Critical Preparation of Plant Material for Autoradiography.
Critical Preparation of Plant Material for Autoradiography.
复制标题
放射自显影植物材料的关键制备。
DOI：
10.1126/science.125.3240.192
复制
发表时间：
1957
期刊：
影响因子：
56.9
通讯作者：
A. Crafts
中科院分区：
文献类型：
--
作者：
J. E. Pallas;A. Crafts
自这些最初的研究以来，在放射自显影技术的许多应用中，有迹象表明，在自显影之前或期间对植物或植物部分进行的某些处理可能会使准确解释实验结果变得困难。在操作过程中以及在工厂死亡之后，移动的放射性示踪剂的移动使得不总是容易识别的伪影成为可能。如果研究的是通过一个特定的、离散的组织系统的运动，这一点尤其正确。密立根（3）观察到，在豌豆叶片的新鲜部分的自显影过程中，放射性锰从脉间组织进入豌豆叶片的静脉。他解释说，这是由于在对薄膜进行渗透时，将植物部分封闭在两片玻璃之间，从而限制了蒸发，并允许树液在静脉中移动。Rice和Rohrbaugh（4）研究了放射性2，4-二氯苯氧乙酸（2，4-D*）在煤油中的运动。他们发现，在施用后1/2小时收获的未切片的豆类植物，放置在植物压榨机中，并在60 ° C的烘箱中干燥，在签名时显示出2，4-D*，而在1小时后收获的切片植物显示出2，4-D* 仅到达茎和顶芽。结果表明，植物在干燥过程中或干燥后发生运动。作者认为，移动的假象可以解释的基础上，煤油通过毛细作用的细胞间隙的运动的容易性。工匠未能认识到的重要性，在干燥过程中的移动的假象在工作中的2，4-D*（5，图8）。这一错误已在随后的论文中指出（6）。目前的工作（7）是在努力测量和界定这一伪影，并找到方法来避免它。红芸豆种植（4英寸的花盆中每盆4粒种子），发芽，并在800英尺-ca的人工光下生长。出苗后不久将植物稀疏至每盆一株。在所有实验中，在第一片三叶叶开始展开时选择具有均匀植物的盆。治疗包括应用O.将含有5微克放射性2，4-D的50%乙醇溶液和0.10%的Nonic 218的01-ml液滴滴到叶片基部上方约1cm的一片初生叶的上表面。液滴被直径为5 mm的羊毛脂环限制。以0、1、2、4和8小时的间隔，通过冲洗根系并在干冰块之间快速冷冻，以8个一组的方式收获植物。然后在植物压榨机中在报纸和温吸墨纸之间干燥四个重复的植物，并且将其他四个重复保持冷冻并在连续冷冻状态下干燥（冻干）。在干燥后通过软木钻除去叶的处理区域。所有植物在冷藏条件下在Kodak No-Screen X射线胶片上签名15天。这部电影是在柯达液体X射线显影剂。
In the many uses of the autoradio-graphic techniquesince these initial studies, there are indications that certain treatments of plants or plant parts before or during autographing may make accurate interpretation ofexperimental results difficult. Movement of a mobile radioactive tracer during manipulation and after the death of the plant makes possible an artifact that is not always easily identifiable. Particularly isthis true if movement via a specific, discrete tissue system is being studied. Millikan (3) observed such a move-ment of radioactive manganese from the interveinal tissues into the veins of pea leaves during the autographing of fresh plant parts. He interpreted this to be a result of enclosing theplant part be-tween two sheets of glass during ex-posure to the films, thus limiting evapo-ration and allowing movement of sap in the veins. Rice and Rohrbaugh (4) studied the movement of radioactive 2, 4-dichlorophenoxyacetic acid (2, 4-D*) in kerosene. They found that unsectioned bean plants that were harvested I/2 hour after application, placed in a plant press, and dried in an oven at 60CC showed 2, 4-D* throughout upon autographing, whereas a sectioned plant harvested after 1 hour showed that 2, 4-D* had reached only the stem and terminal bud. It was pointed out that movement oc-curred while the plants were drying, or afterward. The authors thought that the artifact of movement could be explained on the basis of the ease of movement of kerosene through the intercellular spaces by capillarity.Crafts failed to recognize the importance of the artifact of movement during drying in work on translocation of 2, 4-D*(5, Fig. 8). This error has been pointed out in a subsequent paper (6). The present work (7) was done in an effort to measure and delimit this artifact and to find methods for avoiding it. Red kidney beans were planted (four seeds per pot in 4-inch pots), germinated, and grown under artificial light of 800 ft-ca. The plants were thinned to one per pot shortly after emergence. In all experiments, pots with uniform plants were selected at the time the first trifoliate leaves were beginning to expand. The treatment consisted in applying a O. Ol-ml droplet containing 5 gg of radio-active 2, 4-D in 50-percent alcohol solution with 0.10-percent Nonic 218 to the upper surface of one of the primary leaves about 1 cm above the base of the blade. The droplet was confined by a lanolin ring 5 mm in diameter. At intervals of 0,'/2, 1, 2, 4, and 8 hours, plants were harvested in groups of eight by washing out the root systems and quick-freezing between blocks of Dry Ice. Four replications of plants were then dried between newspaper and warm blotters in a plant press, and the other four replications were kept frozen and dried in the continuous frozen state (lyophylized). The treated areas of the leaves were removed after drying by means of a cork borer. All plants were autographed under refrigeration un Kodak No-Screen x-ray film for 15 days. The film was developed in Kodak liquid x-ray developer.