In order to explore the relationship between the root and leaf growth and yield formation of different nitrogen efficiency rice under different combinations of field drainages and panicle nitrogen fertilizer managements

three field drainage degrees (W1

W2

W3) were set

in which the soil moisture content of 0—20 cm were (53.60±5)%

(40.20±5.00)% and (26.80±5.00)%

respectively

meanwhile three panicle nitrogen fertilizer managements (N1

N2 and N3) were conducted

which mean that applying panicle fertilizer in the first day

the eighth day and the 15th day after the field were rehydrated

respectively. The effects of field drainage and panicle nitrogen fertilizer managements on root morphological characteristics

root dry weight

leaf area index

photosynthetic rate of flag leaves

leaf dry weight

yield and its components of rice were investigated with Dexiang 4103 (nitrogen efficient variety) and Yixiang3724 (nitrogen inefficient variety). The results showed that: (1)The mean yield of Dexiang4103 was 11.57% higher than that of Yixiang3724; (2)The yield of these two varieties had significant positive correlation with the dry weight and LAI of leaf at heading stage

and the yield of Dexiang4103 had significant positive correlation with root dry weight

total root length and root surface area per plant at heading stage and the 15 days after full heading

and the yield of Yixiang3724 only had significant positive correlation with root dry weight per plant at the same stages; (3)Agronomic nitrogen efficiency of Dexiang4103 was significantly positively correlated with root dry weight and root surface area per plant at heading stage

and root length per plant on the 15 days after full heading

the same parameter of Yixiang3724 had significant positive correlation with root length per plant at heading stage

and root dry weight per plant on the 15 days after full heading; (4) In the treatment of W1 and W2

there was no significant difference in total root length and root surface area per plant between nitrogen efficient variety and nitrogen inefficient variety at the heading stage; the total root length of nitrogen efficient variety was significantly less than that of nitrogen inefficient variety on the 15 days after full heading; in the treatment of W3

the total root length and the root surface area per plant of nitrogen inefficient variety were both greater than those of nitrogen efficient variety at heading stage; and there was no significant difference in total root length and root surface area per plant between these two varieties on the 15 days after heading; (5) At maturity

dry weight and LAI of leaf of nitrogen inefficient variety were both higher than those of nitrogen efficient variety

on the contrary

the leaf area attenuation rate of it was much lower than that of nitrogen efficient variety during heading to maturity stage; (6) Applying with the treatment of W1N3 on Dexiang4103

the leaf area attenuation rate was reduced

and the total root length from heading to maturity

leaf photosynthetic rate and yield were all increased; while applying with the treatment of W2N2 on Yixiang3724 could get the same effect. In summary

the effects of paddy field drainages and panicle nitrogen fertilizer management on the root and leaf characteristics were very obvious during middle to latter growth period for different nitrogen efficiency rice. By optimizing paddy field drainage degree combining with applying the panicle nitrogen fertilizer managements for these two varieties

and constructing reasonable root index and leaf system

we could promote the nitrogen absorption of root

and improve the material production and transport capacity of leaf during the filling stage

and finally improve yield.