The Components of Plant Tissue Culture Media ll:
Organic Additions, Osmotic and pH Effects,
Growth and morphogenesis of plant tissue
cultures can be improved by small amounts of some
These are mainly vitamins
(including some substances that are not strictly
animal vitamins), amino acids and certain undefined
The amount of these substances
required for successful culture varies with the species
and genotype, and is probably a reflection of the
synthetic capacity of the explant.
Vitamins are compounds required by animals in
very small amounts as necessary ancillary food
Absence from the diet leads to abnormal
growth and development and an unhealthy condition.
Many of the same substances are also needed by plant
cells as essential intermediates or metabolic catalysts,
but intact plants, unlike animals, are able to produce
their own requirements.
Cultured plant cells and
tissues can however become deficient in some
factors; growth and survival is then improved by their
addition to the culture medium.
In early work, the requirements of tissue cultures
for trace amounts of certain organic substances were
satisfied by “undefined” supplements such as fruit
juices, coconut milk, yeast or malt extracts and
These supplements can contribute
vitamins, amino acids and growth regulants to a
The use of undefined supplements
has declined as the need for specific organic
compounds has been defined, and these have become
listed in catalogues as pure chemicals.
THE DEVELOPMENT OF VITAMIN MIXTURES
The vitamins most frequently used in plant tissue
culture media are thiamine (Vit. B
), nicotinic acid
(niacin) and pyridoxine (Vit. B
) and apart from these
three compounds, and
-inositol, there is little
common agreement about which other vitamins are
The advantage of adding thiamine was discovered
almost simultaneously by Bonner (1937, 1938),
Robbins and Bartley (1937) and White (1937).
Nicotinic acid and pyridoxine appear, in addition to
thiamine, in media published by Bonner (1940),
Gautheret (1942) and White (1943b); this was
following the findings of Bonner and Devirian (1939)
that nicotinic acid improved the growth of isolated
roots of tomato, pea and radish; and the papers of
Robbins and Schmidt (1939a,b) which indicated that
pyridoxine was also required for tomato root culture.
These four vitamins;
-inositol, thiamine, nicotinic
acid, and pyridoxine are ingredients of Murashige
and Skoog (1962) medium and have been used in
varying proportions for the culture of tissues of many
plant species (Chapter 3).
However, unless there has
been research on the requirements of a particular
plant tissue or organ, it is not possible to conclude
that all the vitamins which have been used in a
particular experiment were essential.
The requirements of cells for added vitamins vary