三叶的

The results of our research showed that the chinaberry seed oil, two emulsion formulations of crude toosendanin, Margosan-O, azadirachtin, AZT(NR-2), AZAL-S, petrolem ether extract of the leaf of Tagetes erecta, methyl extract of the root of Tagetes erecta, methyl extract of the whole plant of Bidens pilosa, the oil of Ageratum conyazoides and polygodial had potent toxicity to the larvae of Anopheles sinensis, Culex quinquefasciatus and Aedes albopitus.

中华按蚊Anopheles sinensis、致倦库蚊Culex quinquefa-sciatus和白纹伊蚊Aedes albopictus都是我国重要的传病蚊种。本研究首次证实下列植物的提取物对上述三种蚊虫有毒杀作用：(1)苦楝：苦楝油；(2)川楝：川楝素乳剂、蔬果净；(3)印楝：Margosan-O、印楝素、AZT(NR-2)、AZAL-S；(4)万寿菊：叶石油醚提取物、根甲醇提取物；(5)三叶鬼针草：整株植物甲醇提取物；(6)百花草：精油；(7)水蓼：Polygodial。

As a result of analysis to many of the results of experiment, checked up on specimens, field investigation and combining with the theories of palaeobotany, comparative morphology, evolutional morphology of vascular plants and taxonomy, it can be concluded as following: the primitive sorts of Cycadaceae are the sorts that pinnate leafs are dichotomy; among these, the sort that pinnate leafs are tripinnate-dichotomy is most primitive, from this sort gradually evolve to bipinnate-dichotomy, to only for monopinnate-dichotomy, from this sort evolve to the sorts that pinnate leafs are simply pinna; among the sorts of simply pinna, the species that segments of megasporophyll possess much more triplicate to monodichotomy are most primitive.

经过大量的实验结果分析、查阅标本和野外调查，结合古植物学、比较形态学、演化植物学和分类学等理论进行分析，认为苏铁科原始的类型为羽叶呈二歧状分叉的种类，其中最原始的又是羽叶呈三回二歧状分叉的种类，从这个羽叶类型逐渐演化出一回二歧状分叉的羽叶类型，再演化出羽叶为单羽状的类型；而单羽状叶的类群中，又以大孢子叶侧裂片具三回、二回及一回二歧状分叉数量多的种类为最原始，而侧裂片二歧状分叉数量少的为较进化，侧裂片无二歧分叉的如拳叶苏铁类为最进化的种类。

Amongleaves of various stalk positions,flag and penult leaf had the highestassimilating capacity.

不同叶位间比较，以旗叶和倒二叶的同化功能最强，占单茎同化量的60％以上，倒三叶以下同化能力迅速衰减。

This article study the condition of column chromatogra-phy for separating the total flavonoids in Bidens pilosa L.by polyamide.

本文以三叶鬼针草为研究对象，采用聚酰胺柱层析法对三叶鬼针草中总黄酮成分的分离条件作了研究。

For example, soybean is infected by Bradyrhizobium japonicum while peas nodulate with Rhizobium leguminosarum and clover with Rhizobium trifolii.

波顿（1984）根据对根瘤菌的专一性把豆类作物可分为45组，例如，大豆被大豆慢生根瘤菌细菌侵染，而豌豆被豌豆根瘤菌侵染结瘤，三叶草被三叶草根瘤菌侵染。

Comparing the nucleotide sequences of 16S rRNA gene and ribosomal protein gene, we could find that these two strains have the highest homology of 99.4% and 99.8%, respectively. The nucleotide sequences of 16S rRNA gene for the CWB-YN strain shared higher homology (98.5%,98.9% and 98.0%) with phytoplasma strains in Tomato big bug 16SrI-A group, Western aster yellow (16SrI-B group and Clover phyllody (16SrI-C group). But it is obviously under 97.0% with other phytoplasma groups. The CWB-GZh strain shared higher homology (98.7%,99.1% and 98.3%) with phytoplasma strains in Tomato big bug(16SrI-A group ),Western aster yellow (16SrI-B group) and Clover phyllody (16SrI-C group).

苦楝丛枝病植原体云南株系与其它组16S rRNA基因序列的同源率进行比较，结果与16SrI-A组中的番茄巨芽病植原体(Tomato big bug，BB)、16SrI-B组中的西方翠菊黄化病植原体(Western aster yellow，SAY)和16SrI-C组中的三叶草变病植原体(Clover phyllody，CPh)同源率达最高，分别为98.5%、98.9%和98.0%，而与其它组的植原体16S rRNA基因序列的同源率均低于95%；苦楝丛枝病植原体贵州株系与16Sr I-A组的番茄巨芽病植原体(Tomato big bug，BB)、16Sr I-B组的西方翠菊黄化病植原体(Western aster yellow， SAY)和16SrI-C组中的三叶草变叶病植原体(Clover phyllody，CPh)的同源率达最高，分别为98.7%、99.1%和98.3%。

The resuits showed that there was significant difference of SPAD among different leaves under same nitrogen level.

结果表明，在同一施氮水平下，小麦植株不同叶片SPAD值及光舍速率均为：旗叶〉倒二叶〉倒三叶〉倒四叶，说明小麦叶片叶绿素含量及光舍速率在植株上的分布特征相对固定，受施氮水平的影响较小。

Clover:Any of various herbs of the genus Trifolium in the pea family, having trifoliolate leaves and dense heads of small flowers and including species grown for forage, for erosion control, and as a source of nectar for honeybees.

苜蓿，三叶草：一种豆科三叶草属的草本植物，长有三小叶，开密簇小花，包括用作饲料的、防止水土流失的及作为蜜蜂蜜源的品种

To explore the possibility utilizing mild drought treatment to promote metal ions absorption,uncontinuous drought treatment (1 h, 2 h, 3 h, 4 h each day, lasting for 8 days) and 24 h continuous drought treatment were adopted to wheat seedlings, Fe and Zn content in root, shoot, 1~3 leaves and relative water content in wheat leaves were detected to investigate the effect of different drought treatments on uptake and distribution of Fe and Zn.

中文摘要：为探讨利用轻度干旱处理促进金属离子吸收的可能性，采用液体培养法，研究了不同干旱处理方式对小麦幼苗Fe、Zn两种元素吸收和分布的影响。将10 d苗龄（3叶期）小麦幼苗分为5组，其中4组每天分别干旱1、2、3和4 h后复水，连续8 d，另外一组连续干旱24 h后复水，测定各处理的根、叶相对含水量和根、茎、第一叶、第二叶、第三叶Fe、Zn含量。

When a four-leaf clover is found, it's considered lucky, since they occur on average only once for every 10,000 three-leaf clovers.

当一种四叶苜蓿被发现，它就被认为幸运的象征，因为几乎只有在10000片三叶草中才会找到一片四叶苜蓿。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。