浸提条件对小麦秸秆中化感物质检测结果的影响

通过对比不同浸提条件下小麦秸秆中化感物质的检测结果, 发现浸提温度和时间对化感物质的最终鉴定结果有很大的影响：在室温条件下,化感物质的量随着浸提时间的延长而增加,但在50 ℃时,随着浸提时间的延长,化感物质的量反而降低。化感物质最大量在50 ℃,24 h浸提条件下得到。在高温高压条件下提取到的化感物质的量多于多数条件下得到的量（除少于50 ℃,24 h浸提条件下得到的量）。试验结果表明随着浸提温度升高,植物材料中的化感物质在水中的溶解速度加快,但是性质不稳定,容易分解变性。     

海藻中有机碘的研究Ⅰ.海藻中有机碘含量测定

采用国际上目前通用的差减法来计算海藻中的有机碘,即首先测定海藻中的总碘和无机碘,其差减值为有机碘.碘的测定采用了碘离子选择电极法和中子活化法作为对照。在此基础上,还测定了新鲜海带中碘的含量、分布以及有机碘和无机碘的比例。研究结果表明,海带中碘的平均含量占鲜重的0.133％,其中88％的碘是以碘离子的形式存在,有机碘只占总碘的12％,同时海带不同部位碘的含量不同,叶部外缘含碘较多,是叶中部的2倍左右,尤其叶尖部的含量达到鲜重的0.183％。而有机碘的含量分布规律则不同,有机碘的含量在靠近根部的位置较高,为鲜重的13.9％。这种分布特点可能与海带的生命活动规律有关。     

浸提条件对小麦秸秆中化感物质检测结果的影响

通过对比不同浸提条件下小麦秸秆中化感物质的检测结果,发现浸提温度和时间对化感物质的最终结果有很大的影响,在室温条件下,化感物质的量随着浸提时间的延长而增长,但在50℃时,随着浸提时间的延长,化感物质的量反而降低。化感物质最大量在50℃,24h浸提条件下得到。在高温高压条件下提取到的化感物质的量多于多数条件下得到的量（除少于50℃,24h浸提条件下得到的量）。试验结果表明随着漫提温度升高,植物材料中的化感物质在水中的溶解速度加快,但是性质不稳定,容易分解变性。     

金桂与丹桂醇溶性色素的提取及其稳定性比较

用不同体积分数的乙醇从金桂和丹桂的花瓣中浸提所含的花色苷类色素,用光谱扫描法检测该色素的光吸收特性,比较不同乙醇体积分数、不同浸提时间对色素浸提效果的影响,并进行光敏感性试验和酸碱影响试验。结果显示,金桂和丹桂的花色素用体积分数90%的乙醇浸提具较高的浸出率;延长浸提时间可提高色素浸出率;紫外线直射可使色素的色度大幅度下降,日光灯和散射光也会导致色度在一定程度上的下降;色素在酸性溶液中具一定的稳定性,但在碱性溶液中表现出不稳定性。     

樱桃番茄对根际外源碘的吸收及生理反应特性

在深液流水培的营养液中添加浓度为1.0—6.0mg.L-1的碘离子栽培樱桃番茄.根系、叶片和果实的碘含量均表现随着I-浓度提高而增加的趋势.根系的碘含量在I-处理后1周迅速增加;第2周降低,此后呈现逐渐增加的趋势,而且中高浓度处理(3.0～6.0 mg·L-1)的变化趋势比低浓度处理（1.0～2.0mg·L-1）明显....     

蔬菜吸收不同形态外源碘的动力学特性

采用水培法,研究了两种蔬菜(小白菜和芹菜)对两种不同形态碘源(I-,IO-3)的吸收和积累特性.结果表明:供试蔬菜吸收碘的速率表现为在短时间(＜60 min)内迅速增加,随着时间的延长蔬菜对碘的吸收速率逐渐下降;在低浓度范围内(0.01～0.50 mg/L)蔬菜对IO-3的吸收速率与碘浓度变化曲线符合饱和吸收动力学特征(表现为遵循酶学方程),进一步研究表明,解偶联剂2,4-二硝基苯酚(DNP)对低浓度(＜0.50 mg/L)下蔬菜IO-3吸收速率具有明显的抑制作用,说明两种蔬菜对低浓度的IO-3可能存在主动吸收,而在高浓度范围内(0.50～10.0 mg/L),蔬菜对碘的吸收速率随着碘浓度的提高呈现直线上升的趋势.两种蔬菜相比,在同样条件下芹菜对碘的吸收速率明显大于小白菜.蔬菜可食部分中碘的含量随着碘浓度的提高而增加,在一次加碘条件下表现为先增加后降低的趋势,而在持续加碘条件下蔬菜中碘的含量在整个处理期间表现为不断增加; Cl-的添加对低浓度下蔬菜碘的吸收具有明显的抑制作用,而随着碘浓度的提高Cl-的抑制作用逐渐减弱.供试蔬菜对碘的富集系数随碘浓度的提高而降低,碘在蔬菜不同器官的分配次序表现为根＞叶＞茎.     

绿茶乙醇浸提技术研究

以工业生产上的水提技术为参照,以成品绿茶为材料,探讨乙醇浸提条件下,乙醇浓度、浸提温度、浸提时间、料液比、浸提次数等因子对醇提过程中茶汤品质成分动态浸出规律的影响。结果表明,采用50%乙醇、温度80℃、料液比1/25、连续2次、每次浸提20 min的浸提技术参数,茶叶各品质成分的浸出率最高,总浸出物、氨基酸、茶多酚、蛋白质、碳水化合物的浸出量分别是常规水提的1.39、1.09、1.44、1.52、1.23倍。从茶叶品质成分浸出率的角度考虑,在此技术参数下,用乙醇浸提绿茶优于水提。     

应改为"淀粉遇碘变蓝"

《生物学通报》2 0 0 0年第 5期“‘唾液淀粉酶对淀粉的消化作用’一节探索课的尝试”一文中写道 :“如在设计‘唾液淀粉酶对淀粉的消化作用’实验中 ,启发学生思考实验的原理 ,即淀粉遇碘酒变蓝。唾液中有唾液淀粉酶 ,它能消化淀粉为麦芽糖 ,而麦芽糖遇碘酒不变色。”文中出现“淀粉遇碘酒变蓝”、“麦芽糖遇碘酒不变色”的说法值得商确。“碘酒 ,碘汀俗称 ,是碘和碘化钾的稀酒精溶液 ,在溶液中 I- I2 I-3 。在溶液中极微量的碘与淀粉相遇立即形成深蓝色的加合物 ,这是定性检验碘的灵敏方法。淀粉是由许多葡萄糖分子缩合而成的多糖 ,分子…     

退耕植茶地土壤团聚体及其无机磷组分分布特征

为了揭示土壤团聚体及其无机磷组分对退耕植茶的响应特征,以雅安市名山区中峰乡退耕植茶地(2～3年、9～10年、16～17年)为研究对象,选取邻近耕地为对照,采用野外调查与室内分析相结合的方法开展退耕植茶地土壤团聚体及其无机磷组分分布特征的研究.结果表明: 耕地及退耕植茶地土壤团聚体均以粒径>2 mm团聚体为主.随着退耕植茶年限的延长,各退耕植茶地粒径>5 mm的团聚体含量逐渐增加,粒径<5 mm的团聚体含量却逐渐降低.退耕植茶初期,退耕植茶地土壤团聚体平均质量直径(MWD)和几何平均直径(GMD)值与对照差异不明显,退耕植茶9～10年和退耕植茶16～17年显著高于对照,且随着退耕植茶年限的延长逐渐增大.退耕植茶地与耕地相比,其有效性较高的Al-P、Fe-P含量增加,有效性较低的O-P含量降低,随着退耕植茶年限的延长,各粒径团聚体中有效性较低的O-P逐渐降低,有效性较高的Al-P、Fe-P逐渐增加.耕地及退耕植茶地中Al-P、Ca-P含量随粒径的减小而增加,在<0.25 mm粒径中的含量最高;Fe-P在<0.25 mm粒径团聚体中的含量最多,其次是2～5 mm和0.25～0.5 mm粒径团聚体;退耕植茶后,O-P逐渐向较小粒径中富集,在<2 mm粒径中含量较高.     

水杨酸对黄瓜子叶表皮气孔开度的调节作用

以黄瓜品种中农203(Cucumis sativus L.cv.Zhongnong 203)幼苗为试材,采用SA溶液根部施用和子叶表皮浸泡两种方式,显微观测了不同外源水杨酸(Salicylic acid,SA)溶液处理对其子叶表皮气孔开度的影响,以探讨SA与气孔运动的关系.结果表明:SA子叶表皮浸泡或根部施用后,气孔运动的趋势是随着SA浓度增加而孔径逐渐变小,且SA磷酸缓冲液的作用效果与SA水溶液相似.随着处理时间的延长,气孔开度逐渐变小,且气孔开度与SA处理时间达极显著(r=-0.962**)或显著(r=-0.914*)负相关.溶液低pH值,增强了SA对气孔开度的抑制作用,且SA浓度越高作用越明显;0.1 mmol/L SA处理后,pH为8、7、6溶液的气孔开度抑制率分别为90.2%、93.8%和96.3%,即SA溶液对气孔开度的抑制率随着溶液pH降低而升高.可见,外源SA能够促进气孔关闭,其作用随着SA浓度升高、处理时间延长和溶液pH值降低而增强,相对于磷酸缓冲液,以蒸馏水作为溶剂的SA溶液促进气孔关闭的作用更大.     

On the origin of the Hirudinea and the demise of the Oligochaeta

The phylogenetic relationships of the Clitellata were investigated with a data set of published and new complete 18S rRNA gene sequences of 51 species representing 41 families. Sequences were aligned on the basis of a secondary structure model and analysed with maximum parsimony and maximum likelihood. In contrast to the latter method, parsimony did not recover the monophyly of Clitellata. However, a close scrutiny of the data suggested a spurious attraction between some polychaetes and clitellates. As a rule, molecular trees are closely aligned with morphology-based phylogenies. Acanthobdellida and Euhirudinea were reconciled in their traditional Hirudinea clade and were included in the Oligochaeta with the Branchiobdellida via the Lumbriculidae as a possible link between the two assemblages. While the 18S gene yielded a meaningful historical signal for determining relationships within clitellates, the exact position of Hirudinea and Branchiobdellida within oligochaetes remained unresolved. The lack of phylogenetic signal is interpreted as evidence for a rapid radiation of these taxa. The placement of Clitellata within the Polychaeta remained unresolved. The biological reality of polytomies within annelids is suggested and supports the hypothesis of an extremely ancient radiation of polychaetes and emergence of clitellates.     

On the ontogeny of the haptor and the evolution of the Monogenea

Data on the ontogeny of the posterior haptor of monogeneans were obtained from more than 150 publications and summarised. These data were plotted into diagrams showing evolutionary capacity levels based on the theory of a progressive evolution of marginal hooks, anchors and other attachment components of the posterior haptor in the Monogenea (Malmberg, 1986). 5 + 5 unhinged marginal hooks are assumed to be the most primitive monogenean haptoral condition. Thus the diagrams were founded on a 5 + 5 unhinged marginal hook evolutionary capacity level, and the evolutionary capacity levels of anchors and other haptoral attachement components were arranged according to haptoral ontogenetical sequences. In the final plotting diagram data on hosts, type of spermatozoa, oncomiracidial ciliation, sensilla pattern and protonephridial systems were also included. In this way a number of correlations were revealed. Thus, for example, the number of 5 + 5 marginal hooks correlates with the most primitive monogenean type of spermatozoon and with few sensillae, many ciliated cells and a simple protonephridial system in the oncomiracidium. On the basis of the reviewed data it is concluded that the ancient monogeneans with 5 + 5 unhinged marginal hooks were divided into two main lines, one retaining unhinged marginal hooks and the other evolving hinged marginal hooks. Both main lines have recent representatives at different marginal hook evolutionary capacity levels, i.e. monogeneans retaining a haptor with only marginal hooks. For the main line with hinged marginal hooks the name Articulon-choinea n. subclass is proposed. Members with 8 + 8 hinged marginal hooks only are here called Proanchorea n. superord. Monogeneans with unhinged marginal hooks only are here called Ananchorea n. superord. and three new families are erected for its recent members: Anonchohapteridae n. fam., Acolpentronidae n. fam. and Anacanthoridae n. fam. (with 7 + 7, 8 + 8 and 9 + 9 unhinged marginal hooks, respectively). Except for the families of Articulonchoinea (e.g. Acanthocotylidae, Gyrodactylidae, Tetraonchoididae) Bychowsky's (1957) division of the Monogenea into the Oligonchoinea and Polyonchoinea fits the proposed scheme, i.e. monogeneans with unhinged marginal hooks form one old group, the Oligonchoinea, which have 5 + 5 unhinged marginal hooks, and the other group form the Polyonchoinea, which (with the exception of the Hexabothriidae) has a greater number (7 + 7, 8 + 8 or 9 + 9) of unhinged marginal hooks. It is proposed that both these names, Oligonchoinea (sensu mihi) and Polyonchoinea (sensu mihi), will be retained on one side and Articulonchoinea placed on the other side, which reflects the early monogenean evolution. Except for the members of Ananchorea [Polyonchoinea], all members of the Oligonchoinea and Polyonchoinea have anchors, which imply that they are further evolved, i.e. have passed the 5 + 5 marginal hook evolutionary capacity level (Malmberg, 1986). There are two main types of anchors in the Monogenea: haptoral anchors, with anlages appearing in the haptor, and peduncular anchors, with anlages in the peduncle. There are two types of haptoral anchors: peripheral haptoral anchors, ontogenetically the oldest, and central haptoral anchors. Peduncular anchors, in turn, are ontogenetically younger than peripheral haptoral anchors. There may be two pairs of peduncular anchors: medial peduncular anchors, ontogentically the oldest, and lateral peduncular anchors. Only peduncular (not haptoral) anchors have anchor bars. Monogeneans with haptoral anchors are here called Mediohaptanchorea n. superord. and Laterohaptanchorea n. superord. or haptanchoreans. All oligonchoineans and the oldest polyonchoineans are haptanchoreans. Certain members of Calceostomatidae [Polyonchoinea] are the only monogeneans with both (peripheral) haptoral and peduncular anchors (one pair). These monogeneans are here called Mixanchorea n. superord. Polyonchoineans with peduncular anchors and unhinged marginal hooks are here called the Pedunculanchorea n. superord. The most primitive pedunculanchoreans have only one pair of peduncular anchors with an anchor bar, while the most advanced have both medial and lateral peduncular anchors; each pair having an anchor bar. Certain families of the Articulonchoinea, the Anchorea n. superord., also have peduncular anchors (parallel evolution): only one family, the Sundanonchidae n. fam., has both medial and lateral peduncular anchors, each anchor pair with an anchor bar. Evolutionary lines from different monogenean evolutionary capacity levels are discussed and a new system of classification for the Monogenea is proposed.In agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. EditorIn agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. Editor