Nitrogen Fertility Influence on Ethylene Production and Leaf Water Potential in Cotton

Ken E. Lege', Richard L. Jasoni, and J. Tom Cothren


Nitrogen (N) nutrition has been implicated as a factor that increases the production of ethylene in plants. Similarly, leaf water potential has been reported to be less negative for N deficient plants. In addition, ethylene production has been reported to increase as water deficit increases, although recent findings suggest earlier reports were confounded by technique. Our objective was to investigate the interaction of leaf water potential and ethylene production with regard to N fertility for cotton grown under field conditions. Cotton (cv. Stoneville 453) was seeded in the field on 13 April, 1993 at College Station, Texas and supplied with either 0, 50, 100, or 150 kg N ha-1 applied as NH4NO3. Weekly samplings of ethylene production and chlorophyll content were taken from the topmost fully expanded leaf, and the middle and the bottom leaves of the canopy. Similarly, leaf water potentials were taken on the topmost fully expanded leaf on a weekly basis to indicate the water status for the entire plant. An adequate response to N fertilization was observed, as the chlorophyll content increased with increasing rates of N fertilizer. Ethylene production significantly increased with higher rates of N fertilizer during the bloom period. N deficient plants exhibited less negative water potential values compared with those well-supplied with N, as water deficit increased. Higher ethylene production was associated with a greater water deficit in the topmost fully expanded leaf and the middle leaf of the canopy. Since our plots were well-watered, any change in the water potential was attributed to the interaction between water status and N status of the plant. Therefore, an association may exist between higher ethylene production and higher N status due to this N status by water status interaction. The mechanism of such an interaction and its effects on ethylene production requires further research for elucidation of this response.

Reprinted from Proceedings of the 1994 Beltwide Cotton Conferences pg. 1332
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998