Comparative response of poppy (Papaver somniferum L.) and eight crop and vegetable species to manganese excess in solution culture

The relative response of poppy (Papaver somniferum L.) and eight crop and vegetable species to excess manganese was investigated in a glasshouse, solution culture experiment. Plant yields and manganese concentrations were measured after two and six weeks growth at five levels of manganese (10–800 μM).

Poppies were highly sensitive to manganese toxicity in solution culture and reductions in shoot yield occurred at lower manganese levels in solution and at lower shoot manganese concentrations than that for the following sensitive species, ranked in order of increasing tolerance : brussels sprout, barley, green beans, lucerne and grean pea. In contrast lupins, oats and sugar beet were relatively tolerant producing about 80% or more of maximum shoot yield at the highest solution manganese level (800 μM Mn).

In this study the sensitivity of poppy, and brussels sprout, to manganese excess was attributed to their low shoot manganese “toxicity threshold values”; and their capacity to partition a high proportion of total plant manganese and dry matter to the shoot at solution manganese levels ≥ 100 μM.

The application of these results to field grown poppy is discussed in relation to interactions between manganese and other elements which modify plant tolerance to manganese excess.