濒危植物绵刺光合的生理生态学特征

使用Li-6200便携式光合测定仪,测定了自然状况下绵刺的净光合速率,蒸腾速率,水分利用效率以及气象因子在9：00-19：00的日进程,以白刺等旱生植物为对照。进行了对比研究。研究结果表明,绵刺的日平均净光合速率为8.832μmol·m^-2·s^-1,小于白刺的日平均净光合速率9.449μmol·m^-2·s^-1;绵刺的水分利用效率大于白刺,在13：00之前差异最为明显;同其它沙旱生植物相比,其净光合速率和水分利用效率均介于多种旱生植物之间;绵刺的净光合速率同各个气象因子的相关均不显,水分利用效率同气温以及相对温度之间呈极显相关,与气温,相对温度以及大气CO2浓度之间存在的多元线性关系。相关方程为YWUE=6.306 0.633XRH-0.178XTA 0.0164Xco2。     

极危植物焕镛木的群落学特征及其保护

对广西罗城大黄泥常绿阔叶林进行样方调查,分析了极危植物焕镛木(Woonyoungia septentrionalis (Dandy)taw)群落的组成结构特征.1200 m2样地内有维管植物129种,隶属57科103属,以热带属占绝对优势;优势科为樟科、壳斗科、茜草科等.群落中焕镛木为优势种,重要值最大,为35.06,其次为粗丝木、红锥,重要值分别为22.09和19.66,因此,本群落可命名为焕镛木-粗丝木-红锥群落(Woonyoungia septentrionalis+Gomphandra tetrandra+Castanopsis hickelii Community).群落成层现象明显,可分为乔木层(3亚层)、灌木层和草本层3个层次,层间植物丰富.生活型以中、小高位芽为主,占67.18%.叶型以中、小型革质单叶为主.种群频度分布规律为A>B>CE,属于A级的种类占优势,为总种数的41.09%.乔木径级以小径级为主.焕镛木是我国南亚热带常绿阔叶林中非常珍稀濒危的物种,希望有关部门尽快在此设立保护区,以保护焕镛木的种质基因资源.     

深绿木霉中碳代谢抑制因子CRE1功能特性研究

木霉菌(Trichoderma spp.)是一种广泛存在于土壤及植物根系生境中的丝状真菌,具有拮抗植物病原真菌和促进植物生长的双重功效。碳代谢抑制子CRE1全局性调控细胞生长代谢过程,保障木霉在不同生境中的存活及拮抗病原菌特性。比较深绿木霉(T.atroviride)T23及其Cre1突变株(T23Δcre1)在不同培养基中的生长和代谢特性,结果表明:cre1基因沉默后,T23Δcre1较T23菌丝生长变慢,产孢滞后且降低一个数量级,cre1对菌丝生长和产孢的调控依赖于培养基组分。此外,cre1基因抑制几丁质酶、β-1,3-葡聚糖酶基因转录,区别性调控部分次级代谢合成的非核糖体肽合成酶NRPS和聚酮合成酶PKS基因的表达。综上,碳代谢因子CRE1作为一个多效性的转录调控因子,抑制细胞壁降解酶和代谢产物合成相关的基因表达,赋予木霉菌在环境中的适应性和竞争性,是深绿木霉T23生长的必要因子。     

Vegetation structure and ground cover attributes describe the occurrence of a newly discovered carnivorous marsupial on the Tweed Shield Volcano caldera,the endangered black‐tailed dusky antechinus (Antechinus arktos)

The black‐tailed dusky antechinus (Antechinus arktos) is a recently discovered, endangered, carnivorous marsupial mammal endemic to the Tweed Shield Volcano caldera, straddling the border between Queensland and New South Wales in eastern Australia. The species' preference for cool, high‐altitude habitats makes it particularly vulnerable to a shifting climate as these habitats recede. Aside from basic breeding and dietary patterns, the species' ecology is largely unknown. Understanding fine‐scale habitat attributes preferred by this endangered mammal is critical to employ successful conservation management. Here, we assess vegetation attributes of known habitats over three sites at Springbrook and Border Ranges National Parks, including detailed structure data and broad floristic assessment. Floristic compositional assessment of the high‐altitude cloud rainforest indicated broad similarities. However, only 22% of plant species were shared between all sites indicating a high level of local endemism. This suggests a diverse assemblage of vegetation across A. arktos habitats. Habitat characteristics were related to capture records of A. arktos to determine potential fine‐scale structural habitat requirements. Percentage of rock cover and leaf litter were the strongest predictors of A. arktos captures across survey sites, suggesting a need for foraging substrate and cover. Habitat characteristics described here will inform predictive species distribution models of this federally endangered species and are applicable to other mammal conservation programs.     

The correlation among molecular phylogenetics, morphological data, and growth temperature of the genus Emericella, and a new species

The species of the genus Emericella have been classified and identified on the basis of morphological features. However, the phylogenetic relationships in this genus have not been investigated. To clarify the relationships according to molecular phylogenetics, morphological characteristics, and growth temperature regimens in Emericella, multilocus sequencing analysis based on recent Aspergillus taxonomy was carried out. Various characteristic species formed individual clades, and maximum growth temperature reflected the phylogenetics. Emericella species exhibit various ascospore characteristics, although some species do not have distinct ascospore ornamentation. Species that have smooth-walled ascospores with two equatorial crests are polyphyletic. Here, Emericella pachycristata is described and illustrated as a new species. Its ascospores are similar to those of E. nidulans. These species produce smooth-walled ascospores, but the equatorial crests of E. pachycristata are thicker than those of E. nidulans. On the phylogenetic trees, E. pachycristata is closely related to E. rugulosa, which produces ascospores with ribbed convex surfaces. Thus, E. pachycristata is considered to be a new species both morphologically and phylogenetically.     

单叶蔷薇幼苗根系对不同潜水埋深的适应机制

地下水是影响西北地区植被分布、生长和群落演替的重要因子,通过人工装置模拟30 cm(D30)、40 cm(D40)、50 cm(D50)、60 cm(D60)、70 cm(D70)5个潜水梯度,从生长发育、根系形态、拓扑结构与分形维数以及表型可塑性四个方面来分析不同潜水埋深对单叶蔷薇幼苗的影响,力求揭示单叶蔷薇幼苗对不同水分环境的适应性策略,这将对今后开展单叶蔷薇植被恢复和保育工作具有重要价值。研究结果表明：(1)单叶蔷薇幼苗可通过增加扎根深度、总根长、根表面积、根体积、根尖数量、分支数量、地上干物质和根系干物质来应对不同潜水埋深带来的干旱胁迫,D50、D60、D70和CK处理下的幼苗还可以通过提高根冠比来适应更长久的干旱环境。(2)不同潜水埋深处理下,单叶蔷薇幼苗根系的拓扑指数基本保持在0.8—0.9之间,说明该根系属于典型的人字形分支模式,受环境影响较小。其中,短而细的密集细根(0—2 mm)构成了单叶蔷薇幼苗根系的主体。从资源分配的角度来看,该种拓扑结构相对简单、内部竞争较小、碳消耗少,有利于根系扩大土壤资源获取效率,从而保障植株生长发育的物质供需平衡,这是单叶蔷薇对环境胁迫的适...     

华山松大小蠹及其伴生蓝变真菌对华山松木质部危害的解剖学特征

为揭示华山松大小蠹和伴生蓝变真菌引起秦岭华山松枯萎的机制,选择秦岭北坡沣峪林场境35年树龄的健康华山松Pinus armandi为研究对象,对接种华山松大小蠹Dendroctonus armandi及与其伴生的蓝变真菌Ceratocystis polonica引起的寄主树木木质部形态变化进行了解剖观察。结果表明：接种致病性蓝变真菌C. polonica 1周后的4株华山松 的木质部组织内,蓝变区域显著增加,4～6周后蓝变区域不再增加; 而在接种无菌琼脂的2株对照华山松的木质部组织内,没有检测到蓝变区域。研究结果提示蓝变真菌C. polonica是致死秦岭华山松的重要病原菌,该伴生菌随华山松大小蠹入侵健康寄主华山松木质部组织,在木质部定居并分解木质部,堵塞树脂道,致使寄主华山松树脂代谢和水分代谢紊乱。该研究结果表明,虽然华山松大小蠹长期以来被认为是致死华山松的毁灭性小蠹虫,但是其共生蓝变真菌C. polonica对成熟华山松的致害作用不应该被忽视。     

基于rDNA-ITS序列的散斑壳属系统发育学初步研究

对散斑壳属Lophodermium 22个种的40个rDNA-ITS序列进行分析,研究了该属种间系统发育关系。对以简约法构建的系统进化树分析表明,散斑壳属种间亲缘关系与其寄主有很大的相关性,针叶树和阔叶树上的散斑壳可能是亲缘关系较远的两大类群,寄主和产地的不同导致了L.agathidis、L.australe和L.conigenum等种内遗传变异。同时,子囊果的开口机构和唇细胞的有无及特征在种水平分类上具有重要意义,而rDNA-ITS序列系统学分析并不能证实子囊果埋生位置在散斑壳属分类上的重要性。     

二倍体小麦种间气孔与光合特征差异

选取5个二倍体小麦种为实验材料,利用数码图像显微镜处理系统、气体交换参数测定系统和叶绿素荧光动力学参数测定系统,研究了二倍体小麦种间气孔特征与光合特性的差异.结果表明,二倍体小麦种间气孔和光合特征存在较大的差异:其中S基因型(Ae.Sect.Sitopsis)的气孔长度、周长和面积最大,而其宽度、密度和气孔指数却是最小的;D基因型(Ae.Tauschii)的气孔宽度、密度和气孔指数最大,而其长度、周长和面积却是最小的;D基因型(Ae.Tauschii)的净光合速率最大,而S基因型(Ae.Sect.Sitopsis)的净光合速率最小.气孔周长与气孔面积呈显著正相关关系,而气孔密度与气孔面积呈显著负相关关系.二倍体小麦的净光合速率与气孔导度呈显著正相关关系,同时气孔限制值的变化趋势与细胞间隙CO2浓度的变化趋势相反,说明二倍体小麦的光合能力主要受气孔限制.在几个种中,乌拉尔图小麦(T.urartu)具有较高的净光合速率和气孔导度,同时细胞间隙CO2浓度最低,气孔限制值最大,在光合能力和耐光抑制方面有较明显的优势;而野生一粒小麦(T.boeoticum)则在光合能力和耐光抑制方面不存在优势.同时,乌拉尔图小麦(T.urartu)的叶绿素含量最高,而野生一粒小麦(T.boeoticum)最低,叶绿素含量可能也是造成二倍体种间光合能力差异的原因之一.     

几种虫生真菌菌株的培养性状及其对褐飞虱的毒力

从褐飞虱Nilaparvata lugens (St(a)l)罹病虫体上新分离出的一种黄绿绿僵菌菌株Metarhizium flavoviride (Mf82),与实验室保存的黄绿绿僵菌、金龟于绿僵菌和白僵菌3种菌种5个菌株作为对比,研究了在SDAY和PDA培养基上的培养性状,并测定了它们对褐飞虱成虫的毒力.结果表明:...