The effect of phosphorus nutrition on growth, flowering and chlorophyll fluorescence of New Guinea impatiens 'Pago Pago'.

摘要

Rooted cuttings of New Guinea 'Pago Pago' (Impatiens hawkeri) were planted using a sphagnum peat-based growing medium amended with P (as triple superphosphate) at 0, 0.24, 0.48, 0.97, 1.61 and 2.24 mM before planting. In general, the contents of N,P, K Ca and Mg increased with increasing P levels in the growing medium. P stress, i.e. low P levels, reduced plant height, plant diameter, shoot number, leaf number, leaf length and leaf width. The leaves and flowers of P-deficient plants had darker colour, thus increasing its ornamental value. Low P levels resulted in the earliest flowering, but reduced the number of flower buds. The efficiency of photosystem II, as indicated by chlorophyll fluorescence, was not significantly affected by P stress. These results suggest that low P levels has a favourable effect on flowering time and quality of 'Pago Pago' and can be used as alternative to growth retardants without side effects.