N availability and mechanisms of N conservation in deciduous and semideciduous tropical forest legume trees

Acta Botanica Brasilica

Ana Lúcia Da Silva Lima²  Fábio Zanella²  Marlene Aparecida Schiavianto¹  Claudia Regina Baptista Haddad¹ 

[1] ,Universidade Luterana do Brasil Centro Universitário Luterano de Ji-Paraná Departamento de Biologia e AgronomiaJi-Paraná RO ,Brasil

关键词: leaf life span;    nitrogen fixation;    nitrogen resorption efficiency;    nitrogen resorption proficiency;    nitrogen-use efficiency;    longevidade foliar;    fixação de nitrogênio;    eficiência de reaproveitamento de nitrogênio;    proficiência de reaproveitamento de nitrogênio;    eficiência do uso de nitrogênio;   

DOI  :  10.1590/S0102-33062006000300012

来源: SciELO

【 摘 要 】

Prior to abscission, nutrients are redeployed from leaves and redistributed to other parts of the plant. Data comparing nutrient resorption to soil fertility and leaf life span remains controversial in the literature. We compared nitrogen (N) conservation mechanisms among four legume trees with different leaf life spans (Hymenaea courbaril L. var. stilbocarpa (Hayne) Lee et Lang., Lonchocarpus guilleminianus (Tul.) Malme, Enterolobium contortisiliquum (Vell.) Morong and Peltophorum dubium (Spreng.) Taub.), from a semideciduous tropical forest, remnant of the Atlantic Forest. We hypothesized that these mechanisms differ among the four species and are affected by their leaf life span and by the availability of N, both as a mineral in the soil and, in the case of L. guilleminianus and E. contortisiliquum, from symbiotic nitrogen fixation (SNF), as these species form associations with rhizobia. The plants were grown in a greenhouse using pots filled with forest soil, enriched (50 or 100 mg of NH4NO3 plant-1week-1) or not with nitrogen. H. courbaril, a semideciduous tree, without SNF, and with the highest leaf life span, presented the greatest N-resorption efficiency (NRE), N-resorption proficiency (NRP) and N-use efficiency (NUE). Increase in soil N and the presence of symbiotic N fixation led to a decrease in NRE, NRP and NUE.

【 授权许可】

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