Plant litter decomposition influenced by soil animals and disturbance in a subtropical rainforest of Taiwan

Soil fauna has been postulated as one of the paramount determinants of decomposition in the humid tropics. However, its effect on litter decomposition has only been demonstrated in few forest sites in Central America. In addition, landslide is a common disturbance associated with heavy rainfall brought by tropical cyclones in the tropics and can potentially alter abundance and structure of soil animals and thus affect litter decomposition. In this study, we examined the effect of soil animals on litter decomposition in an Asian subtropical monsoon forest and compared the animal effects in landslide-disturbed (2 years old) and undisturbed sites. Animal exclusion by naphthalene treatment significantly reduced the density and diversity of litterbag animals and slowed down the rate of decomposition in both landslide-disturbed and undisturbed sites. However, density (per unit area) and diversity of the litter animals and litter decomposition rate did not differ between the landslide-disturbed and undisturbed sites for both control and animal-excluded treatments. Our data suggest that the abundance of soil animals is not limited by litter mass. Furthermore, soil fauna recover quickly from landslides, and fauna's facilitative effect on litter decomposition is not altered after their recovery.     

植物生长调节剂（组合）对南方地区淮山药产量及品质的影响

为探索不同植物生长调节剂种类及浓度对南方地区淮山药生产的影响效果,以＂桂淮2号＂淮山药为供试品种,研究矮壮素（CCC）与羟季铵·萘合剂（氯化胆碱CC＋萘乙酸NAA）对南方地区淮山药产量及品质的影响。结果表明,喷施CCC2250mg·L^-1淮山药产量最高,达到33255.15kg·ha^-1,比对照及仅喷0.15%KH2PO4处理增产15.20%和13.22%;喷施CCC2250mg·L^-1有利于提高淮山药鲜薯的干物质含量,增加淮山药块茎干样的水溶性浸出物和醇溶性浸出物含量,促进了淮山药淀粉含量的提高,并同时能维持较高的蛋白质含量,而对可溶性总糖含量影响不显著,从而保证了其具有良好的食用品质和风味。     

Improvement of caper (Capparis spinosa L.) propagation using in vitro culture and gamma irradiation

Some of the factors influencing the propagation of caper (Capparis spinosa L.) plants in vitro and germination of the seed were studied. The number of adventitious shoots emerging from caper stems cultured in vitro increased from 2.2 shoots per explant when the growth medium contained 2 mg/L of gibberellic acid (GA3) to 5.5 when the growth medium contained 2 mg/L zeatin riboside (ZR) and 1 mg/L naphthalene acetic acid (NAA). The best medium for callus formation from leaf and stem parts contained the growth regulators 1 mg/L 6-benzylaminopurine (BAP) and 0.1 mg/L NAA and the best medium for plant regeneration contained 1 mg/L kinetin and 0.1 mg/L indole-3-acetic acid (IAA). The effect of gamma irradiation on the growth of caper shoots in vitro was also studied. A 10 Gy dose of gamma irradiation stimulated growth of shoots up to 200% and increased shoot rooting percentage from 75 to 100%.     

Naphthalene production by microorganisms associated with termites: Evidence from a microcosm experiment

There have been several reports published which suggest that it is possible that the polycyclic aromatic hydrocarbons (PAHs) naphthalene (NAPH), phenanthrene (PHEN) and perylene (PERY) in tropical environments have a biological source. This source might be related to the activity of termites or their associated microorganisms. We aimed to provide direct evidence for the biological production of NAPH, PHEN and PERY by conducting microcosm experiments in the State of Tocantins, Brazil, in which termite nests (with or without termites) were placed in an enclosed environment in which we controlled all PAH fluxes and monitored changes of PAH stocks. The experiments were carried out with termites from a tropical floodplain forest environment at the Estação Canguçu (Ilha do Bananal) in the State of Tocantins, Brazil. We set up the following treatments: live nest of Nasutitermes cf. minor using PAH-poor wood as food (LNW), live nest of Nasutitermes cf. minor using PAH-poor corn as food (LNC), termite nest without live termites called dead nest (DNC) and dead nest with additional treatment by a combined fungicide/bactericide (FDN) in several replicates. In LNW, LNC, and DNC, there were mean increases of 43%, 21%, and 46% in NAPH stock after 20 d while the stocks of the 20 other PAHs studied did not change or even decreased. In contrast, FDN lost 20% of the NAPH stock after 20 d of the microcosm experiment because of dissipation and lack of microbial synthesis of new NAPH. In LNW and LNC, low-molecular weight PAHs (acenaphthylene to chrysene) were significantly lost at a mean percentage which was strongly correlated with the octanol-water partitioning coefficient (K_OW, r = 0.78). This was not the case in DNC and FDN. There were no indications that in the studied termite nests PHEN and PERY were produced. Our microcosm experiments suggest that NAPH can be produced by fungi and bacteria in termite mounds while all other low-molecular weight PAHs are degraded in microcosms with live termite nests. PAH degradation seems to be enhanced by the combined activity of termites and microorganisms.     

萘在土壤上的吸附行为及温度影响的研究

采用批量平衡法研究了多环芳烃萘在塿土耕层土、塿土粘化层土、塿土古土壤、黄壤、紫色土和石灰土上的吸附行为,比较了不同吸附模型方程对实验数据的拟合情况,并探讨了温度对萘在土壤上吸附行为的影响机理及吸附热力学特征。Henry模型、Freundlich模型和deBoer-Zwikker极化模型均能较好地拟合萘的吸附等温线;45℃下的吸附等温线明显地高于25℃的吸附等温线,表现出随温度升高吸附量增大的趋势。Freundlich模型的吸附容量参数Kf和deBoer-Zwikker模型的起始吸附势ε0在两个温度下有极显著的差异;但Freundlich模型的n参数表征了土壤颗粒表面的性质,对温度变化不敏感。在25℃条件下,萘在土壤有机碳上的分配可能是吸附的主要机制,但随着温度增加,吸附机制变得复杂。土壤对萘的吸附是一吸热反应,整个吸附体系中熵增是吸附作用进行的主要驱动力。     

高产漆酶菌的筛选及对污水中萘降解的研究简

[目的]筛选出高产漆酶菌株,研究菌株产漆酶对污水中萘是否有降解能力.[方法]采取液体发酵法和气相色谱法.[结果]主要对21个隶属于担子菌的菌株进行了漆酶活性的比较.首先,平板培养进行比较,之后液体发酵的试验方法培养15 d后得到高酶活的菌株,漆酶酶活高（酶活达到1 000 U/ml以上）的菌株有3个,依次是香栓菌（Trametes suaveolens）、灰管层孔菌（Fomes lignosus）和彩绒革盖菌（Trametes versicolor）.进一步对香栓菌的漆酶性质进行研究,其最适pH为4.5,最适温度为35℃,最适碳源为乳糖,氮源为蛋白胨.通过对其中8种产漆酶菌株对污水中萘（含量）的降解处理,结果表明菌株香栓菌和硬毛栓菌（Trametea trogii）产生的漆酶对污水中的萘降解率均为100％,而一色齿毛菌（Cerrena unicolor）和烟管菌（黑管菌）（Bjerkandera adusta）对污水中的萘降解均能达到50％以上.[结论]得到3株产漆酶酶活较高的菌株.菌株产漆酶对污水中萘具有一定的降解能力.     

1,2,4-三氯苯和萘对水稻抽穗期叶片光合特性的影响

 研究了1,2,4-三氯苯(TCB)和萘（NAP）对抽穗期水稻叶片光合特性的影响。结果表明，随TCB和NAP胁迫浓度的增加，叶绿素含量、净光合速率（Pn）、气孔导度( Gs)、细胞间隙CO2浓度(Ci)、蒸腾速率(Tr)、原初光能转换效率( Fv/Fm) 、PSⅡ潜在活性（Fv/Fo）、光合电子传递量子效率(ΦPSII)、光化学猝灭系数(qP)、非光化学猝灭系数(qN) 均呈下降趋势；而且TCB对以上指标的影响明显大于NAP的影响，汕优63的敏感性要大于武运粳7号；有机污染胁迫下，光合速率下降的原因，在低浓度时主要由于气孔限制引起，而在较高浓度下由气孔限制和非气孔限制共同引起。较高浓度的有机污染物使光合作用受到明显抑制，最终导致水稻产量显著降低。在各叶绿素荧光动力学参数中，以PSⅡ潜在活性（Fv/Fo）和非光化学猝灭系数(qN)对有机污染胁迫最为敏感。建议将这两个参数作为衡量水稻发生有机污染伤害的参考指标。     

不同浓度NAA 溶液对嫁接黄瓜苗期形态及 生理指标的影响

以黄瓜断根嫁接苗为材料,对接穗蘸取5 种浓度的萘乙酸（NAA）溶液进行处理,通过测定
嫁接成活率、苗期形态指标、壮苗指标及根系活力等生理指标,研究了5 种浓度NAA 对断根嫁接苗苗期
质量的影响。试验结果表明：NAA 的使用提高了嫁接成活率,NAA 浓度为40 mg·L^-1 时嫁接成活率最高,
为94%;在0～50 mg·L^-1 浓度范围内,随着NAA 使用浓度的增加,嫁接苗质量先上升后降低,当浓度
达到40 mg·L-1 时,其各项形态及生理指标表现突出;40 mg·L^-1 NAA 能有效促进黄瓜嫁接苗的生长,
提高嫁接苗质量。     

不同化学药剂对银杏果实控制作用的研究

[目的]探究银杏果实控制技术。[方法]在不同时期对银杏树体喷洒不同浓度的萘乙酸、乙烯利和石硫合剂溶液,研究不同化学药剂对银杏果实的控制作用。[结果]不同时期喷洒不同浓度萘乙酸溶液后,银杏叶片出现发黄、枯萎,最后脱落,银杏新梢出现枯萎、枯死等现象,在花期喷洒乙烯利和石硫合剂溶液,可以控制银杏果实的数量,乙烯利溶液以浓度200、400、800 mg/L的处理效果较好,浓度1 200 mg/L处理的银杏会出现药害,喷洒石硫合剂溶液以浓度0.5%、1.0%的处理效果较好,浓度2.0%的处理效果需进一步试验;在果期喷洒乙烯利,对果实的形成无太大影响,对果实的重量、大小有一定影响。[结论]试验结果为相关部门进行银杏管理提供了参考。     

NAA对水分胁迫下一品红幼苗叶绿素荧光参数影响

以一品红千禧品种为试材,对其喷施不同浓度的萘乙酸(NAA)溶液,研究水分胁迫下叶绿素荧光参数的变化.结果表明,低浓度的NAA溶液可缓解水分胁迫对叶绿素荧光参数的影响,高浓度的NAA溶液则会加剧叶绿素荧光参数的变化,各处理中以0.5 mg/L的NAA效果最优.