Leaf nitrogen distribution to maximize the canopy photosynthesis in rice

Spatial Distribution of Leaf Area Index and Leaf N Content In Relation To Grain Yield and Nitrogen Uptake in Rice

“…5), which is consistent with the report of Shiratsuchi et al (2006), and the previous studies with other crop species (Field, 1983;Hirose and Werger, 1987;Pons et al, 1989). Yin et al (2000) described the LNC distribution from the top to basal leaves using an exponential equation, and indicated that the leaves at lower layers senesced when the LNC was lower than the minimum LNC for leaf photosynthesis.…”

“…The difference in the relationships between yield and LNC depending on the position in the canopy suggested that the distribution of LNC in the canopy should be improved for high canopy photosynthesis by increasing LNC of upper leaves and reducing it in lower layers. This was in agreement with a recent study by Shiratsuchi et al (2006), who optimized the LNC for maximum canopy photosynthesis by increasing LNC in the upper leaves and reducing LNC in the lower leaves. Fig.…”

“…This indicates that water management affected the distribution of LNC. Thus, N rates and irrigation method could regulate the spatial distribution of LNC within the canopy, and an optimum distribution of LNC may maximize canopy photosynthesis as proposed in the previous studies (Gimenez et al, 1994;Anten et al, 1995;Connor et al, 1995;Goudriaan, 1995;Shiratsuchi et al, 2006).…”

“…Optimization of leaf N distribution associated with LAI distribution in rice canopy increased canopy photosynthesis by more than 20% during grain filling (Goudriaan, 1995;Shiratsuchi et al, 2006), when most of the grain dry matter is normally produced (Cock and Yoshida, 1972;Murata and Matsushima, 1975;Tsunsoda, 1978;Yoshida, 1984). Thus improving distributions of leaf area index (LAI) and leaf nitrogen content (LNC) in the canopy is possibly a desirable way to increase yield in rice (Goudriaan, 1995;Yin et al, 2000;Shiratsuchi et al, 2006), instead of high nitrogen fertilizer input and much water consumption (Guerra et al, 1998;, which led to the lower nitrogen use efficiency than the present rice production situation in China (Xing and Zhu, 2000;Zhu et al, 2000;Jaynes et al, 2001;Peng et al, 2002). Recently, the site-specific nitrogen fertilizer management in rice was introduced to irrigated rice production, based on the leaf N status with leaf colour chart (LCC), and fertilizing according to LCC to increase N use efficiency as well as high yield (Wang et al, 2001;Alam et al, 2006).…”

Crop Improvement for Nitrogen Use Efficiency in Irrigated Lowland Rice

“…A balance between these two processes is necessary for rice plants to achieve maximum grain yield and NUE. One strategy is to increase nitrogen remobilization from the lower leaves and reduce nitrogen remobilization from the upper leaves so that the gradient of leaf nitrogen concentration in the canopy is steep (Shiratsuchi et al, 2006 ). Simulation modeling suggests that a steeper slope of the vertical nitrogen concentration gradient in the leaf canopy with more nitrogen present in the uppermost stratum enhances canopy photosynthesis (Dingkuhn et al, 1991 ).…”