The aim of this study is to better understand the nutrient utilization strategies and adaptations of plants, the spatio-temporal variation of leaf stoichiometric characteristics, and leaf nutrient contents. We explored the correlations between leaf nutrient contents and leaf carbon/nitrogen, carbon/phosphorus, and nitrogen/phosphorus ratios, and discussed the influence of nitrogen/phosphorus ratios on plant growth, which could provide a theoretical reference for maintaining ecosystem stability in the karst regions. In this study, we measured the following leaf traits: leaf carbon content (LC), leaf nitrogen content (LN), leaf phosphorus content (LP), and leaf potassium content (LK) in 68 species (belonging to 40 families and 62 genera) coexisting in Maolan karst forests. We also considered the influence of species' taxonomic affiliation and calculated stoichiometry ratios for each plant species. The geometric averages of LC, LN, LP, and LK in the karst forests were 445.87, 17.32, 1.35, and 9.86 g/kg, respectively. The arithmetic average of leaf carbon/nitrogen ratio (C:N) was 26.93 and the geometric averages for leaf carbon/phosphorus ratio (C:P), leaf carbon/potassium ratio (C:K), leaf nitrogen/phosphorus ratio (N:P), leaf nitrogen/potassium ratio (N:K), and leaf phosphorus/potassium ratio (P:K) were 330.93, 45.22, 12.85, 1.76, and 0.137, respectively. There was a significantly negative correlation between LC and LN, while LP was positively correlated with LK. The LN was positively correlated with LP and LK, but negatively associated with C:P and C:K. Similarly, LP was positively correlated to LK, but negatively correlated with C:N, C:K, and N:K. However, LK was negatively associated with C:N, C:P, and N:P. Interestingly, all leaf stoichiometric characteristics, including C:N, C:P, C:K, N:K, and N:P, responded non-linearly (which could be expressed approximately as the quadratic function, exponential function, or power function) to LN, LP, and LK. Among all leaf traits, LC had a smaller coefficient of variance than LN, LP, LK, and the leaf stoichiometric ratios. In different growth phases, LC displayed the highest value in shrubs but the lowest in herbs. Herbs also displayed the highest LN, LP, and LK values, while trees displayed the lowest values of these three variables. Among all stages of plant growth, leaf stoichiometric ratios (including C:N, C:P, C:K, N:K, and N:P) were highest in trees and lowest in herbs. It is worth noting that LN, LP, and LK in ferns were greater than those in spermatophytes. On the contrary, leaf stoichiometric ratios in ferns were lower than those in spermatophytes. In each functional group of plants (including trees, shrubs and herbs), leaf nutrient contents were higher during the peak periods of plant growth than at the end of the growth period. Inversely, the C:P, C:K, N:P, and N:K ratios were greater in the later growth period than those in early growth periods in all karst forest species. In ferns, there were no statistically significant differences in leaf stoichiometric ratios between the early stage of growth and the later period of growth. However, the leaf stoichiometric ratios (C:P, C:K, N:P, and N:K) of spermatophytes were higher during the defoliating periods than those during the early stage of growth. Compared with previous studies of the local and global researchers, the growth of trees, shrubs, and herbs at different growth stages was easily influenced by the highly heterogenous nitrogen and phosphorus supply in the karst region. Especially, the higher potassium contents in plants from the karst forests might increase plant ability to adapt to the unfavourable environment. Therefore, it is necessary to provide enough protection with lower anthropogenic disturbances and add extraneous nitrogen in the growth stage, in order to promote plant growth and enhance ecosystem stability and plant resistance. The study also suggested that several forest plant strategies existed for survival in a karst environment, and the results provided an important reference for forest management and conservation in karst areas.