Using Pcloutrzol to Suppress Inflorescence Height of Potted Phlenopsis Orchids A REPORT SUBMITTED TO FINE AMERICAS Linsey Newton nd Erik Runkle Deprtment of Horticulture Spring 28
Using Pcloutrzol to Suppress Inflorescence Height of Potted Phlenopsis Orchids Ojective Linsey Newton nd Erik Runkle To determine the effectiveness of pcloutrzol (Piccolo, Fine Americs) folir spry on inhiiting the inflorescence height of potted Phlenopsis orchids tht hve nturlly tll inflorescences. Experimentl Protocol Three rtes of Piccolo were pplied s folir spry to Phlenopsis t one of two times fter exposure to low temperture tht induces flowering. Plnts were compred with nonspryed (control) plnts. The effects of Piccolo were tested on three different Phlenopsis clones. Ten plnts of ech clone were rndomly ssigned to ech chemicl tretment. Piccolo Tretments 1. none (control) 2. 15 ppm Piccolo 3. 3 ppm Piccolo 4. 45 ppm Piccolo Appliction Times 1. Before flower initition (verge inflorescence height etween 1 nd 2 cm) 2. After flower initition (verge inflorescence height etween 1 nd 18 cm) Phlenopsis Clones 1. Andrew 2. Miss Sigon 3. Smrt Thing Mture Phlenopsis were grown t 29 ºC (86 F) until the strt of the experiment nd were then trnsferred to 23 ºC (73 ºF) on 2 Decemer 27 to induce flowering. Applictions were mde on 18 Jnury 28 nd 4 Ferury 28. The chemicl pplictions were pplied s spry using 2 qurts of solution per 1 squre feet of ench spce. A surfctnt ws not dded to the spry solution. The rtes used were sed on preliminry tril on Phlenopsis Promis, which indicted tht solution contining 3 ppm of Piccolo provided desirle response. Plnts were grown under mximum light intensity of 3 µmol m -2 s -1 (pprox. 1,5 footcndles) nd 16-hour photoperiod. Plnts were fertilized t ech wtering following stndrd plnt production protocols estlished t Michign Stte University. When the plnts were moved from constnt 29 ºC to constnt 23 ºC to induce flowering, the lef numer ws counted nd the lef spn ws mesured on ech plnt (Tle 1). The dte when visile inflorescence (VI) ppered nd the dte the first flower opened ws recorded for ech plnt. The length of ech developing inflorescence ws mesured t the time of Piccolo ppliction nd weekly therefter. When the first flower opened, the numer of inflorescences
nd the numer of flower uds on ech inflorescence were counted, nd the height of the inflorescence to the first flower, totl inflorescence height (height to the end of the inflorescence), nd the length of the internode etween the first nd second flower were mesured. The dimeter of the first open flower on ech plnt ws mesured 2 weeks fter the lst plnt of ech clone flowered so tht petls were fully expnded. Results Inflorescence height The gretest effect of Piccolo spry on height to first flower occurred in Phlenopsis Andrew ; ll three rtes of Piccolo inhiited inflorescence elongtion to the first flower y out 2% when pplied efore flower initition (Figure 1, top grph; Figure 3). The height to first flower ws shorter thn the control plnts on Phlenopsis Miss Sigon treted with 3 ppm Piccolo efore flower initition (Figures 1 nd 4). Piccolo pplictions did not hve sttisticlly significnt effect on height to the first flower of Phlenopsis Smrt Thing t the rtes tested (Figures 1 nd 5). Piccolo only significntly inhiited totl inflorescence elongtion on one of the three Phlenopsis clones studied (Figure 1, ottom grph). Compred with nontreted plnts, inflorescence height of Phlenopsis Andrew t first open flower ws shorter when treted with 15 ppm efore flower initition nd 45 ppm pplied either efore or fter flower initition. The height of these inflorescences ws 19% to 23% shorter thn control plnts. The other Piccolo tretments did not hve sttisticlly significnt effect on totl inflorescence height of Phlenopsis Andrew. The only other instnce t first flowering in which Piccolo produced sttisticlly shorter inflorescences ws 2 weeks fter the first ppliction. On Phlenopsis Andrew, ll three rtes of Piccolo pplied efore flower initition inhiited inflorescence elongtion t this time. Similrly, Phlenopsis Miss Sigon treted with 15 ppm Piccolo efore flower initition hd 28% shorter inflorescences thn the control when mesured 2 weeks fter ppliction. Node Length The effects of Piccolo pplictions on the length of the node etween the first two flowers vried etween clones (Figure 2). Both 3 nd 45 ppm Piccolo pplied fter flower initition on Phlenopsis Andrew cused this internode to e out 2% shorter thn tht of the control plnts. On Phlenopsis Miss Sigon, 15 nd 45 ppm Piccolo pplied fter flower initition reduced elongtion of this sme node y similr mount. In Phlenopsis Smrt Thing, only 3 ppm Piccolo pplied fter flower initition sttisticlly elicited shorter internode. Other flowering chrcteristics Applictions of Piccolo did not influence the time etween VI nd the first open flower t the rtes tested (Tle 2). In ddition, Piccolo did not ffect the numer of inflorescences or flowers formed or the dimeter of the first open flower. Summry Spry pplictions of Piccolo were generlly effective t inhiiting inflorescence height of one of the three Phlenopsis clones t the rtes tested. However, there ws tendency
towrds inhiiting inflorescence elongtion in ll three hyrids. Applictions of Piccolo efore flower initition (soon fter inflorescence emergence) were generlly more effective thn n ppliction mde fter flowers initited (when inflorescences were 9 to 17 cm tller). In ddition, the erly pplictions did not cuse shorter internodes etween the first two flowers like some of the lter pplictions did. Bsed on these results, we mke the following suggestions for growers tht wnt to inhiit inflorescence elongtion of tll Phlenopsis hyrids: Apply sprys soon fter inflorescences emergence, when they re less thn 3 cm tll Apply spry of t lest 3 ppm, depending on the cultivr Consider second spry ppliction if dditionl height control is desired Avoid lte spry pplictions to prevent unching of flowers Growers should conduct their own trils on smll scle to determine pproprite rtes for their cultivrs nd desired response.
Inflorescence Height to First Flower (cm) 6 5 4 3 2 Control 15 ppm efore flower initition 3 ppm efore flower initition 45 ppm efore flower initition 15 ppm fter flower initition 3 ppm fter flower initition 45 ppm fter flower initition 1 9 'Andrew' 'Miss Sigon' 'Smrt Thing' 8 Totl Inflorescence Height (cm) 7 6 5 4 3 2 1 'Andrew' 'Miss Sigon' 'Smrt Thing' Phlenopsis clone Figure 1. The effect of Piccolo sprys on verge height to the first flower (top) nd totl inflorescence height (ottom) for the three Phlenopsis clones studied. Mens within Phlenopsis clone with the sme letter re not significntly different y Tukey's honest significnt difference t P.5. Error rs represent the stndrd error for ech men.
Length of internode etween first nd second flower (cm) 7 6 5 4 3 2 1 c c c Control 15 ppm efore flower initition 3 ppm efore flower initition 45 ppm efore flower initition 15 ppm fter flower initition 3 ppm fter flower initition 45 ppm fter flower initition 'Andrew' 'Miss Sigon' 'Smrt Thing' Phlenopsis clone Figure 2. The effect of Piccolo sprys on verge internode length etween the first nd second flower for the three Phlenopsis clones studied. Mens within Phlenopsis clone with the sme letter re not significntly different y Tukey's honest significnt difference t P.5. Error rs represent the stndrd error for ech men.
8 7 6 Control 15 ppm efore flower initition 3 ppm efore flower initition 45 ppm efore flower initition 15 ppm fter flower initition 3 ppm fter flower initition 45 ppm fter flower initition Inflorescence height (cm) 5 4 3 2 1 1 2 3 4 5 6 7 8 Time fter first ppliction (weeks) finl height Figure 3. Weekly men height of developing inflorescences on Phlenopsis Andrew. The first Piccolo ppliction ws mde t week nd the second ppliction ws mde t week 2. The finl inflorescence height ws mesured when the first flower opened. Error rs represent the stndrd error for ech men.
7 6 5 Control 15 ppm efore flower initition 3 ppm efore flower initition 45 ppm efore flower initition 15 ppm fter flower initition 3 ppm fter flower initition 45 ppm fter flower initition Inflorescence height (cm) 4 3 2 1 1 2 3 4 5 6 7 8 9 Time fter first ppliction (weeks) finl height Figure 4. Weekly men height of developing inflorescences on Phlenopsis Miss Sigon. The first Piccolo ppliction ws mde t week nd the second ppliction ws mde t week 2. The finl inflorescence height ws mesured when the first flower opened. Error rs represent the stndrd error for ech men.
7 6 5 Control 15 ppm efore flower initition 3 ppm efore flower initition 45 ppm efore flower initition 15 ppm fter flower initition 3 ppm fter flower initition 45 ppm fter flower initition Inflorescence height (cm) 4 3 2 1 1 2 3 4 5 6 7 8 Time fter first ppliction (weeks) finl height Figure 5. Weekly men height of developing inflorescences on Phlenopsis Smrt Thing. The first Piccolo ppliction ws mde t week nd the second ppliction ws mde t week 2. The finl inflorescence height ws mesured when the first flower opened. Error rs represent the stndrd error for ech men.
Tle 1. The initil size (lef spn nd numer of leves) of the three Phlenopsis clones treted with Piccolo. Phlenopsis clone Averge lef spn (cm) Averge numer of leves 'Andrew' 53.2 5. 'Miss Sigon' 42.7 5.8 'Smrt Thing' 48.1 7. Tle 2. The effect of Piccolo sprys on flowering chrcteristics of three Phlenopsis orchid clones. Mens within column nd Phlenopsis clone with the sme letter re not significntly different y Tukey's honest significnt difference t P.5. VI = visile inflorescence. Piccolo rte (ppm) Dys from VI to flower Inflorescence numer Numer of flower uds on first inflorescence Numer of flower uds per plnt First flower dimeter (cm) Appliction Time 'Andrew' Control 85.2 1. 1.1 1.1 1.1 Before flower initition 15 82.8 1. 8.5 8.5 9.7 3 82.5 1. 9.3 9.3 1.4 45 84. 1. 9. 9. 1. After flower initition 15 83.3 1. 1.1 1.1 1.3 3 84.8 1.1 8.9 8.6 1.2 45 82.4 1. 8.8 8.8 1.1 'Miss Sigon' Control 84.8 1.3 7.1 8.4 8.1 Before flower initition 15 84.5 1.2 7.1 8.2 8.2 3 84.2 1.1 6.7 7.3 8.1 45 84. 1.4 7.1 9.5 8.4 After flower initition 15 84.4 1.2 6.7 7.8 7.7 3 86.4 1.2 7.2 8.2 8.4 45 88. 1.2 6.3 7.3 8.1 'Smrt Thing' Control 73.2 1.6 9.4 14. 9.1 Before flower initition 15 72.7 1.8 9.1 15.3 8.8 3 73.5 1.6 9.6 14.3 8.5 45 73.6 1.6 11.9 16.6 9. After flower initition 15 73.5 1.8 8.9 14.5 9. 3 73.7 1.9 1.1 17.6 8.9 45 74. 1.6 1.5 15. 8.9