"观察SO2对植物影响"实验的改进

高三选修教材中,选用黄瓜幼苗作实验材料来观察SO2对植物的影响,经过反复实验,发现改用南瓜苗效果非常好。具体做法如下：     

植物单盐毒害实验的改进

单盐毒害是指将植物培养在某种单一的盐溶液中,不久即出现不正常的状态,表现为根系停止生长,生长区细胞粘液化,细胞破坏,变为一团没有结构的粘液,最后整株植物死亡。单盐毒害实验是一个经典的实验,至今仍然列入植物生理学实验教材中(侯福林2004;叶尚红2007)。     

关于"增强UV-B辐射和SO2作用下植物光合响应及其相对抗性"中几个问题的讨论

植声 :有研究表明 ,Fv/Fm的下降在一定程度上不会影响光合速率的下降 ,与本研究的结果相左 ,如何解释 ?孔振令等 :关于Fv/Fm下降。一般意义上讲Fv/Fm下降都会引起光合速率的下降。正如文章所提出它是一个稳定值除非受到胁迫。它表征PSII中心光能转化的效率 ,当它下降时即发生了荧光的　灭 ,表明吸收的光能分配到光合电子传递途径上的量减少 ,而分配到热耗散途径的量增加。Fv/Fm恢复的快慢决定了光合能力能够维持在一个什么样的水平上。因为P(光化反应 ) +D(热耗散 ) +F(荧光 )=1 (或 0 .8) ,其中任何一个成分的变化都会影响其他成分的…     

对"植物体内的转氨基作用"实验的改进

“植物体内的转氨基作用”是生物化学的一个基础实验。在多年的实验教学中,我们发现常用的实验方法（参阅赵亚华主编的《生物化学实验技术教程》,有些步骤值得改进,比如沸水浴加热10min、用针线缝合层析纸、用喷雾器喷雾茚三酮丙酮溶液等操作不方便,且比较复杂、费时,还有有毒物质挥发,影响师生身体健康;又如原实验中规定使用的有些实验仪器如层析缸、喷雾器等并非实验室常用仪器,实验室里不一定具备,影响陔实验的进行。为此,我们结合我校的实际,对该实验进行了一些改进,使实验方法简单、易行,取得了良好的实验效果。     

关于"观察二氧化硫对植物的影响"实验的思考

1 原实验设计所存在的问题 人教版高中《生物》必修教材第2册“实验十二观察二氧化硫对植物的影响”中存在下列不足：①由于先在稀硫酸中投入亚硫酸钠，后加盖玻璃罩，不管动作多么迅速，还是存在二氧化硫逸散现象。②虽然要求在玻璃罩与玻璃板之间用凡士林密封，但就其整个实验装置而言，其气密性还是不够好。③特别是实验完成后，撤离装置时，一揭开玻璃罩，装置内的二氧化硫全部进入空气中。因此上述几个方面都说明，该实验设计存在污染空气和有害师生健康的不足，也不利于对学生进行保护环境方面的教育。     

酸雨和SO2暴露对一些不同抗性幼树的影响

酸雨和ＳＯ２暴露对一些不同抗性幼树的影响陈树元徐和宝谢明云张福珠苗鸿张宏瑞（江苏省中国科学院植物研究所,南京２１００１４）（中国科学院生态环境研究中心,北京１０００８５）ＥｆｅｃｔｓｏｆｔｈｅＡｃｉｄＲａｉｎａｎｄＳｕｌｆｕｒｉｃＤｉｏｘｉｄｅＥｘｐ...     

对"观察细胞质流动"实验的改进

“用高倍显微镜观察叶绿体和细胞质流动”是高中《生物》(必修)教材中的重要实验之一。在辅导学生实验的过程中,我们发现,学生往往只看到叶绿体,难以观察到细胞质流动,这里面有学生自身操作的原因,也与材料和实验方法有关。如何让全体学生都能在实验室观察到细胞质流动现象,笔者对该实验进行了一些改进。     

植物组织水势测定实验的改进

植物组织水势的测定是植物生理学中的基础实验,通过小液流移动方向可以直观地表示植物组织与外界溶液之间水分交换的动向,并准确地求出组织的等渗浓度。在教学过程中,我们发现     

旅游活动对张家界国家森林公园植物的影响

 旅游活动对旅游地环境的影响几乎是不可避免的,尤以对植物的影响最为显著。随着游客的大量增多及旅游宾馆酒楼释放的废气污染物的急剧增加,张家界国家森林公园境内的植物遭受了较为严重的污染和伤害。为了探明旅游活动对张家界国家森林公园植物生长发育、体内化学物质成分及林木树干伤害等方面的影响,该研究采用对比分析法,调查分析了公园内受大气污染较为严重的接待区的几种林木叶内氟化物和SO2含量及杉木(Cunninghamia lanceolata)生长速度的变化,同时还对游道两边树木受游客刻伤的程度进行了调查分析。结果表明,公园接待区杉木、柳杉(Cryptomeria fortunei)、枫杨(Pterocarya hupehensis)叶片中氟化物及SO2含量较对照区增大了1.6～16倍;杉木的直径生长量较对照区降低了32.3%～57.1%;游客的乱刻乱划给金鞭溪、黄石寨等景区游道两边的林木留下了许多伤痕,这些伤痕主要分布在离地面1.2～1.6 m的部位,受伤程度与树种、树皮光滑程度、树干与游道边缘距离及方位有关。为了保护公园内的植物,必须改善公园内的燃料结构,减少接待设施的数量,并加强对游客的环保教育。     

Role of Polyamines in SO2-Polluted Pea Plants

The effect of SO₂ fumigation on free and bound putrescine andspermidine has been investigated in pea plants grown in nitrate-basedand ammonium-containing nutrient solutions. Both amines increasesignificantly more in response to SO₂ fumigation when 50% ofthe nitrate nitrogen is substituted by ammonium. Amine levelsare also increased in the unfumigated, ammonium-supplied plantsrelative to the exclusively nitrate-supplied ones. Since bothSO₂ pollution and ammonium nutrition increase the H⁺ ion concentrationof the cells and cause a shift in the cation/anion ratio, itis concluded that with both treatments amines are synthesizedto bind these H⁺ ions and to compensate the relative cationdeficit. The importance of this mode of metabolic bufferingis discussed and its effectiveness calculated.     

Effect of SO2 on phloem loading

Phloem loading, measured in vivo using carbon-11, is shown to be immediately reduced when SO₂ is applied to a leaf of a C₃ plant, but no immediate effect is seen on a C₄ plant. This C₃-C₄ difference is similar to that seen with anoxia, and it is proposed that it is associated with the different anatomical structures in the vicinity of the vascular tissue, the Kranz anatomy of the C₄ plants providing a barrier so that SO₂ does not have an immediate effect on phloem loading.     

SO2 Tolerance of Tobacco Plants Regenerated from Paraquat-Tolerant Callus

To establish whether SO₂ tolerance of plants is related to theirability to defend themselves against the toxicity of activeoxygen, this study examined the SO₂ tolerance of paraquat-toleranttobacco plants (Nicotiana tabacum L. cv. Samsun), which hadbeen regenerated from paraquattolerant callus. When the testplants, which had higher superoxide dismutase activity thanthe control ones, were fumigated with 2ppm SO₂, they showedtolerance, while the control ones suffered severe damages. Theseresults indicate that SO₂ toxicity in plants is caused by activeoxygen and that superoxide dismutase participates in counteractingSO₂ toxicity. (Received December 17, 1987; Accepted March 24, 1988)     

The Protective Effect of Phosphate Buffer on SO2 Harmed Wheat Seedling

When 1/15 mol/L of phosphate buffer at pH 6. 4, was used to spray wheat seedling three times, the plasmolemma structure become stabilized and k+ efflux was decreased. After fumigation with SO2 the K+ efflux of wheat seedling ,sprayed with phosphate buffer, decreased markedly. At SO2 dosage of 1.54 ppm × 4h, the decreasing rate of K+ efflux was 54. 11%–81.29% and the decrease rate was in concert with the increase of SO2 dosage. Therefore, the authors consider that the phosphate buffer, at pH 6.4, has a good protective effect against SO2 insult.     

The Effect of Plants on Mineral Weathering

This paper is centered on the specific effects of plants on the soil weathering environment; we attempt to address how to quantify this component of the ecosystem and assess feedbacks between plants and weathering processes that influence the degree and rates of mineral weathering. The basic processes whereby plants directly influence the soil chemical environment is through the generation of weathering agents, biocycling of cations, and the production of biogenic minerals. Plants may indirectly influence soil processes through the alteration of regional hydrology and local soil hydrologic regime which determines the residence time of water available for weathering. We provide a brief review of the current state of knowledge regarding the effects of plants on mineral weathering and critical knowledge gaps are highlighted. We summarize approaches that may be used to help quantify the effects of plants on soil weathering such as state factor analyses, mass balance approaches, laboratory batch experiments and isotopic techniques. We assess the changes in the soil chemical environment along a tropical bioclimatic gradient and identify the possible effects of plant production on the soil mineralogical composition. We demonstrate that plants are important in the transfer of atmospheric carbon dioxide into the mineral weathering cycle and speculate how this may be related to ecosystem properties such as NPP. In the soils of Hawaiian rainforests subjected to deforestation, pasture grasses appear to change the proportion of non crystalline to crystalline minerals by altering the soil hydrologic regime or partitioning silica into more stable biogenic forms. A better understanding of the relationship between soil weathering processes and ecosystem productivity will assist in the construction predictive models capable of evaluating the sensitivity of biogeochemical cycles to perturbations.     

Improvement of photoluminescence of Cu+ ion in Li2SO4

The synthesis of the Li₂SO₄: Cu phosphor using a wet chemical method is reported here. The XRD technique showed the crystalline nature of the prepared material. The presence of Na and K in the host affected the observed photoluminescence characteristics of Li₂SO₄: Cu. Photoluminsecent emission spectra of Li₂SO₄: Cu phosphor showed a very strong prominet peak at 387 nm in the indigo region due to 3d⁹ 4 s¹ ? 3d¹⁰ transition of the Cu⁺ ion. The increase in peak intensity of the PL spectrum suggests that Cu⁺ acts as the luminescence center in the present matrix. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of SO2 on control of breathing in anesthetized cats

In seven anesthetized tracheotomized cats we studied the acute respiratory effects of SO2 inhalation at different steady-state levels of arterial CO2 tension (Paco2). During room air breathing, SO2 (0.05%) addition caused a progressive reduction in tidal volume (VT) and increases in both respiratory frequency (f) and pulmonary resistance (RL). Atropine sulfate abolished the bronchoconstriction response to SO2 and thus permitted the study of the influence of SO2 on VT and f in the absence of constricted airways. Despite marked reductions in the VT VS. PaCO2 relationships with SO2 exposure after atropine, the relationship between pulmonary ventilation (VE) and PaCO2 was not signifcantly altered. This was the case since SO2 caused solely a reduction in inspiratory duration (Ti), affecting neither the mean rate of rise of inspiratory activity (i.e., VT/Ti) nor the relationship between Ti and breath duration. Thus, airways irritation with SO2 produced rapid, shallow breathing characterized by a shortening of inspiratory and total respiratory cycle times with no change in the rate of development of inspiratory activity. The findings suggest an influence exclusively concerned with the timing of inspiration. Perhaps premature onset of inspiratory activity accounts for the observed effects.