Effect of organic acid on Cd toxicityin tomato and bean growth

ＥｆｆｅｃｔｏｆｏｒｇａｎｉｃａｃｉｄｏｎＣｄｔｏｘｉｃｉｔｙｉｎｔｏｍａｔｏａｎｄｂｅａｎｇｒｏｗｔｈＸｕｅＤｏｎｇｓｅｎ；ＲｏｂｅｒｔＢ．Ｈａｒｒｉｓｏｎ；ＣｈａｒｌｅｓＬ．Ｈｅｎｒｙ（ＵｎｉｖｅｒｓｉｔｙｏｆＷａｓｈｉｎｇｔｏｎ，ＡＲＩＯＳｅａ...     

Leaf litter ecological fate in the Schelde Estuary in Belgium

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅＳｃｈｅｌｄｅＲｉｖｅｒｏｒｉｇｉｎａｔｅｓｉｎＳａｉｎｔ Ｑｕｅｎｔｉｎ(ＮｏｒｔｈｅｒｎＦｒａｎｃｅ) ,ｐａｓｓｅｓｔｈｒｏｕｇｈＢｅｌｇｉｕｍａｎｄｔｈｅＮｅｔｈｅｒｌａｎｄｓａｎｄｔｈｅｎｆｌｏｗｓｉｎｔｏｔｈｅＮｏｒｔｈＳｅａｉｎＶｌｉｓｓｉｎｇｅｎ .ＩｔｉｓｔｈｅｏｎｌｙｔｒｕｅｅｓｔｕａｒｙｌｅｆｔｉｎｔｈｅＤｅｌｔａａｒｅａ(Ｈｅｒｍａｎ ,1999) .ＴｈｅＢｅｌｇｉａｎｇｏｖｅｒｎｍｅｎｔａｐｐｒｏｖｅｄｔｈｅｓｏ ｃａｌｌｅｄＳＩＧＭＡｐｌａｎｆｏｌｌｏｗ…     

掌叶大黄叶资源的开发与利用

对掌叶大黄叶中的药用成分做了定性分析,运用凯氏定氮法和液相色谱仪对粗蛋白和氨基酸的含量进行了测定。实验结果表明:掌叶大黄叶中含有多种药用成分,含有除色氨酸以外的7种人体必需氨基酸,粗蛋白含量在叶及叶柄中分别为干重的0 5712%和1 896%。在此基础上,对掌叶大黄叶资源的开发与利用进行了讨论。     

NO对Cd2+胁迫下绿豆幼苗DNA及光合作用的影响

以绿豆幼苗为材料,研究了外源一氧化氮(NO)处理对Cd~(2+)胁迫3天和8天时幼苗叶片和根系DNA含量、DNA链间交联程度以及叶片光合参数的影响。结果表明:单独Cd~(2+)胁迫导致叶片和根系DNA含量降低,DNA链间交联程度增加,叶片净光合速率、气孔导度和胞间隙CO2浓度降低,气孔限制值升高;与单独Cd~(2+)胁迫相比,NO和Cd~(2+)复合处理提高了叶片和根系DNA含量,降低了DNA链间交联程度,同时使叶片净光合速率和气孔导度升高,而使胞间隙CO2浓度和气孔限制值降低。结果说明,NO能缓解Cd~(2+)胁迫对绿豆幼苗DNA结构及其代谢的影响;Cd~(2+)胁迫抑制绿豆幼苗光合作用的主要原因是气孔因素,而NO主要通过提高幼苗叶片非气孔因素缓解了Cd~(2+)胁迫对幼苗光合作用的抑制。     

Potential ammonia emission from flag leaves of paddy rice (Oryza sativa L. cv. Koshihikari)

The present study aimed to investigate the potential ammonia (NH₃) emission from flag leaves of paddy rice (Oryza sativa L. cv. Koshihikari). The study was conducted at a paddy field in central Japan that was designed as a free-air CO₂ enrichment (FACE) facility for paddy rice. A dynamic chamber method was used to measure the potential NH₃ emissions. The air concentrations of NH₃ at two heights (2 and 6 m from the ground surface) were measured using a filter-pack method, and the exchange fluxes of NH₃ of the whole paddy field were calculated using a gradient method. The flag leaves showed potential NH₃ emissions of 25-38 ng N cm⁻² h⁻¹ in the daytime from the heading to the maturity stages, and they showed potentials of approximately 22 ng N cm⁻² h⁻¹, even in the nighttime, at the heading and mid-ripening stages. The exchange fluxes of NH₃ of the whole paddy field in the daytime were net emissions of 0.9-3.9 g N ha⁻¹ h⁻¹ whereas the exchange fluxes of NH₃ in the nighttime were approximately zero.     

Sexual contact influences orientation to plant attractant in Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae)

Chemical signals emitted by insects and their hosts are important for sexual communication and host selection. Plant volatiles facilitate the location of suitable hosts for feeding and oviposition, and may moderate responses to sex and aggregation pheromones. While mating has been shown to moderate behavioral responses to pheromones in a number of insects, little is known about the effects of mating on behavioral responses of insects to plant attractants, and even less is known about the mechanisms involved. In this study, mating was shown to decrease behavioral responses of the Colorado potato beetle to a host kairomone within 24 h, and attraction to the kairomone recovers only after 72 h. This decrease in responsiveness also occurs when only contact with the opposite sex is allowed; the effect is not observed with contact among individuals of the same sex. Peripheral olfactory responses to a component of the kairomone correlate with the observed behavioral responses and suggest involvement of antennal receptors in the behavioral change.     

UV-B辐射对亚热带森林凋落叶氮、磷元素释放的影响

UV-B辐射对凋落物分解过程的影响已成为全球变化生态学研究中的前沿和热点问题之一.采用分解袋法对自然和UV-B辐射滤减两种环境下亚热带6种代表性树种(杉木、马尾松、木荷、香樟、青冈和甜槠)凋落叶氮、磷元素的释放动态进行了研究.结果表明,凋落叶氮元素的动态表现为直接富集、释放-富集和释放-富集-释放3种模式,磷元素的动态表现为直接释放、富集-释放-富集和无明显变化3种模式.与对照相比,UV-B辐射滤减显著延缓了甜槠凋落叶氮元素及青冈和甜槠凋落叶磷元素的释放(P<0.05),但促进了香樟凋落叶磷元素的释放(P<0.05),对其他树种凋落叶的氮或磷释放无显著影响.凋落叶的初始氮含量和C/N比值不能解释氮释放动态,C/P比值可以部分解释磷的释放.全球环境变化背景下UV-B辐射在湿润亚热带地区森林生态系统过程中的作用尚需进一步认识和理解.     

Sequestration of toxic Pb(Ⅱ) ions by chemically treated rubber(Hevea brasiliensis) leaf powder

Rubber leaf powder(an agricultural waste) was treated with potassium permanganate followed by sodium carbonate and its performance in the removal of Pb(Ⅱ) ions from aqueous solution was evaluated.The interactions between Pb(Ⅱ) ions and functional groups on the adsorbent surface were confirmed by Fourier transform infrared(FT-IR) spectroscopy,scanning electron microscopy(SEM) coupled with X-ray energy dispersive spectroscopy(EDX).The effects of several important parameters which can affect adsorption capacity such as pH,adsorbent dosage,initial lead concentration and contact time were studied.The optimum pH range for lead adsorption was 4-5.Even at very low adsorbent dosage of 0.02 g,almost 100% of Pb(Ⅱ) ions(23 mg/L) could be removed.The adsorption capacity was also dependent on lead concentration and contact time,and relatively a short period of time(60-90 min) was required to reach equilibrium.The equilibrium data were analyzed with Langmuir,Freundlich and Dubinin-Radushkevich isotherms.Based on Langmuir model,the maximum adsorption capacity of lead was 95.3 mg/g.Three kinetic models including pseudo first-order,pseudo second-order and Boyd were used to analyze the lead adsorption process,and the results showed that the pseudo second-order fitted well with correlation coefficients greater than 0.99.     

长春市主要街路代表性植物叶片铅含量分析

应用火焰原子吸收光谱法,对长春市14条主要街路交通密集地段两侧绿化带中采集到的12种代表性植物叶片的铅含量进行了分析。结果表明,植物叶片的铅含量范围在8.20 mg/kg～58.5 mg/kg之间,平均值为19.7 mg/kg。木本植物叶片的平均铅富集能力略低于草本植物,并且木本植物叶片平均铅含量的空间变异性较大;木本植物中杨树叶片的平均铅富集能力最强而榆树最低,草本植物中绣线菊的叶片平均铅富集能力最强而八宝景天最低;草本植物中绣线菊的叶片在所有供试植物叶片中平均铅富集能力最强,其次为木本植物中杨树的叶片,而草本植物中八宝景天的叶片平均铅富集能力最低。不同植物在同一街路以及同种植物在不同街路之间其叶片的铅含量都不同。     

模拟气候变化对沈阳城市树木光合固碳能力的影响

以生长在沈阳市区内的银杏为试材,使用开顶箱模拟法对倍增CO2浓度（700μmol/mo）l和正常空气CO2浓度（≈350μmol/mo）l条件下,银杏生长参数、叶面积指数、不同天气中净光合速率日变化进行了初步研究,探讨了高浓度CO2对单株银杏光合固碳能力的影响。结果表明：CO2浓度增高可以显著提高银杏枝条的生长量和银杏的叶面积指数。经高浓度CO2处理后,银杏不同天气下光合速率日变化趋势与对照一致,即晴天为双峰曲线,多云天气为单峰曲线,但净光合速率显著高于对照（P〈0.001）。由于净光合速率和叶面积指数升高,高浓度CO2也显著提高了单株银杏的固碳释氧能力（P〈0.01）,晴天比对照提高了119.5%,阴天提高了175.4%。