Implications of landscape configuration on understory forage productivity: a remote sensing assessment of native forests openings

Agroforestry Systems - Sound management of native forests used for cattle grazing requires understanding the dynamics of forage productivity in the openings. Despite their importance, forage...     

Genetic and functional leaf traits variability of Quercus laurina along an oak diversity gradient in Mexico

The ecological literature has documented the effects of plant hybridization on phenotypic variation, and dominant, intermediate, or novel morphological, chemical and physiological traits in hybrids. It is important to understand the ecological consequences of hybridization by evaluating their impact on phenotypic expression of functional traits. We evaluated the relationship between genetic diversity of Quercus laurina and functional foliar traits along an oak diversity gradient. We selected five study sites that represent an oak diversity gradient where Q. laurina is present. Using chloroplast and nuclear microsatellites, we evaluated genetic diversity, measured functional foliar traits of Q. laurina in each site and assessed the effects of local climate variables on the oak community and functional traits. We found a greater abundance of Q. laurina in all study sites. We did not find a relationship between the number of accompanying red oak species and the population genetic diversity in Q. laurina, but higher genetic diversity was found in all study sites in comparison with European oak species. Sites with more oak species had more variation of foliar functional traits. Our results do not support the hypothesis that predicts higher levels of genetic diversity of Q. laurina in communities with greater oak diversity from the same section, but we demonstrated an increase in the foliar functional traits of Q. laurina associated with oak richness and climate variables. We highlight the need to consider environmental and ecological variables linkages as regulatory mechanisms of the phenotypic plasticity expressed in changes of some functional attributes of oaks.

     

Thinning decreased soil respiration differently in two dryland Mediterranean forests with contrasted soil temperature and humidity regimes

The effects of a thinning treatment on soil respiration (Rs) were analysed in two dryland forest types with a Mediterranean climate in east Spain: a dry subhumid holm oak forest (Quercus ilex subsp. ballota) in La Hunde; a semiarid postfire regenerated Aleppo pine (Pinus halepensis) forest in Sierra Calderona. Two twin plots were established at each site: one was thinned and the other was the control. Rs, soil humidity and temperature were measured regularly in the field at nine points per plot distributed into three blocks along the slope for 3 years at HU and for 2 years at CA after forest treatment. Soil heterotrophic activity was measured in laboratory on soil samples obtained bimonthly from December 2012 to June 2013 at the HU site. Seasonal Rs distribution gave low values in winter, began to increase in spring before lowering as soil dried in summer. This scenario indicates that with a semiarid climate, soil respiration is controlled by both soil humidity and soil temperature. Throughout the study period, the mean Rs value in the HU C plot was 13% higher than at HU T, and was 26% higher at CA C than the corresponding CA T plot value, being the differences significantly higher in control plots during active growing periods. Soil microclimatic variables explain the biggest proportion of variability for Rs: soil temperature explained 24.1% of total variability for Rs in the dry subhumid forest; soil humidity accounted for 24.6% of total variability for Rs in the semiarid forest. As Mediterranean climates are characterised by wide interannual variability, Rs showed considerable variability over the years, which can mask the effect caused by thinning treatment.

     

梅PmARF17克隆及其在花发育中与内源激素的调控模式

【目的】分析梅PmARF17的生物学功能,探究梅花发育进程中其表达丰度与内源激素动态变化的关系,为梅花发育的调控研究提供依据。【方法】以梅品种‘大嵌蒂’为试材,克隆PmARF17,利用生物信息学软件分析基因结构、系统进化及其与其他物种同源蛋白的差异;亚细胞定位确定PmARF17蛋白在细胞中作用的部位;以梅品种‘大嵌蒂’和‘龙眼’不同发育阶段的花芽、叶芽、花器官为试材,利用qRT-PCR检测PmARF17时空表达模式,通过UPLC法测定IAA、GA₃、ABA、ZT含量的动态变化,并与PmARF17的表达进行相关性分析;克隆PmARF17启动子,分析启动子的顺式作用元件,利用瞬时表达解析PmARF17与GA₃的调控模式。【结果】从梅品种‘大嵌蒂’中克隆得到PmARF17,系统进化树分析表明PmARF17蛋白与其他植物的ARF蛋白序列高度同源;亚细胞定位表明其作用于细胞核和细胞膜上;qRT-PCR表达和内源激素含量的相关性分析表明,PmARF17的表达与IAA含量的变化趋势没有明显的相关性。PmARF17在雌蕊完好花芽中的表达水平相对不完全花芽显著上调,而GA₃含量与PmARF17的表达趋势一致。ABA和ZT含量总体上与PmARF17的表达呈相反的趋势,表明两者可能抑制PmARF17的表达。PmARF17启动子含有GA顺式元件,且具有启动活性和组织表达特异性,在花瓣、雄蕊及根部特异表达。【结论】 PmARF17可能是梅花发育的正调控基因,促进梅雌蕊的正常发育。PmARF17的表达可能受到GA₃的正调控,其可能通过作用于雄蕊和花瓣,进而影响梅的雌蕊发育进程。     

狭叶润楠和山胡椒的老鹰红茶品质分析

【目的】对狭叶润楠和山胡椒鲜叶制作的老鹰红茶品质进行分析,为贵州当地老鹰茶产业的发展提供理论依据。【方法】以狭叶润楠和山胡椒的鲜叶为试材,参照传统红茶工艺制作老鹰红茶,对2种老鹰红茶进行感官审评、生化成分含量测定及其相关分析,并通过气相色谱—质谱联用仪检测其挥发性物质。【结果】山胡椒老鹰红茶外形卷曲、香气持久高扬、滋味醇和,综合得分为90.08分;狭叶润楠老鹰红茶外形细紧、香气持久、滋味鲜爽甜醇,综合得分为89.84分。山胡椒老鹰红茶的多酚类物质、蛋白质和茶黄素含量分别较狭叶润楠老鹰红茶显著提高62.3%、37.5%和11.1%（P<0.05,下同）,而狭叶润楠老鹰红茶的总黄酮含量较山胡椒老鹰红茶显著提高29.3%。2种老鹰红茶均检测出17种氨基酸组分,其中山胡椒老鹰红茶的氨基酸组分总含量较狭叶润楠老鹰红茶提高5.4%,天门冬氨酸、谷氨酸、赖氨酸和亮氨酸是2种老鹰红茶中含量较高的组分。山胡椒老鹰红茶的水浸出物与茶红素呈显著正相关,与总黄酮、可溶性糖、蛋白质和粗脂肪呈显著负相关;狭叶润楠老鹰红茶的水浸出物与蛋白质呈显著正相关,与总黄酮、茶黄素、粗脂肪和灰分呈负相关。山胡椒老鹰红茶共检测出15种挥发性物质,包括8种萜烯烃类、2种醇类、1种醛类、2种酯类和2种其他类化合物;狭叶润楠老鹰红茶共检测出14种挥发性物质,包括5种萜烯烃类、1种醇类、4种醛类、1种酯类和3种其他类化合物;2种老鹰红茶中含量最高的挥发性物质均为萜烯烃类化合物。【结论】通过感官审评结果、生化成分和挥发性物质的测定,山胡椒和狭叶润楠的鲜叶均适合制作老鹰红茶,其品质均表现良好,各具特点。     

Variable-rate seeding in soybean according to soil attributes related to grain yield

Precision Agriculture - Defining the ideal soybean stand is essential for obtaining maximum grain yield. As a hypothesis of the work, it was questioned whether it is possible to vary seeding...     

秸秆类型对强还原土壤细菌群落及多样性的影响

为对比不同类型秸秆对强还原处理土壤（RSD）理化指标和微生物变化特征的影响,本研究设置了晾干的玉米秸秆（CS）,晾干的芒草秸秆（MS）,晾干的玉米和芒草秸秆混合（CMD）,新鲜的玉米和芒草秸秆混合（CMW）4个处理,并以化学熏蒸和仅淹水处理作为对照,以评估不同强还原物料处理土壤培养过程中理化性质和细菌群落的动态变化。结果表明：在培养期间不同RSD处理增加了土壤有机质和活性有机碳含量,土壤pH呈先升高后降低的趋势,且土壤硝态氮的累积降幅达到83%~98%。与单一秸秆相比,混合晾干秸秆RSD处理显著提高了细菌群落多样性,其中Shannon指数的增幅为49%,而混合新鲜秸秆处理对细菌群落多样性的影响呈先升高后降低的变化趋势。在培养期间,变形菌门（Proteobacteria）是总细菌群落的优势菌门,其相对丰度在CMW组先降低后升高,而在CMD组降低了51%。在细菌属水平上,CMD组伯克氏菌目中未分类的属（UC-Burkholderiales）、丛毛单胞菌科中未分类的属（UC-Comamonadaceae）、厌氧黏细菌属（Anaeromyxobacter）和假单胞菌属（Pseudobacteroides）相对丰度于培养结束时期显著高于其他处理。Mantel检验表明具有特征性的细菌类群（如Anaeromyxobacter和Pseudobacteroides）与土壤pH、有效磷含量呈正相关,且Anaeromyxobacter与硝态氮含量呈显著正相关关系。研究表明,不同强还原物料组成及晾干程度均对土培过程中细菌群落组成及其多样性产生显著影响。     

闽楠种实性状表型多样性与环境地理因子的关系

以14个天然分布在6省的闽楠(Phoebe bournei)林为对象,采用巢式分析、冗余分析、热图等方法,探究不同种源间7个种实表型性状变异特征及闽楠种实表型性状与环境地理因子之间的相互关系.结果表明:闽楠种实的表型性状在种源间、种源内均呈极显著差异,平均表型分化系数为70.83％,表型变异主要来源为种源间.种源间,种形指数的变异系数最高(13.33％),果实横径的变异系数最低(7.03％).种源内,湖南永顺的平均变异系数最高,为7.62％,福建延平最低,为4.93％.种子平均变异系数高于果实,表明果实表型性状比种子更稳定.冗余分析得出,在环境地理影响因子中,年降水为影响种实表型性状的主要因素,随年降水增加,种子呈狭长瘦小的生长趋势.热图将种源按种实表型性状分为3类,江西南部种实较瘦小的为第1类;湖南及周边种实较宽阔饱满的为第2类;福建及东南线种实较狭长的为第3类.     

亚临界提取甜瓜籽油风味与脂肪酸关系分析

【目的】分析5个品种甜瓜籽油的挥发性风味成分与脂肪酸之间的关系。【方法】采用气相色谱-质谱联用仪测定不同品种甜瓜籽油的挥发性风味成分和脂肪酸,采用R语言分析PCA和变量投影重要性。【结果】5个品种甜瓜籽油中共鉴定出65种挥发性化合物,新蜜1号样品检测到的挥发性物质种类最多为37种,皇后品种的油脂中有30种,香瓜和86-1样品中有29种,绿宝石样品检测到最少,为26种,分析发现5个样品之间的挥发性物质有显著性差异。5个品种甜瓜籽油在挥发性物质成分共分成4大类,皇后与绿宝石较相近归为一类。5种甜瓜籽油中富含不饱和脂肪酸,平均为75.34%,其中亚油酸最高,平均含量达56.81%。【结论】二十四酸、十八碳烯酸、花生酸、棕榈酸、亚麻酸、蓖麻油酸与某些香气物质有较强相关性。     

蛋白质组学在番茄非生物逆境胁迫中的研究进展

【目的】回顾近年来蛋白质组学在番茄逆境胁迫中的研究进展,综述蛋白质组学技术在番茄响应非生物(盐碱、干旱、高温、低温、其它)胁迫上的研究进展,为利用蛋白质组学技术进一步研究番茄响应非生物逆境胁迫的分子机制奠定理论基础。【方法】运用统计学方法收集文献资料,并分析汇总蛋白质组学技术在番茄响应非生物(盐碱、干旱、高温、低温等)胁迫的研究文献进展情况。【结果】盐胁迫耐受性(渗透调节,渗透保护,离子稳态,消除氧清除剂,胁迫反应等)与胁迫的持续时间有关;下调的蛋白主要参与代谢和能量转换,上调的蛋白参与信号转导或运输;干旱应答蛋白包括与耐热性和渗透性保护剂的产生、脂质代谢、细胞壁修饰、神经酰胺代谢和丝裂原活化蛋白磷酸化相关的蛋白;蛋白质广泛参与了细胞过程,包括防御/应激反应,离子结合/转运,光合作用和蛋白质合成;最初如何感知胁迫条件,以及植物器官激活了哪些主要反应,可以避免低温胁迫晚期相关蛋白的干扰。【结论】在非生物逆境胁迫条件下,番茄通过改变自身的蛋白质表达水平对各种非生物胁迫作出响应。蛋白质组学研究能够全面揭示番茄响应胁迫时其细胞内蛋白质的动态变化规律,鉴定差异表达的蛋白质,是番茄抗逆生物学研究的重要组成部分。