GROWING GOURMET - Anto2ni.it

eads:
FVITC P2
11/16/92
C # 0825905
This means: the strain,Flammulina velutipes
isolated from Telluride, Colorado, has grown
out over two petri dishes since its inception (in
this case 8190).The collection number refers to
the date the mushrooms were collected in the
wild: it was the fifth group of mushrooms found
that day. (Others sequentially list their collections,
from ito infinity.) The culture should be
referenced to a dried voucher specimen from
which the strain was generated. The dried specimens
are either kept in your own private
herbarium, or, better yet, deposited in an academically
recognized herbarium which
cross-indexes collections by date, species
name, and collector. Keeping a voucher collection
is critical so future researchers can
commonly refer to the same physical standard.
The date "1 1/16/92" refers to the time the
medium was inoculated. Spawn created from
such young cultures, in contrast to one grown
out twenty times as far, gives rise to more highly
productive mycelium. The "P" value system is
essentially a metric ruler for measuring relative
numbers of cell divisions from the culture's
birth. (Note that a square centimeter of mycehum
is generally transferred from one culture
dish to the next.) I have strains in my possession,
from which I regularly regenerate
cultures, which are ten years old and kept at a
P2 or P3. Having ten to twenty back-up culture
slants greatly helps in this pursuit.
For purposes of commercial production, I try
to maintain cell lines within that is, within
10 successive transfers to medium-filled petri
dishes. Many strains of Morels, Shiitake and
King Stropharia express mutations when trans-
THE STOCK CULTURE LIBRARY 107
ferred on media for more than 10 petri dishes.
Morels seem particularly susceptible to degeneration.
Morchella angusticeps loses its ability
to form micro-sc lerotia in as few as 6 or 7 plate
transfers from the original tissue culture.
The slowing of mycelium may also be partly
due to media specificity, i. e. the agar formula
selectively influences the type of mycelial
growth.To ameliorate degenerative effects, the
addition of extracted end-substrates (sawdust,
straw, etc.) favors the normal development of
mycehium. The introduction of the end-substrate
acquaints the mushroom mycelium with
its destined fruiting habitat, challenging the
mycelium and selectively activating its enzymatic
systems. This familiarity with the
end-substrate greatly improves performance
later on. Parent cells retain a"genetic memory"
passed downstream through the mycelial networks.
Mycelia grown in this fashion are far
better prepared than mycelia not exposed to
such cultural conditions. Not only is the speed
of colonization accelerated, but the time to
fruiting is shortened. Only 1-3 grams of substrate
is recommended per liter of nutrient
medium. Substrates high in endospores (such
as manures or soils ) should be treated by first
boiling an aqueous concoction for at least an
hour. After boiling, sugar, agar and other
supplements are added, and the media is sterilized
using standard procedures described in
Chapter 12.
By observing the cultures daily, the changeover
of characteristics defines what is healthy
mycelium and what is not. This book strives to
show the mycelium of each species and its transformafions
leading to fruiting. Variations from the
norm should alert the cultivator that the strain is
in an active state of mutation. Rarely do mutations
in the mycelium result in a stronger strain.
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