The Influence of Humidity Upon Transpiration and Growth in Psilocybe Cubensis

ABSTRACT

The influence of humidity upon individual basidiocarps of of Psilocybe cubensis was studied using an environmentally controlled wind tunnel and a computer program which helped to model growth and development. Regression models were developed which were able to explain 77% of the variation in the transpiration rate and 68% of the variation in growth rate. Transpiration and growth of this mushroom were significantly correlated with the humidity of the air. The fastest growth and the lowest transpiration occurred at the highest humidities. No inhibition of growth was detected at 0 pascals VPD (100% RH). Misting accelerated growth and transpiration while light had no effect. Although humidity was a very important factor influencing transpiration and growth, the size and shape of the mushroom were also important in water relations. The final water content of basidiocarps with thin stipes or those with larger surface area-to-volume ratios was significantly lower that of thickstiped mushrooms or those with small surface area-to-volume ratios even when grown under equal humidity. Growth rates under conditions which promoted the highest levels of hydration of the basidiocarp were rapid (up to estimated 4% increase in dry weight per h).

Key Words:

• transpiration
• humidity
• growth
• mushroom