Transport of Root-Forming Hormone in Woody Cuttings Citation Cooper, William Cecil (1936) Transport of Root-Forming Hormone in Woody Cuttings. Master's thesis, California Institute of Technology. doi:10.7907/G6RJ-EH78. https://resolver.caltech.edu/CaltechETD:etd-04232008-144025 Abstract No abstract. Item Type: Thesis (Master's thesis) Subject Keywords: Biology Degree Grantor: California Institute of Technology Division: Biology Major Option: Biology Thesis Availability: Public (worldwide access) Research Advisor(s): Unknown, Unknown Thesis Committee: Unknown, Unknown Defense Date: 1 January 1936 Record Number: CaltechETD:etd-04232008-144025 Persistent URL: https://resolver.caltech.edu/CaltechETD:etd-04232008-144025 DOI: 10.7907/G6RJ-EH78 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 1480 Collection: CaltechTHESIS Deposited By: Imported from ETD-db Deposited On: 25 Apr 2008 Last Modified: 03 Oct 2019 23:08 Thesis Files Preview PDF (Cooper_w_1936.pdf) - Final Version See Usage Policy. 11MB Repository Staff Only: item control page

thesis by Willien GC. Cooper - in Parbial Fulfillment of the Requirements for the Degree of Master of Selenee, California Institute of Technology, Pasadena, California, 1936. TRANSPORT GF ROOTPORMING HORMONE IN WooDyY cuTTiInes Et has been repeatedly chserved since carly times that if stems fron some of owr common woody plants ere girdled adventitious roots may be formed above the girdle, Although thie regeneration phenomenon way result in part Prom an interruption of food transport, recent evidence indicates that the regeneration is controlled by hormones which are trencperted in the phloem. The grexter part of the experimental work on the neture and transport of these hormones in the plant has been done with sven sdleope tiles and pea (Pisum sativum) cuttings. Went 22) demons frated that a growtheprometing factor from Avena coleoptile tips will diffuse out of them into a layer of ager, and that decapitated coleoptiles will grow con= Sidewably faster if blecks of this agar are placed on the cub surfaces than if they are supplied with pure egere ‘The chemistry of this gromth substance has been worked owt especially by Réel, Haagen Smit and Bexteven'8?), Three different crystalline substances were iseleted, which physiclogically can not be distinguished, They have been mamed auxin e (Cygfies0s)3 auxin b (Cigtgq0a)s and hetercequxin Cindole«Seacetic acides(ygligOgl). Later PhimanhtORLd } found that syabthetic hetercernuxin causes root formation on pea, cubtings as well as promoting growth by cell elengation. Also,Cooper ®) has shown thet heteroeauxin induces root formation on lemon, figy Acalyphs end Lantens sten cuttings, and Zimmerman and Wilcoxon?” ) heve found | ‘thet heteromauzin causes local initiation of advanbitious roots on stems and loaves of tomete and tobacco plants, Experimental work, especially by Van der Way (15526), on the transe port of auxin in Avena has shown that auxin is transported bacipetaliy only, emi thet it is intimately commected with life processes. To gover these facts Went (4S) proposed the theory thet ngturally occurring poten. tial Gifverenses in coleopbiles and other orgeus (apical parts being wegetive against basal parts) would produce an electrophoresis of the negatively charged ions of auxin toward the positive bases. | Tn addition, it was found by Went 4) enat the transport of sub= stances causing reot formation in Acalypha is rectilinear, rigorously polar, aud independent of the transport of carbohydrates, In contrast ta these results showing poler trensport of hormones as a basis of the well know morphologieal polerity in Avene, Acalyphs, and other plante, Hiteheosk and Zimmerman 5) ebsexved ao striekly poler novenent of several synthetic eompounds, including heterowauzing in either stems or leaves af the tomato anc tobaste plants, They found that these substences when applied te the onl in highly concentrated water solutions were absorbed vy the roots and - were ‘transported upward im the zylem in the trauspiretion stream, Also, thes when water solutions were admithed through the cub surface of a stan oy leaf there wae a longitedinal movement in either direction vhrough dead stem tissue, this movement being infinenced by transpiration, Thus shey goncluded that living cells were not essential for the transport of these substances, and thet the main channel of transport is in the trans. piretion stream, These results oblmined by Hitchcock and Zimmerman, however, do not erove that the normal channel of transport of hormon es in the plant Ze in the transpiration stream, The transpiration strean may poseibly provide &@ means for the upward transport of substances absorbed from the sell by Sw the veuts, but 1% dees not provide for the downward transport of hormones found in Leaves’ (tens 4) and avery'!)y, it ig berdly possible thet they would nermelly move downward in the xylem In the opposite direetion Pron the tracnpivation stream. Thet rooteferming substances, extracted from ieaves, do to ward in the stem has been shown by went @4) wien salyphe cubbtingss Also, Sooper (2) has Pound thet heterosquring or some ‘gubstenes im the stem activated by heberaeauxin, will move dowswerd in leaon ewbiings, Therefera, with the above considerations in mind, 2¢ seems highly probable thet rooteforming substances normally move down phlost. Results of girdling and lowal chilling experiments presented in this paper give evidence that rowteforming hormones de move dowaw the phiven in lemon and rose subbings. | Synthetic heterowsuxin was used iu ell experiments and was applied te the cubtings efther by the lanolin method of iaibech'®) or in water solution. By the former method ons part of heterseaucin was mized with O00 parts of pure lenoling isees Os6 mg heterveaucln per gr lenoline* A small portion of this pastessroughiy about 10 mgeewas smeared both on the cub surface of the apleal end of the eutbing and on a email area of ole Side of the entbing near the top which had previously been scraped to renove the epidermis and outer cortical Inyers, This paste was left on throughout the experiment, Weber solubions of varieus concentrations were applied to either the apical or basal end of the cuttings by soaking 6 to 24 hows in the solution: after treatment the cuttings were placed In sani “this concentration was used in all experiments with the lanolin paste. on the propagabing frames Cowbrol ewtbings for the lanclia method were treated with pure lancling while sontrol euttings for the wateresslubton nethod were soaked in tep water for the same leagth of bime and under the same abnospheric conditions as were the tremted owtbings, ALL lemon cubtbings, usually about 12 em long and 5 mm in diemeter, were made from twigs of mature wood of the current season’s growth and were obtained in all instances from the seme srove.in Clavomont, Celit, the cubtings were set in sand either in e sachecovered propagnt= ing frame without bottom heat in the. greenhouse or in a thermostatically consrolled propagating frame at Torrey Pines, Calif,” Ab the letter place the temperature of the sand was kept at 85 to 69°F. At Pasadens the sand usually held a temperature near 75°F, Girdling Reperinents three types of rings, as illustrated in Fleurs 1, were used dx these experiments, in type A (Mig. 1) a complete ring of shiloen abou’ 12 am wide was removed from the stem of the eubbings about 4 em from the base, typo Bwas only partly ringed, a streight verties1 bridge (a) «& wide being left across the ring. Type C wae also only partly Finged, bub in this case a twoerighteangied bridge of phicenm (byc,d} aboot 2 me wide was left auross the ring. These methods of ringing ere-cimilar to these used by Czapek(3) in Ise? in studying the effeobivences of Ietoral transfer * fhe weiter is indebted to Drs LeC.Marshali of the U,S.Departnent of ~ Agriculture, Field Station at Torrey Pines, Gealif, for the use of the prope geting facllities at Torrey Pines and for care of the euttings while in the propagating Dreamed. Figure 1. Diagrams of different types of girdles used. A, complete ring of phloem removed. By, partly ringed with straight vertical bridge of phloem (a) left : s the girdle. C, partly ringed with twoeright- angled bridge of phloem (byesd) left across the girdle. (b) upper vertical arm, (c) horizontal arm, (4d) lower vertical ara. af food through stem euttings.of several woody plants. Since these cuttings were kepl im sashecovered propageting frames where the relative hupidity was always high, it was aot aseessary to take the precawbion of canting the expoved area with warm paraffin to prevent deying out of the sylem issue, as was found nesessary by Curtis(2) with winged tissue on trees out of doors. ‘the fact thet the canbiun often became metive and regenerated new tissue when the bark was removed is evidenee thet the xylem had not dried owt. The effeet of ringing on root formation on lemon cubtings which had been treated with heteroenutin is shown in Table I and figure 24 When both syien and phloem above a complete ring were treated, sither with hetero« auxin lenolin mixture or with heterowauxin water solublony roots formed at the base of the cubbings. When a narrow vertical bridge of phloem was leit auross the ring roots would form at the base, though in smaller number than on the noteringed auttings, This is very good evidence that the HSUSTIeGUNER, OF some rooteforming substance present in the cutting and activated by the heteroeguxin, is transported downward minly in the phloem, Root formation at the base of the cuttings with a throoright-engled bridge of phloem across the ring (Pigs 1-0) was found to be influenced by the horizontal distance (c) between the side of the upper vertical arm (b) end thet of the lower era (4), Where this dis saviee was greater than 2 met. there wae usually a strong callus development at the sides and base of the upper vertical erm but very Livtle om the horizontal arm and none on the Lower vertical arm, In some instenees roots would appear at the base of the upper vertical arm bub none on the horizontal arm or at the base of the cuttings, Eowever, in cuttings where the horizontal arm (c) was less then 2 om Table I EPfeet of Ringing on Root Formation of Heterownusin Treated Lemon Cubbincy® Heterou = Weeks © Average mumbor of Roots per Cutting™* Leaves robot after “Hot. Complete larrow Bridge of — Set tn Ringel Ring phloem straight Sane _atress ring. & cg fanolin wicbure £8 o Batt Pure denolin Bed o — Seer 28 hours &@ SoS 5.2" Bal Gee G Cae ded 0 6 a Be © 8 & & @ = el ng/se water 40 a led for 18 heurs Tap weber 15 bes. 8 Le? 6 5 * Any cuttings treated at apical ends “% Sverace from 10 cubbingss °° two roots on one cubbing. +O BONG, a Ce i a GhseQ, OaNZOTd rw ote out t onreaddo wade oun JO i om. AOR awe : : ouQ So0s08. wootud Ge ah HocRslonal yoot would form at the base of the suttings, bet ab mo time was root formation as great as on ewtbings with a Straight vertical bridge across the girdle, in another experiment with two lots of partly girdled euphlags (type B) hormone solution was applied in one lot to the entire cut ond of the apex (Pig. 2B) and im the other lot only to the side of the eqpen opposite the phloem bridge across the ring (Fig. 26D), to roots were formed om the cuttings te which hormone was applied analy on the side opposite the . bridge, bwb in the other let reots formed at the base of Ehe outings. These vesultsy along with those obbained with the twow'ighteangied type girdle, indicate clearly thet the hormone moves dowenrd in the phicen mainly in straight Mines parallel to the phlosn elements, Machaniels and Curtte (2) eeport that when lateral transfer of food in apple tree trunks was forced by spiral vinging more rapid leberal cone cuetion was provided for by structural changes in the phloem, beginning soon alter Pinging and resulting in the resorientation of the caxbiun ee as te. be Baveliel with the spiral ring. Yhey state thet partial accoumodetion | to the changed condition of conduction probably occurred immediately after Yinging by the first formed elements being connected through their radial walls. Perhaps this would account for the slight leteral movenows of the routelornming hormonm: ohserved with the toerightbeangled type af cirdite on lemin oubbingss. Te Local Chiliing Exper iment Chilling at S3=40°F. end at 36ei6°F, of abowts SO am of the stems meat the mideportion of leafless lemon cubbings wee aceomplished by insert ing the cuttings through special inswlated chilling mits. These were set up in the propagating frame so that bases of the euthings were in the sand which had a temperature near SO°P., BO mm af the mideportion in the chilling devices, and the tips, treated with heteraweucinelanclin pastes in the air ab a temperature near 7O°R, The chilling unit consisted of small wateretight ‘in cans into which were soldered 10 copper tubes in a vertical position and yaraliel to cach other. This arrangement of copper tubes porn tbed insertion of eubtings through the devies so thet when cold water was cre culated through the can the portions of the cuttings in the tubes were chilled without actually soming in comtach with the water. ‘lwo such chill. ing units inevleted with one«helf inch of eelotex were comected with rubber tubing. Wetter at about 32°F, was cixeuleted at a slow rate bhrough the troemmit system for tyo weeks, Cubbings in the firet unit wore ehdlied — Lecally to S38640°F,, and im the second unit to $8.46°r, | Afser two weeks of chilling the heteroeauxinelenclia paste was re- moved fron the tips, the euttings were taken out of the device and reeset au the sande there was ao sign of callus formation at the base of either af the chilled lots; while a strong callus hed formed on the cuttings which nad been treated with hormone bet not locally chilled. One week leter, or thres weeks from bime of sebbting in sand, roots appeared on the nonechiTiled cuttings, while roots did.not appear on the chilled cuttings umtil three weeks after chilling. or five weeks after setting im send, and then tar gely on the S0-0edegree lot. (Table 2). Thus we see that root formation on the TB. Table If Eafivence of Locel Chilling of Lemon Cuttings on Downwar: Movement of Reoteforming Rormous* “Avera, number of roots per cubbl: Bevercw Chilling = a ng aren treatment’ Bud of 2 One week Threa weeks Five weeks - “8 Weeks after after after Chilling _ Chitling Chilling Chilling ae hey . Oe? Bath peo o © + shilied S2.40°F, 06 a Ged Qed G Sa ehilled S¢6°r, G Oe? Ged “Heteroecuxin lanolin paste eppiged at top of eubting ehove chilled area. Be locally chilled cuttings was delayed by two weokgeuthe length of the chilie itig perlodesgnd thet root formetion on chilled cubbtings never did approach thet of the nomechilled lot. Local chilling, then, mest have acted tn preventing the transpert of heberoseauxin dowmard because the for roots @hich formed during the five wools after chilling can be aceounted for by asturally oouurring rooteforming hormone: this seems obvious since the untreated eubiings showed more roots then were formed on the chilicd ewbtingss, this evidence that local chilling aebually does prevent the dewarerd transport of heterc-aucin indicates that living eclly take an active part in the transport of heteroeauxin or some substance in the sten activated by heterowauming Ib therefore seems well established Prom the combined yen sults of the girdling and local ehilling experiments thet the hormone fe ‘tfansported downward in the phloem, Effect of Basel Application of Heterosaucin Solution Root Poras tion Ey soaking the base of lemon or rose cuttings in heterowaucin solution of relatively high concentration (0:5 mg per ce of water) for eight hours before sething in sand @ much greater muther of roots were induced ot, Uhe treated than on control ewttings (Migs. 3 and 4). Also is was found that the aumber of roate were from two to five Simes as great when treated at the bese as when treated at the tip, provided a highly concentrated solution wae used, The definite relation between the time of treatment, concentration of solution, and mumber of roots formed has not been debereiacd. oe ex) a te or we ee 0 Of ad Sey Mp. os orbs “hye a o B Ms a oi /2 wooks aft Pigture + fa cy Bas Oo how A 19. 98 PORVew, aout 4 %e Howevery results shown in Figure 5 for besel treatmont of o04, shy o2s «8 mg heteroeauxin per ec of water indicate that basal treatments ave effective only In concentrations of ol and above for a lGehour treatment of leafy eubbings, and «2 end shove for a lgshour treatment’ of leafless outbings. Mote dilute solutions applied at the base caused no more root formation than wap water. It was oted thet 9S mg per ce solution applied at the base vaussd some injury, so very likely the effecbive range of concentration Sor basal treatment of leuon cubtings for 12 te 16 hours is from el or 22 SG 95 ME per cts a Some idea as to the reason for this reoting response to basal, treat. nents of heterowautin solution is obtained from a study of Table Sy Gute tings im experiments A and 8 were placed in a nearly seburated atmosphere in the propagating frame at Torrey Pines during the period when the bases ef the cubbings were soaked in heteroeauxin solubion, thus very little opportunity was afforded for transpiration. Yet in both instanees there was considerable increase in number of rowts induced on the treated eubbings aver thet of the controls, However, when the portion of the base of the cutting which was actually in the heterseauxin solution (about thresePourths of an inch) was cut off, the effeet of the treatment was eliminated, ‘This suggested thet there was very litle or no mevement of the heteroenexin solution up the stem, The solution was, however, effective only when ap- plied ab the eut end because, when the oul and was sealed over with paraffin before soaking in the heterosauzin solution and the paraffin later removed after the treatment there was no imersase in muber of reots over the conwolss en a ay aaa AUXIN SOLUTION ON ROOT FORMATION | -— EFFECT OF CONCENTRATION OF HETERO- ON LEMON CUTTINGS. {1 | | NUMBER OF ROOTS AFTER 3 WEEKS IN SAND = Mn B @ i oy aD = oO Z f= 2) @) nd lJ oO 7) fF fe) fe) v4 LL O a uJ oO 2 =) Z Q < rd = < co oe eee | 2 = 3 4 MG HETERO-AUXIN PER CC WATER Ob. *SOUMZGUT YO UT Boutegne oF Jo eFeasay # Ot ort o°t ert ] a*0 a*O 9° et as at a ” ot a*t e*g a*t co a*0 6°9 a*y wt at QF “ a ge ary o*F Lt at at’ * ary er O*2E at St bet 3 em org o%F tt 8 e sf a oe og sg are 9 we wz #708 g*t : nn a” + ¥ 20Q08R, go 09 0d Sa “poyeom ———~=*«dSO «QMO pogwedg pegeamy ~qoayuca ater eeewpamerys oneq met pus *z30 pera put ogeg soqem, = Shlett quem uoRgngoe om PONG) OSB 090015 OSE 7 a. “| HHO oeene Beaney *9G siyggne ged sqooa go sequam ofvsoay oreo SNC 2. coon SGuTQgNg Howey so spay tesug og Suypaweay Jo uopQwuaog goo" Ue goegie ong SupmoUE aque acdag EEE otqug 10s iu experiment C, leafy lemon cubbhings were exposed to Laboratory air (temp. 70°F., relative humidity about 75%) dering the fifteen hours the ews end of the bases were im heteroeawrin solution, thus affording opportunity for transpiration, AS @ consequence, an average of 2 ee of solution was taken up by gach cutbings, probably in the xylem in the transe pivetion stream, As a resuli of these conditions the mumber of roots the eubGings with the treated portion of bases out of f was greater than the controls, yet the number was only abowtk onewthird that of the eutbings from which the treated portion of the base had not been out eff. This probable upward movement of the heterowaurin im the aylem however showld not be mistaken for the normal movement of naturally ocourring hormones in the plant because, ac stated by curtis) “When solutions of most eny sert of substance are introduced inte ent etems these solutions are carried extensively and almost oxelusively in the xylem tiesues and at is obvious that transpiration determines both the direction aud rate of movement of the solwhion Introduced”, In experiment C, evidence of possible upward movement of hetero« auxin in the transpiretion stream is of little significance, but the fact ef greatest iwterest is thet if the treated portion ab the base of a eutting Was excised and the base again treated the number of roots formed was MO greater than that of a similar cutting which had avt been restreateds this wae observed again with leafless lemon eubbings in experiment Dy in which a solubion of .5 me of heterosaurin per es of water was used. In this instance the number ef roots on subbings with treated base out off and On Similer eutiings with base treated again was the seme as on controls, while treated eubtings, but with the base not removed, showed nearly three Gimed ag many roots ag contyvols, Results similer te these were also obe ils tained with leafy cuttings of the rese (var, Lady Poricins + it is elear from these leather results that there fe some factor other than heteroeaurin soncernead In root formation. Tf only heberosaucin. base were Involved, rextreating the oubting after venoving the teebed should give nearly the sane response as the origina] $reatmont., In order GO insure equal ancunts of stored food and other substances the fing} iength of the cuttings im all experiments was made the eames Cubbings waose treated bases were to be cut off wore made longer in the begiuning +o allow for the removal of a portion of the stem at the bases Summarizing, we find that (1) when epplied et the base of cutbings for 15 hours only a strong solution of heteronaurin is effective in induc« eliminates the effect of the treatment, (3) retreating after cutting off ing root formation, (2) ousting off the treated portion of the base near the treated base causes no more roots then when not reetreated, To cover these facks it is suggeeted that a strong solution of heberoenuring when applied to the base; causes the rapid movement dowmword of a substance, vhigocaline, present in the leaves and eten and which is necessary for yout formation, Cutbing off threesfourths of an imch of the base after treatememt exts off most of the supply of rhicoealins and further treatment with heterouguxin has littcle effeet since heterseauxia is only one of the Substances necessary for root formations the effectivences of treating the basal ends of lemon or rose sutbings With a strong solution of heterdu;uxin in inducing root formation suggests a new Time of attack in efforts to root cubbings of apple end other woody plants which da not root reddily from cuttings, With Lemon: rose, holly, and Cheysenthomun cubtings this method of treatment was much 26 more effective than the lenolin methed of Laibach, ‘The maximue number of roots per eubGing obtained om lemon eubbings by the lenolin methed was eights while as many as sevemtiywfive were obteimed by soaking the base in heteras suxin eelubion (5 mg per ce of water) for eight hours, The same concentya- tien of solution induced formation of twentyfive roots per cubting on the: Geoll Brimer rose and fourteen roots per cutbing on a species of Chinese holly (flex eornuta) willie the lesolin method produced only five roots ger cutting on the rose and none on the hellys Even more striking results were obtained with Chrysanthemm euthings ac is shown in Figures 6 to 8, but in this Iugtance a hetero-auxin solution of »1 mg per ce of water was found uost effective as stronger solubions were toxic to the tissue of the base.” * Sines preparing this paper Lb has come to the attention of the writer thet Asi sSiteheock and P.W.wimmerman (Contribs Boyes Thompson Inet, GeGSe79, 1956) obtained excellent results with the rooting of certain species of Ties and Jems by soaking the bases of euttings in water solubions of heteremauxian in @ Wamier similar to the method deseribed im the presext paper, ‘these authors iu discussing a former paper by the present wetter, published ia Plant Physielogy(?) state, “The qualitetive and quantitative differences resulting fron treatment of lemon cuttings heaving leaves ave not clear, sinee there is no iliwrtration of cowbrol lete with which to compare the thrse trented Lote shown", Reference to the article will show thet in Table tT, page 7S) ere given the mumber of roots per oubting formed efter “two, three and four weeks on both treated and umtreated leafy lemon owbbingss Although these figuras in themselves pratide complete proof of “qualitative and quantitative aif. ferences", there are also included illustrations of both treated and control cuttings, Reliable date on rooting can mot, of courses; be derived fram illustyvations alone, therefore in this included. paper beth photographs and tables are *qUSUA BOL, degge s7yeas *s2n0l ST bi SOT (S090 [*) woTtentos UpIeED 209, ce Naha) iF RE aca Hd aa i, 403,70 ayoom 2 Y immeuquBeAN *o *2ty . G8. US. Fak ie {1} Ringing experiments with lemon euthings indicate thet hetero=gurin, ee gome substence in the stem activated by heberceaurin, is transported dowwerd in the phloee and in a straight Lime perallel to the phicen clements. (2) Local shilling experiments indleate thet living sells teke an gee pars tn the downer: i transport of the hormone and supports the avidense, obtalned in the rimging experinents, that downwar She hormone takes place in the phicems (3) When the owt ond of the base of a leafy lemon or rose outting ts plesed im heterssauxin solution there is some upward movement of the golubien depending on the rete of transpiration, (43 When solwtions of heterouauxin ere applied at the base of auttings for 15 howrs only strong ones are effective in inducing root formations (55 CGutbing of f the treated portion of the base of eutbings nearly éliwinakes the effect of the treatment, (6) Reetrentbing with heteroenusin solution after eubting off the treated dase of aubbings causes mo more roots than when not reebrentedy (7) fhe hypothesis that a skrong solubion of heteroeaucin, when applied to the base of a outbing, causes the rapid downward movement of a substance, vhiaoealine, which seswre in the leaves end sten and which is mecossary for root formation, iv offered as an explanation of the facts stabed in dy Sg and be (S} the effectivensss of treating at the base eutbings of lemon or rose with strong solutions of hoteroeaucin in causing root formation suggests & now Tine of attack in efforts to root owttings of agple and other woody plawbs which do not root readily from cuttings, Sie Be ae Fa Be Loy lee Avety: G, 5. dro Diterential distribution of phytohormone im the developing leaf of Nicotiana, and its relation to polarized growths Dul», Torrey Glub GaeSlS0eBS0, 1985s Cooper, William C. Hormowes iu relation te reot formation on stem cubtings. Plant Physe 10s78%794, 1935. Gurtis, Otis F,. The translosabion of solutes in plants, 273 pps NeGraw Hill Book Cos, Hew York, 1935. Gzapek, Friedrich. Uber die Leltangswege der orgunischen Beasteffe in PhlanzenkBrper, E. dkeds Wies (Wien), Meth. Natuem. Cl. Siteber., Zxl0Gs Lif-l76, Lev. . | Htchesek, A. B. and P. W. Zimmerman. Absorption and movement of symbhetic growth eubstances from sold as indicated by the eeaponse of aerial perte. Contrib. Boyes ‘thompson Inge Tl4), 4270476, 19855 Righs Fe and H. Erxtebon, Uber dic Konstitubion der Aucin a wid be Zeite. physiol. Chem, 228:5le78. 1954. Eel, Pes Av JeHaagen Smit, and H. Bexleben. Uber olin neues Aurin. (Weterceauxin”) aus Harn, Webts, physiol. Chem, B2Orl06I04. 1054, Latbech, Fy Uber die Auslésung von Zallus ued Wargelbildung durch B « Indolylessigsaures, Ber, doubt, bob. Gogs SS5e8S0e056d, FOSS, SaeDaniels, be Hs and Otis fy Curtis. Effect of spiral ringing on solute translocation and the structure of the regenerated tlesues ef the apple. Cornell Unive Agi’. Exp. Stay Memoir 1831081, 1990. chimemm, Kenneth Ys, and J. B. Koepfli, Identity of the growth. promoting and root«forming substances of plents. Hatwre 1SSe ide Se We Tha meer, Remmeth Yo, and Py YW, Wente On the chemiced aature of the vooteforming hormone. Prag. Kone Abad. Wetensch, Ansberden S7e4SSud59, OSS. Went, PF. W, Wnhehetoff und Wachstuem, Ree. Trave bobs aderi, 25¢ Jel Gy. 19284 Werk, Fe. W. Eine botenische Polarttdtetheorie. Jahrb. wiss. Boty FOsG20e557, 19520 Racines dans les Plentules «et les Boubores des Plentes _« Recherches Expdérimentales sur le Héoformetion des Supdrieures, Apne dards Bot, de Buitenzorg 48y 8716S, 1983. Wey, He Gs vet der, Der Mechanisms des Wachsstefftrausorteds Rety Trews bot. nécrl, Be STOMOST, 1034. Rees bot nderi, Sia 8106887, EoSh5 amy P. We and Prenk Wileowon. Several chemiesd grewtl Der Hecheanismus dec Wuehestefftrausportes IT, substances which cause initiation of roots and other responses in plants. Contrib. Bayes Thompson Tnstye 7{S), 2000229. L925. Se