Physiological changes in the wheat root tip following growth and vernalization.
|Title:||Physiological changes in the wheat root tip following growth and vernalization.|
|Abstract:||Sequential changes in the alcohol soluble amino acid and carbohydrate fractions of vernalized and control root tips of Triticum aestivum var. Marquis (spring) and Rideau (winter) wheats have been followed. Substantial changes in these fractions could be related to developmental changes in the root tip. Vernalization superimposed additional, consistent changes mainly in the content of the amino acids asparagine, glutamine, glycine, and glutamic acid, and of the sugars fructose and sucrose. Incorporation studies using 14C glutamic acid and aspartic acid served to emphasize the distinct metabolic differences between the mitotic and elongating regions of the root tips. In the mitotic region, the highest incorporation of label was in the protein fraction, whereas in the elongating region, the highest activity was recovered in the free amino acid pool. Two enzyme systems, namely amylase and glutamic acid-alanine transaminase were also studied. The possibility of using the uptake of 51Cr as an indicator of metabolic change in wheat root tips, as it is in animal tissues, was also examined. A consistent Patttern of 51Cr incorporation was observed in the serial Sections of both wheat varieties. The changed metabolic state attendant on vernalization was reflected by a higher level of 51Cr incorporation. Histochemical studies of sulphtydryl group distribution along the wheat root tip were also carried out in order to determine whether there exists a relationship between sulphydryl groups and the pattern of 51Cr uptake. No such correlation could be established. The effect of the water content of the grain during vernalization which is known to affect the subsequent root growth, was also examined. Incomplete imbibition led to a lessened metabolic response to the cold treatment.|
|Collection||Thèses, 1910 - 2010 // Theses, 1910 - 2010|