We showed recently that antisense plants with decreased activity of the plastidic ATP/ADP-transporter protein exhibit drastically reduced levels of starch and a decreased amylose/amylopectin ratio, whereas sense plants with increased activity of the transporter possessed more starch than wild-type plants and an increased amylose/amylopectin ratio. In this paper we investigate the effect of alte...

The aim of this work was to use tubers from transgenic lines of potato (Solanum tuberosum) containing increased amounts of ADPglucose pyrophosphorylase to study the role of this enzyme in the control of starch synthesis. A 4-5-fold increase in activity of the enzyme, achieved by transformation with the Escherichia coli ADPglucose pyrophosphorylase gene glgC-16, had no detectable effect on the s...

Potato tubers are modified stems that have differentiated into storage organs. Factors such as day-length, nitrogen supply, and levels of the phytohormones cytokinin and gibberellic acid, are known to control tuberization. Morphological changes during tuber initiation are accompanied by the accumulation of a characteristic set of proteins, thought to be involved in N-storage (i.e. patatin) or d...

The structure of Raw and Processed Amaranth Grains starch was studied by using Scanning Electron Microscopy (SEM). In this study, starch morphological differences were observed between raw and processed (Boiled, Roasted and popped) grains derived from the same cultivar. Among food carbohydrates, starch occupies a unique position. It is the major carbohydrate storage material in many higher plan...

The major isoform of starch synthase from the soluble fraction of developing potato tubers has been purified and used to prepare an antibody and isolate a cDNA. The protein is 140 kD, and it is distinctly different in predicted primary amino acid sequence from other isoforms of the enzyme thus far described. Immunoinhibition and immunoblotting experiments and analysis of tubers in which activit...

The genetic control of dormancy is poorly understood in most plant species, but dormancy is a prominent feature for the potato industry. We used the microtuber system, in which tubers were produced in vitro and stored at 20°C, to perform quantitative trait locus (QTL) analysis for dormancy and gibberellic acid (GA3) content in an F1 population consisting of 178 genotypes derived from an intersp...

This update focuses on the starch that accumulates in the guard cells that control stomatal pore size and thus the exchange of water vapor, CO2, and O2 between the leaf and the atmosphere. Transitory starch in these cells plays a key role in determining the velocity of stomatal opening in the light. This significantly differs from the transitory starch in the mesophyll leaves, which acts primar...

Since the early work of Kihlman and Levan (1949) which demonstrated that caffeine induces chromosomal alterations in plants, other reports are available to show that food additives, edible fats, insecticides etc. could be mutagenic (Sax and Sax 1968, Hollaender 1971, Kihlman et al. 1974). The present work was under taken to study the mutagenic effects, if any of ginger and turmeric which have b...

There is no direct evidence of the effect of lignin metabolism on early storage root development in sweet potato. In this study, we found that heterologous expression of the maize leaf color (Lc) gene in sweet potato increased anthocyanin pigment accumulation in the whole plant and resulted in reduced size with an increased length/width ratio, low yield and less starch content in the early stor...

Changes in the temperature response, fluidity, function and the acyl fatty acid composition, were determined for a mitochondria-rich membrane fraction from Jerusalem artichoke (Helianthus tuberosus L.) tubers during dormancy for a crop which matured in midsummer. The temperature of both the upper and lower limits of the membrane lipid transition decreased during dormancy from 26 C and 1 C to 4 ...