The Characteristics Of Source-Transmit-Sink Of The Different Panicle Weight Types Of Rice

The characteristics of source-transmit-sink of the different panicle weight types of rice were studied on the experimental field of Rice Institute of Sichuan Agricultural University, Wenjing Sichuan, with Gangyou527 and Gngyou881 (Heavy panicle type),Shanyou63 and R527(Middle panicle type),Miyou46 and R047(Light panicle type),and so on as materials .The main results were as follows:(1) The type of source-sink in heavy panicle type and middle panicle type was source-limiting type, but that in light panicle type was sink-limiting type. The filling characteristic of strong and weak grain in heavy panicle type was asynchronous ,but that in middle panicle type and light panicle type was synchromous .(2) On the photosynthesis of flag leaves sides ,the photosynthetic rate of Gangyou527 (heavy panicle type) was higher than that of Shanyou 63 (middle panicle type ) and Miyang 46 (light panicle type ), especially under saturated intensity conditions. The photosynthetic rate of Gangyou 881 was 9.6% and 17.8% higher respectively than that of Shanyou 63 and Miyang 46 under saturated light intensity. Under CO2 concentration of 100~300ul/L the increase of photosynthetic rate of Gangyou 527 was the highest ,Miyang 46 the second ,and Shanyou 63 the slowest. The optimum temperature of photosynthesis for Gangyou 527 and Miyang 46 were about 35℃,and was about 30℃for Shanyou 63.For the stomatalcharacteristics, we thought that higher photosynthetic rate mainly resulted from its high total quantity of stomatal opening degrees.(3) The study on the relationship between culm traits and lodging resistance indicated that thicker culms and the mechanical tissue were a basis structural factor to strengthen lodging ability ;thicker culms were associated with large panicles , the breaking resistant strength of culm was positively correlated with the thickness and the area of culm, so it is important to breed cultivar with thicker culm and improve the development of mechanical tissue to strengthen lodging ability under the circumstances of control plant height properly.(4) At each level of the panicle ,the area of vascular bundle, phloem, xylem of heavy panicle type were larger than those of those of middle panicle type and the latter were than those of light panicle type. The ratio of effective sink to area of all phloem was similar between heavy panicle type and middle panicle type , but they were significant large than it of light panicle type. The characteristics of the tissues of the panicle played an important role to the grain filling and were a basis structural factor to good grain filling.