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| Author(s): |
Tiago Tezotto
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2015-05-18 |
| Examining board members: |
José Laercio Favarin;
Evandro Binotto Fagan;
Dirceu de Mattos Junior;
Paulo Mazzafera;
Joseph Carmine Polacco
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| Advisor: | José Laercio Favarin; Paulo Mazzafera |
| Abstract | |
Nitrogen is the nutrient required in greatest quantity by the coffee and the second most exported within the plant. Usually, N is applied as urea to coffee and urea-N is rapidly metabolized and incorporated into amino acids and amides. The assimilation of N is affected by several micronutrients, including nickel (Ni). Ni is a constituent of urease, the sole enzyme responsible for degradation (and subsequent assimilation) of urea. Understanding Ni interaction with N metabolism and the aging process is important for the efficient use of nitrogen by coffee, and by plants in general. Little is known about Ni nutrition as it relates to N metabolism in leaf senescence and its possible interference in the absorption and transfer of other nutrients. The present study was conducted in coffee to assess whether the application of Ni (i) interferes with the absorption and transfer of other nutrients as well as biomass partitioning; (Ii) increases the nitrogen use efficiency, both for greater degradation of urea via urease activity, and increased redistribution of nitrogen reserves by increased catabolism of arginine; and (iii) delays leaf senescence by decreasing endogenous ethylene production, thereby increasing leaf duration. Ni application reduced biomass of coffee only at the highest level of soil availability (105 mg dm-3). This level also brought about the reduction in biomass concentration and accumulation of macronutrients (N, P, K, Ca and mg). With respect to mineral micronutrients (Cu, Fe, Mn and Zn), gradual increases in available Ni content, either reduced or gradually increased the concentration of these micronutrients. N-use efficiency ratios in coffee were affected only by variations in management of N, and not by changes in available soil Ni . Soil Ni applications to 60 mg dm-3 did not affect the growth of the coffee plant, but increased foliar retention under N limitation. Ni reduced plant ethylene biosynthesis, in spite of the concentrations of MDA and proline increasing rising with increasing soil Ni during pre-anthesis. As Ni levels rose, there was an increase in the redistribution of N of storage organs (branch) to meet the demand of leaf and fruit. (AU) | |
| FAPESP's process: | 11/05928-6 - NICKEL NUTRITION IN COFFEE PLANT AND ITS RELATIONSHIP WITH NITROGEN METABOLISM AND SENESCENCE |
| Grantee: | Tiago Tezotto |
| Support Opportunities: | Scholarships in Brazil - Doctorate |