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Voucher Specimens Stored in Solutions (Vials)

Intact spores are extracted, washed, and collected manually with a pasteur pipette approximately 30 days before a culture is terminated. If the culture contains a mixture of species, then spores of each morphotype are collected either as a mixture and combined in one vial (if no further work is to be done) or separated and placed in individual vials. In general, each two-ml glass vial contains between 100-500 spores immersed in 0.05% sodium azide. Vials are color-coded to genus and numbered sequentially in the order in which they are processed. Each vial is labelled minimally with species name (when possible), INVAM no., and date of set up. Vial number, location, culture and accession information, and any notes of each vial specimen are entered into a voucher database (programmed in Microsoft Access). Vials are arranged in numerical sequence in numbered boxes, which then are stored indefinitely at 4°C.

Racks of test tubes  Samples labeled in box

For reference cultures of described species, and different isolates of undescribed species, vouchers often are collected at the termination of each successive culture cycle. For example, G. intraradices FL208 has passed through three culture cycles, and vouchers were collected from the original accession (V203), first culture cycle (V444), and second culture cycle (V1220).

Stained mycorrhizal roots and auxilary cells also are stored long-term under refrigeration (4°C) in 0.025% sodium azide, either in screw-top tubes or the tissue cassettes in which they were processed.

Sealed petri dishes

Separated spores in watch glasses, when placed in sealed petri dishes, can be stored 2-3 weeks. Stained roots in tissue cassettes can be stored 6-12 months in distilled water and sodium azide. (Above)

Samples in test tubes

The stained roots above have been stored for one year in distilled water and sodium azide. (Above)

Specimens stored short-term (less than 60 days) are transferred either to vials containing sterile distilled water or slightly moistened sterile sand and maintained at 4°C.