SNA Research Conference Vol Growth Regulators Yan Chen Section Editor Plant Growth Regulators

Transcription

1 Growth Regultors Yn Chen Section Editor Plnt Growth Regultors 152

2 Mnging Knock Out Rose nd Loropetlum Growth in the Lndscpe with Cutless.33G Yn Chen, Allen Owings, Regin Brcy, Joey Queedeux Old Covington Highwy, Hmmond LA, Index Words: plnt growth regultor, flurprimidol, grnulr formultion, woody ornmentl Significnce to Industry: Mny shrus nd groundcovers used in the lndscpe require routine pruning or shering to keep their shpe net nd compct. Pruning is significnt expenditure of time nd mjor lor cost for the lndscpe service industry. In ddition, over hlf of the sttes in the U.S. hve pssed lws ginst disposing of yrd wstes in lndfills, which hs incresed the interest in using PGRs to reduce pruning or the mount of clippings. Appliction rtes nd frequency of Cutless.33G were studied in this study for mnging growth of Knock Out rose nd Zhu Zhou loropetlum in the lndscpe. Nture of Work: Knock Out roses nd loropetlums re populr shrus commonly used in the lndscpes. However, they cn esily grow up to five feet tll nd require regulr trimming. Hnd pruning is lor intensive nd my increse disese prolems ssocited with wounding the plnt. Cutless.33G (SePRO Corportion, Crmel, IN) is grnulr formultion of flurprimidol which is gierellic cid iosynthesis inhiitor. It is sored minly y roots. Being grnulr, it is esier to rodcst round plnts thn soil drench liquid product. Other thn growth control, previous oservtions indicte tht flurprimidol my enhnce overll qulity of estlished lndscpe plnts with improved folige color nd flowering. The grnulr formultion for lndscpe use ws effective on zle nd loropetlum in continer production (1). However, few reserch studies hve een conducted on its effectiveness in lndscpe (2). The ojective of this study ws to determine effective rte nd ppliction frequency of Cutless to regulte the growth of Knock Out rose nd Zhu Zhou loropetlum fter eing estlished in the lndscpes. Two experiments were conducted in lndscpe reserch plots t LSU AgCenter Hmmond Reserch Sttion, Hmmond LA from 2009 to In oth experiments, rised eds were mde y dding soil mix (Nture s Best, Bton Rouge, LA) nd pine rk to existing soil. Individul plots (experimentl unit) were 10 feet long x 6 feet wide. A totl of 28 nd 25 plots were used in Expt. 1 nd 2, respectively. Two plnts of the sme species were plnted in ech plot nd treted s su-smples. Plnts were plnted in the fll to llow estlishment of roots during winter, nd then treted with Cutless in the susequent spring when new growth is oserved. In oth experiments, plnts were lightly pruned (15%) t the time of the first Plnt Growth Regultors 153

3 (spring) ppliction ut not the second (fll) ppliction. Overhed irrigtion ws provided which fcilitted the dissolution nd uptke of the ctive ingredient. Tretments in Expt. 1 (Knock Out rose) included Cutless pplied t 0, 5, 10, or 20 ls/1000 ft 2 on Apr. 13, 2010, nd two pplictions of 5, 10, nd 20 ls/1000 ft 2 with the first ppliction in April nd the second ppliction on Aug. 2, After April ppliction, plnt height (including inflorescences) nd width (verge of the two perpendiculr widths) were mesured once per month throughout the study. Plnt visul qulity ws rted monthly y scle rnged from 1 to 5, where 5 represents the est qulity. Flower numer per plnt ws recorded weekly from June to August. Lef greenness ws mesured using chlorophyll (SPAD) meter on the youngest fully expnded (YFE) leves on June 7 nd July 12. Dt were nlyzed s CRBD with four replictions ech hving two su-smples. Tretments in experiment 2 (Zhu Zhou loropetlum) included single ppliction of 0, 7, or 14 ls/1000 ft 2 Cutless on Mrch 3, 2011, nd two pplictions of 7 or 14 ls/1000 ft 2 on Mrch 3 nd August 23. Plnt height nd width were mesured once per month throughout the study. Plnt visul qulity ws recorded using the sme rting scle s for Knock Out rose in Expt. 1. Dt were nlyzed s CRBD with four replictions ech hving two susmples. Results nd Discussions: For Knock Out rose, height reduction of 35% ws oserved t four weeks fter the second ppliction t 10 ls/1000 ft 2. Two pplictions of 20 ls/1000 ft 2 resulted in similr height reduction nd visul qulity s 2x10 ls/1000 ft 2. Single ppliction of either 10 or 20 ls rte provided 10% to 15% height reduction, which ws not stisfctory ecuse Knock Out rose is vigorous plnt (Fig.1). Overll improvement in plnt qulity ws lso oserved, including incresed lterl rnching nd drker lef color in treted plnts. The control effect lsted for t lest five months nd more dt re eing collected for estimting control durtion on this populr lndscpe rose. For Zhu Zhou loropetlum, results indicted tht Cutless t 14 ls/1000 ft 2 pplied once in the spring is effective on controlling shoot growth from spring to summer. Additionl ppliction in August did not provide further growth control compred to single ppliction in April (Fig. 2). Drker purple leves were noted nd confirmed y chlorophyll content meter. These results were similr to wht ws found with nother vriety, Merlot Lce (2). 1. Bnko, T.J. nd M.A. Stefni Cutless nd Atrimmec for controlling growth of woody lndscpe plnts in continers. Journl of Environmentl Horticulture. 13(1): Chen, Y., R. Brcy, nd A. Owings Growth regultion of loropetlum nd zle in lndscpe eds. SNA Res. Conf. 54: Plnt Growth Regultors 154

4 A B Plnt height (cm) c c c c c x2 10x220x2 Visul qulity rting (1-5) c c c c x2 10x220x2 Cutless.33G rte (l/1000 ft2) Cutless.33G rte (l/1000 ft2) Figure 1. Plnt height (A) nd overll visul qulity (B) of Knock Out roses t 4 weeks fter the 2 nd tretment of Cutless.33G in August First ppliction ws pplied in Mrch Plnt heihgt (cm) x2 14x2 Cutless.33G rte (ls/1000 ft 2 ) Figure 2. Loropetlum Zhuzhou plnt height t 4 weeks fter the 2 nd ppliction of Cutless.33 G in August. First ppliction ws pplied in April Plnt Growth Regultors 155

5 Plnt Growth Regultor Impct on Clircho nd Veren Brnching Genhu Niu 1, Brent Pemerton 2, Pedro Osun 3, Denise S. Rodriguez 1 1 Texs AgriLife Reserch nd Extension Center t El Pso, Texs A&M University System, 1380 A&M Circle, El Pso, TX Texs AgriLife Reserch nd Extension Center t Overton Texs A&M University System, Overton, TX Universidd Autonom de Cd. Jurez; Chihuhu, Mexico gniu@g.tmu.edu Index Words: lterl rnching, height control, phytotoxicity, Augeo, Configure, Florel Significnce to Industry: Clircho sp. nd veren sp. re two populr ornmentl plnts nd mny commercil cultivrs re ville. Some cultivrs hve more rnches thn others. Consumers prefer well rnched, compct plnts with undnt flowering shoots. Plnt growth regultors (PGR) re often used to enhnce rnching nd hence increse the numer of flowering shoots. However, the effectiveness of PGR on rnching depends on the type of PGR, ppliction rte, nd the genotype of the plnt (1, 2). In this study, four cultivrs of clircho nd four cultivrs of veren were treted with three PGRs, Augeo, Configure, nd Florel, t two rtes s folir spry. Effects of PGRs on plnt performnce vried with type of PGR nd cultivrs. Nture of Work: On My 17, rooted cuttings of clircho Blcnpt Cn-Cn Apricot, Blcno Cn-Cn Moch, Blcnorn Cn-Cn Ornge, Blcnerry Cn-Cn Strwerry, nd veren Blzvelu Aztec Blue Velvet, Blzreve Aztec Red Velvet, Blzwilro Aztec Wild Rose, Blwildred Wildfire Drk Red were received in El Pso, TX from Bll Horticulture (Chicgo, IL). Uniform un-pinched rooted cuttings were selected nd susequently trnsplnted to 4-in dimeter round plstic pots filled with No. 1 Sunshine Mix (SunGro Hort., Bellevue, WA). Plnts were then grown in the greenhouse nd irrigted with nutrient solution mde from 15N-5P- 15K Cl-Mg Specil (Scotts, Mrysville, OH) with totl N t 125 ppm. On My 25, plnts were spryed with PGRs fter plnts were well wtered (Tle 1). Before sprying, plnts were rrnged in four completely rndomized locks with 16 or 10 plnts per lock, depending on cultivr. Cn-Cn Apricot nd Cn-Cn Moch clircho nd Aztec Blue Velvet nd Aztec Wild Rose veren hd 16 plnts per lock. The remining cultivrs hd 10 plnts per lock. Eight pots were plced in ech flt (9.5 inch wide y 20 inch long). To compre the efficcy of PGRs, group of untreted nd un-pinched plnts served s control, nd nother group of untreted ut pinched plnts served s pinched control. The greenhouse temperture ws controlled y pd-nd-fn cooling system. The verge dily mximum temperture in the greenhouse during the experimentl period were 30.3 ± 1.2 C, verge dily minimum Plnt Growth Regultors 156

6 temperture were 23.7 ± 1.6 C, reltive humidity rnged from 20 to 45%, nd dily light integrl rnged from 15 to 21 mol m -2 d -1. At the end of the experiment (6 weeks fter PGR tretments), plnt width (two perpendiculr widths) ws mesured for ll plnts, nd plnt height ws mesured for veren. Totl numer of shoots nd numer of looming shoots were counted. Visul qulity ws evluted t 9, 21, nd 33 dys fter PGR tretments. Phytotoxicity ws lso rted 21 dys fter PGR tretments. Criteri of evlution re noted in the footnote of the result tles. Results nd Discussions: For clircho, Augeo treted plnts improved rnching slightly compred to untreted control nd pinched control plnts nd hd the est visul qulity mong ll tretments. Augeo 400 nd 800 ppm treted plnts hd more or similr numer of shoots compred to untreted nd pinched control plnts (Tle 2). Configure nd Florel did not improve rnching, regrdless of cultivrs. Similr to totl shoot numer, Augeo 400 nd 800 ppm treted plnts hd similr numer of looming shoots compred to untreted control nd pinched control plnts for ll cultivrs (Tle 3). Florel 500 nd 1000 ppm lso resulted in similr numers of looming shoots in Cn-Cn Ornge nd Cn-Cn Strwerry compred to untreted nd pinched control plnts. Plnts treted with Configure t oth rtes resulted in the lowest numers of looming shoots. Right fter the Configure folir spry, plnts ppered stressed nd growth ws stunted for while. By the time the experiment ws terminted, the mjority of plnts reched pek flowering. Configure treted plnts hd mny smll shoots tht were in vegettive growth without flower uds. This my indicte tht Configure rtes, 150 nd 300 ppm my e too high for clircho. The effects of PGRs on finl plnt size were similr to their effects on rnching. Augeo 400 nd 800 ppm treted plnts hd similr widths or were igger compred to untreted nd pinched control plnts. Other PGR tretments led to smller plnts (Tle 4). Similrly, plnts treted with Augeo 400 ppm hd the est visul qulity scores, followed y those treted with Augeo 800 ppm in ll clircho cultivrs (Tle 5). Configure 300 ppm nd Florel 1000 ppm treted plnts tended to hve lower qulities. Minor phytotoxicity ws oserved in clircho cultivrs. For veren, none of the PGR tretments improved rnching, regrdless of cultivr. For Aztec Blue Velvet, plnts treted with Configure 300 ppm nd Florel 500 ppm hd similr totl shoot numers s the untreted nd pinched control plnts, while ll other PGR tretments reduced shoot numer (Tle 6). For Aztec Wild Rose, plnts treted with Configure 150 ppm nd 300 ppm nd Florel 500 ppm hd similr shoot numers s the untreted nd pinched control plnts nd ll other PGR treted plnts hd fewer shoots. For Aztec Red Velvet nd Wildfire Drk Red, ll PGR treted plnts hd fewer shoots thn the untreted nd pinched plnts except for Augeo 400 ppm on Wildfire Drk Red. Therefore, PGR tretments reduced shoot numer in these two cultivrs (Tle 6). PGRs did not ffect plnt height in Aztec Blue Velvet. All PGR tretments led to shorter nd more compct plnts compred to untreted nd pinched control plnts except for Configure 150 nd 300 ppm nd Florel 500 ppm in Aztec Wild Rose (Tle Plnt Growth Regultors 157

7 7). Pinched plnts hd the est visul qulity compred to PGR treted plnts, regrdless of cultivr (Tle 8). The effect of PGR tretments on visul qulity vried with cultivr. For exmple, Configure 150 nd Florel 500 ppm resulted in etter qulity in Aztec Blue Velvet nd Aztec Wild Rose thn other PGR tretments. However, for Wildfire Drk Red, Augeo 400 ppm hd etter visul score (3.7) thn ny other PGR tretment. All veren cultivrs exhiited phytotoxicity (Tle 9), lthough the degree of dmge vried with cultivr nd PGR. For exmple, in Aztec Blue Velvet, the most severe phytotoxicity (2.2) ws oserved with Configure 300 ppm tretment, while in Aztec Red Velvet the most severe phytotoxicity (4.2) ws oserved with Augeo 800 ppm tretment. In summry, for clircho cultivrs, Augeo treted plnts improved rnching slightly compred to untreted control nd pinched control plnts nd hd the est visul qulity. For veren, none of the PGR enhnced rnching nd improved qulity. Little phytotoxicity ws oserved in clircho cultivrs, while ll veren cultivrs exhiited phytotoxicity with vrying degrees of dmge depending on cultivr, PGR, nd ppliction rte. Acknowledgements. We pprecite the dontion of plnts from Bll Horticulture nd the chemicls from OHP, Inc. Fine Americs, nd Monterey Ag Resources. References 1. Ltimer, J. nd J. Freeorn New uses of PGRs in ornmentls: Configure (6- BA) increses rnching of herceous perennils. Proc. Plnt Growth Regultion Society of Americ Thoms, P.A., J.G. Ltimer, D. Zhng, nd S. Hrtzler Effects of plnt growth regultors on lterl rnching nd shoot growth of hypericum. SNA 37: Plnt Growth Regultors 158

8 Tle 1. List of plnt growth regultors, ppliction rte nd time. Appliction Dte of Crop Growth Product Rte(s) Type Appliction Stge Augeo (dikegulc) Configure (enzyldenine) Florel (ethephon) Untreted, not pinched 400 ppm 800 ppm 150 ppm * 300 ppm 500 ppm 1000 ppm Folir spry Folir spry Folir spry My 25, 2011 My 25, 2011 My 25, dys fter trnsplnting 8 dys fter trnsplnting 8 dys fter trnsplnting Appliction Volume One gllon per tretment One gllon per tretment One gllon per tretment Untreted, pinched *Two pplictions t 1 week intervl. Tle 2. Finl numer of shoots of Clircho cultivrs counted on Dy 33. Tretment Cn-Cn Cn-Cn Cn-Cn Cn-Cn Apricot Moch Ornge Strwerry Control 58.5 c Pinched c Augeo Augeo c Configure cd 56.3 c 48.0 cd 74.2 c Configure e d 62.9 c Florel c 58.6 c 57.5 c 63.9 c Florel de 45.4 c 47.9 cd 58.3 c Mens in the sme column with sme letters re not significntly different. Tle 3. Finl numer of looming shoots for Clircho cultivrs counted on Dy 33. Tretment Cn-Cn Cn-Cn Cn-Cn Cn-Cn Apricot Moch Ornge Strwerry Control Pinched Augeo Augeo Configure c 32.8 c Configure c 25.0 c 7.5 c 8.3 Florel Florel c Mens in the sme column with sme letters re not significntly different. Plnt Growth Regultors 159

9 Tle 4. Finl width [(width 1 + width 2)/2] of Clircho cultivrs mesured on Dy 33. Tretment Cn-Cn Cn-Cn Cn-Cn Cn-Cn Apricot Moch Ornge Strwerry Control Pinched c 31.1 Augeo c Augeo cd 28.6 cd 29.2 Configure d 24.8 cd 24.6 d 24.5 Configure e 22.4 de 19.3 e 21.3 Florel c 22.7 de 29.6 cd 24.5 Florel de 20.9 e 26.5 d 21.7 Mens in the sme column with sme letters re not significntly different. Tle 5. Visul qulity of Clircho recorded 9, 21, nd 33 dys fter tretment. Tretment Cn-Cn Cn-Cn Cn-Cn Cn-Cn Apricot Moch Ornge Strwerry D9 D21 D33 D9 D21 D33 D9 D21 D33 D9 D21 D33 Control Pinched Augeo Augeo Configure Configure Florel Florel Evlution criterion: 1 = significntly worse thn untreted; 2 = modertely worse thn untreted; 3 = slightly worse thn untreted; 4 = no difference from untreted; 5 = slightly etter thn untreted; 6 = modertely etter thn untreted; 7 = significntly etter thn untreted. Tle 6. Finl numer of totl nd looming shoots of veren cultivrs counted on Dy 33. Tretment Aztec Blue Velvet Aztec Red Velvet Aztec Wild Rose Wildfire Drk Red Totl Blooming Totl Blooming Totl Blooming Totl Blooming Control Pinched c Augeo c 4.9 de c c Augeo d 3.5 e 2.3 c 0.9 d c 1.7 c 1.1 d Configure c 6.3 cd c c 1.6 d Configure cd c c 0.9 d Florel c Florel c 5.9 cd 2.6 c 0.6 d c 4.7 c 2.3 d Men in the sme column with sme letters re not significntly different. Plnt Growth Regultors 160

10 Tle 7. Finl height nd width [(width1 + width2)/2] of veren cultivrs mesured on Dy 33. Tretment Aztec Blue Velvet Aztec Red Velvet Aztec Wild Rose Wildfire Drk Red Height Width Height Width Height Width Height Width Control Pinched c c 36.6 Augeo cd 8.0 c 14.0 cd 9.0 c 14.9 cd Augeo d 5.8 c 9.8 d 9.5 c 10.7 e 8.0 d 9.0 d Configure cd c cd 15.6 c Configure c d c 7.7 d 10.5 cd Florel c 20.8 Florel c 6.9 c 11.1 d 8.5 c 13.7 de 10.7 cd 14.5 cd Mens in the sme column with sme letters re not significntly different. Tle 8. Visul qulity of veren cultivrs recorded on 9, 21, nd 33 dys fter tretment. Tretment Aztec Blue Velvet Aztec Red Velvet Aztec Wild Rose Wildfire Drk Red D9 D21 D33 D9 D21 D33 D9 D21 D33 D9 D21 D33 Control Pinched Augeo Augeo Conf Conf Florel Florel Evlution criteri: 1 = significntly worse thn untreted; 2 = modertely worse thn untreted; 3 = slightly worse thn untreted; 4 = no difference from untreted; 5 = slightly etter thn untreted; 6 = modertely etter thn untreted; 7 = significntly etter thn untreted. Tle 9. Phytotoxicity of veren cultivrs ssessed 21 dys fter PGR tretment. Tretment Aztec Blue Velvet Aztec Red Velvet Aztec Wild Rose Wildfire Drk Red Control Pinched Augeo Augeo Conf Conf Florel Florel Phytotoxicity rting: on scle of 0 to 10 (0 = No phytotoxicity; 10 = Complete kill) tken on Dy 21. Plnt Growth Regultors 161

11 Growth Regultion in Continer Produciton with TopflorG Yn Chen, Allen Owings, Regin Brcy, Joey Queedeux Old Covington Highwy, Hmmond LA, Index Words: flurprimidol, grnulr formultion, herceous perennil, greenhouse production Significnce to Industry: Mny herceous perennils need to e pruned severl times during production for fuller growth nd compct shpe. Pruning is significnt expenditure of time nd lor in their production costs. Plnt growth regultor my help reduce pruning needs nd improve plnt qulity. A grnulr formultion of flurprimidol (TopflorG) ws tested in production greenhouse on three herceous perennils. Results indicte tht TopflorG provided effect nd long-lsting growth control on ll three vrieties. However, there were issues with crop qulity possily ecuse of ppliction timing. Further reserch is needed for mking pproprite ppliction recommendtions. Nture of Work: TopflorG (SePRO Corp., Crmel, IN) is grnulr formultion of flurprimidol (0.17%) which is gierellic cid iosynthesis inhiitor. It is sored minly through roots nd stems. Being grnulr, it is esier to e rodcst round plnts thn spry-drench or soil drench of liquid product. The slow-relese feture my provide longer growth control compred to some other PGRs currently ville for greenhouse production. Other thn growth control, previous oservtions indicte tht flurprimidol my enhnce the overll qulity of plnts with drker green folige (1), more flowers (2), improved drought tolernce in folige plnt (3), nd reduced cold injury in Frser fir (4). Severl ppliction spects of this PGR hve not een fully tested with herceous perennils in continer production. For exmple, ppliction timing, effective rtes, nd residul effect fter eing trnsplnted into the lndscpe, re still unknown for mny commonly used vrieties. The ojective of this preliminry study ws to determine effects of TopflorG t vrious rtes on the growth nd qulity of lntn, Mexicn Hether, nd veren. The study ws conducted in greenhouse t the Brcy s Nursery (Amite, LA) in Rooted cuttings of New Gold lntn, Mexicn hether, nd Homested Purple veren were trnsplnted into trde gllon pots (1.4L) on Mrch 22. Potting mix ws custom pine rk mix. A single cutting ws plnted per pot for Mexicn Hether nd veren, while two cuttings were plnted in ech pot for lntn s grower s prctice to otin fuller plnts. A totl of 24 pots of ech vriety were treted with Topflor t 0, 1/8, or 1/6 tespoons with eight plnts treted for ech rte. A soft pinch ws conducted on veren nd lntn efore tretments. After ppliction, plnts were mintined y Plnt Growth Regultors 162

12 nursery stff with the sme prctices cross tretments nd vrieties. Plnt height (including inflorescences) nd width (verge of the two perpendiculr widths) were mesured t 3, 5, nd 7 weeks fter tretment (WAT). Numer of inflorescences in lntn nd veren were recorded t 5 WAT. Overll crop qulity ws ssessed for ech plnt s slle or unslle t 8 WAT sed on criteri provided y the grower. A slle plnt needs to e full (cnopy cover the pot surfce, no medium cn e seen from top view), lnced, nd with good numer of flowers presented on top of cnopy. Plnts tht were not le to cover the pot (medium cn e seen), skewed to one side of the pot, or without flowers re considered unslle. All dt, except slility ssessment, were nlyzed s Completely Rndomized Design with eight replictions. Results nd Discussion: All three vrieties responded to TopflorG from 3 WAT. Compred with untreted control, lntn treted with 1/8 or 1/6 tespoons hd 50% to 60% less increse in height y 3 WAT, nd 70% to 75% less increse in height y 5 WAT (Fig. 1A). Mexicn Hether plnts treted t oth rtes hd 40% to 60% less increse in height, nd veren hd 50% to 65% less increse in height (dt not shown). Effects were lso significnt with plnt width in lntn (Fig. 1B) nd the other two vrieties (dt not shown). The difference in numers of flowers ws not sttisticlly significnt mong tretments (lntn dt in Fig. 1C); however, there ws trend tht plnts treted with higher rtes my hve fewer flowers in oth lntn nd veren. In ddition, the tretments plnts hd etter flower presenttion possily ecuse the cnopy of treted plnts ws more compct nd flowers were presented on shorter stems (Fig. 2). Lntn ws the only vriety plnted with two cuttings in ech pot. Aout 25% pots treted with TopflorG exhiited some degree of difference in terms of receiving nd responding to the tretment etween the two cuttings (Fig. 3). Among treted plnts t oth rtes, out 50% to 56% lntn, 31% Mexicn Hether, nd 31% to 44% veren plnts (either rte) were unslle either ecuse plnt cnopy ws not full enough or plnt skewed to side of pot (Fig. 4). In summry, TopflorG is effective in controlling growth of the three perennils tested, ut issues such s uneven growth etween multiple cuttings nd unle to produce full cnopy were found nd possily relted to ppliction timing. Apprently, pplying erly t the time of trnsplnt (s recommended y mnufcture) or very erly stge of production, plnt my not hve enough time to grow nd cover the pot, or, root development of multiple cuttings re limited to smll soil mount tht my miss the mteril pplied nery. Further study is needed for etter timing. Literture Cited: 1. Chen, Y., R. Brcy, nd A. Owings Growth regultion of loropetlum nd zle in lndscpe eds. SNA Res. Conf. 54: Bnko, T.J. nd M.A. Stefni Cutless nd Atrimmec for controlling growth of woody lndscpe plnts in continers. J. of Environ. Hort. 13: Burton, A.L., S.V. Pennisi, nd M.W. vn Iersel Morphology nd posthrvest performnce of Geogennthus undutus C. Koch & Linden Inc fter ppliction of ncymidol or flurprimidol. HortSci. 42: Plnt Growth Regultors 163

13 4. Nzokou, P nd P. Nikiem The influence of three plnt growth regultors on susceptiility to cold injury following wrm winter spells in Frser fir [Aies frseri (Pursh) Poir] nd Colordo lue spruce (Pice pungens). HortSci. 43: A. Increse in height B. Increse in width Increse (cm) Untreted 1/8 tsp 1/6 tsp Increse (cm) c 0 3 WAT 5 WAT 0 3 WAT 5 WAT C. Numer of flowers WAT Untreted 1/8 tsp 1/6 tsp Figure 1. Increse in plnt height (A) nd width (B) t 3 nd 5 weeks fter tretments (WAT), nd numer of inflorescences t 5 WAT in lntn treted with Topflor 3 dys fter trnsplnt. Plnt Growth Regultors 164

14 Figure 2. Untreted lntn plnts, nd those treted with TopflorG t 1/8 or 1/6 tespoon, showing etter flower presenttion on treted plnts. Figure 3. One of the issues found with lntn is tht the grnulr mteril my not distriute evenly etween the two cuttings plnted in the sme pot, or these cuttings my not respond eqully. In this photo, the cutting on the right (circled) received nd responded to the tretment ut the cutting on the left did not. Plnt Growth Regultors 165

15 Figure 4. Untreted Mexicn Hether (ove) or Homested Purple veren (elow), nd plnts treted with 1/8 or 1/6 tespoon of TopFlorG. Both photos indicte tht if tretment ws pplied too erly (3 dys fter trnsplnt in this study); growth ws suppressed efore the cnopy cn cover the pot. Plnt Growth Regultors 166