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.
Tuber Water and Pressure Potentials Decrease and Sucrose Contents Increase in Response to Moderate Drought and Heat Stress
Environmental stress during the growing season can reduce the quality of stored Solanum tuberosum (potato) tubers. Changes in greenhouse grown Russet Burbank tuber water potential and tuber composition following periods of moderate drought, heat, or drought and heat stress were characterized. Decreased leaf and tuber water potentials were observed at the end of stress treatments. Decreased tuber water potential caused dramatic declines in tuber pressure potential. Tuber sucrose content increased with the severity of stress. Changes in tuber glucose and malic acid contents were also observed. Stress during early tuber bulking had a larger effect on tuber sugars at the end of the stress period than stress during late bulking. Stem-end glucose concentration of tubers at harvest after vine senescence was greater in tubers from plants stressed at early tuber bulking compared to late bulking.ResumenEl agobio ambiental durante el ciclo de cultivo puede reducir la calidad de tubérculos de Solanum tuberosum (papa) almacenados. Se caracterizaron cambios en el potencial hídrico del tubérculo y su composición en Russet Burbank cultivada en invernadero, después de períodos de sequía moderada, calor, o sequía y agobio por calor. Se observó disminución en el potencial hídrico de la hoja y del tubérculo al final de los tratamientos de agobio. La disminución del potencial hídrico del tubérculo causó dramática disminución en el potencial de presión del tubérculo. Aumentó el contenido de sacarosa en el tubérculo con la severidad del agobio. También se observaron cambios en los contenidos de glucosa y ácido málico del tubérculo. El agobio al inicio de la tuberización tuvo un efecto mayor en azúcares del tubérculo al final del período de agobio que el agobio al final de la tuberización. La concentración de la glucosa en la base de los tubérculos a la cosecha, después de la senectud del follaje, fue mayor en tubérculos de plantas agobiadas al inicio de la tuberización comparada con agobio al final.
An adaptable staining schedule for plant tissues.
A general schedule for staining meristematic, maturing, and mature plant tissues is described. Treatment with a dilute aqueous solution of Delafield's hematoxylin is followed with staining in 0.1% safranin in 60% alcohol. Destaining of safranin may be partly accomplished in alcohol and completed by counterstaining with dilute fast green FCF in a xylene and alcohol mixture. Various modifications and adaptations are briefly discussed.