The mushroom cultivator. A practical guide to growing mushrooms at home

Paul Stamets. The mushroom cultivator. A practical guide to growing mushrooms at home. - Agarikon press, 1983

Содержание

FOREWORD by Dr. Andrew Weil

PREFACE

I. INTRODUCTION TO MUSHROOM CULTURE

II. STERILE TECHNIQUE AND AGAR CULTURE

III. GRAIN CULTURE

IV. THE MUSHROOM GROWING ROOM

V. COMPOST PREPARATION

VI. NON-COMPOSTED SUBSTRATES

VII. SPAWNING AND SPAWN RUNNING IN BULK SUBSTRATES

VIII. THE CASING LAYER

IX. STRATEGIES FOR MUSHROOM FORMATION (PINHEAD INITIATION)

X. ENVIRONMENTAL FACTORS: SUSTAINING THE MUSHROOM CROP

XL GROWING PARAMETERS FOR VARIOUS MUSHROOM SPECIES

XII. CULTIVATION PROBLEMS AND THEIR SOLUTIONS: A TROUBLESHOOTING GUIDE

XIII. THE CONTAMINANTS OF MUSHROOM CULTURE: IDENTIFICATION AND CONTROL

XIV. THE PESTS OF MUSHROOM CULTURE

XV. MUSHROOM GENETICS

APPENDICES

GLOSSARY

BIBLIOGRAPHY

INDEX

PHOTOGRAPHY AND ILLUSTRATION CREDITS

ACKNOWLEDGEMENTS

OCR
Sterile Technique and Agar Culture/37

STOCK CULTURES: METHODS FOR
PRESERVING MUSHROOM STRAINS
Once a pure strain has been created and isolated, saving it in the form of a "stock culture" is
wise. Stock cultures—or "slants" as they are commonly called—are media filled glass test tubes
which are sterilized and then inoculated with mushroom mycelium. A suitable size for a culture tube
is 20 mm. x 1 00 mm. with a screw cap. Every experienced cultivator maintains a collection of stock
cultures, known as a "species bank". The species bank is an integral part of the cultivation process.
With it, a cultivator may preserve strains for years.
To prepare slants, first mix any of the agar media formulas discussed earlier in this chapter. Fill
test tubes one third of the way, plug with cotton and cover with aluminum foil or simply screw on the
cap if the tubes are of this type. Sterilize in a pressure cooker for 30 minutes at 1 5 psi. Allow the
cooker to return to atmospheric pressure and then take it into the sterile room before opening. Remove the slants, gently shake them to distribute the liquified media and lay them at a 1 5-30 degree
angle to cool and solidify.
When ready, inoculate the slants with a fragment of mushroom mycelium. Label each tube
with the date, type of agar, species and strain. Make at least three slants per strain to insure against
loss. Incubate for one week at 750 F. (24° C.). Once the mycelia has covered a major portion of
the agar's surface and appears to be free of contamination, store at 35-40 0 F. (2.40 C.). At these
temperatures, the metabolic activity of most mycelia is lowered to a level where growth and nutrient
absorbtion virtually stops. Ideally one should check the vitality of stored cultures every six months by

removing fragments of mycelium and inoculating more petri dishes. Once the mycelium has
colonized two-thirds of the media dish, select for strandy growth (rhizomorphism) and reinoculate
more slants. Label and store until needed. Often, growing out minicultures is a good way to check a
stored strain's vitality and fruiting ability.
An excellent method to save cultures is by the buddy system: passing duplicates of each
species or of strains to a cultivator friend. Mushroom strains are more easily lost than one might ex-

pect. Once lost, they may never be recovered.
In most cases, the method described above safely preserves cultures. Avid cultivators, however,
can easily acquire fifty to a hundred strains and having to regularly revitalize them becomes tedious
and time consuming. When a library of cultures has expanded to this point, there are several additional measures that further extend the life span of stock cultures.
A simple method for preserving cultures over long periods of time calls for the application of a
thin layer of sterile mineral oil over the live mycelium once it has been established in a test tube. The
mineral oil is non-toxic to the mycelium, greatly reduces the mycelium's metabolism and inhibits
water evaporation from the agar base. The culture is then stored at 37-41 ° F. until needed. In a re-

cent study (Perrin, 1 979), all of the 30 wood inhabiting species stored under mineral oil for 27
years produced a viable culture. To reactivate the strains, slants were first inverted upside down so
the oil would drain off and then incubated at 77 ° F. Within three weeks each slant showed renewed
signs of growth and when subcultured onto agar plates they yielded uncontaminated cultures.

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