外源铁对铅污染土壤中宽叶香蒲铅积累的影响

采用温室盆栽方法,研究添加外源铁对不同铅浓度(0、100、500和1000 mg·kg-1)污染土壤中宽叶香蒲铅积累的影响.结果表明:各铅浓度条件下,与添加100 mg Fe·kg-1相比,添加500 mg Fe·kg-1处理的宽叶香蒲地上部和根的铅含量均增高.土壤铅浓度为1000mg·kg-1时,添加500 mg Fe·kg-1处理根的铅含量比100 mg Fe·kg-1处理增加33.7％,地上部铅含量增加50.5％.添加500 mg Fe·kg-1处理的根际土壤中可交换态铅比100mg Fe·kg-1处理增加77.0％～114.6％.除500 mg·kg-1铅浓度外,各铅浓度条件下添加500mg Fe·kg-1处理根干质量均显著低于100 mg Fe·kg-1处理.在铅污染的湿地环境中添加适量铁可以提高铅的有效性,促进铅积累.     

铅锌矿废水中重金属在宽叶香蒲（Typha latifolia）的积累与分布

 本文通过对净化塘系统和对照点的水、土和宽叶香蒲组织的分析结果指出：宽叶香蒲具有较强的忍耐、吸收和积累Pb、Zn等重金属的能力。Pb、Zn等重金属在宽叶香蒲体内的积累数量与分布规律是根>地下茎>叶;老地下茎>嫩地下茎;Pb在叶的分布是老叶>成熟叶>嫩叶。在净化塘系统内,各种重金属在宽叶香蒲根部积累比例最大的是Pb,其次是Zn、Cu、Cd、Ni、Mn。     

蒙古香蒲,宽叶香蒲和长苞香蒲花粉的黄酮类化合物的研究

蒙古香蒲(Typha davidiana Hand.-Mazz.)宽叶香蒲(Typha latifolia L.)和长苞香蒲(Typha angustata Bory et Chaub)的干燥花粉中分别分离得到柚皮素(Ⅰ),异鼠李素(Ⅱ),檞皮素(Ⅲ),异鼠李素-3-O-(2~G-α-L-鼠李糖基)-芸香糖甙(Ⅳ),檞皮素-3-O-(2~G-α-L-鼠李糖基)-芸香糖甙(Ⅴ),异鼠李素-3-O-芸香糖甙(Ⅵ),异鼠李素-3-O-新橙皮糖甙(Ⅶ)和山奈酚-3-O-新橙皮糖甙(Ⅷ)。     

宽叶香蒲净化塘系统净化铅／锌矿废水效应的研究

研究了以宽叶香蒲(Typha latifolia)为优势群落的净化塘系统来处理广东韶关凡口铅/锌矿选矿废水。经5年多的监测结果表明,该系统能有效地净化铅/锌石广废水。在进入净化塘系统前,未处理的废水合有高浓度的悬浮物(4 635mg/L)和重金属[Fb(1.61mg/L)、Zn(1.96mg/L)和Cd(0.022mg/L)]等,经过净化后,水质明显改善,pH从8.03下降到7.74,总悬浮物去除率达99％,Pb去除率为90％,Zn和Cd去除率为84％,其它重金属如Cu、Fe和Al等也都有不同程度的降低。     

锌废水对宽叶香蒲（Typhalatifolia）生理生态的影响

沙培模拟实验表明,300mg/L浓度以上的锌会使宽叶香蒲受害致死;100mg/L浓度的锌能使宽叶香蒲根系尖力,蒸腾强度,叶绿素含量,光合作用,植株高度,分孽,生物量的同程度的降低,植株光呼吸,音呼吸,叶片氨酸含量增高,加速叶片衰老。     

中亚热带森林群落不同演替阶段优势种凋落物分解试验

选择我国亚热带森林群落3个主要演替阶段的7个优势种（其中马尾松代表演替初期优势种,木荷和香樟代表演替中期优势种,甜槠、小叶青冈栎、青冈和乐昌含笑代表演替后期优势种）的凋落物,采用网袋法进行分解试验. 结果表明:马尾松凋落物分解得最慢,年分解速率为0.51;木荷和香樟居中,分别为0.55和0.61;小叶青冈栎和乐昌含笑分解得最快,分别为0.89和1.12.沿着植被顺向演替的梯度,凋落物分解速度呈现加快的趋势. 分解速率同凋落物的初始P、N和木质素含量及木质素/N比值呈极显著相关(P<0.01),同C/N比值有显著相关关系(P<0.05).凋落物的P、N和木质素含量及木质素/N比值是预测凋落物分解快慢的良好指标.     

镉胁迫对狭叶香蒲某些生理指标的影响

利用水培法研究了Cd胁迫对狭叶香蒲(Typha angustifolia L.)某些生理指标的影响。结果表明,Cd浓度在0.4和1.0 mg.L-1时,狭叶香蒲的叶绿素含量呈上升趋势;Cd浓度高于1.0 mg.L-1时,叶绿素含量有所下降。当Cd浓度达1.5 mg.L-1时,狭叶香蒲的根系活力明显降低。随Cd浓度的增加,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性基本呈现低浓度时上升高浓度时下降的变化趋势;丙二醛(MDA)含量则呈上升趋势。     

净化污水植物香蒲形态解剖特征的比较研究

用高浓度铅锌废水和清洁水中生长的香蒲Typhalatifolia为材料,制片供显微观察,进行形态解剖特征的比较研究。结果表明：生活在铅锌废水中的香蒲叶表皮细胞变小变方形,出现质壁分离。叶绿休的数量减少,而气孔的数量增加。     

Aspects of methane flow from sediment through emergent cattail (Typha latifolia) plants

We measured the flow of methane in Typha latifolia L. (cattail)-dominated wetlands from microbial production in anoxic sediment into, through, and out of emergent T. latifolia shoots (i.e. plant transport). The purpose was to identify key environmental and plant factors that might affect rates of methane efflux from wetlands to the Earth's atmosphere. Methane accumulated in leafy T. latifolia shoots overnight, reaching concentrations up to 10000 μl l⁻¹ (vs. atmospheric concentrations <4 μl l⁻¹), suggesting that lower stomatal conductance at night limits methane efflux from the plant into ambient air. Daytime light and (or) lower atmospheric humidity that induce convective gas flow through the plant coincided with ( a ) an increase in the rate of methane efflux from T. latifolia leaves to ambient air (from <0·1 to >2·0 μmol m⁻² (leaf) s⁻¹) and ( b ) a decrease in shoot methane concentration to <70 μl l⁻¹. Very short fluctuation in stomatal conductance during the day did not affect the methane efflux rate unless, possibly, the rate of photosynthesis decreased. A strong relationship between the maximum daily rate of methane efflux and shoot methane concentration (measured before the onset of convective gas flow) suggests T. latifolia plants behave like a capacitor (filling with methane at night, emitting the stored methane during the day). Experimentally cutting leaves (to prevent pressurization) reduced plant capacitance for methane.     

Comparative study on removal of enteric pathogens from domestic wastewater using Typha latifolia and Cyperus rotundus along with different substrates

A comparative study was carried out to evaluate the efficiency of different substrate materials along with macrophytes Typha latifolia and Cyperus rotundus in treating domestic wastewater intended for reuse in agriculture. The study was conducted over a period of 6 months with different retention times, and observations were taken twice per month. One-way analysis of variance and Tukey's Honest Significant Difference (HSD) tests were used to determine statistical significant differences between experimental columns. Treatment with T. latifolia planted in sand and mix substrate with 4-day retention time remarkably reduced the concentration of all bacterial pathogens. Log reductions observed were approximately 5.01 and 4.82 for total coliform (TC), 4.46 and 3.93 for Escherichia coli, and 5.52 and 5.48 for Shigella, respectively. Moreover, these treatments were also efficient in completely removing fecal coliform (FC) and Salmonella.Maximum parasites were removed by the treatment having sand alone as a substrate containing C. rotundus, but the difference was not significant from those planted with T. latifolia in the same substrate. The results suggest that T. latifolia aids in bacterial pathogens removal, while C. rotundus aids in parasites removal. Thus, wastewater treatment through constructed wetland having mix plantation of these species along with sand can eliminate some of the major enteric pathogens.     

Pb2+在甜菜夜蛾体内的积累及对种群的影响

重金属的污染及其治理是目前倍受关注的生态学问题之一.甜菜夜蛾是我国长江流域及以南地区蔬菜、棉花等作物上的主要害虫,近几年突发趋势明显.本文以甜菜夜蛾为靶标对象,设计5个浓度(0.3、1.2、4.8、19.2、76.8 mg · kg^-1)重金属Pb²⁺处理,探讨处理后甜菜夜蛾各虫态体内Pb²⁺的积累和排泄,并根据甜菜夜蛾各虫态的生长与存活情况,构建了该虫连续3个世代的种群生命表.结果表明: 取食含有不同浓度Pb²⁺的人工饲料后,各虫态甜菜夜蛾体内Pb²⁺的浓度在同一世代不同处理间存在显著差异,且呈显著的剂量 反应关系.各虫态体内Pb²⁺的浓度基本上随胁迫世代数的延长而增加.受Pb²⁺胁迫后,各虫态体内Pb²⁺的浓度顺序为5龄幼虫＞成虫＞蛹;该虫可通过粪便、预蛹蜕和蛹壳排泄体内部分重金属,且粪便和预蛹蜕中的Pb²⁺浓度远大于蛹蜕中的浓度;根据Pb²⁺不同浓度条件下甜菜夜蛾各虫态的存活率、雌性比和产卵量,构建的种群生命表表明,低浓度Pb²⁺胁迫可促进甜菜夜蛾的种群增长,而高浓度胁迫使种群增长衰退;且随着重金属的持续胁迫,其种群衰退更明显.研究结果为长期、客观评价重金属的危害性以及对重要农业害虫的种群影响提供了借鉴.     

GA3与EDTA强化黑麦草修复Pb污染土壤及其解毒机制

采用盆栽土培方法研究了生长调节剂GA₃和重金属螯合剂EDTA强化黑麦草修复Pb外源浓度分别为250和500 mg·kg^-1的污染土壤以及黑麦草Pb解毒机制.结果表明： 细胞壁沉积和液泡区室化在黑麦草地上部分Pb的解毒中起重要作用.EDTA单独使用提高了植物体内Pb的浓度和Pb在细胞可溶组分和细胞器组分中的比例,增强了Pb对植物的毒害作用,从而使植物生物量显著下降(P<0.05).叶面喷洒低浓度GA₃(1或10 μmol·L^-1)显著促进黑麦草对Pb的富集,但Pb在细胞器组分中的比例降低,缓解了Pb对植物细胞的伤害,从而促进了黑麦草的生长(P<0.05),其中1 μmol·L^-1 GA₃作用最显著.100 μmol·L^-1 GA₃降低了黑麦草体内Pb浓度,但Pb在细胞可溶组分和细胞器组分中的比例提高,使黑麦草的生物量明显低于对照.低浓度GA₃可在一定程度上缓解Pb和/或EDTA对黑麦草的毒害,生物量表现为低浓度GA₃ 单独>低浓度GA₃+EDTA>EDTA单独使用.低浓度GA₃和EDTA联用时的协同作用强化了黑麦草对Pb的富集,其中,在外源Pb浓度为500 mg·kg^-1处理组中,EDTA+1 μmol·L^-1 GA₃使黑麦草地上部分Pb浓度和提取效率分别达到1250.6 mg·kg^-1和1.1%.因此,1 μmol·L^-1 GA₃与EDTA联用在强化Pb污染土壤植物修复中具有很好的应用潜力.     

Studies on the Flavonoids from the Pollens of Typha davidiana,T. Latifolia and T. angustata(Pu Huang)

Eight identical flavonoids were isolated from the alcoholic extract of the pollen of Typha davidiana Hand.-Mazz., Typha latifolia L. and Typha angustata Bory et Chaub. On the basis of spectroscopic (IR, UV, MS and NMR) analysis and the identification of the acidic hydrolytic products, they were identified as naringenin (Ⅰ), isorhamnetin (Ⅱ), quercetin (Ⅲ), isorhamnetin-3-O-(2G-α-L-rhamnopyrano-syl)-rutinoside(Ⅳ), quercetin-3-O-(2G-α-L-rhamnopyranosyl)-rutinoside (Ⅴ), iso-rhamnetin-3-O-rutinoside (Ⅵ),isorhamnetin-3-O-neohesperidoside (Ⅶ), kampferol-3-O-neohesperidoside (Ⅷ). Compound Ⅴ was found in this genus for the first time.     

Cold-induced purpling of Pinus contorta seedlings depends on previous daylength treatment

The characteristic cold-induced foliar accumulation of anthocyanin (‘purpling’) seen in many species of pine seedlings in the autumn can be contingent upon photoperiod received months previously. In nursery-grown seedlings of Pinus contorta Dougl. var. latifolia Engelm., a 4-week exposure during August of 10-h days followed by return to ambient photoperiod diminished the frequency of purpling following the November onset of cold weather (21% compared to 71% of the untreated controls). Anthocyanin accumulation (primarily cyanidin 3-glucoside) was controlled differently than general phenolic metabolism, and involved the integration of two temporally separated environmental signals.     

Effects of Exogenous Spermidine on Antioxidant System Responses of Typha latifolia L. Under Cd^2＋ Stress

The effects of foliar spraying with spermidine (Spd), ranging in concentration from 0.25 to 0.50 mmol/L, on the antioxidant system under Cd^2 stress (range 0.1- 0.2 mmol/L Cd^2 ) in Typha latifolia L. grown hydroponically were investigated in order to offer a referenced evidence for an understanding of the mechanism by which polyamines (PAs) relieve the damage to plants by heavy metal and improve the phytoremediation efficiency of heavy metal-contaminated water. The results showed that Cd^2 stress induced oxidative injury, as evidenced by an increase in the generation of superoxide anion (O2), as well as the hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents in both leaves and caudices. With the exception of superoxide dismutase (SOD) activity in the leaves, an increase in the activities of catalase (CAT), guaiacol peroxidase (GPX), and glutathione reductase (GR) was observed in both leaves and caudices, SOD activity was increased in caudices, and ascorbate peroxidase (APX) activity was increased in leaves following Cd^2 treatment. The reduced glutathione (GSH) content in both leaves and caudices and the reductive ascorbate content in leaves was obviously increased, which were prompted by the application of exogenous Spd. Spraying with Spd increased the activity of GR and APX in both leaves and caudices, whereas the activity of SOD, CAT, and GPX was increased only in caudices following spraying with Spd. The generation of O2 and the H2O2 and MDA content in both leaves and caudices decreased after spraying with Spd. The decrease in MDA was more obvious following the application of 0.25 than 0.50 mmol/L Spd. It is supposed that exogenous Spd elevated the tolerance of T. latifolia under Cd^2 stress primarily by increasing GR activity and the GSH level.     

Ostryopsis davidiana seedlings inoculated with ectomycorrhizal fungi facilitate formation of mycorrhizae on Pinus tabulaeformis seedlings

Reforestation in China is important for reversing anthropogenic activities that degrade the environment. Pinus tabulaeformis is desired for these activities, but survival and growth of seedlings can be hampered by lack of ectomycorrhizae. When outplanted in association with Ostryopsis davidiana plants on reforestation sites, P. tabulaeformis seedlings become mycorrhizal and survival and growth are enhanced; without O. davidiana, pines often remain without mycorrhizae and performance is poorer. To better understand this relationship, we initiated an experiment using rhizoboxes that restricted root and tested the hypothesis that O. davidiana seedlings facilitated ectomycorrhizae formation on P. tabulaeformis seedlings through hyphal contact. We found that without O. davidiana seedlings, inocula of five indigenous ectomycorrhizal fungi were unable to grow and associate with P. tabulaeformis seedlings. Inocula placed alongside O. davidiana seedlings, however, resulted in enhanced growth and nutritional status of O. davidiana and P. tabulaeformis seedlings, and also altered rhizosphere pH and phosphatase activity. We speculate that these species form a common mycorrhizal network and this association enhances outplanting performance of P. tabulaeformis seedlings used for forest restoration.     

黄土高原人工油松林林冠截留动态过程研究

林冠截留量的大小直接影响着大气降水产生地表径流量的多少 ,也决定着森林涵蓄降水能力的大小 ,是评价森林保持水土效益的关键指标之一。因此 ,一直是森林水文和水土保持研究的重点 ,特别是林冠截留的动态过程的研究 ,对揭示径流、泥沙过程有积极的意义。由于影响林冠截留过程因素复杂 ,目前国内外在林冠截留动态方面的研究较少[1～ 3] ,缺乏好的模型描述此过程[4～ 7] ,限制了森林保持水土机理研究的进展。研究林冠截留的动态过程不仅能够阐明森林保持水土的机理 ,而且对研究林地土壤侵蚀过程有重要意义。1　研究地区与方法1 1　自然概况试…