Semi-dwarf narrow rolled leaf mutant in rice: Photosynthetic efficiency and physiological response to gibberellic acid (GA3)

Leaf is the major component for fixation of carbondioxide to produce more photoassimilates and maintains source sink relationship in plants. The present investigation was carried out to study the photosynthetic efficiency and physiological response of GA3 of semi-dwraf narrow rolled leaf mutant. Semi-dwarf narrow rolled leaf mutant exhibited reduced plant height, reduced leaf width, reduced panicle length and number of grains per panicle when compared to wild type. Photosynthetic efficiency study revealed that the mutant showed higher photosynthetic efficiency than wild type. Complementation test with GA3 clearly revealed that this mutant is sensitive to GA3 and revert to normal plant height. Scanning Electron Microscope study revealed that mutant had exhibited minimum number of inter-veins between veins, minimum distance between midrib and has slightly larger cell size. Hence, this loss of function mutant is very useful to map the regions associated with panicle length, number of grains per panicle and other traits related to enhancement of yield. The result provides an important clue for further understanding the mechanism of rice leaf development and plant architecture.