地上有草

如果一块土地能很好地生长庄稼,那么它就一定能生长出一片丰茂的草来;如果一片土地不能很好地生长出庄稼,那么,它也可能会长出一片丰茂的草来。     

普罗旺斯:美到极致的简约格调

世界上只有很少的几个地方,清晨可以这样优雅地醒来。这里的天空,似乎永远是湛蓝色的,金色的阳光仿佛从天上倾泻下来,浓密而黏稠。这里,就是熏衣草的天堂普罗旺斯,从地中海沿岸延伸到内陆的丘陵地区,自古就以饱满的阳光和蔚蓝的天空令世人惊艳。从诞生之日起,普罗旺斯就谨慎地保守着她的秘密,直到英国人彼得·梅     

与巴金对话——《鸟的天堂》教学新思考

巴金先生的《鸟的天堂》自编入小学教材以来，其文本意蕴从美的角度、善的角度、博爱的角度、环保的角度等被人们进行了充分的挖掘。人们探讨了“天堂”的美、神奇与和谐，感受了鸟的快乐与无忧，并为它建构了各种极具个性的学习模式。然而，捧起文本，再仔细品读，发现巴金先生似乎不只是要告诉我们这些。在他的文章里“鸟”与“天堂”都是重点．[第一段]     

落雪时节最思乡

冬日,是思念的季节。这个季节,我的思念是那一片片的雪花。这个季节的寒冷让我想念故乡家中的火炕,想起,大山脚下的村庄。倾听,那风的怒吼声,心哆嗦,眼角竟然流出一滴泪水。我珍惜每一个落雪的日子。落雪时节,人间成了黑与白的世界。那散发着温暖的家是我们心灵的天堂。     

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。     

精英与草根

“那是最美好的时代,那是最糟糕的时代;那是智慧的年头,那是愚昧的年头;那是信仰的时期,那是怀疑的时期;那是光明的季节,那是黑暗的季节;那是希望的春天,那是失望的冬天;我们面前什么都有,我们面前什么也没有;我们全都在直奔天堂,我们全都在直奔相反的方向。”这是英国大文豪狄更斯在他的名著《双城记》的经典开场自,说它经典,是因为一百多年之后,这个评价即使原封不动地挪过来作为对这个时代的概括,恐怕也还是相当之贴切的。     

身下地狱，心在天堂——黄山西海大峡谷徙步大穿越

自小在衡山脚下生长,见多了山中深厚的寺庙文化,烟雾缭绕。却常听人说“五岳归来不看山,黄山归来不看岳”,倒也惦念起来,黄山的奇松、怪石、云海,频频出现在各大媒体。如此这般的美伦美奂,让人心动。心动不如行动,尤其于我这般酷好登山之人。     

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.