Phyllochron duration and changes through rice development shape the vertical leaf size profile

Abstract

SummaryWell-irrigated aerobic rice (Oryza sativa L.) plants are often shorter with smaller leaves, and the leaf appearance rate is slower in well-irrigated than in flooded environments. This observation questions the functional relationship between the leaf appearance rate, which is correlated with the apical cell production rate, and leaf length that is in turn correlated with the leaf division zone length.Meristem size, blade size, and appearance were monitored for all leaves from leaf 6 on the main stem of rice plants in field experiments using two varieties, two watering systems, and three sowing dates.Leaf blade and division zone lengths were correlated in all leaves of the main stem of rice plants. New stable linear relationships were found between the leaf division zone growth duration and internal cell production rate, which changed after leaf 11. These stable relationships imply a stable link between the rates of cell production in the stem apex and leaf meristem, explaining the vertical leaf size profile.Overall, faster leaf appearance leads to shorter leaves and organs in rice because of a functional link, which is counterbalanced by additional acclimation in transplanted plants.