Dry matter content of apical and basal portions of Russet Burbank potatoes
Studies were made over a 4-year period of some factors affecting the dry matter content of the apical and basal portions of growing Russet Burbank potatoes. The greatest difference between portions was obtained from tubers of the normally irrigated plots of 1969. The amounts in the two portions in 1970 were nearly equal throughout the growing season. The major differences between the 2 years was a slightly cooler June and warmer maximum temperatures in July of the 1970 growing season. Moisture stress, particularly, early in the stage of tuber development (1972 season) caused a switch in amount of dry matter in the apical and; basal portions. Stress later in the development stage (1969 season) did not cause a switch. Fertility level was not as influential as moisture stress in affecting the ratio of dry matter in the two ends, whether under stress or normal moisture conditions.
Changes in malic and citric acid contents during growth and storage ofSolanum tuberosum L.
Changes in malic and citric acid contents of apical and basal portions of tubers were followed during growth and development and in storage. Malic acid content was highest in the early harvested potatoes and decreased as the growing season progressed until a minimum level was reached approximately the first to the middle of September, and then started to increase again as temperatures got cooler in the fall. Malic acid content closely paralleled sucrose content during growth and development. The period at which low malic acid content was observed coincided with optimum time of harvest. Citric acid content did not show a definite pattern of behavior with increase in maturity. Low temperature storage resulted in decreased pH and an increase in malic and citric acid contents of tubers. Both acid contents were higher in the apical portion, although the pH was lower in the basal portion. No significant correlation was found between pH and content of either acid.ResumenCambios en los contenidos de ácido málico y ácido cítrico de prociones apicales y basales de tubérculos fueron evaluados durante el crecimiento, desarrollo y almacenaje.El contenido de ácido málico fue el más alto en las papas cosechadas más temprano y disminuyó a medida que avanzaba la temporada de crecimiento hasta alcanzar un nivel mínimo aproximadamente al inicio y mediados de setiembre, y luego empezó a aumentar nuevamente a medida que las temperaturas se hicieron más frías en el otoño.El contenido de ácido málico fue muy paralelo al contenido de azúcar durante el crecimiento y desarrollo.El período en el cual se observó bajo contenido de ácido málico coincidió con el momento óptimo de cosechar.El contenido de ácido cítrico no mostró un patrón definido de comportamiento al aumentar en la maduración.El almacenaje a baja temperatura determinó una disminución del pH y un aumento en los contenidos de ácido málico y ácido cítrico en tubérculos.El contenido de ambos ácidos fue mayor en la porción apical, a pesar que el pH fue el más bajo en la porción basal. No se encontró una correlación significativa entre pH y contenido de alguno de los ácidos.
Histological Analysis of Wound Healing in Potatoes Treated to Inhibit Sprouting 1. CIPC (Isopropyl-N-3-Chlorophenyl Carbamate) Treatments
SUMMARY 
 
Both wound periderm and sprouting were completely inhibited in freshly harvested cut potatoes treated by evaporation of CIPC (isopropyl-N-3-chlorophenyl carbamate) at 10 ppm and 100 ppm (based on tuber weight) and then incubated at 70–75°F and 88% relative humidity. At 1 ppm CIPC, sprouting at room temperature was only slightly retarded. Wound periderm was completely inhibited in the central tissues and markedly retarded in the cortex of the tubers. 
 
 
 
Application of CIPC did not prevent suberization at the wound surface, but the walls of intact cells immediately subjacent were less suberized than those of the cut cells. Concomitant with inhibition of wound periderm, there was a marked enlargement of those cells that would normally have given rise to the wound periderm. 
 
 
 
Variability of wound healing rates within different tissue zones of single tubers, and other variation between tubers, are considered significant to problems of sprout control and storage.