MN-EFFICIENCY IN OLD WHEAT PLANTS

摘要

Deficiency of Mn~(2+) occurs world-wide and it is one of the most important metal element deficiencies in some regions of the UK. Annually a large quantity of manganese fertilizer is required to correct the deficiency in arable crops and to allow production of expected yields. The aim of this project is to test some old wheat cultivars in UK to identify the presence of resistance to Mn~(2+) deficiency and establish the physiological basis of such resistance. If this is achieved it should potentiallyallow the genetic basis of the resistance trait to be characterized. Solution culture trials (hydroponic system) were undertaken for identifying the extent of physiological inhibition caused by Mn~(2+) deficiency in five old cultivars of wheat (Triticumasetivum) in comparison with a modern cultivar. The total absence of Mn~(2+) produced significant inhibition of growth, accompanied by normal visual symptoms of Mn~(2+) deficiency in all cultivars, however, some significant differences in performances were apparent in old cultivars. In the modern wheat cv. Claire, the reduction in growth rate and photosynthetic quantum yield, compared to controls, was 76% and 79.4% respectively. In the old spring wheat cv. Butler reductions in growth rate and photosynthetic quantum yield were only 57% and 55.7% respectively, and in the winter cv. Mega the respective values were 64% and 66%. No significant differences were observed between cultivars in respect of chlorophyll fluorescence emission or chlorophyll content.The results suggest the presence of some resistance to Mn~(2+) deficiency in the old wheat cultivars cv. Butler and Mega, which have a high efficient photosynthetic performance.