马尾松-肉桂人工复层林生物量及生产力研究

应用相对生长法和样方收获法研究了广西岑溪市马尾松不同光环境处理下营造的马尾松-肉桂人工复层林的生物量及生产力.结果显示:(1)不同处理中,枯落物层生物量随林分郁闭度的增加而增加,灌木层、草本层生物量则随着林分郁闭度的增加而减少;马尾松-肉桂人工复层林模式下林分的生物量、生产力以及群落总生物量远大于马尾松单层林.(2)不同处理的马尾松-肉桂人工复层林林分净生产量均大于马尾松单层林,且上层林马尾松郁闭度在0.5～0.7条件下与肉桂形成的复层林更有利于提高环境资源的获取能力,其中以马尾松林分郁闭度为0.5、密度781株/hm2以及肉桂密度5 952株/hm2的人工复层林模式的成层性最明显,群落生物量、乔木层生物量、净生产力水平最高,分别达167.64 t/hm2、160.549 t/hm2、9.146 t/(hm2·a),且分别高于马尾松单层林14.9％、18.5％、68.7％,是经济效益和生态效益最理想的复合林模式.研究表明,光环境处理对群落生物量空间分布有显著影响,对林分各器官生物量的分配有较大影响,复层林能提高乔木层生物量在总群落生物量中的分配.人工复层混交林比单层林更有利于提高获取环境资源的能力并增加林分的稳定性.     

桂林岩溶石山阴香种群结构的研究

探讨了桂林岩溶石山阴香种群的高度、胸径和冠幅结构以及三者间的相互关系,并采用分异指数量化了种群个体间高度、胸围和冠幅结构的差异程度。结果表明:阴香种群个体高度集中分布在2-8m;胸径集中分布在2-6cm;冠幅多集中分布在1-4m,少数分布在5-7m之间;阴香种群个体的高度、胸围和冠幅多数为中等分异;阴香种群以幼树和小树个体占多数,自然更新能力较好,处于稳定的增长状态,这将有利于增加种群结构的复杂性和稳定性。     

南京中山植物园鸟类对香樟 果实（种子）的取食

香樟(Cinnamomum camphora)是亚热带地区广泛分布的常绿阔叶树种,其果实数量多、果期长,可为鸟类提供大量食物资源。2018年11月至2019年2月,借助Safari 10×26变焦双筒望远镜,采用焦点扫描法对南京中山植物园内访问香樟果实(种子)的鸟类行为进行观察,详细记录鸟类的种类、取食基质、取食次数、取食时间、取食数量和取食方式等信息。研究期间有效记录达48d,累计记录到27种鸟类1021次取食香樟果实(种子)行为,存在2种取食基质(地面和树上)和3种取食方式(整吞果实、啄食果肉和取食种子)。T检验显示,不同鸟类对香樟果实(种子)的取食次数存在显著差异(t=3.096,df=26,P 0.01);不同月份间鸟类对香樟香樟果实(种子)的平均访问只数、平均取食次数、平均取食时间和取食数量均存在极显著差异(P0.001)。白头鹎(Pycnonotussinensis)、乌鸫(Turdusmendarinus)和灰喜鹊(Cyanopicacyanus)是访问次数及取食量最多的3种鸟类。单因素方差分析(One-way ANOVA)表明,上述这3种鸟类的取食数量存在极显著差异(F3, 598=25.219,P 0.001)。按照时间统计,11月份访问的鸟类种类和数量最多,1月份鸟类的取食次数、时间和数量最多。鸟类的形态特征(体重、体长和嘴峰长)与取食数量呈显著正相关,其中,体重和体长对取食数量的影响比嘴峰长的影响更显著,但嘴峰长影响鸟类对果实的取食方式。在鸟类常活动和停歇的树木下方地面往往散落着较多表面洁净、无果肉包裹的香樟种子,且园内人工林和自然更新林地可见许多香樟幼苗,表明鸟类对香樟具有潜在传播作用。     

Morpho-molecular analysis as a prognostic model for repulsive feedback of the medicinal plant “Andrographis paniculata” to allogamy

Andrographis paniculata Nees. (AP) is a self-pollinated medicinal herb with a wide range of pharmaceutical properties, facing a low diversity in Malaysia. Cross-pollination of AP accessions leads to considerable rates of heterosis in the agro-morphological characteristics and anticancer phytochemicals of this eminent medicinal herb. However, the poor crossability of the plant at the interpopulation or intraspecific levels is an obstacle from the evolutionary and breeding points of view as an average of 4.56% crossability was recorded for AP in this study. Hence, this research aimed to elicit the impact of parental genetic distances (GDs) on the rate of crossability of AP using seven accessions in 21 possible cross combinations. To this end, a set of 55 randomly amplified polymorphic DNA (RAPD) primers and a total of 13 agro-morphological markers were employed to test the hypothesis. Twenty-two out of the 55 RAPD primers amplified a total of 257 bands of which 107 bands were found to be polymorphic. The principal component analysis (PCA) based on the RAPD markers revealed that the studied AP accessions were distributed to three distinct groups. Furthermore, it was noticed that even a minor increase in GD between two parents can cause a decline in their crossability. Unlike, the morphological-based GDs acted neutrally to crossability. This finding suggests that, despite the low genetic diversity among the Malaysian APs, a population prescreening using RAPD markers would be useful to enhance the rate of fruit set through selecting the genetically adjacent parents.     

不同化学型樟树叶挥发性成分组成的多变量分析

为明确不同化学型樟树(Cinnamomum camphora)叶挥发性成分的异同,以5种不同樟树叶的25个样本为实验材料,采用静态顶空-气相色谱-质谱联用法(SHS-GC-MS)研究了其挥发性成分组成,并运用主成分分析(PCA)、聚类分析(CA)和判别分析(DA)等对不同化学型樟树叶挥发性成分组成进行了多变量分析。研究结果表明,不同化学型樟树叶的挥发性成分共有8种:β-芳樟醇、莰烯、β-愈创木烯、γ-松油烯、α-侧柏烯、2-乙基呋喃、α-石竹烯和大牛儿烯;不同化学型樟树叶的挥发性化合物种类和含量存在显著差异。检测出的平均化合物数量分别为52(异樟)、40(脑樟)、37(油樟)、34(芳樟)和33(龙脑樟)。主成分分析提取了3个主成分因子,累计贡献率达到86.40%。聚类分析和判别分析结果表明,其中的12种挥发性成分能够对5种化学型樟树进行较好的区分,准确率分别为96%和100%。实验结果说明,这12种挥发性成分可以较好地用于樟树化学型分类。     

香樟凋落叶分解物对辣椒生长发育的影响

采用盆栽试验,研究了香樟(Cinnamomum camphora)凋落叶(0、25、50、75、100g凋落叶分别与10kg土壤混合)分解过程中对辣椒(Capsicum annuum)及其子代生长发育的影响,并采用气质联用(GC-MS)技术对凋落叶分解前后的萜类物质进行了检测和对比。结果显示:(1)香樟凋落叶分解物显著地抑制了辣椒的叶片数量、整株叶面积以及株高和基径生长,抑制效应随凋落叶剂量的增大而增强,而分解过的凋落叶和塑料片替代凋落叶原样的试验并不抑制辣椒的生长。(2)观察期内(处理45~76d),辣椒的现蕾数、开花数和结实数在各凋落叶处理下均明显低于同期对照;采用指数方程拟合的现蕾、开花和结实动态显示,25g凋落叶处理使辣椒的始蕾期、始花期和始果期分别推迟了0.81、0.17和1.35d,50g处理使这3项参数分别推迟了4.69、5.78和6.27d,而75g和100g处理均使这3项参数推迟10d以上。(3)辣椒的单株果实产量在凋落叶处理下降低29.44%~61.29%,而单果重受到的影响相对较小。(4)辣椒产出的种子千粒重和子代的生长状况并未受到凋落叶分解物的影响。(5)凋落叶的正己烷提取物中萜类占78.05%,而分解后其相对总量下降至40.76%,峰面积下降至原样的约1%。研究认为:香樟凋落叶添加处理对辣椒营养生长和生殖生长产生的明显抑制作用,不是由凋落叶添加对土壤通气透水性或对受体生长造成机械阻隔引起的,其在分解过程中释放樟脑(Camphor)、1,8-桉叶油醇(1,8-cineole)等萜类物质引起化感作用可能才是关键原因。     

二氧化氮对樟树幼苗生长及光合作用的影响

采用开顶式人工熏气装置,对1年生樟树幼苗进行了为期2个月不同体积分数NO₂(0.1、0.5和4.0 μl·L^-1)熏气试验,研究其对幼苗生长及光合作用的影响.结果表明:0.5和0.1 μl·L^-1 NO₂处理促进了樟树幼苗生长,而4.0 μl·L^-1 NO₂处理则抑制其生长.各处理樟树幼苗叶片净光合速率(P_n)日变化呈不对称的双峰型曲线,存在光合“午休”现象;在光合日进程中,0.5 μl·L^-1 NO₂处理使叶片P_n提高,最大值达8.542 μmol CO₂·m^-2s^-1,4.0 μl·L^-1NO₂处理的大多数时段使P_n降低,而0.1 μl·L^-1 NO₂处理对P_n的影响则依时段而不同;0.5和4.0 μl·L^-1 NO₂处理提高了叶片气孔导度(G_s)和胞间CO₂浓度(C_i)的最大值和最小值,0.1 μl·L^-1 NO₂处理提高了C_i的最大值和最小值,降低了G_s的最大值和最小值.熏气处理中、后期,0.5μl·L^-1 NO₂处理叶片的日均净光合速率显著高于其他处理.在熏气处理前期,0.5和4.0 μl·L^-1 NO₂处理使叶片最大PSⅡ的光能转换效率(F_v/F_m)显著下降;在熏气处理后期,4.0 μl·L^-1 NO₂处理的叶片F_v/F_m仍显著低于对照.     

Platelet-activating factor (PAF) receptor-binding antagonist activity of Malaysian medicinal plants

Forty-nine methanol extracts of 37 species of Malaysian medicinal plants were investigated for their inhibitory effects on platelet-activating factor (PAF) binding to rabbit platelets, using 3H-PAF as a ligand. Among them, the extracts of six Zingiberaceae species (Alpinia galanga Swartz., Boesenbergia pandurata Roxb., Curcuma ochorrhiza Val., C. aeruginosa Roxb., Zingiber officinale Rosc. and Z. zerumbet Koenig.), two Cinnamomum species (C. altissimum Kosterm. and C. pubescens Kochummen.), Goniothalamus malayanus Hook. f. Momordica charantia Linn. and Piper aduncum L. are potential sources of new PAF antagonists, as they showed significant inhibitory effects with IC50 values ranging from 1.2 to 18.4 microg ml(-1).     

Aggregated seed dispersal by wreathed hornbills at a roost site in a moist evergreen forest of Thailand

Hornbills (Bucerotidae) are widely regarded as important seed dispersers in tropical forests in Africa and Asia. We investigated how the roosting behavior of wreathed hornbills (Aceros undulatus) influences seed deposition and seedling survival at a roost site in a moist evergreen forest of Khao Yai National Park, Thailand. Fallen fruits and seeds were collected in traps that were placed around a roosting site for 14 months, and seedlings were monitored in adjacent quadrats for 3 years. Seedfall and seedlings of species represented in the hornbill diet occurred at significantly higher densities in the traps and quadrats located beneath the crown of the roosting tree than in those located beyond the crown. With the exception of Cinnamomum subavenium, the seeds and seedlings of most diet species rarely survived beyond the first year. The quality of hornbill dispersal to this roosting site may be poor due to the highly concentrated seedfall, which results in high seed and seedling mortality. However, the number of seeds deposited by each hornbill each day at roosting sites is relatively low. Wreathed hornbills are primarily scatter dispersers during the day and probably serve as agents of seed dispersal in the moist evergreen forest of Khao Yai.     

不同栽培技术对芳香樟穗条产量的影响

为营建芳香樟高产采穗圃,提供优质穗条,对采穗圃采取截干、施肥试验,分析不同栽培技术对穗条产量和质量的影响。结果表明,截干高度以低台式修剪的穗条产量最高,且穗条短粗,质量较好,而中柱式效果次之,高柱式效果最差;截干时间以7月或3月初效果较好,5月中旬最差;施肥时间以3月和8月各施肥1次效果最佳。