CO? Injury 
Injury from CO) (brown heart) has been reported to occur on a number of 
apple varieties. Carne (14) in 1948 described brown heart as being caused by 
a concentration of CO) in the storage atmosphere in excess of a critical limit 
which varies depending upon the variety, temperature, and maturity of the fruit. 
Martin and Carne (50) reported that Sturmer apples could be injured by as 
little as 3 percent CO» and Jonathan by a 12 percent level. They also found 
more mature fruit, to a point, to be more susceptible to CO. injury and the 
injury generally to be more severe at 33° F. than at 38° to 43°. Dewey, et al. 
(18), however, found considerable CO, injury on Michigan Jonathans in 2.5, 5, 
or 7 percent CO, levels at 40°, less injury at 36°, and only slight injury in 
the 7 percent CO) atmosphere at 32° F, Mandeno and Padfield (48) also have 
found CO» injury in Jonathans occurred at levels of 8 percent or more when 
stored at 40° F. or above. On McIntosh, in his studies of brown core, Smock 
(84) did not find that high levels of CO, aggravated the development of this 
disorder at 32° or 36°, but at 40° such feeaic of CO, when accompanied by rela- 
tively high 05 concentrations did seem to cause an increase in brown core, 
Hulme (39) associated co, injury in apples with the accumulation of 
succinic acid, Fruit were injured more readily at 37° than at 50° F. Apples 
stored in 20 percent COy at 37° contained 21 mg. of succinic acid per 100 gm. 
of fruit, and the fruit showed COj damage. Fruit stored at 50° contained only 
1.10 mg. of succinic acid, and no visible injury was apparent. Nyhlen (55) 
studied CO. injury in apples from a nutritional and environmental standpoint. 
He found damaged fruit had a high potassium and low phosphorous content. Soil 
analyses also showed a high Kj)0/P ratio. The contents of boron and manganese 
did not appear to be related to the damage. 
In an evaluation of the separate effects of CO,, 0,, and temperature on 
McIntosh in CA storage, Blanpied and Smock (12) reported that firmer fruit with 
less scald was associated with low temperatures, low O09 and high CO, levels. 
Also less external CO) injury was found to occur at 32° than at 36° or 38° F. 
Scald 
A number of investigators have reported that low levels of 0, tend to 
reduce the development or severity of scald (48, 51, 60, 61, 85, 885. Others, 
however, have failed to show that the level of 0. has an effect on the develop- 
ment of scald (74) or that the mixture of CO, and 05 has affected this disorder 
in any way (82). 
The results on the effects of CO, on scald have likewise been somewhat 
variable. Stevenson (93) found less scald in low CO, atmospheres on early 
maturity fruit, but on later maturity fruit less aie occurred in a higher CO 
atmosphere, Phillips (78), Martin and Cerny (51), and Hall and Sykes (34) found 
scald to be greater in atmospheres containing CO, or in increasing concentra- 
tions of C09. Mandeno and Padfield (48) found no consistent effect of C09 
levels on the development of scald but did find scald greater at 36° and 38° 
than at 34° F, Patterson (60) and Patterson and Workman (61), on the other 
hand, found increasing levels of CO, delayed scald. Budiselich (13) observed 
scald on all his treatments except the 5 percent CO, and 2 percent 0. treatment. 
The extent to which apple volatiles accumulate in CA storages and the 
effects these volatiles may have on the stored fruit (scald particularly) are 
reported in a number of publications, Fidler (26) found the concentration of 
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