Growth, Flowering, and Postharvest Performance of Single-stemmed Rose (Rosa hybrida L.) Plants in Response to Light Quantum Integral and Plant Population Density

Abstract

<jats:p>The cut rose, grown as a single-stemmed crop, resembles a potted plant and can be adapted to transportable bench systems. Potentially, this cultivation method could increase control of rose development, flexibility of production and produce, and automation of difficult or laborious cultural operations. Synchronous growth and flowering is considered important. The effects of increased quantum irradiation integral and plant density on shoot growth, fresh biomass production, and bloom quality were studied as single-stemmed rose plants (<jats:italic>Rosa hybrida</jats:italic> L.) `Kordapa' Lambada, `Tanettahn' Manhattan Blue, `Tanorelav' Red Velvet, and `Sweet Promise' Sonia grown under 20 hours photoperiods at 23 °C average air temperature. Plants were grown in rockwool cubes on ebb and flood benches irrigated with a complete nutrient solution, and were supplied with carbon dioxide at 1000 μmol·mol<jats:sup>-1</jats:sup>. Increased the daily quantum integral from 17.8 to 21.0 mol·m<jats:sup>-2</jats:sup>·d<jats:sup>-1</jats:sup> increased fresh biomass efficiency, stem diameter, and specific fresh mass while number of nodes, number of five-leaflet-leaves, plastochron value, and stem length at anthesis decreased. Fresh mass at anthesis was not affected by the treatments. Increasing plant population density from 100 to 178 plants/m<jats:sup>2</jats:sup> increased stem length at visible flower bud, and reduced both fresh biomass efficiency and specific fresh mass. These effects are suggested to be related to assimilate supply and translocation, and light perception of the roses. High quantum integral slightly reduced flower diameter but in general, quantum integral or plant density did not affect bloom quality or vase life. Use of preservative floral solution generally improved rose flower diameter and vase life. In Lambada increased light quantum integral prolonged vase life, but use of preservative solution did not. The cultivars Sonia and Red Velvet required 19 to 20 days from cutting/planting until onset of bud growth, 29 to 34 days until visible flower bud, and 39 to 49 days until anthesis. Red Velvet roses were ≈60 cm long at anthesis, and had larger stem diameter and growth rate, accumulated more fresh biomass, were most efficient producing fresh biomass, and had higher specific fresh mass among the cultivars. Light quantum integral is suggested to be used as a means to synchronize single-stemmed rose plant development.</jats:p>

Propagation temperature, PPFD, auxin treatment, cutting size and cutting position affect root formation, axillary bud growth and shoot development in miniature rose (Rosa hybridaL.) plants and alter homogeneity

“…PPFD level during propagation did not significantly affect shoot growth in this experiment. Thus, contrary to what has been indicated for cut rose (Moe, 1973;Bredmose, 1998), PPFD at 46 µmol m -2 s -1 during propagation as compared to 72 µmol m -2 s -1 was apparently sufficient for later shoot growth in 'Heidi' miniature rose plants. However, in cut rose 'Madelon' total plantlet dry weight was related to leaf area indicating a connection between irradiance during propagation and cutting growth (Costa and Challa, 2002).…”

“…Temperature optima for leaf photosynthesis and carbon export rate in cut rose 'Samantha' were both c 25°C (Jiao and Grodzinski, 1998). Though high PPFD could weaken inhibition and promote axillary bud growth in cut rose (Mor et al, 1980;Bredmose, 1998), this was not found in the present experiment, suggesting that a PPFD at 46 µmol m -2 s -1 was sufficient, or that 72 µmol m -2 s -1 was too low for further effect. The growth of axillary buds in extra short cuttings was delayed.…”

“…Further, high temperature was favourable for root formation; and root number and root length in 'Roswytha' rose cuttings apparently were enhanced at increased irradiance (Moe, 1973). Light perception by axillary buds and shoot tips has been documented in roses (Mor et al, 1980), and a beneficial response to increased photosynthetic photon flux density (PPFD) for rose cuttings has been indicated (Bredmose, 1998).…”

Effects of node position, number of leaflets left, and light intensity during cutting propagation on rooting and subsequent growth of domestic roses

“…Similar results were reported by Moe (1973) who described that rooting of 'Roswytha' rose cuttings was enhanced at increased irradiance. Bredmose (1998) also, reported an enhanced response resulting from increased photosynthetic photon flux density (PPFD) for rose cuttings. In 'Gouni', however, the optimum light intensity for rooting was 180 µmol m -2 s -1 .…”

Effects of temperature on photosynthesis and plant growth in the assimilation shoots of a rose

“…The uppermost, young leaf was used throughout the experimental period. As roses are generally cultivated over a range of 20–30°C for day temperature and 18–20°C for night temperature (Beeson 1990; Bredmose 1998; Gonzalez‐Real and Baille 2000; Jiao and Grodzinski 1998; Kim and Lieth 2003; Kool et al . 1996), we grew the assimilation shoots at two different day/night temperature regimes of 20/15°C and 30/25°C.…”