Page 510 - Biosystems Engineering

482 Cha pte r Se v e ntee n

Advantages of tetrazolium test are

1. Results are available within a few hours.
2. Very little equipment is necessary to carry out the test.
3. Close examination of individual seeds will often reveal the
reason for poor germination.

Germination Method Using Paper
Top of Papers (TP) The seeds are germinated on top of one or more
layers of paper, which are placed in any of the following ways:
1. Enclosed in transparent Petri dishes
2. Put directly on germination trays in a cabinet or in a room-
type germinator
In the first method, water is supplied to the paper at regular inter-
vals, and germination takes place under ambient temperature. In the
second method, the relative humidity in the germinator must be main-
tained close to saturation level. Moistened porous paper or absorbent
cotton can be used as a base for the paper or even as an immediate
substratum.

Between Paper (BP) The seeds are germinated between two layers of
germination paper that are placed in any of the following ways:
1. Directly on germination trays in a cabinet or a room-type
germinator
2. In metal, plastic, or glass boxes
In this method, the relative humidity will be maintained close to
saturation level. The paper can be folded or rolled and placed in a flat
or upright position. Metal, glass, or plastic frames can be inserted
between papers to ensure ventilation. Moistened porous paper or
cotton can be used as a base for paper or even as an immediate
substratum.

Germination Method Using Sand
In a sand culture, the seeds are placed in a uniform layer of moist
sand and covered to a depth of 1 to 3 cm with sand, which is left
loose. The amount of water to be added to the sand will depend on its
characteristics and size of seed to be tested. Cereals except maize may
be germinated in sand moistened to 50 percent of its water-holding
capacity. For large-seeded legumes and maize the sand should be
moistened to 60 percent of its water-holding capacity. Proper spacing