Tissue-specific response of primary metabolites in tomato plants affected by different K nutrition status

As one of the most important mineral nutrient elements, potassium (K) plays crucial roles in many fundamental processes, including enzyme activation, membrane transport, anion neutralization and osmo-regulation, and determines the yield and quality of crop production. In order to better understand and elucidate plant tissue-specific primary metabolic changes under different K nutrition status. Four-week-old tomato plants were subjected to different K nutrition situations: low (0.25 mM); normal (2.5 mM); and high (10.0 mM); and the emerging leaves, fully expanded leaves, petioles, stem and roots were harvested at 15 and 30 days, time points which the external symptoms are observed, after K treatments. Primary metabolites, amino acids, organic acids and sugars, extracted from each tomato tissue were measured with HPLC system. Several interesting findings from this study could be summarized as follows: (1) metabolites showed K-dependent responses, which indicated that the rates of an increase and decrease in low K-affected were 50 % : 50 % ;whereas, 80 % : 20 % in high K; (2) the petioles revealed the most sensitive plant tissue in response to K nutrition status; and (3) metabolites such as glucose and fructose (soluble sugars), malate and citrate (organic acids), and glutamine, asparagine, glutamate and aspartate (amino acids) strongly fluctuated (up or down) by the K nutrition ratio. These findings may contribute to a better understanding and elucidating the tissue-specific biosynthetic patterns and primary metabolite accumulation under different K nutrition ratios, and provide a new strategy for comprehensive information involved in the spatio-temporal metabolic networks