Axillary buddevelopmen t inros e C.A.M.Marceli s -va nAcke r Promotoren: dr. J.Tromp , hoogleraari nd etuinbouwplantenteelt , inhe tbijzonde r de overblijvende gewassen dr.M.T.M .Willemse , hoogleraar ind eplantkund e Co-promotoren:dr .ir .C.J . Keijzer, universitairdocen tbi jd evakgroe pPlantencytologi e en -Morfologie dr.ir .P.A . van dePol , universitair hoofddocent bij devakgroe p Tuinbouwplantenteelt ^OFZÖ' [ISS' Axillary buddevelopmen t inros e Ontvange',;' i 16 NOV. 1994 UB-CARDEX C.A.M. Marcelis - van Acker Proefschrift terverkrijgin g vand egraa dva n doctori nd elandbouw -e n milieuwetenschappen, opgeza gva n derecto r magnificus, dr. C.M. Karssen, inhe topenbaa r te verdedigen opvrijda g 18novembe r 1994 desnamiddag s tetwe euu ri nd eAul a vand eLandbouwuniversitei t teWageningen . ^- SIV35 « CIP-DATA KONINKLIJKE BIBLIOTHEEK, DENHAA G Marcelis-vanAcker ,C.A.M . Axillary buddevelopmen t inros e/ C.A.M.Marcelis-va n Acker. - [S.l. :s.n.] .- 111 . ThesisWageningen . -Wit href .- Wit h summary inDutch . ISBN 90-5485-309-3 Subject headings:bu ddevelopmen t ; roses. Thisthesi scontain sresult s of aresearc hprojec t ofth eWageninge n Agricultural University, Department of Horticulture,Haagstee g 3,670 8P MWageninge n andDepartmen t of Plant Cytology andMorphology , Arboretumlaan 4,6703B DWageningen , TheNetherlands . Publication ofthi sthesi s wasfinanciall y supportedby : • Boomkwekerij Bert Rombouts BV teHaper t • LEB-fonds BIBLIOTHEEK BXNDBOUWL'MN'ïiRSrriüa WAGENINGEN Stellingen 1. Bloemknopaanleg bij deroo svind tpa splaat sn aopheffe n vand eapical edominantie . Dit proefschrift 2. Effecten vanteeltconditie s tijdens deaanle gva n okselknoppen bijd e roos op de uitgroei van die knoppen komen voornamelijk tot stand viabeïnvloedin g van het overige gedeelte van de plant. Dit proefschrift 3. Het aantal okselknoppen aan de basis van de rozestruik is niet beperkend voor de vorming van grondscheuten. Dit proefschrift 4. Door bij de vermeerdering gebruik te maken van dubbelstekken in plaats van enkelstekken wordt deuniformitei t engroeikrach t van hetplantmateriaa l sterk bevorderd. Marcelis-van Acker, C.A.M. & Leutscher, K.J., 1993. Effect of type of cutting on heterogeneity and growth of Rosa hybrida cv. Motrea and Schefflera arboricola cv. Compacta. Sei. Hortic. 54: 59-67. 5. Bostrack gaat bij het verklaren van de waargenomen anatomische en morfologische verschillen tussen scheuten van diverse hoogten uit de boom voorbij aan mogelijke verschillen inleeftij d vand eknoppe n dieto tdez e scheuten uitgroeien. Bostrack, J.M., 1993. The relationship between size of shoot apices and morphological features of mature leaves and stems of four species of angiosperm trees. Ann. Bot. 72: 341-347. 6. Hooggekwalificeerde medewerkers vormen geen garantie voor succes zolang de teamgeest ontbreekt. 7. Gezien de veelal lange wachttijd voor professionele medische hulp bij een ongeval dient een iederzic ht ebekwame n in hetverlene n vanEerst e HulpBi j Ongevallen. 8. Eenproefschrif t schrijven isgewoo n werk. 9. Door betere communicatie in de keten zal de Nederlandse boer meer brood gaan zien in baktarwe. 10. Het steeds frequenter in de publiciteit brengen van premature onderzoeksresultaten brengt hetwetenschappelij k onderzoek indiskrediet . 11. Bij dalende werkgelegenheid wordte rdoo rwerkende n enwerkloze n harder gewerkt. 'rùj (7 12. Het ambivalente van de Nederlander (m/v) ten aanzien van emancipatie isenerzijd s het niet begrijpen waarom een vrouw een proefschrift schrijft en anderzijds het pas voor vol aanzien van eenvrou w alsz egepromoveer dis*> . *' Intermediair, 10-1-1992: Gepromoveerde vrouwen zijn betrouwbaar. 13. Het hebben van een niet-alledaagse naam in combinatie met het spreken met een accent verhoogt de herkenbaarheid. 14. De LUW dient zich te realiseren dat met de voorgestelde uitholling van haar 'groene' richtingen/activiteiten haar bestaansrecht als zelfstandige (landbouw?)universiteit in het geding komt. 15. Somsmoetj e vergaa no mdichtbi j tekunne n zien. Stellingenbehorend ebi j het proefschrift: 'Axillary buddevelopmen t inrose ' C.A.M.Marceli s -va nAcke r Wageningen, 18novembe r 1994 Abstract Marcelis-van Acker C.A.M., 1994. Axillary bud development in rose. Dissertation Wageningen Agricultural University,Wageningen ,Th eNetherlands . 131pp;Englis h andDutc hsummaries . Axillarybud s form the basis of flower production of a rose crop. Within a rose crop there exists an undesired large variation in shoot number and size, which affects flower yield. Part of this variation mayb e traced back to early variation in axillary buds.Th e aimo f the research reported in this thesis was to enlarge the knowledge and insight in the development of axillary buds. It was investigated to what extent the growth of an axillary bud into a shoot can be influenced during axillary bud formation and to what extent during actual outgrowth into a shoot. Factors studied were bud age, bud position, assimilate supply and temperature. Growth potential of the buds was studied both in situ and in isolation (grafted or in vitro), enabling to distinguish between directeffect s onth ebud s andindirec t effects viath eparen t plant. An axillary bud contains the lower part of the future shoot. The axillary buds which are most likely to form the first basal shoots are already present as secondary buds in the bud which is used for propagation. Later formed basal shoots usually develop from basal axillary buds of the basal shoots.Eac h basal shoot was shown to be connected to only a segment of the root xylem. Later formed basal shoots mayrestric t the growth of the older basal shoots by limitingth e xylem servingth eolde rbasa lshoots . Axillary buds needed a certain developmental stage to be able to break. Bud break also required release from correlative inhibition. As long as axillary buds were correlatively inhibited, they remained in the vegetative stage. They were not dormant, but continued to grow although at a low rate. When released from inhibition their developmental programme (bud break, leaf initiation and flower initiation) was already set to a large extent. However, they displayed ahig h degreeo fplasticit y inthei r development into a shoot, inrespons e to ambient conditions inwhic h they were growing. Number of leaves preceding the flower appeared to be determined during axillary bud formation and increased with increasing bud age, decreasing position along the shoot,increasin g assimilate supply anddecreasin g temperature.Rat eo f bud break increased with increasing position, increasing temperature during bud formation and increasing temperature after release from inhibition. Shoot diameter correlated with pith diameter. Number of pith cells in the axillary bud reflects the potential diameter of the subsequent shoot. Final pith diameter was dependent on cell expansion after bud break and was reached soon after start of shoot growth. Increased assimilate supply and decreasing temperature positively affected expansion of the pith cells and as a result the pith diameter. Length and weight of the shoot at harvest and growth period were largely dependent on the assimilate supply and the temperature after release from inhibition. Key words: age, anatomy, assimilate supply, axillary bud, basal shoots, bottom breaks, bud break, cell expansion, correlative inhibition, determination, developmental programme, dyes, flowering, in vitro, leaf initiation, morphology, ontogeny, pith, position, primordium, Rosa hybrida, rose, shoot growth, temperature, xylempathways . We mustall be morphologists beforewe can be biologists ofany sort. (E.W. Sinnott, 1960) Aanmij n ouders Contents 1. General introduction 1 2. Development of axillary buds and shoots 7 2.1.Ontogen yo faxillar y buds and shoots:Lea f initiation andpit h development 7 2.2.Morphologica l studyo fth eformatio n anddevelopmen t ofbasa l shoots 17 2.3.Xyle mpathway s inrelatio n tobasa l shoot development 25 3. Growth of axillary buds: An in vitro model system 31 4. Development and growth potential of axillary buds as affected before release from correlative inhibition 39 4.1. Effect ofbu dag eo ndevelopmen t andgrowt hpotentia lo faxillar y buds 39 4.2. Effect ofbu d position on development andgrowt hpotentia l ofaxillar y buds 49 4.3. Effect ofassimilat e supply ondevelopmen t andgrowt hpotentia l ofaxillar y buds 63 4.4. Effect oftemperatur e ondevelopmen t andgrowt h potentialo faxillar y buds 73 5. Bud break and shoot growth as affected after release from correlative inhibition 81 5.1. Effect ofassimilat e supply onbu dbrea k and shoot growth 81 5.2. Effect oftemperatur e onbu d break and shoot growth 89 6. General discussion 97 References 107 Summary 119 Samenvatting 123 Nawoord 129 Curriculum vitae 131 Account The Chapters 2-5 have been submitted for publication in international journals. The following chapters havealread y been published oraccepte d for publication: Chapter 2.1: Marcelis-van Acker C.A.M., 1994. Ontogeny of axillary buds and shoots in roses: Leaf initiation andpit h development. Scientia Horticulturae 57: 111-122. Chapter 2.2: Marcelis-van Acker C.A.M., 1993. Morphological study of the formation and develop­ ment of basal shoots inroses .Scienti a Horticulturae 54: 143-152. Chapter 2.3: Marcelis-van Acker C.A.M., Keijzer C.J. & Van de Pol P.A., 1993.Xyle m pathways in rose plants in relation to basal shoot development. Acta Botanica Neerlandica 42: 313- 318. Chapter 4.1: Marcelis-van Acker C.A.M., 1994. Development and growth potential of axillary buds inrose s as affected by bud age.Annal s of Botany (inpress) . Chapter 4.3: Marcelis-van Acker C.A.M., 1994. Effect of assimilate supply on development and growth potential of axillary buds in roses.Annal s of Botany 73:415-420 . 1.Genera l introduction In the Netherlands the rose is the most impor­ combinations (De Vries 1993; Fuchs 1994), tant glasshouse cut flower having in 1993 a harvesting procedures (Zieslin 1981; Kool & production area of 898 ha (Anonymous 1993) Van de Pol 1993), growth regulators (Mor & and an auction turnover of 781 million Dutch Zieslin 1987) and environmental factors (Van guilders (Anonymous 1994).