(1 China National Rice Research Institute，Hangzhou 310006,China; 2 Institute of Applied Ecology, Nanjing Agricultural University, Nanjing 210095, China; 3 Institute of Food Crops, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; #These authors contributed equally to this paper; *Corresponding author, E-mail: firstname.lastname@example.org)
Dissolved oxygen and N forms have important effects on rice root growth and N availability. Indica hybrid rice Guodao 1 and conventional japonica rice Xiushui 09 were cultured for six weeks in hypoxic nutrient solution with NH4NO3 or (NH4)2SO4 as nitrogen source; Four weeks later, Guodao 1 was transferred to the split-root system at different dissolved oxygen contents (DOTs). The biomass, root morphological traits and nitrogen accumulation were investigated. Under lower rhizosphere oxygen (DOT 0 to 1.0 mg/L), NH4NO3 -N significantly increased the plant biomass in comparison with sole NH4+ -N, about 69% in Guodao 1 and 41% in Xiushui 09. In addition, the root number, the longest root length, the root dry weight and the root activity for Guodao 1 and Xiushui 09 were also increased under NH4NO3-N nutrition. NH4NO3-N enhanced the N accumulation in roots and shoots of Guodao 1 by 60% and 52%, in roots and shoots of Xiushui 09 by 41% and 33%, respectively. In the split-root system, because of increased rhizosphere oxygen (DOT 8.0 to 9.0 mg/L), the root biomass was increased by 21.6%, the root number by 27%, the longest root length by 14% and the root volume by 10%. The N accumulation in roots was enhanced by 11% under higher rhizosphere oxygen. In conclusion, improvement of dissolved oxygen and ammonium-nitrate N source have positive effect on the root growth and N accumulation of rice plants.
ZHAO Feng ,# ,XU Chun-mei et al. Effects of Rhizosphere Dissolved Oxygen and Nitrogen Form on Root Characteristics and Nitrogen Accumulation of Rice[J]. , 2011, 25(2): 195-200 .
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