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1、植物病害标本的采集制作与保存（Collection and preservation of plant disease specimens）Collection and preservation of plant disease specimensPlant disease is an indispensable material for the undergraduate teaching of plant pathology in higher agricultural colleges. It has the characteristics of intuitionistic, unse
2、asonal and regional restriction in teaching. Therefore, the collection, production and preservation of plant disease specimens are essential knowledge and skills in the experimental teaching of plant pathology.Collection of plant disease specimensBecause of the clear season in the north, the crop va
3、riety is abundant, the plant disease is frequent, most of the plant disease samples can be collected from the fields. However, the occurrence of disease has a certain rule, it is necessary to master the seasonal law of the disease and the growth rule of the host to obtain the typical specimens.1.1 t
4、ools for collection of disease specimensPlant disease occurs mostly in the root, stem, leaf and fruit, so the tools used for different parts, the commonly used tools have knives, scissors, hoe, saw, etc., and specimen holder, small specimens of specimen box, paper, glass bottle, paper bags, tags, an
5、d pads, etc.1.2 specimen collectionThe field collection is mainly divided into season and host collection. Seasonal collection is mainly aimed at the diseases that occur at certain times of the year. The wheat powdery mildew can be collected from may to June every year, such as powdery mildew. The p
6、lants grey mould is prone to disease in cold and rainy conditions and is easiest to pick up from march to may. According to host collection, mainly for the wide range of diseases, such as downy mildew, can be found on the leaves of many plant diseases, common lettuce, grape, cabbage, etc. Diseases s
7、uch as tomato, potato, pepper and so on.1.3 record of specimen collectionIn order to distinguish different specimens collected, records should be recorded. It mainly includes the host name, time and place, the name of the collection person, the main occurrence situation and the necessary ecological
8、environment factor.The preparation of plant disease samplesAfter the specimen has been collected, it is usually preserved by drying or impregnation, and the original character of the specimen can be preserved as far as possible. Minor can make glass specimens, more difficult to save and special of s
9、pecimens by multimedia scanning system or microscopic system in the computer, made the corresponding style graphics, animation, video, images, etc.2.1 specimen drying method2.1.1 suppression. The collected plant disease specimens, if dry and easy to retract (such as rice leaves), preferably with the
10、 pressure. The other can be put in the collection box to take back pressure on the water absorbent paper, with the specimen clamping, sun drying. In the meantime, change the specimen paper frequently. Summer temperature and humidity are high, easy to make the specimen mouldy and discolored, specimen
11、 paper to be replaced frequently. Usually the first 3 4 d is 1 2 / d, and 2 3d-3d-3d-1, until the specimen is completely dry.2.1.2 hot dry or silica gel drying method. These two methods can be used for specimens that are not prepared for separation. Specimens in order to speed up the drying speed, b
12、etter keep specimens from the original color, just the samples can be rapidly back and forth on absorbent paper or cloth with electric iron very hot dry or paper and loads it dry specimen holder of silicon powder were bound tightly,In 50 oven for 2 3 d, make the dry quickly.2.1.3 microwave oven dryi
13、ng and preserving color method. In order to make up for the deficiency of hot dry method, liu chunyuan et al. (2003) reported on the quality of the samples of plant diseases, and fumbled a set of microwave drying and colorizing method. This method is dry and fast, the color preserving effect is bett
14、er, but it can be kept for a long time and will not fade. If the leaf of leguminous plant disease 1 min, the effect is optimal, the symptom is preserved intact.2.1.4 freeze-drying method. Its a good way to do it. The specimen is dried in freezing conditions and almost completely retains its original
15、 color and shape.2.1.5 natural drying method. Water few specimens such as the branch of stem disease, do not need to take any dry means, in the air naturally dry can.The method of preparation of the dipping specimenThe impregnation can be preserved by impregnation of the fruit disease and the diseas
16、e of the juice and the granule of the fleshy and basidiomycetes. However, this method occupies a large area and has limited storage time. It can only be used to save a small number of specimens, which are mostly used for teaching and demonstration. The preparation of the impregnated specimen requires various types of impregnation fluid, mainly including various preservative and preservative preservative
