138
L. W. WOODSTOCK
Effect oj storage conditions on respiration and gr01vth in corn: In this investigation, we [16] measured the respiration of samples of corn seeds having
undergone different amounts of deterioration due to various conditions of
temperature and humidity during long-term storage. Respiration was
measured between 2 and 30 hrs after the start of imbibition as O 2 uptake and
CO 2 evolution and was compared with several indices of seedling growth
(Fig. 1a). There was a striking positive correlation between rates of 02
uptake only 3 hrs after the start of imbibition and the shoot lengths of
5-day-old seedlings. An equally striking negative correlation between the
respiratory quotients and seedling growth rates was observed (Fig. 1b).
Both correlations were significant at the 1 % level.
a)
1
b)
•
•
•
•
•
60
E
E
•
. ~ 45 -
•
L
•
•
~
2
.::;'30
•
•
0
0
•
•
L
15
----~--.
07
14
2.1
28
16
3.2
48
6.4
III 02 absorbed/hr/seed (In air)
Respiratory quotient
Fig. la. Relationship between respiratory rates of corn seeds, measured between
2 and 6 hrs after the start of imbibition, and shoot lenght of 5-day-old seedlings, where differences between seed lots were due to different storage conditions.
Fig. lb. Relationship between respiratory quotients of corn seeds and average
shoot length of 5-day-old seedlings. (From: WOODSTOCK and GRABE, Plant
Physiology 42, 1071 (1967)).
Because radicle emergence was not observed until 20 hrs after the start
of imbibition, differences in respiration were assumed to precede differences
in growth rates. To test this assumption, rates of water uptake in vigorous
seeds and in seeds weakened by heat treatments were compared with respiration at 2 and 4 hrs after the start of imbibition [16]. The heat treatments
markedly inhibited seedling growth. They also inhibited respiration and
increased the respiratory quotients, but did not inhibit water uptake during
the initial 4 hrs. Had there been differences between heated and control
seeds in imbibition or rates of embryo elongation during this period,
differences in water uptake would have been observed. Thus, differences
L. W. WOODSTOCK
Effect oj storage conditions on respiration and gr01vth in corn: In this investigation, we [16] measured the respiration of samples of corn seeds having
undergone different amounts of deterioration due to various conditions of
temperature and humidity during long-term storage. Respiration was
measured between 2 and 30 hrs after the start of imbibition as O 2 uptake and
CO 2 evolution and was compared with several indices of seedling growth
(Fig. 1a). There was a striking positive correlation between rates of 02
uptake only 3 hrs after the start of imbibition and the shoot lengths of
5-day-old seedlings. An equally striking negative correlation between the
respiratory quotients and seedling growth rates was observed (Fig. 1b).
Both correlations were significant at the 1 % level.
a)
1
b)
•
•
•
•
•
60
E
E
•
. ~ 45 -
•
L
•
•
~
2
.::;'30
•
•
0
0
•
•
L
15
----~--.
07
14
2.1
28
16
3.2
48
6.4
III 02 absorbed/hr/seed (In air)
Respiratory quotient
Fig. la. Relationship between respiratory rates of corn seeds, measured between
2 and 6 hrs after the start of imbibition, and shoot lenght of 5-day-old seedlings, where differences between seed lots were due to different storage conditions.
Fig. lb. Relationship between respiratory quotients of corn seeds and average
shoot length of 5-day-old seedlings. (From: WOODSTOCK and GRABE, Plant
Physiology 42, 1071 (1967)).
Because radicle emergence was not observed until 20 hrs after the start
of imbibition, differences in respiration were assumed to precede differences
in growth rates. To test this assumption, rates of water uptake in vigorous
seeds and in seeds weakened by heat treatments were compared with respiration at 2 and 4 hrs after the start of imbibition [16]. The heat treatments
markedly inhibited seedling growth. They also inhibited respiration and
increased the respiratory quotients, but did not inhibit water uptake during
the initial 4 hrs. Had there been differences between heated and control
seeds in imbibition or rates of embryo elongation during this period,
differences in water uptake would have been observed. Thus, differences