Abstract :

Lycopersicon esculentum leaves cultivated hydroponically for 24 and 48 hrs with various specific mineral deficits had their photosynthetic characteristics examined. After 24 hrs of K+, NO3-, and PO42- deficiency, a substantial induction of net photosynthetic rate was observed. The net photosynthetic rate of SO42-, Mg2+, Fe2+, NO3-, Ca2+ and PO42- deficits was significantly induced by the 48 hr exposure. After 24 hrs of deficiencies in SO42-, Mg2+, Fe2+, NO3-, Ca2+ and PO42-, stomata conductance was dramatically increased. Deficiencies in SO42-, Fe2+, NO3-, Ca2+ and PO42- were continuously induced over 48 hrs. After 24 hrs of SO42-, Fe2+, NO3-, Ca2+ and PO42- deficiencies, intercellular CO2 concentration shows a considerable induction. After 48 hrs of K+, SO42-, Mg2+ and NO3-deficits, this behavior remained strongly induced. Water use efficiency considerably decreased in response to these changes after 24 hrs of SO42-, Fe2+, NO3- and PO42- deficiencies and this effect continued after 48 hrs of Mg2+, NO3-, Ca2+ and PO42- deficiencies. Deficits in K+, SO42-, Mg2+, Fe2+, NO3-, Ca2+ and PO42- for 24 hrs dramatically increased transpiration rate, which was modified by those deficiencies. A 48 hr exposure to NO3-, Ca2+ and PO42- deficiency dramatically increased the transpiration rate. After 48 hrs, an SO42- deficit drastically decreased the transpiration rate. The findings indicate that after a short term of exposure, it may be possible to diagnose a specific mineral shortage and determine which mineral influenced the parameters of photosynthesis in such a way that the selected parameters responded in a manner that was consistent with the duration of exposure.

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