Acta Botanica Croatica, Vol. 40 No. 1, 1981.
Original scientific paper
On the Water Relations of Evergreen Oak and Pubescent Oak Under Soil Watering Conditions in Southern Istra (Croatia)
Ljudevit Ilijanić
; Hrvatska
Jasenka Topić
; Hrvatska
Abstract
The paper presents the results of comparative studies of transpiration and water saturation deficit in the leaves of the evergreen oak (Quercus ilex) and the pubescent oak (Q pubescens) carried out in 1973 in a garden at Premantura, where the soil was abundantly watered for vegetable cultivation from spring to autumn.
The results obtained for the evergreen oak at Premantura were compared with those of 1970 and 1971 on the island of Rab under natural edaphic and climatic conditions (Ilijanić and Gračanin 1972).
The phytogeographic position of both localities, the climatic conditions of the regions and the results are shown in Figs. 1—7 and Tables 1—5 in the German version of the paper.
At increased soil humidity the evergreen oak at Premantura in summer transpired considerably more intensively than on the island of Rab under natural conditions. In early May the differences were not great, since the soil at Rab was still relatively humid, which resulted in a somewhat higher transpiration.
The pubescent oak at Premantura, after the leaves were fully developed, transpired more intensively from June to October than the evergreen oak, if transpiration is expressed in mgxg"1 x min-1. If transpiration is calculated per unit of leaf area (mg dm-2 min-1), the difference is less pronounced, and the values obtained in July were higher for the evergreen oak than for the pubescent oak.
The water saturation deficit in the leaves of the evergreen oak at Premantura was higher than in the island of Rab, except in early October. It can, thus, be concluded that the evergreen oak controlled its water balance under natural edaphic and climatic conditions better than under artificially increased humidity of soil.
It would be interesting to continue the investigation of the same individual evergreen and pubescent oak trees at Premantura after the watering has been cut off completely for a prolonged period.
Keywords
Hrčak ID:
158441
URI
Publication date:
31.12.1981.
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