Abstract
In rice, the developmental process in leaf formation can be divided into 6 stages (stages P1-P6). We investigated physiological change in the developing leaves at the key stage P4, during which leaf greening and establishment of primary leaf structure occur. Chlorophyll content and Rubisco accumulation were negligible at early P4 and increased rapidly as leaf enters the late P4 phase. Chlorophyll fluorescence ratio (Fv/Fm) also increased markedly and the final value was comparable with that of mature leaves at P5-P6 stages. RNAs mainly transcribed by NEP increased rapidly during early P4 and then declined slowly as PEP-derived RNAs increased. Proportion of carbon in leaf cells was kept constant through the P4 stage, while that of nitrogen decreased with increasing C:N ratio. These observations suggest that in the leaves at P4 developmental stage, chloroplast develops rapidly and effects on the physiological status of leaf cells largely.
