Development of water stress in kale leaves of different insertion levels

Pospíšilová J.
BIOLOGIA PLANTARUM 17: 392-399, 1975

Klíčová slova: water potential, osmotic potential, pressure potential, Brassica oleracea
Abstrakt: Abstraet. The mutual relationship between the water potential (Vw), its components, namely the osmotic potential (~s) and the pressure potential (yJp), and the water saturation deficit (AWsat) were determined in the leaves of different insertion levels. During the water stress development in kale plants induced by decreasing soil moisture, the ~w decreased parallely in all the leaves but the same decrease of y~,o was accompanied by the highest decrease of the ~,. probably due to the accumulation of osmotically active solutes, and the lowest decrease of v2~ in th~ upper leaves and with the lowest decrease of ~P8 and the highest decrease of ~ in the lower leaves. Also the corresponding values of the AWsa~ were always lower in the upper than in the middle and lower leaves. Thus the upper leaves wilted at more negative values of v2w than the other leaves. On the contrary, during the wilting of the cut off leaves the relationship between ~Pw and A Wsat in the upper, middle and lower leaves was practically the same. The very slightly higher decrease of ~s in the upper leaves in comparison with the other leaves was compensated by a lower decrease of their y)p. These changes in the ratios of ~0~., ~s, ~p, and AWsat with the leaf insertion levels enabled the preference of the upper leaves in retaining the necessary water supply during the wilting of plants in situ.
DOI: 10.1007/02921048
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