Protective effects of nitrogen nutrition against photoinhibition in Coffea arabica cv. catuai
Coffee plants with 18 months, grown in a shaded greenhouse were fertilized with two levels (0 and 2 mmol) of nitrogen (NO3NH4) and transfered one month later to full sunlight and night air humidity conditions. Fertilized plants showed a better initial status and better response in the evaluated parameters. Water soluble protein content and Rubisco activity showed a stimulation on fertilized plants but were quite constant along the stress period in not fertilized ones. Photosynthetic capacity and the quantum yield decreased in both groups, mainly in not fertilized plants. Fluorescence parameters showed also the existence of problems in both groups, at the level of the reaction centers and electron transport, since Fv/Fm ratio and photochemical quenching decreased in both groups. After 30 days of hight stress the leaf area was substantialy destroyed specially in the not fertilized plants.
| Main Authors: | , , |
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| Format: | biblioteca |
| Published: |
1992
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| Subjects: | COFFEA ARABICA, CATUAI, FERTILIZANTES NITROGENADOS, FOTOSINTESIS, |
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| Summary: | Coffee plants with 18 months, grown in a shaded greenhouse were fertilized with two levels (0 and 2 mmol) of nitrogen (NO3NH4) and transfered one month later to full sunlight and night air humidity conditions. Fertilized plants showed a better initial status and better response in the evaluated parameters. Water soluble protein content and Rubisco activity showed a stimulation on fertilized plants but were quite constant along the stress period in not fertilized ones. Photosynthetic capacity and the quantum yield decreased in both groups, mainly in not fertilized plants. Fluorescence parameters showed also the existence of problems in both groups, at the level of the reaction centers and electron transport, since Fv/Fm ratio and photochemical quenching decreased in both groups. After 30 days of hight stress the leaf area was substantialy destroyed specially in the not fertilized plants. |
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