Kimura, Kazuyoshi

Tukey, H.B.

Simplified Chinese

Okayama University Scientific Achievement Repository

INFLUENCE OF MIST ON FLORAL INITIATION OF PHARBITIS NIL* Kazuyoshi KIMURA and H. B. TUKEY， JR.. * INTRODUCTION Rain， dew， fog， and mist may have a modifying influence uJX>n plant growth and development. Some modifi伺 tions伺 nbe attributed directly to leaching of sul:栂tanωfromplants， a phenomenon which has加enreJX>rted previously by a number of workers (Arens， 1934; Le Clerc and Br'回zeale，1908; M回， 1954; Stenlid， 1958; Tukey， 1970). Lo時esby 1回 chingof mineral nutrients，伺r加.hydrates， amino and organic acids， and growth regulating substanc田 influenceplant size， nutrient content and nutritive value， crop yield and quality， and certain metabolic proce蹴 ssuch as f10wer and r，∞t initiation， leaf abscission， and dormancy (Cholodny， 1932; Kozel and Tukey， 1968; Tukey， 1970; Tukeyet a1.， 1969). However， in釦 me国民sit is not ap戸rentwhether modifi伺 tionsinduced by rain and mist are due to 1朗 ching，or to other factors as荻>eIatedwi白血e紅白t・ment itself. Thus， Lees (1956) observed that considerable rainfall during one y回 rreduced the num民rof flowers and fruit on Malus domestica Bork. the following y但 r，but the m配 hanismwas not elucidated. Theex戸rimentsd田cribedherein investigated the influence of water mist on floral initiation of Pharbitis nil Chois as a first step in separating the leaching and physiological effects of the mist treatment. MATERIAL AND METHODS The material， Pharbitis nil Chois，“Violet "， u民din the pre記 ntr白田rchis known as one of the m倒 tsensitive short day plants. It initiat回日目alprimo吋iafollowing application of a single dark period of adequate length. In al the experiments 戸田entedherein， plants were cultured on a medium of fine silica阻 ndin a plastic tray. A11 plants we回 grownfor 4 days after geロ叫-nation under ∞ntinuous illumination in a controlled environment chamber and were then subj配ted句 vario崎 photo戸riodand mist treatments. The light釦urcein the chamber consisted of 凶thincandescent and fluorescent lam戸 withan intensity of 15， 000μw/cm'. Water was atom包edat an air pr回sureof 30問 ωform a fine mist which was applied continuo凶lyto the plants throughout the tr回 t・* Contribution NYO-2598-50 of U. S. A同凶ICEnergy Commission Con回 ctAT (>>-1)品 98，from the Deμrtment of FloricultureむldOmamental Hぽ6叫畑町 Comell U山町sity，1伽 ca，New Yc町k，U.S.A. 判De卵丘mentof Floriculture and Ornamental Hぽticulture，Cornel UIUversity， Ithaca， New York， U.S.A. 62 K. Kimura & H. B. Tukey， Jr. ment戸riodat the rate of 3 ml/cm~/hr using an overhead mist ap何回tus.After the treatments of photo戸riodand misting， the plants were transferred to a gr<田 nhou民 under∞ntinuous il1umination (artificial incand蹴 entlight during the night) with maximum day tem戸ratureat 250C and night tem戸ratureof 200C. The plants were fertilized once戸rW<“主 witha 20-ー20ー 20fertilizer. Twenty days after the treatment， they were dissected under a binoc叫arrmcro-scope to observe f10ral primordia. The experiments were re開ated配veraltim回and always gave similar results. Typical results from at least 24 pla凶 S戸rtr，回t-ment are given in the pre記 ntpape巴RESULTS 1. Mistρrecedingρhotoind uctiveρeriod. Plants were misted for 12 con配cutivehours in the light. Immediately after misting， the plants were subjected to a dark tr田 tmentfor 12， 14， and 16 hours at 270C， and then grown on for 20 days in the gr偲 nhou民. As shown in Table 1， TABLE 1. Flowering response of Pharbitis nil “Violet" subjected to water mist for 12 hours in the 1泡htpreceding various photoinductive戸ri叫s.Hours of Treatment % of plants with Flow釘 budsper 96t町cdmplaln包aoweitrh darkn簡 flower buds 10 plants bud No mist 29.2 3.0 。12 Mist 。 0* 。14 No mist 95.8 15.2 。Mist 87.5 9.2キ 。16 No mist 100 32.0 。Mist 1∞ 23.3キ 。キ Significantlylower than valu飽 fromnon-misted pla曲目 the1 % level. f10wering was induced by al 3 dark treatments， and the intensity of the r回pon配was great1y increased as the hours of darkness increa配dfrom 12 to 16 hours. The f10wering r田pon配swere suppressed by 12 hours of mist immediately pr<配 ed-ing the dark trea tment，開rticular1yin the 12-hr dark treatment， when the photo-period effect was completely negated by the mist treatment. The e妊配tof the mist on the戸rcentageof plants with f10wer buds decreased as the length of the dark period was increased， and at 16 hours of darkness， the effect of the mist was gr回t1yreduced. The number of f10wer buds was decreased in al 3 dark treatments by the mist treatment. ln a配 condex戸riment，plants were misted for 0， 4， 8， 12， and 24 hours in the light and suh記quent1yexp<既dto darkness for 16 hours. The r，田ultsare Inf1uenc坦ofMist on FIOnl  lnitiation of Plarbitis nil 60 50 . 包三40:= 』• 色. 可3:) 酒色』• 23E 20 . 10 。。'" a 12 24 Hourl 01 Milt Fig. 1. Flow回ng闇 ponseof Plarbitis nil“Violet" sub枠制 towat釘 mistfor various durations preceding 8悼ωoinductive戸riodof 16 hours darkn邸.63 shown in Fig. 1. Plants expo:配dto mist for 4 hours prior to darkness initiated the阻 menumber of floral primordia as plants which were not misted (，∞ntrols)， but as the ex卯sureto mist was inロ回艶4 出enumber of flower buds was decrl回配dup to almost 50妬.Th田eresults indi回 tethat mi銑ingimmediately prior to a photoinductive period is inhibitory to flowering in Pharbitis nil “Violet". n. Mist during ρhotoinductive period. T油 LE2. Flowering respon田 ofPhal'bitis nil“Violet" subjected to water mist during various photoinductive peri叫 s.H四四 of Treatment % of plants with Flower buds per %回cmdipnld ana包oweidr1 darkn闘 a何ぽ buds 10 plan飽 bud No nおt 36.6 4.0 。12 加fist 93.3 10.0本 。14 No mist 1∞ 19.3 。Mist 100 23.6紳 。16 No mist 100 39.4 。Mist 1∞ 40.2 6.6 * or紳 difersfrom valu旬。，fnon-misted plan包 at也el%， or5%， 1町出.r田伊凶vely.64 K. Kimura & H. B. Tukey， Jr.Plants were偲戸閣dto mist during the photoinductive 戸riodof 12， 14， and 16 hours of darkness. Twenty days after the tr'伺 tmentflowering r回pon田swere examined and the results are shown in Table 2. The plants subjected to mist initiated a larger number of flower buds than did the non-misted plants，開rti・cular1y during the 12-hr dark戸Z協iII. Mist followingρhotoinductiveρeriod. Plants were subj院tedto mist for 12 hours in the light immediately fo11owing a photoinductive戸riodof 12， 14， or 16 hours of darkness. As shown in Table 3， TABLB 3. Flowering respon田 ofPhOTbitis nil “Violet" subj田飴dto water mist for 12 hours in the light following various photoinductive periods. H凶 rsof Treatment % of pl且n包 with Flower buds per %町cmdipm1血1f1飽owtirth darkn箇 f10wer buds 10 plan包 bud No mist 79.2 9.3 。12 Mist 58.3 5.8・* 。14 No mist l∞ 20.0 。Mist 95.8 13.5* 。16 No mist 1∞ 44.8 25.1 Mist 100 20.8* 。* or柿 dif，間仕切nvalu飴 ofnon-mis凶p1an包 atthe 1形町 5% levels， respective1y. plants under the mist tr回 tmentinitiated a sma11er number of flower buds than did plants which were not misted. As in the other ex戸riments， the effect of the mist on the 戸町entageof plants with flower buds was incr田町das the length of the photoinductive 戸riodwas decrea艶d The number of flower buds was d配r回 sedin a113 dark treatments by the mist 紅白tment.ln another ex戸riment， mist tr回 tmentswere applied for 4 to 24 hours in血elight fo11owing a photoinductive戸riodof 16 hours darkn国s. The flowering respo蹴 (Fig.2) was suppr田町dby a1 the mist tr田tments. Regardless of the length of the mist 紅白tment， the number of flower buds per plant subjected to mist was about half that of the non-misted∞ntrols. To amplify this experiment， plants we問 ex戸商品to mist for 24 hours in the light at daily intervals fo11owing a photoinductive period of 16 hours of darkn鰯 .As shown in Table 4， when the plants were misted on出e1st and 2nd day after the photoinductive 紅白tment， flowering r田pon配 wasgreat1y decr'回 sed. How-ever， after the 3rd day， there was 00 ap戸rentdifference in number of flower buds. Thus， for up to 2 days fo11owing photoinductioo， f1oweriog r，回pon民民emsto remain in an unstable state which is aff配tedby the mist treatment. Influence of Mist on Flora1 Initiation of Pharbitjs "jJ . -e • 60 50 A. "0 電2・F 』-a 右 302 ・2』• ~ 。20. 10 t' s 12 2 .HoufI of Mht Fig. 2. Fl，阿国ngresponse of Pharbitis "jJ “Vi01et" subjec凶 ωwat町 mistf，ぽvarious durations following a pho凶nd町tive戸主iodof 16 hoursゐrkn儲.TABLE 4. Flowering respon田 ofPhol'bitis nil “Violet" subjected to water mist for 24 hours in the light at intervals following a photo-inductive period of 16 hours darkness. EphapdfEdEdluowction g 56fEld owp町hzzh包awsith F10wer hI.UlS per 10 plan包 tE96mid naIphanowts哩zwihd No mist 100 42.3 36.6 1 100 19.8'本 。2 1∞ 33.3ホ 16.6 3 100 38.4 24.1 4 100 39.2 43.5 5 100 37.2 40.0 7 100 38.1 30.0 ホSigI岨cantly1，側喧r伽 nvalu句 fromnon-mIs凶 p1an鈎 atthe1%1軒 el.IV. Effect of tem，ρerature onρhotoρeriodic induction. 65 One of the possible influences of the rnist tr伺 tmentis to reduce leaf and air temperat山崎 perha戸田 muchas to have a temperature effect upon photoinduc・tion. The optimal temperature for pho旬periodicinduction of floral initiation in Pharbitis nil is ranged from 200 to 300C (lmamura， 1967). Therefore， the plants were grown in controlled environment chambers at a constant 270C， and 66 K. Kimura & H. B. Tukeゎ Jr.the misting water was incu凶tedat 300C before misting. Measurements of temper-atur，伺 withinthe chambers showed 270C with no mist and 240C with misting ∞nditions. In a supplemental ex戸riment，plants were exposed to 230C and 270C with-out mist at various perio也 preceding，during， and fol1owing a photoinductive period of 14 hours of darkn回s. As shown in Table 5， no significant differenc回TABLE 5. Effect of temperature on photoperi叫icinductioD in Pharbitis nil “Violet". T個'...... ・-(O-c) F司司匹 '司-ー・:. 形ofplan包 with Flower buds per {1L2ihnt .) Dark LitLt) 日owerbuds 10 plAn匂(14 hrs.) お 27 27 100 21.4 27 23 27 100 21.8 27 27 23 100 23.0 27 27 27 100 24.5 were found in the number of flower buds of plants which were位向edto th蹴tem戸rature紅白tments. Thus， the eH配ton flower initiation noted in th蹴 ex-periments is ap戸rentlyan effect of the mist itself rather than an effect of the conditions produced by mist tr回 tment.DlSCUSSION In the present experiment， flowering respon錨 weresuppressed when plants were misted in the light either immediately pr配.edingor fol1owing a photoinduc・tive peri品 Incontrast， the flowering respon関 waspromoted slightly when the plants were misted during a photoinductive period. In explanation， Tukey et a1. (1957) demonstrated出at四rbohy世at回 werel回 chedfrom leav回 bywater mist in relation to the light intensity pre田ntduring the lea必 ngperiod. In addition， K但 eland Tukey (1968) re抑制thatgibberel-lins were 1回 chedin far gr回 terquantiti回 fromChrysanthemum morifolium in darkn部 thanin light. Since many workers have re伊rted出atcar1:幻hydrat回 andgibbere出nshave釦merelationship with flower induction， th悦自吋ingssugg回tthat the differenc国民tw伺 n出.eflowering respon艶 ofmisted and non-misted plants of Pharbitis nil maY arise in part from the 1回chingof th田esubstanc碕 bymist. A1though both回 rbohydrat回 andgibberellins are 1田 chedfrom Pharbitis nil， a dir配 trelationship between 1回 chinga吋 floweringhas not been回tablished.Many factors other than leaching eff配 tof mist may influence flower initia・tion， such as oxygen deficiency， d配r回 singtemperature， and change of民 nsitivityof lea ves to photo戸riodicinduction by misting. From the r，倒utsin Table 5， tem戸ratured悶即t配emto be a factor in the挺experimen也 Further，oxygen deficiency d田 snot配emto be a factor， inasmuch Influence of Mist on F1低温1Initiation of Pharbilis "il 67 as air at a pressure of 30 psi was used to form the atomized water mist with which the plants were 紅白ted. But to rnake the relationship clear， more detailed ex戸rimantswill be r明uired団関ciallyto田paratethe influence of 1但 ched伺 rbohydrat田 andgrowth regulating su凶tanc国.SUMMARY Plants of Pharbitis nil “Violet" were sub炉tedto an atomized water mist 紅白tmentpreceding， during， and following photoinduction of floral initiation. Mist 仕組tmentin the light immediately pr配吋ingphotoinduction suppre濁dflowering r田pon部. Mist tr田 tmentduring photoinduction promoted floral initia. tion. Flowering res伊 n配swere suppr，掛edby mist of 4 hours or more immedi. ately following photoinduction. on the 1st and 2nd ay following photoinduction， flowering respo師団関emto be in an unstable state which回 nbea任配tedby mist. However， after 3 days following photoinduction， floral initiation was not inhibited by subs伺uentex戸lSureto mist. REFERENCES Arens， K. 1934. Die kutikul且reExkretion d釘Laubbla悦町.Jahrb. Wi鎚.Bot. 80: 248-300. Cholodny， N. 1932. Zur K，阻ntnisd町 durchd包 regn町民heweter verusachten Ertragsabnahme bei Getreideart阻.Ber. Deut. Bot. Ges. 50: 562ー 570.Imamura， S.1967. Physiology of flow町ingin Pharbitis "iI. Japan. Soc. Plant Physiol.， Tokyo， Ja戸n.K噌 1，P. C. and Tukey， H. B.， Jr. 1968. Loss of gibberellins by leaching from stems and foliage of Chrysa"themum morilolium 'Prince鑓Anne'.Amer. J. Bot. 55: 1184-1189. Le Cl町， J. A. and Breazeale， J.F. 1908. Plant foc:xl removed加 ngrowing pla胞 byrain or dew. U. S. Dept. Agr. Y，白血児kAgr. pp.389-402. Le鎚， A. H. 1926. F配torsgover叫ngfruit加dformation. VII. Influence of SUmmer rainfal and previousα'Op on the fruiting of apples. Ann. Rpt. Long Ashton Agr. Hort. Res. Sta. pp. 42-59. Mes， M.G. 1954. Exc剖 on(r問就i∞)of phosphorus a吋 o出ermineral elemen包 byleaves under the influence of rain. S. African J. Sci. 50: 167-172. S国 ilid，G. 1968. Salt lc溺匂 andr吋istributionof salts in high町 plan包. Handb. Pflanzen・physio1句ie4: 615-637. Tukey， H. B.， Jr.1970. The leaching of substanc鎚 fromplants. Ann. Rev. Plant Physiol. 21: 305-324. Tukey， H. B.， Jr.， Koze1， P. C.， Kimura， K. and Le， C.I. 1969. Leaching of growth regulating substances from plan包. Abstr. XI In附n.Bot. Cong. (Sea凶e)p.222. Tukey， H. B.， Jr.， Wittwer， S.H. and Tukey， H. B. 1967. Leaching of carbohydra臨 from. plant foliage剖 relatedto Iight in惚nsity.Scienc泡 126: 120--121. 

INFLUENCE OF MIST ON FLORAL INITIATION OF PHARBITIS NIL*

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