The effect of indole-3-acetic-acid on the photosynthetic apparatus of Sinapis alba.
The influence of indole-3-acetic-acid (IAA) during the development of primary leaves of Sinapis alba was studied. IAA treatment (4 ppm ≈ 22.8 μM) caused a decrease of dry weight, soluble reducing sugars, soluble protein, chlorophylls, carotenoids and cytochrome f; it also caused a lower ratio of protein to chlorophyll, a lower ratio of chlorophyll a to chlorophyll b and a higher ratio of chlorophyll per cytochrome f. Furthermore, IAA treatment induced a significantly lower rate of CO2 fixation and a depressed nitrite reductase activity. Similar effects could also be observed in adaptation reactions brought about by red light and low-light (or shade) conditions.
Institut für Allgemeine Botanik der Universität Mainz, Saarstr. 21, D-6500, Federal Republic of Germany.
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