ISHS Acta Horticulturae 531: II ISHS Conference on Fruit Production in the Tropics and Subtropics
CITRUS ROOTS RESPONSES TO ANOXIA |
| Authors: | M. Zude-Sasse, P. Lüdders |
| Keywords: | Citrus volckameriana, chlorosis, redox rootstock |
| Abstract:
During temporary soil anoxia the lack of oxygen leads to an enhanced redox potential in the soil solution. In the present investigation it is postulated, that at the same time the reducing capacity in the root tissue increases. Short-term soil anoxia enhances iron uptake, whereas in alkaline carbonate-containing soil symptoms of iron deficiency often occur. In citrus, expensive iron chelates are used to improve iron supply in arid and semi-arid regions. The present investigation was carried out using the rootstock Citrus volckameriana under controlled greenhouse conditions. Test plants were supplied with alkaline carbonate-containing nutrient solution. Prior to the treatments with iron chelates all plants showed iron deficiency chlorosis. Treatments were conducted with different iron chelates and by inducing anoxia in the root zone. Iron application enhanced chlorophyll content and leaves gas exchange. In iron-deficient plants iso-citrate concentration increased in roots and leaves. Leaves iso-citrate increased further with additional soil anoxia treatment. Furthermore, anoxia induced a shift in the root NAD redox charge with the preference of the reduced compound. Our results lend experimental support to the hypothesis that an endogenous redox charge shift during anoxia in the citrus roots is associated with increased iron uptake. | |
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