There were strong gradients in yield and yield components in relation to the distance from the tree rows. Leaf area and total dry matter of cotton in rows close to the tree lines were reduced, especially in the rows next to the trees. Moreover, biomass allocation to cotton fruits was reduced in these rows. Competitive influences from the trees on cotton performance extended two rows deep in a six-year old jujube stand, and even three rows deep in a seven-year old stand. Shading effects on cotton yield were compensated by increasing plant density as a result of greater boll numbers per unit ground area. Data from this study help guide the design of optimal plant density of cotton in jujube plantations and give insight in the spatial distribution and dynamics of competitive effects in agroforestry systems in general.     

CD31可作为分离纯化猪肝窦内皮细胞的标记分子

血小板-内皮细胞粘附分子(platelet endothelial cell adhesion molecule-1,CD31)是内皮细胞表面一种重要的膜分子,常作为特异性标记鉴定内皮细胞.然而,CD31是否可作为纯化猪(Sus scrofa)肝窦内皮细胞(porcine liver sinusoidal endothelial cell,pLSEC)的特异性标记还有待验证.本实验通过CD31流式分选分离纯化pLSEC,观察分离后的pLSEC是否具有标志性的窗孔结构.以α-1,3-半乳糖苷转移酶基因敲除(α-1,3-galactosyltransferase knockout,GTKO)的五指山小型猪为研究材料,采用胶原酶原位肝脏灌注、离体消化,Percoll梯度离心,异硫氰酸荧光素(fluorescein isothiocyanate,FITC)-CD31标记pLSEC进行流式分选.结果表明,分离得到的pLSEC在倒置显微镜下细胞呈典型的内皮细胞形态,铺路石样排列;通过透射电镜观察到细胞具有窗孔结构,通过环境扫描电镜观察到pLSEC与猪主动脉内皮细胞(porcine arterial endothelial cell,pAEC)细胞表面结构具有明显区别,pLSEC具有特殊的窗孔结构.利用实时荧光定量PCR检测pLSEC、pAEC和猪耳成纤维细胞(porcine ear fibroblast cell,pEFC)的CD31、细胞粘附因子(cell adhesion molecules,CD146)、血友病因子Ⅷ基因(hemophilia factorⅧ,Ⅷ-F)、血管性血友病因子基因(von willebrand factor,vWF)的表达.结果表明,pLSEC的CD31、CD146、Ⅷ-F和vWF表达量显著高于pAEC和pEFC.利用免疫荧光法检测到pLSEC具有摄取细胞膜红色荧光探针(1,1’-dioctadecyl-3,3,3’,3’-tetramethylindocarbocyanine perchlorate,DiI)标记的乙酰化低密度脂蛋白(acetylated low density lipoprotein,Ac-LDL)的内吞功能.总之,利用CD31分离纯化的pLSEC,具有典型窗孔结构和内吞功能,同时高表达CD146、Ⅷ-F和vWF等肝窦内皮细胞的标记分子,为进一步研究异种肝移植的血小板减少症的问题提供了良好的细胞材料.     

投喂频率对虎龙斑摄食?生长?饲料转化率的影响

[目的]研究投喂频率对虎龙斑摄食、生长和饲料转化率等指标的影响。[方法]试验共设置5个处理组,对平均始重(6.42±1.09)g的虎龙斑(Hulong grouper)进行不同频率的投喂,研究不同投喂频率对虎龙斑摄食率、生长和饲料转化率等指标的影响。[结果]投喂频率对虎龙斑存活的影响较大,投喂频率对虎龙斑的摄食率(Feeding rate,FR)和饲料转化率(Feed conversion rate,FCR)有显著影响(P0.05),但是投喂频率对虎龙斑末重的影响不显著(P0.05)。[结论]该研究结果可为虎龙斑的科学养殖管理提供理论依据。     

盐胁迫对小麦代换系光合性状的影响及染色体效应研究

为了选育小麦耐盐基因型,以中国春-Synthetic 6x小麦染色体代换系及其亲本为材料,设置对照(0mmol·L~(-1) NaCl)和盐胁迫(150mmol·L~(-1) NaCl)2个处理,通过测定不同处理条件下代换系幼苗比叶重、叶绿素和类胡萝卜素含量及光合速率的变化,探讨盐胁迫对小麦代换系幼苗光合性状的影响,并对其调控相关特性的基因进行染色体定位。结果表明,盐胁迫导致多数小麦代换系叶绿素和类胡萝卜素含量、比叶重、光合速率降低;盐胁迫条件下,Synthetic 6x的2D染色体上可能存在诱导比叶重升高的基因,1A、5A、7A、2B、3B、5B、6B和6D染色体上可能存在诱导叶绿素含量增加的基因,1A、4A、7A和5B染色体上可能存在诱导类胡萝卜素含量增加的基因,1A和7D染色体上可能存在诱导幼苗光合速率增强的基因,即Synthetic 6x的1A染色体上可能存在调控光合特性的关键基因。     

玉米人工合成群体产量相关性状选择潜势及杂种优势模式分析

采用NCⅡ遗传交配设计 ,以分属于不同杂种优势群的 6个自交系做测验种 ,与 6个合成群体组配成 36个组合。结果表明 :单株产量的GCA以LBM最高 ,其次为WBM ,从株型、穗型性状的SCA分析合成群体与自交系组成了 9个优良杂种优势模式。单株产量最高的组合为HZ85×WBM ,其均值为 10 8 75g。通过对优良杂优模式内的变异参数估计 ,在群体内有丰富的变异个体 ,具有很强的选择潜势。组合内个体产量分布以及出现的频率对选系和轮回选择具有明确的指导意义。人工合成群体具有丰富的遗传变异 ,分属于不同的杂种优势类群 ,具有多元种质的特性。作为选系和轮回选择群体 ,具有明显的选择潜势