LABORATORY PROCEDURES FOR PLANT CELL LINES
REFERENCE NO.: PC/1998/3/1.1
TITLE: EVALUATION OF GROWTH COLOUR AND MORPHOLOGICAL CHARACTERS OF CALLUS CULTURES
To be able to recognise changes in the characters of callus morphological characteristics, cell line growth and colour are evaluated and recorded by quick and simple means. The major aim is that ease and simplicity of the method guarantees the practicability and regular update of the evaluation process. To achieve these goals it is accepted that the evaluation is not based on quantitative measurements but on personal judgement made by a specialist.
1. Evaluation of all characters has to be carried out by at least two members of the staff who have to agree on the characters observed.
2. Evaluation of all characters should be performed with each culture once a year.
3. Evaluation should start with the observation of growth. Evaluation of all other characters of one cell line has to be finished within one month after entering the code number for growth into the computer.
4. For the evaluation of growth the increase in callus volume is observed over two growth cycles.
The following code numbers are used to describe growth: no growth = code no. 0; 30 - 50 % increase of cell material (callus volume) = code no. 1; 50 - 100 % increase of cell material (callus volume) = code no. 2, 100 % increase of cell material (callus volume) or more = code no. 3
5. Consistency of the callus should be judged shortly after or ideally during regular transfer
The following code numbers are used to describe the consistency of callus: very soft = code no. -2; soft = code no. -1; medium = code no. 0; rigid = code no. +1; very rigid = code no. +2.
6. The colour has to be judged in a late growth stage of the culture whilst no signs of deterioration occurs.
The following abbreviations are used for colours: K = black; U = blue; G = green; B = blue; Y = yellow; O = orange; R = red; V = violet; W = white.
A distinct colour is described by one or the combination of two code letters (example: R = red; YO = yellowish-orange).
When two different distinct colours occur in one callus, the colour letters for the different colours are separated by / (example R/W = the callus has parts which are completely white and other parts which are completely red).
Each colour is characterized also by a code number for its intensity; code numbers are: 1 = low intensity; 2 = strong intensity; 3 = very strong intensity.
Example: GU1/RV3 = a callus which has greenish-blue parts of low colour intensity and reddish-violet parts of very strong color intensity.
7. The morphology of the callus should be also judged at the late growth stage. It is described by 6 words which should represent typical forms of callus material (the words have originally been chosen by the technical staff of the collection - the original words are German, a translation into English is difficult and may characterize the original words only partially).
Code words for callus morphology (original German words): K = knochig; B = brockig; Ö = bröselig; H = homogen; W = wattig; S = schleimig
Code words for callus morphology (English translation): K = bony; B = friable; O = very friable; H = homogeneous; W = cotton like; S = slimy
8. The occurrence of differentiated structures in the callus material should be recorded by a code letter.
Code Letters are: W = Wurzeln (English: roots); S = Sprosse (English: shoots); E = Embryonen oder embryonenaähnliche Strukturen (English: embryos/ embryogenic structures).
Guidelines prepared for CABRI by DSMZ, 20 Jan. 1998
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