الفهرس 
Structure of barley grainOnly 14 pages are availabe for public view
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Abstract
Seeds deteriorate and lose their germinalilty during periods of prolonged storage. This phenomenon is known ageing which involves the accumdation of degenerative changes in a seed lot until eventually the ability of seeds to germinate is lost. The two most important environmental factors that influence the speed of seed -. ageing are the relative humidity of the air, which controls seed moisture content; and the temperature, which affects the rate of biochemical processes in seeds. Studies dealing with the effect of seed ageing on quality are intrinsically difficult because they require considerable time. Accelerated aging is a physiological stress test using high temperature an( relative humidity which permit controlled deterioration of the seeds. It has been extmsively used to predict the storage potential of seeds and to compare their vigour. The aim of the present work is to demonstrate the effect of accelerated ageing on the barley grains. The ageing-induced deterioration of seeds was investigated at two main levels. The first is the effect of ageing on germination which was monitored by the comparison of aged and normal seeds stocks by carrying out the standard germination and vigour tests. The second involves the effect of ageing on germination-mediated biochemical processes. A very little work of this kind has been applied to investigate the ageing phenomenon in seeds. In order to understand the biochemical basis of ageing in barley grains, changes of storage proteins as well as three enzyme systems which are involved in tht; mobilization of major grain reserves during germination (a-amylase; P-amylase and protease) have been studied in artificially aged barley seeds both dry and during germination.