Chemistry, asked by twinklesinha202020, 5 hours ago

herbarium- is a collection of preserved plant specimens prepare a herbarium for type of each type of crop​

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Answered by RiyazAly2003
1

Answer:

Introduction

Herbarium is the collection of plant specimens arranged in the sequence of an accepted calcification. Plant specimens are dried, pressed and mounted on sheets. Fleshy parts of plants are collected in 4% formalin solution of F.A.A. Herbaria helps in providing correct knowledge of plants through representative specimens. Classification of Bentham and Hooker is followed in Common Wealth Countries including India.

Objectives

The main objectives of herbaria making are :

To preserve plant specimens for reference.

To identify plants on the basis of herbarium specimens.

To study the vegetation different localities at of various times intervals.

Equipment

The following equipment are used in the preparation of herbaria:

Herbarium Press

Vasculum

Scissors

One sharp knife

One pair of forceps

Hand lens and pocket lens

pocket diary

Method for the preparation of herbarium

Plant materials from Pteriodphyta, Gymnosperm and Angiosperms are normally preserved as dried and pressed specimens on herbarium sheets. Infect flowers and fruits should be taken while collecting Angiosperms, because without flowers and fruits identification of plants will be difficult. Therefore, 3 to 4 specimens of the same pants from different localities and different seasons are collected. Students should visit same habitat in different seasons to collect plant specimens. The main step to prepare herbarium sheet are:

Collection and pressing of specimens

Fresh materials are pressed in plant press in herbarium press. Three to four specimens of the same plant should be pressed. If the specimens is large then it should be pressed in "V" or "N" manner. If leaves and flower are crowded on the stem, then flowers and leaves can be detached and pressed on sheet in their natural arrangement. Underground parts should be made dust free before preserving. Aquatic plants should be properly spread in water and then uplifted and pressed carefully. To press fleshy organs, sponge pads should be used.

Drying of specimens

For drying of specimens, following two methods are used:

Drying of specimens without artificial heat : In this process plants are kept in herbarium press for 24 hours. Blotting paper will absorb moisture. Again this process is repeated with fresh blotting pater for 24 to 72 hours. Specimens become dry after such process but remain vulnerable to infection of mould and pests.

Drying of specimens with the help of artificial heat:

This is slightly different from previous method, here previously pressed and dried specimens are kept in drying press at adequate temperature ,water vapourizes and materials gets dried in short duration. Temperature management is important in this method because plants turn brown and brittle at high temperature.

Mounting of specimens on herbarium sheets

Well – pressed and dried specimens are mounted on 12'' X 18" herbariums sheets with the help of gum or fevicol containing 1% HgCl2 . Sometimes mixture of ethylcellulose and resin or cello-tape is used as mounting media. Holland cloth is also used for fixing specimens. In certain museums specimens are tagged to herbarium sheets with the help of needle and thread. Labeling is done after mounting.

Labeling of specimens

After fixing specimens on herbarium sheet the following information is entered at right side of the lower corner of herbarium sheet.

Serial number : -------

Botanical name : -------

Family : ---------

Genus : -------

Species : -------

Local name : --------

Place : --------

Habit : ---------

Date of collection : ----------

Place of collection : ---------

Collected by : ---------

Storage and filling of herbarium sheets

Properly mounted and labeled herbarium sheets are preserved for future records. Specimens are arranged according to recognized system of classification, i.e. Bentham and Hooker's, Engler and Prantl's system of classification. Indexing should be done for easy operation of herbarium.

Protection of herbarium sheets

The specimens mounted on sheets may be destroyed by beetles, booklouse, drugstore beetles and other insects during storage. This problem may be overcome by fumigation with suitable insecticides. DDT, Lauryl phenyl chlorophenate, carbon tetrachloride and other insecticides may also be sprayed on specimen. Naphthalene balls may also be used as repellent.

Conclusion

By following above methods and steps you would be able to prepare a good herbarium yourselves without any doubt. Please follow above procedure step by step to prepare a good herbarium.

Explanation:

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