科学技术正改变着三大绿魔

众所周知的三大绿魔，是祸害西南部的紫茎泽兰、祸害东南部河道的水葫芦、祸害沿海滩涂的大米草。在一段时间内，三大绿魔疯狂肆虐，给我国的生态造成了巨大灾难，负责生态重建的科学家们正在不遗余力地努力对它们进行根治，尽管困难重重，但是科学家们的不懈努力，还是给人们带来了鼓舞和希望。     

Effects of osmotic stress on antioxidant enzymes activities in leaf discs of P<Subscript>SAG12</Subscript>-<Emphasis Type="Italic">IPT</Emphasis> modified gerbera

Leaf senescence is often caused by water deficit and the chimeric gene PSA612-1PT is an auto-regulated gene delaying leaf senescence. Using in vitro leaf discs culture system, the changes of contents of chlorophylls, carotenoids, soluble protein and thiobarbituric acid reactive substance （TBARS） and antioxidant enzymes activities were investigated during leaf senescence of PSA612-1PT modified gerbera induced by osmotic stress compared with the control plant （wild type）. Leaf discs were incubated in 20%, 40% （w/v） polyethylene glycol （PEG） 6 000 nutrient solution for 20 h under continuous light [ 130 μmol/（m^2·s）]. The results showed that the contents of chlorophylls, carotenoids and soluble protein were decreased by osmotic stress with the decrease being more pronounced at 40% PEG, but that, at the same PEG concentration the decrease in the transgenic plants was significantly lower than that in the control plant. The activities of superoxide dismutase （SOD）, catalases （CAT）, ascorbate peroxidase （APX）, guaiacol peroxidase （GPX） and dehydroascorbate reductase （DHAR） were stimulated by PEG treatment. However, the increases were higher in PSA612-IPT transgenic plants than in the control plants, particularly at 40% PEG treatment. Lipid peroxidation （TBARS content） was increased by PEG treatment with the increase being much lower in transgenic plant than in the control plant. It could be concluded that the increases in the activities ofantioxidant enzymes including SOD, CAT, APX, GPX and DHAR were responsible for the delay of leaf senescence induced by osmotic stress.     

生命中的那些草儿

<正>一草是农民保留到最后的一份遗产,草是牧民缩写在大地上的柔韧鞭影,草是沙漠尽头生命的第一见证,草是孤守野花的忠诚卫士,草是倒写在人们心中的"小"字。     

粉花月见草中总黄酮含量的分析测定

目的：测定粉花月见草中总黄酮的含量。方法：以无水乙醇作为回流提取溶剂,在375nm处用紫外可见分光光度法测定粉花月见草中总黄酮的含量。结果：测得粉花月见草中总黄酮的含量为1.4435mg/g,精密度RSD=0.14%（n=5）,回收率为90.87%～98.98%。结论：该方法操作简便、准确、可靠,可用于植物中总黄酮的含量测定。     

为心灵除“草”

一群即将出师的弟子正坐在草地上等待老师出考题．只见老师挥手指了指四周说：“我们的周围是一片杂草丛生的旷野．我想问大家的是：要除去这些杂草,用什么方法最好？”     

南方菟丝子寄生对喜旱莲子草叶片光合特性的影响

以盆栽的喜旱莲子草（Alternanthera philoxeroides）为实验材料,研究了南方菟丝子（Cuscuta australis R.Br.）寄生对喜旱莲子草叶片光合特性的影响。结果表明,南方菟丝子寄生致使喜旱莲子草叶片的净光合速率（Pn）、蒸腾速率（E）、气孔导度（Gs）、水分利用率（WUE）、气孔限制值（Ls）、Fm值、Fv/Fm值和相对叶绿素含量都呈现明显的下降,而胞间CO2浓度（Ci）和Fo值表现出相反的趋势。南方菟丝子的寄生减弱了喜旱莲子草的光合作用,而净光合速率的下降主要是由非气孔因素限制引起的。     

一个农民·一座城市·一部心灵成长史——刘玉栋长篇新作《年日如草》研讨

在长篇小说创作凋零和缺失状况下,刘玉栋《年日如草》的出版,对于刘玉栋本人和整个70后作家群来说,都是一个很重要的突破。从＂二十世中国文学史＂的角度来看农民与城市的关系,农民如何融入城市、进入城市是一个现代化、城市化的中心问题。刘玉栋的《年日如草》塑造了一个适应现代城市生活的二代农民形象,一个带有某种狡黠而不失善良本性的、以法律取代人情意识的农民形象。这是以往文学史所没有的,具有突破性意义。     

探研氮素对返魂草生长的影响

以采自通化县兴林镇朝阳林场修正返魂草生产基地的返魂草实生苗为试材,采用砂培法对返魂草进行缺氮培养,并检测有缺素表现时植株内氮含量.结果表明,返魂草缺氮时,植株生长受阻,老叶首先出现黄斑,黄斑逐渐扩增至整个叶片,至叶片全部枯黄,并且生长点干枯,严重时死亡;随着缺氮培养时间的增加返魂草体内氮含量逐渐降低.