Effects of chemical and botanical insecticides used for locust control on Metarhizium anisopliae var. acridum conidia after short- to medium-term storage at 30°C

The short- to medium-term viability and growth of Metarhizium anisopliae var. acridum conidia were investigated when combined with six insecticides, at three different concentrations. All of the insecticides used in this study were suitable for immediate spraying with M. anisopliae var. acridum conidia except for fenitrothion. Fipronil, teflubenzuron, and fenitrothion formulations significantly reduced conidial viability over time. The 10% teflubenzuron treatment caused loss of viability relatively quickly with 9.9% germination after 28 days. Mycelial growth was affected by all the treatments except fenitrothion.     

In Vitro Effects of Ginseng and the Seed of Zizyphus jujuba var. spinosa on Gut Microbiota of Rats with Spleen Deficiency

Ginseng and the seed of Zizyphus jujuba var. spinosa, which are traditional Chinese medicinal materials, were often used in ancient Chinese recipes as a pair of medicines. They can replenish the primordial qi and tonify the spleen. This study investigated the effects of ginseng and the seed of Zizyphus jujuba var. spinosa (GS) extract on gut microbiota diversity in rats with spleen deficiency syndrome (SDS). A total of 52 compounds (including 16 flavonoids, 35 saponins, and 1 alkaloid) were identified and analyzed from the GS extract by UPLC‐Q‐Orbitrap‐MS/MS. The GS extract significantly increased the relative abundance of Firmicutes and Bacteroidetes in rats with SDS but decreased that of Proteobacteria and Actinobacteria. At the genus level, the GS extract significantly increased the relative abundance of Lactobacillus and Bifidobacterium in rats with SDS but decreased that of Streptococcus, Escherichia‐Shigella, Veillonella, and Enterococcus. In addition, the GS extract influenced glucose and amino acid metabolism. In summary, the results showed that the GS extract changed the structure and diversity of gut microbiota in rats with SDS and balanced the metabolic process.     

紫叶小檗刺的形态与发生——对小檗属植物刺的重新认识

针对目前人们对小檗属植物刺的来源存在不同见解,本研究通过实体解剖及石蜡切片技术,以紫叶小檗为代表研究小檗属植物刺的形态和发生,结果表明,紫叶小檗的刺均为叶刺,而非茎刺,明确了小檗属的刺为叶的变态。     

马蔺IlWRKY28基因的克隆与表达分析

马蔺(Iris lactea var. chinensis)是鸢尾属多年生草本盐生植物,具有很高的耐盐性和观赏价值。为研究马蔺耐盐的分子机制,通过cDNA末端快速扩增技术(RACE)从马蔺中克隆到一个WRKY转录因子基因IlWRKY28,获得了1 302 bp的全长cDNA序列,其包含一个108 bp 5′末端非翻译区(UTR),一个174 bp 3′末端UTR和一个1 020 bp开放阅读框。IlWRKY28编码339个氨基酸,预测的蛋白质分子量为37.22 kD,等电点为7.04。氨基酸序列分析显示,IlWRKY28包含一个保守的WRKY基序和一个C2H2型锌指结构域。系统发育分析表明,马蔺IlWRKY28与菠萝(Ananas comosus)AcWRKY28和藏北嵩草(Kobresia littledalei)ClWRKY28亲缘关系最近。荧光定量PCR分析显示,盐处理后,IlWRKY28基因在马蔺地上部显著上调表达。该研究结果为进一步研究IlWRKY28在马蔺适应高盐胁迫中的功能和作用机制奠定了重要的分子基础。     

松栎林天然更新模拟与不确定性分析

森林天然更新的复杂性和不确定性是森林生态系统动态预测中的关键问题。本研究引入贝叶斯技术和全局敏感性分析,构建基于竞争、气候和地形3类因子的秦岭松栎林天然更新模型。备选模型形式以泊松(Poisson)模型、负二项(negative binomial,NB)模型、零膨胀泊松(zero-inflated Poisson,ZIP)模型和零膨胀负二项(zero-inflated negative binomial,ZINB)模型为基础。同时,根据模型参数传递的不确定性量化分析结果,阐释影响森林更新小概率事件的主导因子。结果表明: ZINB模型在油松和锐齿栎更新模拟中均优于其他模型。林分总断面积、光截留、坡位和生长季最低温是影响松栎林中油松天然更新的最关键因子;而林分总断面积、坡向与海拔的组合、年均温和最热季节降水量则是影响松栎林中锐齿栎天然更新的关键因子。油松更新模拟中,各类因子对模型输出的不确定性贡献率从小到大依次为: 竞争因子(25%)＜气候因子(29%)＜地形因子(46%);锐齿栎更新模拟中为: 气候因子(12%)＜竞争因子(24%)＜地形因子(64%)。油松天然更新数量对生长季最低温和最干季节降水量为正响应,对最干季节均温为负响应;锐齿栎天然更新数量对年均温、生长季最低温和最热季节降水量为正响应,对最干季节均温为负响应。基于贝叶斯技术的ZINB模型可以量化森林更新的影响因子,并解释参数传递的不确定性,是预测森林天然更新的有力工具。     

Studies on reproductive strategies of Vitex negundo L. var. heterophylla (Franch.) Rehder (Lamiaceae) based on morphological characteristics and SSR markers

Vitex negundo L. var. heterophylla (Franch.) Rehder (Lamiaceae) is an important tree species for soil and water conservation, yet the reproductive ecology of this species remains to be elucidated. To investigate the reproductive traits of V. negundo var. heterophylla, the phenology, morphological characteristics (a suite of characters was assessed: floral morphology, nectar production, pollen viability, and stigma receptivity) and mating system of this species were systematically revealed for the first time in this study. Phenological observations, morphological measurements, and nectar production analysis were conducted during anthesis. Pollen viability and stigma receptivity at different flowering stages were measured by biochemical methods. Finally, genetic analysis based on SSR markers was used to reveal the mating system; outcrossing index and pollen‐ovule ratio were also calculated to help analysis. V. negundo var. heterophylla showed several obvious characteristics of outcrossing, such as abundant and attractive flowers, secreting nectar, and emitting scent. In addition, mechanisms such as homogamy and a short anther‐stigma distance that can promote self‐fertilization were also identified in this species. The coexistence of selfing and outcrossing characteristics demonstrates a predominantly outcrossed mixed mating system (outcrossing rate, t = 95%). The scientific information provided by this study may contribute to conservation of V. negundo var. heterophylla from a reproductive perspective.     

珍稀濒危植物长白松(Pinus sylvestris var. sylvestriformis)天然种群生存压力

为了揭示珍稀濒危植物长白松（Pinus sylvestris var. sylvestriformis）天然种群生存压力状况,在全面调查长白山国家级自然保护区长白松分布的基础上,基于邻体干扰模型,引入树高、冠幅、方位等因子,提出3种生存压力指数：个体生存压力指数、种群生存压力指数和群落生存压力指数,分析天然长白松所处6种群落类型中的生存压力。结果表明：长白松承受群落生存压力（PI）从大到小依次为：白桦-臭冷杉群落（PI=21.532）、红松-长白松群落（PI=14.185）、白桦群落（PI=13.262）、臭冷杉-长白松群落（PI=8.752）、长白落叶松-鱼鳞云杉群落（PI=7.780）和蒙古栎群落（PI=5.440）。多重比较单向方差分析表明,6种群落类型中长白松生存压力总体上差异明显,白桦-臭冷杉群落中长白松生存压力最大,显著高于其他5种群落;竞争树种主要为长白落叶松、红松、长白松、山杨和白桦,这5个树种生存压力大小占群落生存压力的87%;红松-长白松群落和白桦群落中长白松生存压力无明显差异,但显著高于臭冷杉-长白松群落、长白落叶松-鱼鳞云杉群落和蒙古栎群落;臭冷杉-长白松群落、长白落叶松-鱼鳞云杉群落和蒙古栎群落中长白松生存压力相对较小,彼此无明显差异。长白松生存压力与其所处植物群落演替阶段及其龄级结构有关。目前,保护区采取严格保护和管理方式不完全有利于长白松种群的稳定发展。根据长白松种群所处的植物群落生境特点、种群生存压力状况并结合种群年龄结构特征,针对不同群落类型提出相应抚育措施建议以期为长白松天然种群的保护提供参考。     

间伐强度对坝上樟子松林下持水能力的影响

河北坝上地区地势复杂、气候条件较差,导致了水土流失和地质灾害的发生,使华北地区生态安全受到严重威胁。为了改善当地生态环境,樟子松、落叶松等耐贫瘠速生树种被大面积种植,然而不合理的植被密度会导致降雨的低效率利用。本研究以5种间伐强度(0、20%、40%、60%、80%)的樟子松林为对象,分析间伐强度对林下草本、枯落物、土壤各层以及整体持水能力的影响。结果表明: 草本层持水率变化幅度为47.7%～90.7%,且随着间伐强度增加持水能力整体呈减小趋势,间伐强度小于40%时减速较缓,之后迅速减小。随间伐强度的增大,枯落物未分解层、半分解层自然含水率和最大持水率均逐渐减小,而有效持水能力大小依次为60%>40%>20%>80%>0,且半分解层持水能力均优于未分解层。土壤持水能力随间伐强度的增强逐渐降低,间伐强度小于40%时对持水能力起促进作用。不同间伐强度下,林下总持水率是8.3%～14.3%,依次为20%>0>40%>60%>80%。 鉴于林下各层及整体变化,研究区内选择强度为20%的间伐措施能有效提高林下持水能力,实现更好的生态效益。     

呼伦贝尔沙地樟子松径向生长特征的VS模型模拟分析

利用Vaganov-Shashkin模型对呼伦贝尔地区4个样点的沙地樟子松标准化宽度年表进行模拟研究,在2000年以前时段拟合度较好,而2000年以后时段拟合度较差。进而选取2000年以前的模拟结果进行径向生长过程分析。结果表明: 呼伦贝尔沙地樟子松主要的生长季为每年的5—9月,温度对每年樟子松生长初期与末期具有显著影响,而在树木生长季旺盛期,土壤湿度的不足是制约树木生长的主要因素。极端窄年树木径向生长速率受土壤湿度的影响较极端宽年明显,生长季中期7—8月树木径向生长速率在宽窄年份均呈降低趋势,表明该时期沙地樟子松生长均受到不同程度的干旱胁迫。研究结果与我国半干旱地区树木年轮生理模型分析特征相符,模型对呼伦贝尔沙地樟子松径向生长模拟具有一定的适用性。     

镉胁迫对吊兰及银边吊兰生长及镉富集特性的影响

选择吊兰和银边吊兰为试验材料,采用水培法研究其在不同Cd²⁺处理浓度(0、20、80、200 μmol·L^-1)下生长及生理特性的变化。结果表明: 20 μmol·L^-1镉对两种吊兰的影响较小,单叶面积、总叶面积、叶绿素(Chl)a含量、总叶绿素[Chl (a+b)]含量、类胡萝卜素含量、Chl a/Chl b值、胞间二氧化碳浓度(C_i)和蒸腾速率(T_r)与对照(CK)基本无显著差异;80 μmol·L^-1镉胁迫下两种吊兰叶片初始荧光(F_o)和非光化学淬灭系数(NPQ)升至最高水平;200 μmol·L^-1镉胁迫下,两种吊兰生物量、叶绿素含量、最大净光合速率(P_n)、气孔导度(g_s)、最大光化学量子产量(F_v/F_m)、实际光化学量子产量Y_(II)、转移系数(TF)以及各部分生物量均降至最低水平,而两种吊兰的过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)及过氧化氢酶(CAT)活性和银边吊兰的丙二醛(MDA)含量均有不同程度的增加。随着镉处理浓度的增加,两种吊兰各器官Cd含量持续升高,且主要富集在根部;吊兰各器官Cd含量及富集系数(BCF)在胁迫处理下均高于银边吊兰。研究表明,两种吊兰对镉具有一定的耐性,其中吊兰对Cd的耐受能力强于银边吊兰,可考虑作为绿化植物用于修复镉污染水体或土壤。