Different aspects of inhibition of growth and photosynthesis of maize (Zea mays L.) by the phosphonate herbicide sulphosate, 1: Root manipulation

Effects of the herbicide sulphosate on growth, accumulation and partitioning of dry weight and photosynthesis in maize plants subjected to source-sink manipulation at the root were studied. The findings indicate that growth and dry weight accumulation correlate significantly only with the dry mass ratio and/or volume of the root (RMR, Vr, respectively), while a significant negative correlation was found with stem mass ratio (SMR) and generally with leaf mass ratio (LMR), which reflects an irregular distribution of carbohydrate metabolism in maize plants. As the root is where cytokinins, the plant hormons essential for maintaining photosynthetic structures, are synthesized, we assumed that the root status under stress caused by the herbicide sulphosate could be one of the factors of stability/sensitivity of photosynthesis/photosynthetic structures in plants exposed to this herbicide.