Water balance in leaf tissue

Pospíšilová J.
BIOLOGIA PLANTARUM 11: 119-129, 1969

Klíčová slova: Water uptake, transpiration, WSD, fodder cabbage
Abstrakt: Received February 22, 1968 Abstract. Samples of the leaf tissue (14 cm ~) were placed in a plexiglass chamber which consisted of three parts. Water absorbed by the leaf tissue on one side of the sample was transported through the middle part of the sample to the opposite side and was transpirated there. The in. tensity of transpiration the intensity of water absorption and water saturation deficit (w.s.d.) were determined simultaneously in this tissue by gravimetry. Water balance was studied either in saturated samples of leaf tissue or in tissue where w.s.d. (10%, 20~o, 30~o, 40%) was established in advance. Although conditions for water absorption in leaf segments were optimal, w.s.d, originated in the saturated leaf tissue under all given external conditions (evaporation from 41-7 to 17.8 mg cm -2 h-l). W.s.d. which was established in advance for the most part increased during the experiment and reached even high values (more than 60~/o). The equilibration was reached only under conditions of low evaporation and initial w.s.d, higher than 20~o in young leaves and higher than 30~o in adult leaves. A positive correlation between the ratio of the intensity of water absorption to the intensity of transpiration and w.s.d, was found only under conditions of lower evaporation (17.8 and 23.2 mg cm-~h-1). The maximal values of w.s.d, were limited in this way. Water balance was studied: 1. in leaf tissue of upper, middle and lower leaves of fodder cabbage, 2. in leaf tissue of middle leaves of young and adult plants of fodder cabbage, 3. in leaf tissue of dicots (fodder cabbage) with different vessel orientation in respect to water transport, 4. in leaf tissue of monocote (banana-tree) with water transport upright to the vessel orientation. Considerable change of water balance was observed when the water transport was prolonged by two incisions in the middle part of the sample. Results of all these experiments revealed the possibility of water stress origin even in leaf tissue sufficiently supplied with water.
DOI: 10.1007/BF02921730
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