Sezonske promene sadržaja ukupne vode u lišću jezgrastih voćaka

Abstract

The subject of the research in this work were the fluctuations in the total water contents in the leaves of nut fruits, in a region characterized by modest rainfall and frequent drought periods. The work shows average results over a five-year period, between 1999 and 2003, obtained for cultivars of walnut (11), hazelnut (22) and almond (2) in collection plantations near Zaječar. The results show that the total water contents in the leaves are highly dependent on a number of various factors, some of the most important being the amount of rainfall and air temperature. During the research period, the total water contents in the leaves of walnut and hazelnut stagnated from April to October. As opposed to this, the total water contents in the leaves of hazelnut stagnated from April to August, showing signs of a slight increase in the September, end of the vegetation period. The highest water contents were found at the beginning of the vegetation period, ranging from 77.9% to 69.9%, whereas the lowest values were recorded at the end of this period, ranging between 59.2% and 56.2%. In the period of the research, the average total water contents in the walnut leaves were 66.2% (67.5-63.6%), 60.9% (62.1-58.1%) in the hazelnut and 65.8% (67.3-61.6%) in the almond leaves. The differences in the average annual values of total water contents were 5.8% for the walnut, 6.4% for the hazelnut and 10.2% for the almond. As for the differences between the highest and the lowest total water contents, they were higher in all of the vegetations. On the average, this difference was the highest in the almond leaves - 19.2% (35.6-11.0%) and walnut - 17.7% (21.3-18.8%), while it was slightly lower in the hazelnut leaves - 13.7% (20.0-7.5%). In the research period, there was a positive middle correlation between the total water contents in the leaves and the recorded precipitation. As for the total water contents in leaves and the air temperature, the correlation was found to be low and negative. The recorded precipitation had a direct effect on the total water contents in the leaves of nut fruits.

Izučavane su sezonske promene sadržaja ukupne vode u lišću jezgrastog voća sa područja koje se odlikuje skromnim padavinama i čestim sušnim periodima. Prikazani su prosečni petogodišnji rezultati (1999-2003. god.) za sorte oraha (11), leske (22) i badema (2) iz kolekcionih zasada u okolini Zaječara. Rezultati ukazuju na visoku zavisnost sadržaja ukupne vode u lišću od različitih faktora, a posebno od padavina i temperature vazduha, što potvrđuje i dobijeni koeficijent korelacije. Sadržaj ukupne vode u lišću oraha i leske je stagnirao od aprila do oktobra. Nasuprot tome u lišću badema sadržaj ukupne vode je stagnirao od aprila do avgusta, dok je u septembru kada se završavala vegetacija došlo do blagog povećanja. U svim godinama prosečno, najveći sadržaj ukupne vode bio je u lišću oraha (66,2%), manji kod badema (65,8%), a najmanji kod leske (60,9%).