滇中退化山地不同植被恢复下土壤碳氮磷储量与生态化学计量特征

植被恢复对土壤营养元素的存赋及其生态化学计量特征的影响广受关注,为了深入了解不同植被恢复类型下土壤碳、氮、磷储量与生态化学计量特征,选择滇中地区退化山地飒马场流域具有代表性的4种不同修复阶段的典型植被(荒坡灌草丛、云南松林、针阔混交林和次生常绿阔叶林)为研究对象,分析了不同植被类型下不同深度土壤中有机碳(SOC)、全氮(TN)、全磷(TP)储量和化学计量变化特征。结果表明,退化山地的植被恢复显著改变土壤碳氮磷储存能力和化学计量比,这种改变作用整体上随土壤深度增加而降低。其中,在0—60 cm土层上,SOC储量在次生常绿阔叶林最高,达123.41 t/hm~2,其次是针阔混交林(115.69 t/hm~2)和云南松林(93.08 t/hm~2),荒坡灌草丛(89.56 t/hm~2)最低;TN储量针阔混交林(4.91 t/hm~2)次生常绿阔叶林(4.58 t/hm~2)云南松林(4.43 t/hm~2)荒坡灌草丛(3.98 t/hm~2),4种植被类型间差异显著;TP储量云南松林最高(2.57 t/hm~2),次生常绿阔叶林(2.2 t/hm~2)最低;4种植被类型下土壤C/N介于15.77—30.18,C/P介于29.24—65.33,N/P介于1.28—2.68之间,在0—60 cm土层上均以次生常绿阔叶林最高。植被类型和土壤深度及其交互作用显著影响研究区的SOC、TN和TP储量和化学计量比。分析认为,退化山地不同植被类型对土壤碳氮磷储量和化学计量的影响过程复杂,修复演替进入到次生常绿阔叶林阶段土壤理化性质显著提升,该地区植被修复主要受到氮的限制。研究表征了滇中退化环境植被恢复过程中土壤主要元素变化特征,为揭示植被恢复与土壤生态功能演变关系提供数据支持。     

林隙大小对不同林型天然红松混交林土壤有机碳和全氮的影响

在天然红松混交林3种不同林型(椴树红松混交林(TP)、云冷杉红松混交林(PAP)、枫桦红松混交林(BP))内,各选取小、中、大3个林隙,并分别以各自的郁闭林分作为对照,分析了2012年6—9月各林型不同大小林隙及其郁闭林分0~10 cm的土壤有机碳(SOC)和全氮(TN)含量,旨在阐明林隙大小对不同类型天然红松混交林土壤有机碳和全氮变化的影响,从而为小兴安岭林区天然红松混交林林隙更新和森林可持续经营提供基础数据。结果表明:在3种天然红松混交林内,林隙大小对SOC含量影响不显著;仅在PAP内,林隙大小对TN含量影响显著,在其他林型内均不显著;SOC、TN含量在3种林型内均呈现随月份不同差异显著的趋势(P0.05),而且相同月份不同林型之间的SOC和TN含量均差异显著(P0.05);PAP和BP林隙内SOC含量表现为大林隙小林隙中林隙,TN含量为大林隙中林隙小林隙,TP林隙内SOC、TN含量随林隙大小变化均为中林隙小林隙大林隙;SOC含量在3种林型内均表现为林隙内郁闭林分,TN含量在TP和BP内均为林隙内郁闭林分,PAP内却相反;SOC含量在不同林型林隙内的大小次序均为PAPTPBP,TN含量却为TPPAPBP;SOC、TN含量随月份变化大部分呈现单峰型曲线,在7或8月达到峰值,PAP林隙内TN含量在9月达到峰值;土壤碳氮比(C/N)在3个林型内不同大小林隙及郁闭林分之间均没有显著差异(P0.05)。     

川西北高寒沙地不同生态治理模式下土壤碳氮磷储量及生态化学计量特征

选取单植牧草、单植灌木、灌草间作、灌药间作4种生态模式治理5年后的川西北高寒沙地为研究对象,以未治理裸沙地为对照,分析了土壤碳氮磷含量及生态化学计量比特征。结果表明: 生态治理能显著提升土壤有机碳(SOC)、总氮(TN)、总磷(TP)含量和储量以及C/N、C/P、N/P,其中灌草间作提升效果最显著,其0～10和10～20 cm土层的SOC、TN含量均显著高于其他模式,且0～40 cm土层SOC储量分别比单植牧草、单植灌木、灌草间作、对照高13.4%、15.6%、17.1%、43.2%。0～10和10～20 cm土层土壤碱解氮、速效磷、速效钾、含水量与SOC、TN和TP含量呈显著正相关,土壤容重则与SOC、TN和TP含量呈显著负相关;土壤碱解氮、速效磷、速效钾和含水量与C/N、C/P在10～20 cm土层呈显著正相关。川西北高寒沙地土壤碳氮磷及其化学计量比受生态治理措施和土层深度的影响,本研究条件下灌草间作模式最有利于改善沙地土壤环境质量。     

秦岭典型林分土壤有机碳储量及碳氮垂直分布

以秦岭典型林分锐齿栎(马头滩林区)、油松、华山松、松栎混交林、云杉、锐齿栎(辛家山林区)为对象,研究了不同林分土壤剖面上有机碳、全氮、有机碳储量的分布规律。结果表明:在秦岭地区,随着土壤剖面深度增加,不同林分的土壤有机碳、全氮含量均逐渐降低;不同林分的土壤有机碳、氮素的积累和分解存在一定差异。其中,云杉和松栎混交林的土壤有机碳、全氮含量较高,锐齿栎(辛家山林区)含量较低,不同林分土壤剖面有机碳、全氮含量平均值分别为13.46—26.41 g/kg、4.47—9.51 g/kg,大小顺序均为云杉松栎混交林锐齿栎(马头滩林区)油松华山松锐齿栎(辛家山林区);各个林分的土壤C/N在5.93—15.47之间,C/N平均值大小为松栎混交林﹥华山松﹥油松﹥云杉﹥锐齿栎(辛家山林区)﹥锐齿栎(马头滩林区);各个林分0—60 cm土层的土壤有机碳储量大小为云杉锐齿栎(马头滩林区)松栎混交林华山松锐齿栎(辛家山林区)油松,分别为150.94、135.28、124.93、109.24、102.15、96.62 t/hm2;各个林分土壤有机碳含量与土壤全氮含量存在极显著正相关,土壤有机碳、全氮与C/N则没有明显相关性。     

中国南亚热带不同造林模式碳汇林土壤碳、氮、磷的积累及化学计量特征

碳汇林的固碳效益十分显著，是实现“碳中和”的主要碳增汇途径之一，在研究南亚热带地区不同造林模式碳汇林土壤碳汇的同时，研究碳汇林土壤氮、磷储量及土壤碳、氮、磷的生态化学计量特征，能够为不同造林模式碳汇林的土壤碳、氮、磷储量的评估提供科学依据。采取单因素随机区组设计，选择立地条件基本一致的研究区和4种造林模式(新造林、封山育林、补植套种、更新改造)的碳汇林，分析了不同造林模式土壤有机碳(SOC)、全氮(TN)、全磷(TP)的含量、储量、生态化学计量比，以及微生物生物量碳(MBC)的变化特征。结果表明，不同造林模式碳汇林的土壤理化性质，碳氮磷储量、化学计量比及微生物生物量碳含量差异显著，且土壤碳氮磷储量随土壤深度增加而减少，表现出明显的垂直变化特征。4种造林模式下碳氮比(C/N)介于11.11—17.86,碳磷比(C/P)介于17.00—242.59,氮磷比(N/P)介于1.18—15.99之间，在0—60 cm土层上均以更新改造模式林最低，封山育林模式下C/P和N/P均显著高于其他造林模式。土壤SOC与TN、N/P呈极显著正相关关系，土壤TN与C/P呈极显著正相关关系。综合来看，封山育林模...     

不同生态恢复模式对黄土残塬沟壑区深层土壤有机碳的影响

黄土高原退耕还林近20年来,大量生态恢复工程的实施,势必对土壤碳库产生影响。为评估生态恢复的土壤碳汇效益,本研究以黄土残塬沟壑区天然次生林、人工生态林和人工经济林等3种生态恢复模式为对象,研究其4 m土壤有机碳(SOC)储量。结果表明:(1)三种生态恢复模式具有明显的碳汇效益。天然次生林4 m SOC储量为(166.40±42.90) t/hm~2比坡中农地((58.73±4.73) t/hm~2显著增加了183.33%;人工生态林和人工经济林分别为(111.32±13.30) t/hm~2、(104.60±7.10) t/hm~2比坡中农地高89.54%、78.11%;(2)0—60 cm SOC含量随深度的增加显著降低(P0.05),由表层的(11.03±7.51) g/kg减少到(2.40±0.93) g/kg,降幅达78.22%,表现出明显的表聚性;60—400 cm SOC含量变化较为稳定,含量较低为(1.81±0.88) g/kg;(3)三种恢复模式深层(1—4 m)SOC储量与坡中农地相比分别提高109.43%、76.43%、65.06%;深层SOC储量天然次生林((77.81±8.40) t/hm~2)、人工生态林((65.55±7.71) t/hm~2)、人工经济林((61.32±3.16) t/hm~2)分别占4 m剖面有机碳储量的46.76%、58.89%、58.62%。结果表明天然次生林和人工混交林是黄土高原残塬沟壑区良好的生态恢复模式,且深层SOC在土壤碳库中不可忽视。     

河西走廊中段绿洲退化土地退耕种植苜蓿的固碳效应

土地利用变化和耕作管理是人类影响陆地生态系统碳过程一个重要方面.对河西走廊中段张掖绿洲退化土地退耕种植苜蓿5a后土壤性状的分析表明, 49个退耕苜蓿地土壤与相邻未退耕农田土壤配对样本的比较,退耕苜蓿地0～15cm土层土壤粒级组成和容重并未发生显著变化,但土壤pH平均提高了0.11个单位,电导率降低34.8%,土壤有机碳(SOC)和全氮(全N)含量较对照农田土壤平均提高18.5%和9.3%,活性有机碳(labile C)增加53.3%.SOC含量受海拔高度和土壤粒粉粒含量的影响,退耕后SOC和全N的增加幅度沙壤土高于粉壤土,而labile C的增加幅度沙壤土低于粉壤土.退耕苜蓿地0～15cm土层SOC和全N储量较农田土壤分别增加2.84Mg hm~(-2)和0.21Mg hm~(-2),土壤C、N的固存率平均为0.57Mg hm~(-2)a~(-1)和0.04 Mg hm~(-2)a~(-1),表明退化土地由1年生作物向多年生牧草的转变有显著的固碳效应和潜力.活性有机碳的变化较总有机碳的变化更为显著,表明活性有机碳对土地利用变化的响应更为敏感.     

内蒙古包头黄河湿地土壤碳氮磷含量及其生态化学计量学特征

为探究内蒙古包头黄河湿地土壤空间分布特征、生态化学计量学特征及其指示意义,以黄河包头段沿线从东到西的3种典型类型共6块湿地为研究对象,对其不同土层土壤碳(C)、氮(N)和磷(P)化学计量特征及环境因素进行研究分析。结果表明:1)SOC、TN和TP平均值分别为11.20、0.42、0.98 g/kg,SOC、TN含量随土层深度增加而垂直波动减小,TP含量垂直方向上差异不显著。2)土壤C/N、C/P、N/P平均值分别为25.39、9.26、0.37,与中国淋溶土、干旱土和沼泽湿地土壤相比,包头市黄河湿地土壤TN含量、C/P和N/P较低,TP含量较高。3)相关性分析结果显示,土壤TN与SOC、TP、N/P和C/P具极显著正相关(P0.01),与C/N相关性不显著;土壤TP与SOC、TN、C/N和C/P呈极显著正相关(P0.01),与N/P相关性不显著,TP含量高但有效性较低,TN含量及其有效性可能是限制包头黄河湿地土壤碳、氮、磷等元素循环及其生态化学计量特征的关键因子。研究结果将为包头黄河湿地的植被重建、生态修复和科学管理提供理论依据。     

马衔山不同海拔土壤碳、氮、磷含量及生态化学计量特征

研究半干旱地区土壤碳、氮、磷化学计量特征,了解其空间变化规律,有助于揭示半干旱地区C、N、P循环对全球气候变化的响应。本研究以半干旱区的马衔山为对象,选择5个海拔的7个样地,采集0～15、15～30 cm层的土壤,测定其有机碳(SOC)、全氮(TN)、全磷(TP)、pH、含水率等理化性质,分析其SOC、TN、TP化学计量与土壤理化因子之间的关系。结果表明:(1) 0～15 cm土壤SOC、TN、TP含量高于15～30 cm土壤。表层土壤SOC、TN含量随海拔升高呈增加趋势,TP含量随海拔升高变化较小。(2) C∶N随海拔增加呈先增加后降低趋势,C∶P、N∶P随海拔升高均呈增加趋势。(3)在0～15 cm土壤中,pH与SOC、TN含量及C∶P呈显著负相关,在15～30 cm土层中,pH与SOC、TN、TP含量及化学计量特征关系不显著;土壤含水率与0～15、15～30 cm层土壤中SOC、TN含量均呈极显著正相关。本研究显示,在半干旱区的马衔山地区,土壤含水率随海拔增加而增加,而SOC、TN含量及C∶P、N∶P也呈增加趋势,土壤养分含量及化学计量均受土壤含水率影响。     

红壤侵蚀地不同人工恢复林对土壤总有机碳和活性有机碳的影响

土壤有机碳尤其是活性有机碳可快速反映土壤肥力和土壤质量的恢复程度。研究了南方红壤侵蚀地3种典型人工恢复林(马尾松与阔叶复层林(Pinus massoniana-broadleaved multiple layer forest(PB))、木荷与马尾松混交林(Schima superba-Pinus massoniana mixed forest(SP))、阔叶混交林(broad-leaved mixed forest(BF)))土壤(0—60 cm)总有机碳和不同活性有机碳的垂直分布特征及其差异。结果表明:不同恢复林分土壤总有机碳(SOC)含量和有机碳储量均表现为PBSPBF,均随土层深度的增加而逐渐降低;土壤表层有机碳富集系数为0.49—0.55,表明表层土壤具有较高的有机碳恢复水平和保持强度。不同林分土壤易氧化有机碳(ROC)、水溶性有机碳(DOC)和微生物量碳(MBC)含量变化范围为0.92—9.17 g/kg、535.89—800.46 mg/kg和27.24—261.31 mg/kg,且均随土层深度的增加而降低,土壤活性有机碳含量总体以BF较高。土壤活性有机碳分配比例以ROC/SOC最高,DOC/SOC次之,MBC/SOC最低,且随土层深度的增加,ROC/SOC的值呈逐渐降低趋势,DOC/SOC的值却呈逐渐升高趋势,MBC/SOC(微生物熵)则变化规律不明显;不同林分间土壤活性有机碳分配比例以BF最高,表明阔叶混交林更有利于活性碳的积累。因此,对于红壤侵蚀地森林恢复初期,可适当密植和立体种植,以提高土壤碳储量和土壤肥力,并在马尾松等先锋树种林分中补植阔叶树种,以增加土壤活性有机碳含量,从而有利于退化生态系统土壤速效养分和土壤功能的快速恢复。     

Growth and physiological responses of Kandelia candel and Bruguiera gymnorrhiza to livestock wastewater

Growth and physiological responses of two mangrove species (Kandelia candel and Bruguiera gymnorrhiza) to livestock wastewater under two salinity conditions (seawater with salinity of 30þ and freshwater) were examined in greenhouse pot-cultivation systems for 144 days. Wastewater treatment significantly enhanced growth of Kandelia candel and Bruguiera gymnorrhiza in terms of stem height, stem basal diameter, leaf production, maximum unit leaf area and relative growth rate. Wastewater discharges and salinity levels did not significantly change biomass partitioning of Kandelia candel, however, more biomass of Bruguiera gymnorrhiza was allocated to leaf due to wastewater discharges. In Bruguiera gymnorrhiza, contents of chlorophyll a and chlorophyll b increased with wastewater discharges but such increase was not observed in Kandelia candel. On the other hand, livestock wastewater increased leaf electric conductance in Kandelia candel but not in Bruguiera gymnorrhiza. The peroxidase activity in stem and root of Kandelia candel under both salinity conditions increased due to wastewater discharges, while the activity in root of the treated Bruguiera gymnorrhiza seedlings decreased under freshwater condition but increased at seawater salinity. The superoxide dismutase activity in treated Bruguiera gymnorrhiza decreased but did not show any significant change in Kandelia candel receiving livestock wastewater.     

Soil salinity and pH in Japanese mangrove forests and growth of cultivated mangrove plants in different soil conditions

Soil conditions of mangrove forests in southern Japan were found to correlate largely with zonal distributions of the species.Kandelia candel grew in soils with low salinity and low pH,Avicennia marina, Rhizophora stylosa andSonneratia alba in soils with high salinity and high pH, andBruguiera gymnorrhiza in soil with a wide range of pH but limited range of salinity.Lumnitzera racemosa colonized soil with a wide range of pH and medium salinity. Seedlings ofKandelia candel, Bruguiera gymnorrhiza andRhizophora stylosa were planted in soils with differing salinity and pH. Optimum seedling growth ofKandelia, Bruguiera andRhizophora occurred when plants were cultivated in soils similar to those of their natural habitats, suggesting that growth of mangrove species and their zonal distributions were regulated by salinity and soil pH.     

Isolation and characterization of microsatellite loci in the red mangrove Rhizophora mangle (Rhizophoraceae) and its related species

Fourteen microsatellite markers were isolated from the red mangrove Rhizophora mangle (Rhizophoraceae), a widely distributed mangrove plant in the New World and West Africa. The range of expected heterozygosity of these markers was 0.000–0.672 in the two populations of R. mangle. Cross-species testing was examined for five other species of Rhizophora, and Kandelia candel and Bruguiera gymnorrhiza. All 14 markers could be amplified in R. samoensis, thirteen in R. racemosa, and six markers in all other species of Rhizophora. Our findings greatly increase the utility of these markers.     

Isolating high-quality RNA from mangroves without liquid nitrogen

Mangroves form unique communities in tropical coastal regions and tidal lowlands. Isolating RNA from mangrove leaves is difficult because of high amounts of secondary metabolites and polysaccharides. Conventional extraction methods produce poor-quality mangrove RNA. We present a simple, fast, and convenient protocol for isolating RNA from 5 mangrove species:Aegiceras corniculatum, Bruguiera gymnorrhiza, Ceriops tagal, Kandelia candel, andSonneratia apetala. Isolating RNA from other mangrove species is also possible. Obtained RNA was of high quality and used in an RT-PCR reaction that amplified 0.6 kb of theA. corniculatum CPI-1 gene.     

Chloroplast microsatellite markers for the mangrove tree species Bruguiera gymnorrhiza, Kandelia candel, and Rhizophora stylosa, and cross-amplification in other mangrove species

Chloroplast microsatellite (cpSSR) markers were developed for three ecologically and economically important tree species in the mangrove family, Rhizophoraceae: Bruguiera gymnorrhiza, Kandelia candel, and Rhizophora stylosa. Noncoding regions of chloroplast DNA (cpDNA) from each species were separately amplified using universal chloroplast primers. Six, two, and three polymorphic cpSSR loci in B. gymnorrhiza, K. candel, and R. stylosa, respectively, were developed from amplified noncoding cpDNA regions. Characterization of 216, 156, and 253 individuals of B. gymnorrhiza, K. candel, and R. stylosa, respectively, collected from different natural mangrove populations (B. gymnorrhiza, 9; K. candel, 7; R. stylosa, 9) on Iriomote Island in Japan showed that these loci provide cpSSR markers with polymorphisms ranging from two to four alleles per locus and gene diversity between 0.027 and 0.480. These cpSSR markers will be useful for analyzing the maternal lineage distributions and population genetic structures of the three species. Several of these markers may also be useful in similar studies of other mangrove species.     

不同生长光强下8种红树植物幼苗叶片的光响应特征

为探讨红树植物光适应的生理生态策略,对6种真红树植物[无瓣海桑(Sonneratia apetala)、秋茄(Kandelia candel)、木榄(Bruguiera gymnorrhiza)、桐花树(Aegiceras corniculatum)、老鼠簕(Acanthus ilicifolius)、卤蕨(Acrostichum aureum)]和2种半红树植物[银叶树(Heritiera littoralis)、黄槿(Hibiscus tiliaceus)]的1 a生幼苗在不同生长光强(自然光强的100%、45%、30%、10%)下的光合光响应特征进行了研究。结果表明,不同生长光强对红树植物光响应特征的影响因物种而异,遮荫显著提高了秋茄和木榄的最大净光合速率(Pmax),而对其他红树植物的Pmax没有显著影响;秋茄在45%光强下具有较高的Pmax,木榄的Pmax则在45%和30%光强下显著高于其他2个处理。随着生长光强的下降,秋茄幼苗叶片的光饱和点显著上升,木榄、老鼠簕和卤蕨的光补偿点呈下降趋势,木榄和卤蕨的表观量子效率升高的同时暗呼吸速率下降。木榄、老鼠簕和卤蕨具有较强的耐荫性,...     

无瓣海桑与乡土红树植物混交对林地大型底栖动物的影响

选择广东省雷州市附城镇和珠海市淇澳岛沿海1年生无瓣海桑人工林,分别在林下混种乡土红树植物红海榄或木榄幼苗,对混交林和无瓣海桑纯林林地大型底栖动物群落进行比较,探讨无瓣海桑与乡土红树植物混交对林地大型底栖动物的影响。结果显示,混交林和无瓣海桑纯林之间大型底栖动物群落的优势种存在差异;相似性分析检验(One-Way ANOSIM)、等级聚类和非参数多变量标序结果均表明1年无瓣海桑+红海榄混交林、1年无瓣海桑+木榄混交林和1年无瓣海桑纯林之间大型底栖动物群落结构差异显著。研究还发现在无瓣海桑人工林林下混交红海榄或木榄这两种乡土红树植物,可提高林地底栖动物的生物量和物种多样性。BIOENV分析说明大型底栖动物分布与红海榄或木榄这两种混交的乡土树种的凋落物量密切相关,这进一步证实了混交乡土红树植物对林地底栖动物多样性和分布的影响。两个研究地实验结果均显示,在无瓣海桑林下种植木榄的效果要优于红海榄,表现在木榄的平均苗高、凋落物量、凋落物量占群落凋落物总量百分比和幼苗成活率均高于红海榄,其对提高林地大型底栖动物生物量和物种多样性的效果也明显优于红海榄。     

Lipid composition of mangrove and its relevance to salt tolerance

Lipid compositions of mangrove trees were studied in relation to the salt-tolerance mechanism. Leaves and roots were obtained from seven mature mangrove trees on Iriomote Island, Okinawa: Bruguiera gymnorrhiza, Rhizophora stylosa, Kandelia candel, Lumnitzera racemosa, Avicennia marina, Pemphis acidula and Sonneratia alba. Lipids of mangrove leaves mainly consisted of 11 lipid classes: polar lipids, unknown (UK) 1–6, sterols, triacyl glycerols, wax ester and sterol ester (UK 3 and 4 were found to be tri-terpenoid alcohol in this study). Of these lipid classes, sterol ester was the main lipid in all species comprising 17.6–33.7% of total lipids. Analysis of the chemical structure found that the sterol esters mainly consisted of fatty acid esters of tri-terpenoid alcohols. One major tri-terpenoid alcohol was identified to be lupeol by interpretation of infrared resonance, nuclear magnetic resonance and mass spectrometry. Because of the unique anatomy of the mangrove root, lipid analyses were made separately for epidermis, cortex and innermost stele, respectively. The concentration of free tri-terpenoid alcohols showed a higher tendency in the outside part than in the inside portion of the roots, suggesting their protective roles. Relevance of lipid composition to salt tolerance was studied with propagules of K. candel and B. gymnorrhiza planted with varied salt concentrations. The proportions of free tri-terpenoids increased with salinity in both leaves and roots of K. candel, and only in roots of B. gymnorrhiza. No salt-dependent changes were noted in the phospholipid and fatty acid compositions in both species. These findings suggested that salt stress specifically modulated the terpenoid concentrations in mangroves. Electronic Publication     

五种红树植物叶片结构的比较研究

以木榄(Bruguiera gymnorrhiza)、桐花树(Aegiceras corniculatum)、拉关木(Laguncularia racemosa)、海芒果(Cerbera manghas)、杨叶肖槿(Thespesia populnea)五种红树植物为材料,采用常规石蜡切片法对它们的叶片横切面结构进行显微观察,比较真红树植物和半红树植物叶片结构的特点及变化规律,研究红树植物叶对盐浸环境的适应性。结果表明:除杨叶肖槿为异面叶、掌状网脉外;拉关木为等面叶、羽状脉,其它三种植物为异面叶、羽状网脉;五种材料具4级叶脉,3级、4级脉具明显维管束鞘。木榄、桐花树、拉关木、杨叶肖槿1级脉为半周韧无限维管束,海芒果1级脉为外韧无限维管束。五种材料叶肉具有分泌腔,除海芒果外,具有含晶体细胞;木榄、桐花树有内皮层,拉关木有贮水组织;桐花树、海芒果有含单宁细胞;桐花树、拉关木、杨叶肖槿有盐腺。这五种植物的叶片结构体现出不同植物对盐浸环境适应性的特征。相比较而言,真红树植物的特化结构较半红树植物多。     

Tannin Dynamics of Propagules and Leaves of Kandelia candel and Bruguiera gymnorrhiza in the Jiulong River Estuary, Fujian, China

Changes in the total phenolics, condensed tannins (CT), protein-precipitable phenolics content and protein precipitation capacity were determined on a series of mangrove leaves from two true viviparous mangrove species (Kandelia candel and Bruguiera gymnorrhiza) at various stages of development and decomposition in the Jiulong River Estuary, Fujian, China. Similar measurements were also done for the propagules at different developmental stages. The results showed that the total phenolics, extractable condensed tannins, total condensed tannins, protein-precipitable phenolics content and protein precipitation capacity in young leaves were higher than those in mature and senescent leaves. Tannin dynamics during leaf decomposition varied with species, and the rapid loss of phenolics observed during decomposition can be ascribed to leaching and degradation. Protein-bound CT and fibre-bound CT tended to increase with leaf decomposition, with CT binding more strongly to protein than to fibre. Protein-bound CT was higher than fibre-bound CT with the exception of mature leaves. Total phenolics, extractable CT and protein-precipitable phenolics contents in flower tissues were relatively lower than those in hypocotyls at different developmental stages. Protein precipitation capacity fluctuated with the development of propagules. Increases in nitrogen in decaying litter, and declines in contents of total phenolics and total condensed tannins of detritus support the general conclusion that decomposing mangrove detritus can be a more palatable heterotrophic substrate than living leaves.