What is the summary of the collection and production of plant specimens?

Plant specimens are of great value for mastering the basic knowledge of botany, scientific research materials and popular science propaganda, and providing scientific basis for the development and utilization of national natural resources. Learning to collect and make plant specimens is an important step to cultivate the practical ability of plant taxonomy and identify and classify plants, and it is also the basic skill for students to engage in related teaching and scientific research in the future. Through the collection of plant specimens, we can not only master the collection method, but also observe and study the morphology, phenology, ecological environment characteristics and distribution law of plants on the spot.

Plant specimens can be divided into the following four types according to the purpose of use.

(1) entire sample

The whole specimen is mainly used to identify plants, scientific names and Chinese herbal medicines. Usually, this specimen is also used for vegetation investigation in a certain area. For example, when investigating the plant resources of a school or a hill, the vegetative organs of higher plants, such as roots, stems and leaves, are one of the basis for identifying plants, but they are often different due to different growing environments, while flowers and fruits have relatively stable heritability, which can best reflect the inherent characteristics of plants and are an important basis for identifying and identifying plants. Therefore, when collecting specimens, we must try to collect specimens with roots, stems, leaves, flowers and fruits. Herbs also have to dig underground. It can be seen from the root system whether it is annual or perennial. In addition to rhizome, there are often abnormal roots and stems in the underground part, such as water chestnut, lily, Jerusalem artichoke, Chinese cabbage, Polygonatum sibiricum, Fritillaria, seven leaves and one flower. Woody plants should collect representative branches, preferably with a small piece of bark. The shape and arrangement of sporangium, rhizome, scales and indumentum are important taxonomic characteristics of ferns, which should be paid attention to when collecting. The whole specimen is often made into wax leaf specimen and primary color impregnation specimen.

(2) Anatomical specimens

Anatomical specimens are mainly used to observe and study the internal tissue structure of an organ of a plant. For example, dissect the bulb of onion and observe the structure of its basal plate, bud, bulb and fibrous root. Observe the lateral membrane placentation and seed placement position of melon in the cross section of cucumber; Cut the peach blossom vertically and observe the various parts and shapes of the flower. To collect such specimens, only one healthy and representative organ needs to be selected, and it is not necessary to collect the whole branch. Anatomical specimens are usually made into preservative impregnated specimens.

(3) Phylogenetic specimens

The purpose of making phylogenetic specimens is to observe and study the life history of plants, that is, the process of a plant from seed germination to growth, flowering and fruiting, which is often used in biology teaching, introduction and cultivation and scientific research. Specimens of such plants must be collected at different growth and development stages, such as the germination process of kidney bean and corn seeds, the germination of their embryos, the growth of main roots and buds, and the growth of true leaves. This specimen can be made into wax leaf specimen or impregnated specimen.

(4) Comparing specimens

Comparative specimens mainly compare the similarities and differences of an organ of different plants. For example, to compare the seed morphology of dicotyledonous plants and monocotyledonous plants, it is necessary to collect mature fruits, such as rape, soybean, cucumber and tomato, remove the peel, dry the seeds, and collect the fruits of wheat, rice and corn for comparison. Compared with various forms of roots, we can collect cotton with straight roots, rice and wheat with fibrous roots, radish with bulbous roots, carrot with conical roots, radish with cylindrical roots, adventitious roots of tuber sweet potato, corn and sugarcane, and parasitic roots of Cuscuta chinensis and Taxilli. Comparing stems of various shapes, we can collect peaches and banyans with erect stems, morning glory and honeysuckle wrapped around the stems, creeping strawberries, grapes, gourds and Parthenocissus tricuspidata, prickly hawthorn and acacia, succulent cactus and epiphyllum, water chestnut and cabbage with bulbs, onion and garlic with bulbs, etc. Compared with various corollas, we can collect peach blossoms with petals, rape and shepherd's purse with cross corollas, soybeans, rosewood and broad beans with butterfly corollas, safflower with tubular flowers, Jerusalem artichoke with tongue-shaped flowers, and wheat flowers with monocotyledonous leaves. Comparing various inflorescences, we can collect Chinese cabbage in raceme, plantain in spike, sunflower in umbel and sunflower in head. Comparing fruits of various shapes, we can collect plums and apricots and drupes, persimmons and grapes and berries, apples and pears and pears, peas and Robinia pseudoacacia and pods, radishes and Indigofera and pods, sunflowers and achenes, rice and wheat and caryopsis, elms and Acer and samara. The contrast specimens can be made into wax leaves or air-dried specimens, and the effect of soaking fruits in primary colors is better.