Partial nitrate nutrition amends photosynthetic characteristics in rice (Oryza sativa L. var. japonica) differing in nitrogen use efficiency

Abstract

Partial nitrate nutrition (PNN) was found to improve rice (Oryza sativa L. var. japonica) growth. However, how PNN is related to photosynthesis in rice cultivars with different nitrogen use efficiency (NUE) is still not clear. Two rice cultivars, Nanguang (high NUE) and Elio (low NUE), were grown under sole NH 4? and PNN at a total nitrogen concentration of 2.86 mM. The dry weight, leaf area, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and gas exchange parameters were measured. Nitrogen and Rubisco contents in the newly expanded leaves of cv. Nanguang were similar to those of cv. Elio when only NH 4? was supplemented in the nutrient solution. However, in cv. Nanguang, nitrogen and Rubisco contents increased under PNN than under sole NH 4 ? nutrition. Higher nitrogen and Rubisco contents were recorded in cv. Nanguang than in cv. Elio under PNN. The ratio of carboxylation efficiency (CE) to Rubisco content in cv. Nanguang was 11 and 14% higher than that in cv. Elio under NH 4 ? and PNN, respectively. CE was 14% higher in cv. Nanguang than that in cv. Elio. The results suggest that PNN causes an increase in photosynthesis in cv. Nanguang. It is concluded that differences in Rubisco activity, rather than stomatal limitation, are responsible for the differences in photosynthesis between the two cultivars. The presence of nitrate increases Rubisco content in rice with a high NUE, which leads to faster biomass accumulation at later growth stages.

Nitrate supply affects root growth differentially in two rice cultivars differing in nitrogen use efficiency

“…'*' indicates significant difference between the two genotypes parameters and root physiological characteristics in the growth stages. Zhang et al (2010) found that higher plant biomass was observed in cv. Elio than in cv.…”

Appropriate Ammonium-Nitrate Ratio Improves Nutrient Accumulation and Fruit Quality in Pepper (Capsicum annuum L.)

“…However, the N form is beneficial for plant growth, yield, and quality may vary with plant species [12][13][14] and many other factors [15][16][17]. Supplying the two forms of nitrogen in a specific ratio will lead to the optimum growth; this finding has been reported in species such as apple (Malus domestica Borkh) [18,19], tomato (Solanum lycopersicum L.) [20,21], and rice (Oryza sativa L.) [22][23][24]. Predominant sources of ammonia N may also negatively affect the whole plant biomass deposition in some species, such as Arabidopsis thaliana [25,26]; while in another study, Arabidopsis plants displayed the potential of stimulating glucosinolate metabolism with ammonium nutrition [27].…”

Natural leaf senescence: probed by chlorophyll fluorescence, CO2 photosynthetic rate and antioxidant enzyme activities during grain filling in different rice cultivars

“…The relationship between rate of leaf senescence and grain growth is complex. Grain growth along with leaf senescence is influenced by climatic conditions, varietal types and many other factors (Yamazaki and Kamimura 2001;Huang et al 2004;Zhao et al 2007;Damanik et al 2010;Zhang et al 2010b). Natural leaf senescence is faster in Indica than in Japonica types and in warm regions than in cool regions.…”