Photosynthesis and leaf lipoxygenase activity in soybean genotypes lacking seed lipoxygenases isozymes

Abstract

Plants from eight soybean genotypes, including a triple null line (TNL) without seed lipoxygenase isozymes, were grown in a greenhouse to evaluate the effect of genetic elimination of seed lipoxygenases (LOX) on carbon assimilation and leaf LOX activity. Specific leaf matter, carbohydrate and chlorophyll concentration were assessed in plants from the TNL whose floral buds had been continuously removed. There was no difference among genotypes on rates of photosynthesis. Leaf LOX activity, however, was greater in the genotype with the three seed LOX isozymes than in the TNL. The removal of floral buds in the TNL increased leaf LOX activity, as well as, leaf carbohydrate and chlorophyll concentration as compared to control plants, allowed to develop seeds; the contrary was true for the rates of photosynthesis.