小麦旗叶的某些生理变化与子粒灌浆关系的研究

Study on Some Physiological Changes of Flag Leaf After Florescence and the Relationship Between Them and Seedfilling

The study indicated that there was a cumulative increase in the content of malondialdehyde (MDA), a product of membrane-lipid peroxidation of flag leaf with aging. Parallel with this increase in the level of lipid peroxidation was a rapid increase in the membrane permeability (solute leakage). The content of MDA was positively correlated to solute leakage. The activity of catalase dccreased markcdly with the aging of flag leaf after florescence. It was negatively correlated to the content of MDA and the solute leakage. The results suggested that leaf senescence might be a consequence of cumulative membrane deterioration due to the increase of the level of lipid peroxidation probably controlled by, among other factors, the activity of catalase. The activity of peroxidase of flag leaf increased rapidly after florescence, declined after the appearance of a peak, and reached the minimum when the leaf became withered and yellow. There was a close relationship between the activity of peroxidase of flag leaf and seedfilling. It showed that the filling intensity increased with the enhancing in the activity of peroxidase. The maximum of activity of peroxidase was constantly followed by that of filling intensity. The maximum daily increment of thousand-grain weight was positively correlated to the maximum activity of peroxidase (r=0.986). The application of scavengers for active oxygen (ASA, sodium benozate), plant growth regulator (NAA) and some chemical such as NaHSO_3, retarded lipid peroxidation and increased thousand-grain weight.