7. Finish drying when seed eRH has not changed in 24 h or a flat
curve is given when measuring with a computer-linked “Rotronic.” However, total drying time should not exceed 4 weeks for
most samples or 3–14 days for very short-lived samples (Salix
and Populus spp.).
3.2 Use of a
“Rotronic” Water
Activity Sensor
1. Place the seed sample into the “Rotronic” measurement chamber (see Note 10). The headspace should be minimized; ideally
the seed sample should fill at least 20–50% of the space (including headspace of the Rotronic chamber [29]. Use the appropriately sized “Rotronic” measurement pan as necessary (sizes
from <3–64 cm
3 available).
2. Close the unit containing the seed sample, and wait at least
20 min for equilibration [29].
3. Record the eRH and temperature given on the unit for that
sensor (see Note 11). Ideally, multiple measurements should be
taken to ensure equilibrium has been reached, or data can be
graphically presented using software or exported to excel (see
Note 12).
Table 1
Comparison of moisture content at 18 ˚C and 30% relative humidity (RH) for species with a range of
oil contents
Species
Oil content (%)
MC % (fwb)
(18
C and 30% RH)
Pisum sativum
1
8.7
Ranunculus sceleratus
25.9
6.7
Helianthus annuus
37.9
5.6
Table 2
Comparison of moisture content under different temperature and humidity conditions for Ranunculus
sceleratus
Drying conditions
Drying temp
(
C)
Drying RH
(%)
Storage MC (%
fwb)
MSB drying room for conventional storage
18
15
4.6
MSB drying cabinet for cryo-storage
18
30–32
6.7–6.9
NLGRP drying room for cryo- and conventional
storage
5
24
6.6
CPC for cryo- and conventional storage
5
32
7.7
CPC for cryo- and conventional storage
15–25
35
7.5–6.9
670
Daniel Ballesteros et al.
curve is given when measuring with a computer-linked “Rotronic.” However, total drying time should not exceed 4 weeks for
most samples or 3–14 days for very short-lived samples (Salix
and Populus spp.).
3.2 Use of a
“Rotronic” Water
Activity Sensor
1. Place the seed sample into the “Rotronic” measurement chamber (see Note 10). The headspace should be minimized; ideally
the seed sample should fill at least 20–50% of the space (including headspace of the Rotronic chamber [29]. Use the appropriately sized “Rotronic” measurement pan as necessary (sizes
from <3–64 cm
3 available).
2. Close the unit containing the seed sample, and wait at least
20 min for equilibration [29].
3. Record the eRH and temperature given on the unit for that
sensor (see Note 11). Ideally, multiple measurements should be
taken to ensure equilibrium has been reached, or data can be
graphically presented using software or exported to excel (see
Note 12).
Table 1
Comparison of moisture content at 18 ˚C and 30% relative humidity (RH) for species with a range of
oil contents
Species
Oil content (%)
MC % (fwb)
(18
C and 30% RH)
Pisum sativum
1
8.7
Ranunculus sceleratus
25.9
6.7
Helianthus annuus
37.9
5.6
Table 2
Comparison of moisture content under different temperature and humidity conditions for Ranunculus
sceleratus
Drying conditions
Drying temp
(
C)
Drying RH
(%)
Storage MC (%
fwb)
MSB drying room for conventional storage
18
15
4.6
MSB drying cabinet for cryo-storage
18
30–32
6.7–6.9
NLGRP drying room for cryo- and conventional
storage
5
24
6.6
CPC for cryo- and conventional storage
5
32
7.7
CPC for cryo- and conventional storage
15–25
35
7.5–6.9
670
Daniel Ballesteros et al.