Difference of Characteristics of Photosynthesis, Matter Production and Translocation between Indica and Japonica Super Rice

Abstract

This study was to reveal the difference of characteristics of dry matter accumulation and photosynthetic production between indica and japonica super rice. Field experiments were conducted by using five representative super hybrid indica combinations and five conventional japonica super rice varieties planted on a large scale in Jiangsu region with rice-wheat double cropping rotation. Dry matter accumulation, distribution and translocation, leaf area, leaf area duration(LAD), crop growth rate(CGR), net assimilation rate(NAR), seedling quality and leaf type were analyzed systematically. Results showed that, dry matter accumulation, LAD, CGR, and NAR at the early growth stage(from transplanting to jointing), leaf length, leaf base angle, angle between stem and leaf and drooping angle in top three leaves, leaf area decreasing per day after heading and harvest index of japonica rice were less than those of indica rice significantly, while dry matter accumulation, LAD, CGR, and NAR at the middle and later growth stages(from jointing to maturity), ratio of leaf area of productive tillers, ratio of leaf area of top three leaves, grain-leaf ratio(spikelets per cm2 leaf area, filled grains per cm2 leaf area and grain weight per cm2 leaf area), maximum leaf area index, total filling, grain yield, biological yield, maximum output and apparent output and their ratio were larger than those ofindica rice significantly. Although dry matter weight per stem of japonica rice at the main growth stages was lower than that of indica rice, the superiority of population quantity suggested that japonica rice would possess higher dry matter accumulation and leaf area. With the advancement of growth and development, the superiority of photosynthesis and matter production of japonica rice was increasing, with a higher dry matter accumulation more than that of indica rice 25 d after heading approximately. The growth potential of japonica rice remained strong at the late period of grain-filling(from milky stage to maturity), while stored matter kept in the stem and sheath exported appropriately at the early period of grain-filling(from heading to milky stage), ensuring the security of efficient photosynthetic layer and the enrichment of high accumulation yield sink. Therefore, balanced formation of high biological yield, stable-increasing-slow-decreasing tendency of leaf area, and the large amounts of high efficient photosynthate production from jointing to maturity are the important characteristics and causes for the efficient and sustainable output of photosynthetic systems, more grain-filling and high yield formation in japonica rice.