Book with abstracts from the COST Action 0905 meeting in ... - UMB

NICKEL IMPROVES THE NITROGEN USE EFFICIENCY OF
SOYBEAN AND PREVENTS TOXİCİTY OF FOLİAR UREA
Bahar Yildiz Kutman, U. Baris Kutman, Ismail Cakmak
Sabanci University, Faculty of Engineering and Natural Sciences, Istanbul, Turkey
Nickel (Ni) acts as the cofactor of urease, which catalyzes the breakdown of urea to
ammonia. Urea is the most commonly used nitrogen (N) fertilizer, due to its low cost and
high N content. Beneficial effects of Ni have been mentioned in literature, but the potential
of Ni fertilization for crop production needs to be investigated. In this study, soybean seeds
with different Ni concentrations were obtained by growing soybean hydroponically at
different Ni levels. Selected seeds were used in another experiment where plants were
grown in growth chamber at limited N supply, with or without Ni from solution and with
or without foliar urea application. Both seed Ni and externally-applied Ni alleviated
toxicity symptoms of foliar urea and reduced the number of leaves lost due to urea toxicity.
Ni-rich plants, especially those sprayed with urea, had greater biomass than Ni-poor plants.
Moreover, Ni-rich plants exhibited a higher elongation rate, and SPAD measurements
revealed higher chlorophyll concentrations in young leaves of Ni-rich plants, indicating
improved N use efficiency by better Ni supply. Urease assay results suggest that the
observed positive effects of Ni may at least partially be attributed to urease activity. A
sufficiently high Ni availability is required to improve N use efficiency and the utilization
of foliarly-applied urea in soybean.