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Greenhouse Quality Control

Procedures in the greenhouse focus on maximizing productivity of cultures (optimal relationship between plant growth, mycorrhiza biomass, and fungal sporulation) and insuring that these cultures remain free of contaminating microbes and pests that might spread particulates from one culture to another or be a detriment to plant health.

Select any room to see procedures used in that location.

  Lab   Growth

South Agricultural Sciences BuildingThe greenhouse space in the map above and in the photo at right has been dismantled in order to reface the South Agricultural Sciences Building with brick (to match all other new buildings now being constructed on the Evansdale campus). This greenhouse was used extensively between 2006 and 2012, but it had many problems because there was no cross-through ventilation. As a result, temperatures were stratified so that often in winter months temperature at plant level was 80-90°F during the day, but 50-60°F at the pot level or below. Benches were at a fixed height, preventing any height adjustment of pot cultures. In the winter of 2012, about 5% of cultures were lost because of this limitation. With better temperature control in the new greenhouse bay, culture productivity showed a dramatic rise for strains in all genera.

Greenhouse spaceIn the bay assigned to INVAM in the new greenhouse (shown here), all benches are constructed of heavy aluminum mesh for good drainage and for cleaning with a 5% chlorox solution. Floors are sealed concrete with a drain in the center of the room (under the stainless steel sink between benches). Benches are disinfected at bi-monthly intervals and floors are washed as needed to remove debris. All watering is performed manually by INVAM personnel to avoid any chance of pot-to-pot contamination and to closely monitor culture development.

High pressure sodium vapor lamps run 14 hours each day to insure a minimum light intensity of 400 µE m-2 s-1 at plant height.

Pot ready for plantingPots and deepots are overseeded for several important reasons: (i) to minimize any bare surfaces where may be passively deposited, (ii) to minimize splashing and movement of surface particulates, and (iii) force plants to grow more slowly and to a similar height (to control lighting, detect any plant health problems, and make it easier to water or apply sprays).

Most cultures, regardless of pot size in which they are maintained, are grown for 4-5 months to minimize buildup of saprophytes in the growth medium and excessive senescence of roots. If grown for > 5 months, watering is carefully regulated and plant health monitored daily.

Two pot with samplesInsect pests are controlled immediately upon detection (plants examined each day at watering time) either with soap or chemical spray. With any signs of nutrient deficiencies, a dilute fertilizer solution is applied for 2-3 days. With any symptoms suggesting presence of a soil-borne pathogen (reduced growth, chlorosis, thinning, etc.), pot contents are inspected. If any pathogen is detected (especially nematodes), the culture is immediately restarted from extracted and cleaned spores and original pot contents are autoclaved.