2003和2004年春季台北大气悬浮物中的水溶性离子(英文)

IntroductionTheoccurrenceofAsianduststorms(ADS)iscommonduringthemonthsoflatewinterandspringinEastAsia.Underfavorablesynopticconditions,significantamountsoftheAsiandustmaybetransportedtoTaiwan(Chen&Chen1987).Inrecentyears,ADSoverTaiwanreceivedsubstantialattentionbecauseoftheirimpactontheairquality.Besideshigherconcentrationsofmineralelements,highlevelsofanthropogenicspeciessuchassulfateandnitratehavebeenobservedintheoutflowfromtheAsiancontinent(Clarkeetal.2001).Thus,inthiswork,theinfluen…     

Degradation and sorption of atrazine, hexazinone and procymidone in coastal sand aquifer media

The degradation, sorption and transport of atrazine, hexazinone and procymidone in saturated coastal sand aquifer media were investigated in batch and column experiments. The pesticides were incubated with sterilised and non-sterilised groundwater or a mixture of groundwater and the aquifer material in the dark at 15 degrees C for 120 days. The estimated half-lives of the pesticides (and their ranges) in the mixture of groundwater and aquifer sand were 36 (31-40), 54 (40-77) and 84 (46-260) days for atrazine, procymidone and hexazinone, respectively. Compared with the relevant results for the groundwater-sand mixture phase, the estimated half-life of pesticides in the groundwater phase alone was shorter for procymidone (21 days) but longer for hexazinone (134 days); atrazine was not degraded in the groundwater phase. Chemical degradation appeared to have played the predominant role in the degradation of hexazinone and procymidone in the aquifer system, while both chemical and biological processes seemed to be important for the degradation of atrazine. Batch isothermal experiments were carried out at pH 4.6-4.7 to obtain sorption coefficients under equilibrium conditions. The isothermal data of the pesticides fitted well with the non-linear Freundlich function with an exponent of sorption coefficient that was greater than one. Contrary to reports in the literature, sorption of atrazine was the greatest, and procymidone was slightly more sorbed than hexazinone. A column experiment was conducted at a typical field-flow velocity of 0.5 m day(-1) over 60 days to study pesticide attenuation and transport in flow dynamic conditions. Retardation factors, R, derived from a two-site sorption/desorption model were 8.22, 1.76 and 1.63 for atrazine, procymidone and hexazinone, respectively. Atrazine displayed the lowest mobility and the mobility of procymidone was only slightly less than that of hexazinone, which is consistent with observations in the batch experiment. A possible explanation for these observations is that ionic atrazine is bound to oppositely charged ionic oxides, and ionic oxides have less effect on the sorption of the non-ionic procymidone. The significant tailing in the pesticide breakthrough curves (BTCs) in comparison with the bromide BTC, together with model-simulated results, suggests that the transport of the pesticides was under chemical non-equilibrium conditions with R values that were less than their equivalent values predicted using the batch equilibrium isothermal data. As a result of non-linear kinetic sorption, retardation factors of the pesticides in groundwater systems would not be constant and will decrease with decreasing pesticide concentrations and increasing flow velocities. Hence, the use of equilibrium isotherm data will probably over-predict the sorption of pesticides in groundwater systems. Rhodamine WT, a commonly used groundwater tracer, was significantly retarded (R = 5.48) and its BTC was much more spread out than the bromide BTC. Therefore, it would not be a good tracer for the indication of groundwater flow velocity and dispersion for the coastal sand aquifer system. In contrast to some aquifer media, the dye tracer was unsuitable as a marker of the appearance of atrazine in a coastal sand aquifer system.     

陕西省商洛市从陕北调运马铃薯脱毒种薯存在的问题及对策

分析近年来陕西省商洛市从陕北榆林等地区调运马铃薯脱毒种薯存在的一些主要问题,针对这些问题提出切实可行的应对措施,为更好地解决制约马铃薯产业发展的种薯生产与调运等问题,促进商洛市马铃薯产业进一步做大做强,尽早成为"百万亩"马铃薯产业大市。     

生长素对迷迭香插条生根影响研究初报

用IBA、2,4-D、ABT等3种生长素的不同质量水平对迷迭香当年生枝条分别进行绿枝和顶芽扦插,于沙床上全光照喷雾管理。用SPSS统计软件10．0对试验数据进行分析。结果表明3种生长素对迷迭香生根和成活有促进和提高作用。不同生长素的有效质量范围和作用效果存在差异。其中2,4-D表现最优,有效质量水平为1．0～2．0mg／L,质量水平越低,生根效果越好;其次为IBA,有效质量水平0．5～1．0mg／L,质量水平越高,生根能力越强;ABT最弱。     

亮叶忍冬嫩枝扦插繁殖技术研究

采用L9（3。）正交试验法,研究不同基质、生长素类型以及新梢枝段对亮叶忍冬（Loniceranitida‘Maigrun’）嫩枝扦插繁殖效果的影响。对扦插成活率、生根数、根系总长度、根鲜重、新梢数、新梢总长度、新梢鲜重等指标进行了测定分析,结果表明：以河沙或珍珠岩为扦插基质时,各测定指标均极显著高于草炭处理;吲哚丁酸（IBA）或萘乙酸和吲哚丁酸等量混合液（N＋I）处理的扦插成活率极显著高于萘乙酸（NAA）处理,其它各指标则均无显著差异;以新梢基部段位为插条时,生根数极显著高于其它枝段,基部和中部枝段为插条的新梢总长度和新梢鲜重极显著高于梢部,其余各测定指标在不同枝段间的差异不显著。综合各测定指标,进行亮叶忍冬嫩枝扦插繁殖时,以河沙或珍珠岩为扦插基质,采用亮叶忍冬新梢基部或中部段位作为插条,经浓度为1000mg·L。吲哚丁酸和萘乙酸等量混合液（N＋I）或吲哚丁酸（IBA）处理,可获得较高成活率（70％以上）以及较高质量的扦插苗。     

毛白杨PtAUX1超表达诱导体状胚发生

体状胚的发生由一个生长素信号级联系统控制,其发生过程需要大量的生长素,随后在去除生长素或降低生长素浓度的条件下,体状胚趋于成熟。除植物激素外,环境胁迫也是体状胚发生所必须的,激素和环境胁迫协同诱导细胞的脱分化、再分化和体状胚的发生。目前发现的参与体状胚发生的主要基因有SERK、PKL和BBM等,它们作用于体状胚的不同发育阶段。本研究中,在毛白杨35S::PtAUX1超表达植株中发现叶片表面产生大量体状胚,体状胚分散在叶片主脉及侧脉两侧或聚集在叶片边缘,其中部分体状胚可发育成成熟体状胚。将成熟体状胚取下,置于MS0培养基上进行培养,体状胚发芽并缓慢产生根。研究结果表明,PtAUX1通过建立新的生长素浓度梯度,诱导体细胞转化成胚性细胞,从而使叶片产生出体状胚。除上述基因外,PtAUX1也参与体状胚的发生,这一研究发现现尚未见报道。     

三种生长调节剂对金边虎尾兰、月季与天竺葵扦插生根的影响

以金边虎尾兰、月季与天竺葵为试材,研究不同生长调节剂及其浓度对3种园林植物扦插生根的影响。结果表明:金边虎尾兰叶基段以100mg/L浓度的IBA或NAA扦插效果较好,叶尖段以IBA 100～200mg/L或NAA 200mg/L扦插效果较好,生根率均达到100%;100～200mg/L浓度的IBA与100mg/L浓度的NAA对月季茎插生根效果较好,生根率达75.6%～77.8%;天竺葵茎插各处理的生根率均达到100%,但从平均生根数上比较,100mg/L NAA或25mg/L IBA对其扦插生根效果最佳,25～300mg/L的IAA对其生根数有抑制作用。