engleski

Seasonal changes in nitrogen concentration of bearing plum shoots

Seasonal changes of N concentration in particular parts of plum shoots cv. Bistrica (bark, wood, buds and leaves) were observed over two growing seasons. There were two variants in the investigation: control trees, grown in grass without regular pruning or fertilization and the experimental treatment, in which the trees were under improved management. The investigation showed that management had no effect on the seasonal tendency, but had high effect on N concentration level which was considerably higher in the particular shoot parts under improved management. The seasonal changes of N concentration were different in particular parts of the shoot but the general course could be distinguished in two periods: one from the beginning of vegetation to the end of blooming and the second one from the shoot growth cessation to the end of growing season. The biggest change in N concentration occurred in the vegetative and generative buds in the period from the beginning of vegetation until the end of blooming. During this period N concentration was increasing and reached a maximum value at full blooming. In the same period there was also an appreciable increase in the N level in the wood and bark tissues of the previous year shoot. A sharp fall in N concentration occurred in the bark and wood of the new growth from the period when the shoot growth ceased to the middle of August when it reached its minimum and then gradually rose to the end of vegetation. There was simultaneous minimum of N in the wood and bark of the previous year shoots. The concentration of N in the leaf blade and leaf petiole was the highest at the time of new shoot growth cessation in May, then decreased fairly smoothly to leaf fall. Nitrogen concentration in whole fruits was the highest in the period when terminal shoots stopped growing. After that, nitrogen concentration declined rapidly to the period when stone in the fruit was hardened and then it fell slowly to the time of fruit ripening.

Prunus domestica; cultivar Bistrica; soil management; mineral nutrition; developmental stages

nije evidentirano