Accumulation and distribution characteristics for nitrogen, phosphorus and potassium in different cultivars of Petunia hybrida Vlim.

The management of mineral nutrition through fertilization is a key factor determining the ornamental value and marketability of potted plants. In this study, three cultivars of potted petunia (representing the double florabunda (DF), single milliflora (SM), and single florabunda (SF) types) were compared. Their dry matter accumulation characteristics, as well as NPK accumulation and distribution at different developmental stages were investigated in a soil–sand substrate. The different cultivars of petunia exhibited similar uptake ratios of N > K > P with mean NPK ratios of 1:0.11:0.71, but with differing levels of NPK accumulation in the total plant biomass. SF showed the highest accumulation of N, P and K nutrients and dry matter. There was a significant positive correlation between the accumulation of dry matter and nutrients, indicating that the nutrient demands of petunia plants may be estimated indirectly by dry matter accumulation. The maximum dry matter accumulation reached 0.24 g d−1 for stems, 0.30 g d−1 for leaves, 0.09 g d−1 for roots, 0.18 g d−1 for capsules and 0.02 g d−1 for flowers. During the vegetative growth period, the mineral nutrients mostly accumulated in the leaves and stems. However, some of the mineral nutrients were translocated into the capsules and flowers at the flowering stage. N, P and K accumulation were 170.91 mg plant−1, 15.34 mg plant−1 and 136.71 mg plant−1 respectively, before flowering stage, which possessed the highest accumulation of 441.6 mg plant−1 (N), 76.48 mg plant−1 (P) and 214.47 mg plant−1 (K) during the senescence stage. Based on the experimental results, a recommended fertilization regime is 40% N, 80% P and 60% K as a base fertilizer, 30% N at bud stage, and 30% N, 20% P and 40% K after flowering.

► The different cultivars of Petunia exhibited similar uptake ratios of N > K > P with mean NPK ratios of 1:0.11:0.71.
► There was a significant positive correlation between the accumulation of dry matter and nutrients.
► 2.61% N and 36.54% K were translocated from vegetative organ to reproductive organ at the full-bloom stage.
► A recommended fertilization regime is 40% N, 80% P and 60% K as a base fertilizer, 30% N at bud stage, and 30% N, 20% P and 40% K after flowering.