热岛效应下亚热带城市植被叶气孔权衡特征及其与叶功能性状的关系

叶片气孔不仅是植物平衡光合-蒸腾关系的重要门户,也是影响大气碳循环与水循环的关键结构。分析热岛效应下福州市乔木、灌木、草本3种生活型和常绿、落叶2种叶习性植物的气孔性状间的差异及其与其他叶功能性状间的权衡关系有助于探究不同类型植物在热环境下的适应策略。以福州市区的自然和半自然植被为研究对象,测定441个植物样本的气孔特征、化学计量特征和形态特征,结果表明：（1）3种生活型、2种叶习性植物的气孔长度（SL）、气孔密度（SD）差异显著（P<0.05）,潜在气孔导度指数（PCI）不存在显著差异（P>0.05）。草本的SL高于灌木和乔木,乔木的SD最高,灌木次之,草本最低;落叶植物的SL高于常绿植物,SD低于常绿植物。（2）SL与SD间的权衡关系稳定存在于3种生活型和2种叶习性植物中,且随着不同生活型和落叶习性植物的生态策略而呈现各异的权衡特征,即当SL一定时,乔木的SD最大,灌木的SD最小,常绿植物的SD大于落叶植物。（3）气孔性状和叶片形态、化学计量特征紧密联系,SL与比叶面积（SLA）正相关（P<0.01）,与叶面积（LA）负相关（P<0.01）;SD与叶氮含量（LNC）、叶磷含量（LPC）、SLA负相关（P<0.01）,与LA正相关（P<0.01）;PCI与LNC、SLA负相关（P<0.01）,与叶厚度（LT）正相关（P<0.05）。（4）复杂的环境是气孔性状变异的重要驱动因素,SL、PCI均与年均温（MAT）负相关（P<0.05）。     

西安4种落叶乔木物候期对气候变化的响应

以西安1979—2018年的气候资料和植物物候观测资料为基础,采用分段回归和趋势倾向率等方法,分析了毛白杨(Populus tomentosa)、杜梨(Pyrus betulifolia)、七叶树(Aesculus chinensis)和灯台树(Bothrocaryum controversum)4种落叶乔木展叶盛期和叶全变色期的生长趋势,使用偏相关分析探讨了气温、降水和日照时数与物候期的关系并通过偏最小二乘回归(Partial Least Squares, PLS)判断气候变量对物候期的综合影响。结果表明：(1)1979—2018年,4种乔木的生长季长度延长,整体表现为春季物候期提前,秋季物候期推迟;(2)展叶盛期物候指标与叶全变色期物候指标,转折均发生在1982年;转折后,物候特征变化显著,春季物候的提前速率和秋季物候的推迟速率加快,展叶盛期平均提前3.8d/10a,叶全变色期平均推迟4.7d/10a;(3)展叶盛期与春季气温表现为极显著负相关,叶变色期与秋季气温表现为显著正相关;降水对植物物候的影响不显著;春季物候与日照时数呈现极显著负相关关系,秋季物候期与日照时数呈不显著正相关...     

放牧管理模式对高原鼢鼠(Eospalax baileyi)鼠丘形态特征的影响

为明晰放牧对高原鼢鼠（Eospalax baileyi）造丘活动的影响,于2019年5月、8月和10月分别对禁牧（No grazing,NG）、生长季休牧（Rest grazing in growing season,RG）、传统放牧（Traditional grazing,TG）和连续放牧（Continuous grazing,CG）4种放牧管理模式样地下高原鼢鼠的新鼠丘（2个月内形成）半径、高度、表面积和体积等进行测定,并分析其表面积、体积与土壤和植被生物量间的关系。结果发现：放牧管理模式显著影响了高原鼢鼠鼠丘形态特征,且具有季节性差异。NG下鼠丘的半径、表面积和体积最大,而CG下鼠丘的体积和表面积显著变小（P<0.05）,在8月和10月,鼠丘半径在CG样地显著小于其他3种放牧模式样地（P<0.05）;8月TG下鼠丘高度最高,而5月和10月NG下鼠丘高度最高,鼠丘高度在CG样地显著小于NG样地（P<0.05）。冗余分析2个排序轴几乎全部解释了土壤因子及地下生物量与鼠丘特征之间的关系,但各放牧管理模式下影响因子不同,NG样地的土壤容重（P<0.05）、土壤紧实度（P<0.01）和莎草科植物的地上生物量（P<0.01）,RG样地的地下生物量（P<0.01）、土壤紧实度（P<0.01）和豆科植物的地上生物量（P<0.01）,TG样地的禾本科和豆科植物的地上生物量（P<0.01）,CG样地的土壤水分、地下生生物量、土壤紧实度（P<0.05）和莎草科植物的地上生物量（P<0.01）均显著影响了鼠丘的形态特征。可见,放牧会影响高原鼢鼠的鼠丘形态特征,进而对草地的演替产生不同的影响。     

槭叶铁线莲(Clematis acerifolia Maxim.)群落物种生态位研究

槭叶铁线莲（Clematis acerifolia）为太行山特有植物,但数量稀少且分布零散,其生存状况受到学者和政府部门的高度关注。本文通过对河北省易县葫芦峪沟谷新发现的槭叶铁线莲群落的典型样地调查,以物种重要值作为生态位计量指标,对各物种生态位宽度、生态位重叠和生态位相似性进行了定量分析,对槭叶铁线莲的生存安全状况进行了评估。结果表明：在调查样地中共记录到14科15属17种植物,群落物种组成较为简单,槭叶铁线莲在大部分调查样地中的重要值最大,占据优势地位,其他物种重要值相对较低;群落内所有物种中,槭叶铁线莲的生态位宽度最大（B_i=6.264）,绒毛绣线菊（Spiraea dasyantha）次之（B_i=5.144）,其他种类较小;所有物种组成的136个种对中,生态位完全重叠（Q_ik=1）、重叠程度较高（0.5≤Q_ik<1）和重叠程度较低（Q_ik<0.5）的种对比例分别为8.09%、16.91%和75.00%,生态位完全相似（C_ik=1）、相似程度较高（0.5≤C_ik<1）和相似程度较低（C_ik<0.5）的种对比例分别为8.09%、5.88%和86.03%,大部分物种之间生态位重叠程度和相似性都处于较低水平;槭叶铁线莲与其他物种构成的16个种对中,62.50%的种对生态位重叠程度较低（Q_ik<0.5）,81.25%的种对生态位相似性程度较低（C_ik<0.5）,反映出群落内各物种间对资源和空间的竞争较为温和,群落较为稳定,槭叶铁线莲在其分布生境中生存状况相对安全;本文研究表明,利用生态位分析方法可以作为珍稀濒危物种生存状态和安全风险评估的一种方法。     

半干旱草地不同植物枯落物分解对放牧和封育的响应

为探究放牧和封育对半干旱草地植物枯落物分解的影响,选取赖草、牛枝子及其混合物为研究对象,调查了不同网孔分解袋中宁夏半干旱草地植物枯落物分解特征及对放牧和封育的响应规律。结果表明：（1）放牧样地250目网孔中,枯落物质量残留率表现为牛枝子显著高于赖草和混合物（P<0.05）,而在放牧样地30目网孔、封育样地2种网孔中,枯落物质量残留率均表现为3种枯落物间无显著差异。（2）250目网孔中,放牧和封育样地枯落物分解衰减常数均表现为混合物显著高于牛枝子,而赖草居中;并且,牛枝子枯落物分解衰减常数表现为封育样地显著高于放牧样地。30目网孔中,放牧和封育样地枯落物分解衰减常数均表现为赖草、混合物显著高于牛枝子（P<0.05）;并且,牛枝子枯落物分解衰减常数表现为封育样地显著高于放牧样地（P<0.05）。（3）在放牧样地,仅牛枝子枯落物R_m表现为30目显著低于250目网孔（P<0.05）,k表现为30目显著高于250目网孔（P<0.05）;土壤动物对枯落物分解的贡献率表现为混合物显著低于牛枝子,赖草居中（P<0.05）。而在封育样地,仅牛枝子枯落物k表现为30目显著高于250目网孔（P<0.05）;土壤动物对枯落物分解的贡献率表现为混合物和牛枝子均显著高于赖草,且混合枯落物的土壤动物贡献率表现为封育样地显著高于放牧样地（P<0.05）。（4）枯落物残留率与其初始N、P、木质素/N、C/P呈显著相关性（P<0.05）;枯落物分解衰减常数与其初始N、P、木质素、N/P、C/P和木质素/P间均呈显著相关性（P<0.05）。研究表明,植物种类组成显著影响枯落物的残留率和分解衰减常数。放牧与封育管理通过影响网孔中土壤动物分布来调控半干旱区草地植物枯落物的分解,而且封育管理更有利于促进土壤动物对低质量枯落物（牛枝子）的分解。     

崆峒山国家级风景名胜区野生植物群落特征研究

采用样地调查的方法对崆峒山国家级风景名胜区野生植物群落进行野外调查，共布设26个20 m×20 m的标准样地，共调查野生维管植物86科230属323种。对植物群落外貌分析发现，研究区野生群落的外貌结构层次清晰，其中高位芽占比达到43.34%，地面芽植物占比23.30%，地上芽植物和一年生植物分别占比为18.58%和8.98%，地下芽植物最少，仅有5.80%；主要以纸质4级中型叶的中高位芽植物和草质3级小型叶的地面芽植物为主，反映出半湿润暖温带气候区所具有的谱系特征。野生植物群落在垂直结构上，乔木层以青榨槭（Acer davidii）、鹅耳枥（Carpinus turczaninowii）、少脉椴（Tilia paucicostata）、毛桃（Prunus davidiana）等为主要的优势种；灌木层以箭竹（Fargesia nitida）、毛叶欧李（Cerasus dictyoneura）、栓翅卫矛（Euonymus phellomanus）分布密集，为主要的优势种；草本层中除了有较多的蕨类草本植物外，其优势种主要有地丁草（Corydalis bungeana）、委陵菜（Potentilla chinensis）等。在径级结构分析中，径级分布比较规整，随着径级等级的增加从Ⅰ至Ⅴ，植株数整体呈急剧下降的趋势。采用Margalef丰富度、Shannon-Wiener多样性、Simpson优势度和Pielou均匀度指数对崆峒山国家级风景名胜区典型野生植物群落进行分析，不同的野生群落物种多样性存在明显差异，但四个指数在群落层次的变化趋势中均表现为乔木层>灌木层>草本层。     

祁连山青海云杉物候对水热驱动的响应

祁连山是西北地区重要的生态屏障,青海云杉是祁连山中段森林生态系统的主要乔木建群种,对维系祁连山生态安全有着重要战略意义。物候是森林响应环境变化的指示器,准确分析流域尺度上森林对气候变化的物候响应是研究全球变化对生态系统影响的关键,也是当前环境变化条件下评价森林生态系统养分、水分、能量以及碳循环等的关键。对林木物候与气候的关系进行深入研究、精确分析,可以为准确描述森林的结构、功能和生态水文过程提供科学依据,也可为水源涵养林可持续经营提供理论指导。对青海云杉展叶和球果成熟物进行了连续两年（2015-2016年）观测,分析了青海云杉展叶和球果成熟物候变化动态,研究了它们与空气温度、降雨、土壤温度以及土壤含水量的关系,得到以下结论：研究区海拔2700m处2016年平均气温比2015年升高了0.37℃,2016年青海云杉展叶期开始日期比2015年提前了3d,2016年青海云杉球果成熟期开始日期比2015年提前了2d。积温增加是物候持续期增加的原因,积温达到一定值时,青海云杉的物候变化就会发生。青海云杉展叶期持续日数与上个月的降雨呈极显著正相关（P < 0.01）,球果成熟期持续日数与上个月的降雨呈极显著负相关（P < 0.01）,展叶期和球果成熟期持续日数都受上一月降雨的影响显著,降雨对青海云杉展叶期和球果成熟期物候的影响具有一定程度的滞后性。青海云杉展叶期持续日数与展叶期开始月的土壤温度极显著正相关（P < 0.01）,即土壤温度升高展叶物候持续期延长。球果成熟期持续日数与展叶期开始月的土壤温度极显著负相关（P < 0.01）,即土壤温度升高球果成熟期物候持续期缩短。青海云杉展叶期和球果成熟期物候都受上一月土壤含水量的影响显著,土壤含水量也对青海云杉展叶期物候和球果成熟期物候的影响具有一定程度的滞后性。     

中国青藓科植物分类学修订（一）：异叶藓属

在对世界异叶藓属（Kindbergia Ochyra）植物进行系统研究基础上,作者对中国分布的该属植物进行了分类学修订。结果表明：（1）中国分布的“树状异叶藓”［K.arbuscula(Broth.)Ochyra］、“异叶藓”［K.praelonga(Hedw.)Ochyra］和密枝燕尾藓［Bryhnia serricuspis(Müll Hal.)Y.F.Wang & R.L.Hu］为K.dumosa(Mitt.)Ignatov & Huttunen的错误鉴定;（2）因树状分枝的植物体、异形的茎枝叶、近及顶的强壮中肋和明显下延的叶基等特征不同于青藓科现存任一类群,故将中国分布的“异叶藓属”植物移入新建属——拟异叶藓属（Pseudokindbergia M.Li,Y.F.Wang,Ignatov & B.C.Tan）中;（3）拟异叶藓属区别于异叶藓属的主要形态特征为：假鳞毛半圆形至三角状半圆形,先端钝或平截;孢蒴倾立至水平;蒴盖圆锥形。（4）到目前为止,中国尚未发现异叶藓属植物的分布。     

内蒙古高原湖滨湿地优势植物功能性状特征及其适应性

受人类活动和气候变化的影响,湖泊湖滨带退化速度显著加快。植物功能性状的方法可以量化植物特征,预测植物对外界环境干扰的反应,有助于理解退化湖滨带湿地植物应对环境变化所表现出的适应机制,对湖泊湖滨湿地生态系统植被的恢复与重建具有重要意义。在内蒙古高原典型湖泊湖滨湿地选取芦苇（Phragmites australis）、赖草（Leymus secalinus）、毛茛（Ranunculus japonicus）、鹅绒委陵菜（Potentilla anserina）、碱蓬（Suaeda glauca）、盐角草（Salicornia europaea）和拂子茅（Calamagrostis epigeios）7种优势植物的叶片和根系作为研究对象,对不同湿地植物的11种功能性状变化规律及其与环境因子的关系进行研究。旨在探究环境变化影响下湖滨带湿地植物的物种分布和功能性状的差异,以及湿地植物在不同湖滨带湿地生境下的适应策略。在评估植物功能性状差异基础上,采用环境矩阵连接性状矩阵（RLQ）结合第四角分析（Fourth-Corner）的方法分析环境因子对植物功能性状的影响。结果表明,内蒙古湖滨带湿地中7种优势植物为了适应不同的环境的影响,植物的功能性状均产生不同程度的种间与种内变异,在湖滨带湿地中植物的植株高度、叶片碳含量、叶片氮含量、叶片碳氮比、比根长、根组织密度、根氮含量对环境变化的响应比较敏感,土壤pH与叶片干物质含量呈显著负相关;土壤盐分与植株高度、叶片碳含量和叶碳氮比显著负相关,与叶片氮含量、根组织密度显著正相关;土壤的总氮含量与植株高度显著正相关,与比根长显著负相关;土壤碳氮比与植株高度和叶片碳含量显著负相关,与植物比根长显著正相关;土壤容重与根氮含量显著负相关。研究表明内蒙古高原湖滨带湿地植物的功能性状受环境的作用强烈,植物采取了不同的性状策略来适应环境。     

亚热带常绿林不同冠层小枝叶面积-叶生物量关系研究

叶面积与叶生物量的关系对于理解植物叶片的碳收益和投资权衡策略具有重要意义。收益递减假说认为植物的叶面积与叶生物量成显著异速生长关系,其异速生长指数<1.0,但该假说是否适用于不同生活型（常绿与落叶）亚热带木本植物不同冠层高度（上下冠层）当年生小枝的叶片仍不清楚。以江西亚热带常绿阔叶林的69种常绿与落叶木本植物当年生小枝上的叶为研究对象,采用标准化主轴回归估计（standardized major axis estimation,SMA）方法检验不同冠层高度和生活型叶面积与叶生物量的异速生长关系。结果显示：（1）当年生小枝叶生物量在不同冠层高度和生活型的植物中无显著差异（P>0.05）,叶面积在常绿和落叶植物中有显著差异（P<0.05）,常绿和落叶植物的比叶重存在显著差异（P<0.05）,而落叶植物的比叶重在不同冠层高度存在显著差异（P<0.05）,同一冠层,常绿植物比叶重显著高于落叶植物（P<0.05）;（2）69种植物的叶面积与叶生物量异速生长指数具有物种特异性,60.9%的物种叶面积与叶生物量呈等速生长关系;（3）不同冠层和生活型植物的叶面积与叶生物量呈等速生长关系,但其异速生长常数在不同冠层高度与生活型间存在差异。这些结果表明冠层高度和生活型未改变叶面积-生物量之间的等速生长关系,不支持"收益递减"假说。     

澳门大潭山垃圾填埋场植物群落景观恢复的现状与评价

为了解澳门大潭山垃圾填埋场的景观恢复情况,采用样方法调查分析了群落的种类组成、垂直结构、区系成分、群落外貌等特征,并对景观恢复进行了评价。结果表明,在1200 m2样地中共有维管植物83种,区系成分以泛热带分布属占优势(38.98%),群落外貌主要由草质、单叶和小型叶的小、中高位芽植物所决定。植物群落现状的各指标与自然群落相似,说明自然恢复良好。同时,提出了垃圾填埋场景观恢复的优选物种和改造建议。建议对垃圾填埋场的景观恢复应分期进行,在不同的演替阶段进行适当的人工干预,以加速景观恢复并获得更好的景观效果。     

Mycorrhizal feedback is not associated with the outcome of competition in old‐field perennial plants

The symbiosis between plants and arbuscular mycorrhizal (AM) fungi is hypothesized to be an important contributor to plant–soil feedbacks, which can influence the outcome of inter‐specific competition. Mycorrhizal feedbacks can be conspecific, which affects individuals of the same species, or heterospecific, which affects individuals of a different species. When heterospecific feedbacks are more positive than conspecific feedbacks, heterospecific individuals are expected to outcompete conspecific individuals. To test this hypothesis, we quantified conspecific mycorrhizal feedback for Plantago lanceolata as a focal species, and heterospecific mycorrhizal feedbacks for 21 competitor old‐field species using mycorrhizae cultured with P. lanceolata. We quantified inter‐specific competition against the focal species by growing the 21 old‐field species with and without P. lanceolata in the presence of mycorrhizae cultured with P. lanceolata. Heterospecific and conspecific feedbacks were both positive, and average heterospecific feedbacks exceeded conspecific feedback by 75%. Competition suppressed P. lanceolata biomass by 14% and average competitor biomass was reduced by 44% in the presence of P. lanceolata, and these effects varied with competitor species identity. Contrary to predictions, the magnitude of heterospecific feedbacks did not predict the ability of competitor species to either suppress or resist suppression by P. lanceolata. Instead, the outcome of competition was significantly and positively correlated with intrinsic growth rate, measured as biomass of competitor species five weeks after germination in non‐inoculated conditions. Our findings suggest that species experiencing more positive mycorrhizal feedbacks than a competitor do not necessarily have a competitive advantage. Mycorrhizal mediated soil feedbacks may be less important than intrinsic differences in growth rate in determining competitive outcomes.     

Morphological and molecular identification of Colletotrichum siamense,a novel leaf pathogen associated with Sterculia lanceolata recorded in China

Sterculia lanceolata, an important tropical woody plant, has high ornamental and medicinal value. To our knowledge, only brown root disease in this plant has been reported. In Nanning, Guangxi, China, an outbreak of leaf blight disease was observed on S. lanceolata in June 2019, with the leaf infection rate ranging from 80% to 100%. The disease seriously affected the leaves of trees and caused economic loss. Eight isolates were recovered from the infected leaves of different trees, and the pathogenicity was then determined by the methods of mycelial disc and conidial suspension, fulfilling Koch's postulates. According to the morphological and molecular biological characteristics of isolates, the pathogen causing leaf blight on S. lanceolata was identified as Colletotrichum siamense. Accurate identification of the pathogen provides a reliable basis for the control of the disease.     

尾叶桉林下5种植物的耐阴性、生物量及其个体消长

为了解尾叶桉林下不同植物种类的生理生态特性和生长适应性,在鹤山站尾叶桉林中选取分布较多且药用价值和经济价值较高的5种林下植物为研究对象,测定各植物的叶片特征、叶绿素含量和光合-光响应曲线,同时结合2006年和2011年尾叶桉林的样方调查数据分析了5种林下植物生物量的变化和个体数量的消长。结果表明:(1)野牡丹叶片的宽度、厚度、单片叶面积等指标最大,梅叶冬青最小,桃金娘、栀子和山苍子处于两者之间;桃金娘、野牡丹和山苍子的光合速率随光照的增强迅速增大,其光饱和点较高;梅叶冬青和栀子的光合速率也随光照的增强而增大,但其斜率比野牡丹和山苍子大,并很快就达到光饱和点。综合聚类分析植物的耐阴程度,5种植物可分为2类:第1类为耐阴性较强的梅叶冬青、栀子,第2类为耐阴性较弱的野牡丹、山苍子和桃金娘。(2)随着尾叶桉林的生长,5种林下植物的生物量都有不同程度的增加,其中增幅较大的是野牡丹和桃金娘分别增加74倍和18倍,增幅最小的是栀子仅1.3倍。野牡丹、桃金娘和山苍子这3个种生物量的增加主要是由个体高度和地径的增长引起,而栀子和梅叶冬青生物量的增加是其个体数量、株高和地径做出的贡献。(3)在尾叶桉林生长过程中,耐阴种类梅叶冬青随着个体密度、株高和地径的增长,其在林内发展成为主要优势灌木种类;栀子的密度虽然有一定的增大,但其株高和地径增加量小,生物量也小,发展为次要灌木种类。野牡丹、桃金娘和山苍子等3种的个体密度都在下降,虽然其地径、株高和生物量也有一定的增长,但其较强的阳生性不能适应林内的荫蔽环境,只适于林窗或林缘光照较强的地方生长。因此,在桉树林经营管理过程中应适当保护和种植梅叶冬青和栀子;在短轮伐期经营模式下,林窗和林缘也可适当保留野牡丹、桃金娘和山苍子。     

Phylogeographic Analyses Suggest Multiple Lineages of Crystallaria asprella (Percidae: Etheostominae)

The crystal darter, Crystallaria asprella, exists in geographically isolated populations that may be glacial relicts from its former, wide distribution in the Eastern U.S. An initial phylogeographic survey of C. asprella based upon the mitochondrial cytochrome b (cyt b) gene indicated that there were at least four distinct populations within the species: Ohio River basin, Upper Mississippi River, Gulf coast, and lower Mississippi River. In particular, the most divergent population was the most recently discovered, from the Elk River, WV, in the Ohio River basin, and it was postulated that this population represents an undescribed, potentially threatened species. However, differentiation observed at a single gene region is generally not considered sufficient evidence to establish taxonomic status. In the present study, nucleotide variation at the mitochondrial control region and a nuclear S7 ribosomal gene intron were compared to provide independent verification of phylogeographic results between individuals collected from the same five disjunct populations previously surveyed. Variation between populations at the control region was substantial (except between Gulf drainages) and was concordant with patterns of sequence divergence from cyt b. Only the Elk River population was resolved as monophyletic based upon nuclear S7, but significant differences based upon Φ_ST statistics were observed between most populations. Morphometric data were consistent with molecular data regarding the distinctiveness of the Elk River population. It is proposed that populations of C. asprella consist of at least four distinct population segments, and that the Elk River group likely constitutes a distinct species.     

Phenological patterns among plant life-forms in a subtropical forest in southern Brazil

Phenological patterns in tropical plants usually are associated with the clear seasonality of rainfall associated with very different wet and dry seasons. In southern Brazil, in a subtropical forest with no pronounced dry season (average annual precipitation = 1389 mm, minimum monthly average c. 75 mm), plant phenology was studied to test for patterns (periodicity), to examine how phenological patterns vary among life-forms, and to test whether phenological cycles are associated with climatic variables. Thirty-seven plant species in four life-forms (trees, shrubs, lianas and epiphytes) were studied for 2 yr (1996-98) in an Araucaria forest remnant in southern Brazil, in the state of Paraná. Correlation and multiple regression methods established relationships between phenology and climate in terms of daylength, temperature and rainfall. In this Araucaria forest, plants showed seasonality in most life-forms and phenological phases. Leaf-fall, with its peak during the drier months (April to July), was the most seasonal. Flushing and flowering occurred during the wetter months (September to December), while fruiting occurred all year long. Phenologies varied among life-forms, and were strongly associated with daylength or temperature of preceding months, suggesting that plants receive their phenological cues well in advance of their phenological response. Phenologies in this Araucaria forest appear to be associated with the most predictable and highly correlated of the climatic variables, daylength and temperature and least so with rainfall, which is unpredictable.     

Comparing the reproductive biological characteristics of the alien invasive Coreopsis lanceolata to those of the non-invasive alien congener Coreopsis tinctoria

It is important to determine the characteristics associated with the success of alien species. However, there is no universal syndrome of invasion reproductive characteristics to explain the success of invasiveness has not been identified. Comparative studies on congeneric successful or non-successful alien species are beneficial for revealing the drivers of invasion success and predicting future distributions. Reproductive biological characteristics, including the mating system, phenology of flowering, floral syndrome, pollination biology and seed germination have been investigated in the invasive Coreopsis lanceolata and non-successful congener alien species Coreopsis tinctoria. The results revealed that C. lanceolata significantly attracted insect visitors by 11.67 times more than its congener, and the corolla density of C. lanceolata was positively correlated with the number of visiting insects. The high attraction of local insect bees Apis cerana guarantees the reproductive success and high seed production of C. lanceolata. Nevertheless, there was no versatile mating system, because its congener non-successful alien species C. lanceolata still successfully invaded due to the combination strategies of self-compatibility and presence of rhizomes. Furthermore, the ability of seed germination of C. lanceolata was lower than that of C. tinctoria, especially under drought and Al³⁺ stress, suggesting that germination performance can serve as a reference indicator. However, this was not an absolute trait for invasiveness. Hence, these germination traits might slow down the invasiveness of C. lanceolata in south China. These present findings highlight that the combination of self-incompatibility and rhizomes should be given attention in the risk assessment protocols for plant invasiveness.     

近30年北京自然历的主要物候期、物候季节变化及归因

根据中国物候观测网资料并结合气象观测数据, 重新编制了北京颐和园地区1981-2010年的自然历。通过与原自然历比较, 揭示了北京物候季节变化特征, 分析了1963年以来物候季节变化的可能原因。研究发现: 与原自然历相比, 1981-2010年北京的春、夏季开始时间分别提前了2天和5天, 秋、冬季开始时间分别推迟了1天和4天; 夏、秋季长度分别延长了6天和3天, 春、冬季长度则分别缩短了3天和6天; 各个物候期的平均日期、最早日期、最晚日期在春、夏季以提前为主, 在秋、冬季以推迟为主; 且春、秋、冬季节内部分物候期次序也出现了不同程度的变化。春、夏、冬季开始日期前的气温变化和秋季开始日期前的日照时数变化可能是北京颐和园地区物候季节变化的主要原因; 不同物种、不同物候期对气温变化的响应程度不同, 导致了物候季节内各种物候现象出现的先后顺序发生变化。     

Phenology of Dryopteris affinis ssp. affinis and Polystichum aculeatum: modeling relationships to the climatic variables in a Mediterranean area

The phenology of leaves and stages from immature sori to spore release were studied in natural populations of two perennial herbaceous ferns, Dryopteris affinis ssp. affinis and Polystichum aculeatum, for 2 years in Italy. The Generalized Additive Model for Location, Scale and Shape (GAMLSS) was used to predict a particular phenological event from the climatic variables. Both fern species are evergreen with leaf lifespan of 13–14 months in D. affinis ssp. affinis and 15–24 months in P. aculeatum. Their leaf production is seasonal with most flushed in spring. In D. affinis ssp. affinis the decaying of old leaves is sudden whereas in P. aculeatum it is gradual, and in both types the decaying is accelerated just as the new leaves emerge. Temperature is the best predictor for the development of sori and spore release. The end of spore release and leaf emergence are positively affected by temperature and negatively affected by rainfall and snow cover for P. aculeatum. An almost similar response to climatic factors of emergent and senescent leaves and their phenology supportsthe hypothesis that old leaves serve as nutrient storage organs for new leaf growth. Comparison the phenological patterns between the 2 years indicated that the time lapses between each phenological event were the same within seasons for D. affinis ssp. affinis but show some differences for P. aculeatum. We also hypothesize that endogenous factors may play an important role in the phenology of P. aculeatum.     

Restriction fragment length polymorphism and allozyme linkage map of Cuphea lanceolata

Summary Cuphea lanceolata Ait. has had a significant role in the domestication of Cuphea and is a useful experimental organism for investigating how medium-chain lipids are synthesized in developing seeds. To expand the genetics of this species, a linkage map of the C. lanceolata genome was constructed using five allozyme and 32 restriction-fragment-length-polymorphism (RFLP) marker loci. These loci were assigned to six linkage groups that correspond to the six chromosomes of this species. Map length is 288 cM. Levels of polymorphism were estimated for three inbred lines of C. lanceolata and an inbred line of C. viscosissima using 84 random genomic clones and two restriction enzymes, EcoRI and HindIII. Of the probes 29% detected RFLPs between C. lanceolata and C. viscosissima lines. Crosses between these species can be exploited to expand the map.