Influence of Magnesium on Photosynthetic Characteristics and Growth Effects of Sugarcane at Seedling Stage

In this study, the effects of different concentrations of magnesium on photosynthetic characteristics and growth of sugarcane cultivars Roc22 and YT00-236 at seedling stage were investigated by combined cultivation of sand culture with nutrient solution. The results showed that under the stress of low magnesium, the synthesis and photosynthesis of chlorophyll are blocked with significantly decreased biomass accumulation, increased root-shoot ratio and slowed growth rate. Appropriate treatment of magnesium (0.1mmol/L) can promote sugarcane photosynthesis with maximal biomass, significantly decreased root-shoot ratio and increased growth rate. Excess With excessive treatment of magnesium (1mmol/L), the photosynthetic rate is lower than the value under low magnesium stress; Once the overall growth of sugarcane is inhibited, however, the growth is better than low magnesium stress. It is found that the photosynthesis and growth effects of ROC22 are stronger than that of YT00-236. It is preliminarily deduced that ROC22 is a sensitive variety of magnesium.