Vegetative Propagation of Cordia Alliodora (Ruiz & Pavon) Oken the Effects of IBA

8/7/2019 Vegetative Propagation of Cordia Alliodora (Ruiz & Pavon) Oken the Effects of IBA

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ELSEVIER Forest Ecology and Management 92 (1997) 45-54

Pores~~~ologyManagement

Vegetative propagation of Cordia alliodora (Ruiz & Pavon)Oken: the effects of IBA concentration, propagation medium andcutting originF. Mesh a, A.C. Newton b- , R.R.B. Leakey b~1

a Centro Agrondmico Tropica l de Inrestigacibn y Enseiianza (CATIE), Turrialba 7170. Costa Ricab Institute of Terrestrial Ecology (ITE), Bush Estate, Penicuik EH26 OQB, UK

Accepted 21 October 1996

AbstractThe effectsof different concentrationsf IBA, rootingmediaandcutting originson the rooting of leafy stemcuttingsof

Cordiu alliodoru (Ruiz & Pavon) Oken were investigatedn three experiments singnon-mistpropagators. uring therooting period, changesn dry mass, hotosyntheticate, stomata1onductance nd relative water content RWC) of thecuttingswereassessed.n Experiment1, cuttings reatedwith 1.6% BA achieved 0% ootingafter 9 weeks.Bud growth ncuttingswas nhibitedby increasing oncentrationsf IBA, which wereassociatedith higher inal rootingpercentages. osignificant reatment ifferencesn RWC or dry masswere found between BA concentrations,lthough he dry mass fcuttings n all treatmentsended o increase uring he rooting period. n Experiment2, higher ooting percentages ererecordedn gravel 89%) andsand 88%) than n sawdust76%).Although he watercontentof sawdust as elatively high,cuttings n this treatment isplayed ignificantly ower stomata1onductancesg,>, which may be attributed o deathof stemtissue esulting rom anoxia. In Experiment 3, highly significantdifferences P < 0.01) were recordedbetweennodepositions with respect o rootingpercentage, alues anging rom 21.3% or Node2 to 46.3% or Node5 (basal).Cuttingsactively photosynthesized during the rooting period, with photosynthetic rates (P,> of 0.68-6.70pmolCO, m-* s- recorded.However,no clear elationship etweenP, and ootingability wasapparent.Contrary o previousstudies ith thisspecies,t wasconcudedhat C.alliodoru cuttingsmay be rooted elatively easilyusing he propagation ystem escribed.However, he close elationshipsecorded etweenP,, irradiance nd eaf-air vapourpressure eficit (VPD) suggesthatpropagator microclimate should be carefully managed if optimal rooting percentages are to be achieved.Keywords: Vegetative propagation; IBA; Rooting medium; Photosynthesis; Water relations

1. IntroductionCordia alliodora (Ruiz & Pavon) Oken(Boraginaceae) is a valued timber tree native totropical America, distributed from central Mexico tonorthern Argentina and in parts of the Caribbean(Greaves and McCarter, 1990). It has also been

* Corresponding author. Inst itute of Ecology and ResourceManagement, University of Edinburgh, Kings Building s, MayfieldRoad, Edinburgh EH9 3JU, UK.

Present address: International Centre for Research in Agro-forestry (ICRAF). P.O. Box 30677, Nairobi, Kenya.0378-l 127/97/$17.00 Copyright 0 1997 Elsevier Scie nce B.V. All rights reservedPII SO378- 1127(96)03960-6


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46 F. Mesh rt ~/./Forest Ecolo gy and Manqernenf Y2 CIYY 7J 35-54

introduced to other tropical countries where, in somecases (e.g. Vanuatu), it has become the major refor-estation species (Hudson, 1984; Neil and Jacovelli,1985). C. all iodora is found on a wide range of sitesat altitudes from sea-level to 2000m. and is widelycultivated in agroforestry systems as well as planta-tions (Greaves and McCarter. 19901. In CentralAmerica, it is found in both the Atlantic (O-900mabove sea-level (a.s.l.>) and the Pacific regions (O-18OOm a.s.l.), but is most common in the former,where the tallest and best-formed trees are found(Boshier and Me&, 1987. Boshier and Me&n,1988). On these sites, the bole has a monopodialgrowth habit, essentially straight, cylindrical andclear of branches for 50-60% of the total tree height.However, both in natural and in planted stands, thetrees show a high variation both in growth and form,indicat ing the potential for genetic improvement(Boshier and Me&n, 1987).

A number of tree improvement programmes usingtraditional techniques are currently in progress withthis species (Me&n et al., 1994). It is now widelyappreciated that vegetative propagation and clonalselection techniques offer the possibility of rapidgenetic gains in such improvement programmes(Zobel and Talbert, 1984). To develop a clonal pro-gramme with C. alliodora, vegetative propagationtechniques need to be developed to allow the multi-plication of selected genotypes. The experiments de-scribed here investigated the effects of rooting me-dia, IBA concentration and cutting origin on therooting abili ty of single-node cuttings of C. al-liodora, using low-technology, non-mist propagatorsas described by Leakey et al. (1990). This propaga-tion system is relat ively cheap and easy to maintain,and is therefore highly appropriate for use in ruraltropical areas.

2. Materials and methodsPropagators were constructed following the de-

sign of Leakey et al. (1990). A wooden frame wasenclosed in clear polythene so that the base waswater-tight. The base was covered with successivelayers of large stones (6-lOcm), small stones (3-6cm) and gravel, and topped with an appropriate

rooting medium to a total depth of approximately25 cm. The basal 20cm was then filled with water.The propagators were placed in the Tree Improve-ment Project nursery, at the Centro AgroncimicoTropical de Investigation y Ensenanza (CATIE) inTurrialba. Costa Rica (954N, 834OW, 600ma.s.l.1. under a shade screen constructed of nylonnetting.

Plants were derived from open-pollinated progenyof plus trees selected by the CATIE Tree Improve-ment Project (TIP) in Costa Rica. Original seedlingswere grown 1 m apart in beds at the CATIE nursery.cut back to maintain a supply of coppice shoots andused as a source of cuttings to build up clonalpopulations. Rooted cuttings were potted into blackpolythene bags (600 cm31 containing a I : 1: 1 mixtureof forest soil, sand and organic compost, then weanedunder shade and decreasing watering during a 2 -3 week period. After this weaning period. cuttingswere planted in beds beside the original stockplant.at a spacing of 20cm X 20cm. The clonal plantswere given fortnightly soil applications of a pow-dered fertilizer (FERTICA, Puntarenas, Costa Rica1containing 10% N, 30% P and 10% K, at a rate otapproximately 30g per plant. The beds themselveswere made up of the potting mixture described above.Mean annual rainfal l in Turrialba is 2600mm, withno month below 50mm. Consequently. watering wasnot usually necessary, but the plants were watered tofield capacity when there was no rain for two con-secutive days (typically in January and February).

In Experiment 1, 250 cuttings of a standard lengthof 5 cm were collected from each of three clones(Clones 2, 4 and 81, after trimming their leaf area toa single leaf of approximately 30cm. The tip ofeach shoot was discarded and cuttings were takensequentially down the stem, recording node position.Cuttings were then treated immediately with one offive indole-3-butyric acid (IBA) concentrations (0%.0.2%. 0.4%. 0.8% and 1.6%) dissolved in methanolsolution. The IBA was applied to the clean-cut baseof the cuttings in 10 ~1 droplets using a micrometersyringe. The alcohol was evaporated off in a streamof cold air from a fan before inserting the cuttings insand in the propagators (following Leakey et al.(1982)). The control treatment received 10 ~1 ofmethanol only. Cuttings were inserted in ten random-ized blocks in fine sand propagation medium, During


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the course of the experiment, two fine spray water-ings were given daily to the cuttings to keep theleaves moist, at 07:OO and 15:00 h.

Each cutting was assessed weekly for number ofroots and presence of shoots for 9 weeks in total. Inaddition, ten cuttings from each clone were harvestedfor assessments of init ial stem and leaf fresh and drymass at Day 1, and then destructive samples weretaken after 14, 28 and 42days, for measurement offresh and dry mass of leaves, stems and new shoots.Each clone-treatment combination was representedby five cuttings at each harvest. Foliar relative watercontent (RWC) was calculated following Beadle etal. (1985), as ((FM - DM)/(TM - DM)) x lOO%,where FM, TM and DM are fresh mass, turgor massand dry mass, respectively. Turgor mass was ob-tained after floating the leaves in distilled water for24 h. To determine dry mass, the cuttings were ovendried at 80C for 24 h.

In Experiment 2, a propagator was subdividedinto 12 compartments, and each one was assignedrandomly to one of three rooting media-fine sand,gravel or sawdust. When the stockplants shoots hadgrown to a height of 30-40 cm, 360 cuttings of 5 cmlength were taken down the stem as described inExperiment 1, 120 from each of three clones (Clones19, 22 and 35). Leaves were trimmed to 30cmusing paper templates and the cutting base was treatedwith IBA in methanol at a concentration of 1.6%, asdescribed above. Cuttings from each clone wereassigned randomly to the compartments in the propa-gator, each receiving 30 cuttings, ten from eachclone. Cuttings were assessed weekly as described inExperiment 1 for a total of 6 weeks.

A data logger (2 1X Micrologger, Campbell Scien-tific Ltd., Loughborough, UK) was used to character-ize propagator microclimate during propagation. Airtemperature was measured using thermocouples(Type K chromel-alumel; T.C., Ltd., Uxbridge, UK),humidity using a thermistor probe (MP. 100 Rotronicprobe, Campbell Scientific Ltd.), substrate tempera-ture using a 107-thermistor probe (Campbell Scien-tific Ltd.) and irradiance using quantum sensors (SkyeInstruments Ltd., Llandrindod Wells, UK, suppliedby Campbell Scientific Ltd.). All sensors of eachtype were cross-calibrated before use. The loggerwas programmed to record each sensor every 10 s,and to calculate and store mean readings every

15min. The 107-thermistor probes were inserted inthe rooting medium to a depth of 2-3 cm. For mea-surements of leaf temperature, the thermocoupleswere attached to the lower leaf surface.To determine the relative proportion of solids, airand water in the rooting media, three 100cm3 sam-ples of each medium were taken. The air volume ineach sample was determined by measuring theamount of added water required to saturate the airspaces. The water content was determined by thedifference between wet and dry mass. The resultswere expressed as percentage of each component byvolume.

Measurements of net photosynthetic rate ( P,) andstomata1 conductance (g,) were taken at Week 1, 2and 3 in a randomly selected sample of six cuttingsfrom each medium. For the assessments of P, andg,, an IR gas analyser was used (LCA-3, AnalyticalDevelopment Co. Ltd., Hoddesdon, UK). Measure-ments were made of cuttings in situ in the respectivemedia.

In Experiment 3, stockplants from Clones 18, 19,22, 23, 25, 29, 33, 35, 37 and 38 were cut to a heightof 20cm. Three weeks later, stockplants were prunedto the three most vigorous shoots. When the shootshad grown to heights of 30-40cm, the tip of eachshoot was discarded and six single-node, leafy stemcuttings were taken sequentially down the stem, andtheir leaf areas trimmed to 30cm*. IBA in a 1.6%solution was applied to the base of the cuttings asdescribed in Experiment 1, before inserting the cut-tings in sand in non-mist propagators. The cuttingswere allocated to eight randomized blocks, eachblock contain ing 60 cuttings (ten clones X six nodepositions in the shoot). One week after insertion, thestem length and midpoint diameter of each cuttingwere measured. Each cutting was assessed for num-ber of roots at weekly intervals for 9 weeks in total.As with the other experiments, rooting percentageswere calculated on the basis of these assessments.

Photosynthetic rates and stomata1 conductancewere measured in situ in six randomly selected cut-tings (including al l node positions) from Clones 18,19. 22, 23 and 29 on Days 14, 21 and 28 afterinsertion. For these measurements, a portable gasexchange system with IR gas analyser (IRGA) at-tached to a Parkinson lea f chamber was used, asdescribed above. Measurements of propagator micro-


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climate were made throughout the rooting period asdescribed for Experiment 2.

80

In al l three experiments, rooting data were sub-jected to analyses of variance, followed by mul tip lerange tests where appropriate (SAS Institute, Inc..1980). Percentage data were arcsin transformed be-fore analysis, following Snedecor and Cochran(1980). Interactions between the treatment factorswere included in the ANOVA in each experiment. Inaddition, rooting results were subjected to analysis ofdeviance for stepwise regression in Genstat 5 (Payneet al., 1987) to determine the influence of differentvariables on rooting ability. In Experiment 1, esti-mates of leaf and stem dry mass at Day 1 wereobtained by mult iplying the total fresh mass of thecuttings at Day 1 by a reduction factor obtained froma sample of 30 cuttings from the three clones, de-structively harvested at Day 1.

70z83

60m 505,o 40BP3 058 20a 10

aa r-7

00.2 0.4 0.8 1.6

IBA concentration (%)

a

b

3. Results3.1. Experiment 1

0.4 0.8IBA concentration (%)

-T -1.6

Nine weeks after insertion, highly significant dif-ferences in rooting percentage were found betweenIBA concentrations (P < 0.001, ANOVA), with avalue of 70% recorded in cuttings treated with 1.6%IBA, compared with only 10% for the control cut-tings (Fig. l(a)>. The effect of IBA concentration onnumber of roots per rooted cutting was also signifi-cant (P < 0.01, ANOVA). This trait showed a simi-lar trend to that of rooting percentage, with highervalues recorded with successive increases n IBAconcentration (Fig. l(b)). Stepwise analysis of de-viance confirmed that rooting was highly dependenton IBA concentration, but also highlighted a signifi-cant effect of the presence of shoots and leaves inthe cuttings, cutting diameter and clone, which waspositive in the former two cases P < 0.01 in eachcase).

Fig. I. The effects of five different concentrations of IBA (0. 0.2.0.4, 0.8 and 1.6%) on (a) the rooting percenta ge and


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0 10 20 30 40 50 So 70 SOShoot production (%)

Fig. 2. The relationship between the percentage of Cordia al-liodora cuttings rooted after 9weeks and the percentage of cut-tings with actively growing shoots at the third week after insertionin non-mist propagators at Turrialba, Costa R ica ( y = - 1.16x+83.8). V alues were calculated for each of 15 clonextreatmentcomb inations (3 clones X 5 treatments), with 40 cuttings per com-bination.

declined to around 75%, gradually increasing there-after.

No significant differences in foliar dry mass werefound between cuttings subjected to different IBAconcentrations during the 6 weeks after insertion.The foliar dry mass of all treatments decreased dur-ing the first 2 weeks after insertion, increasing there-after to reach values similar to those obtained ini-tia lly, by Week 6. In terms of tota l cutting dry mass,most IBA treatments showed a steady increase dur-ing the 6 weeks in the propagator. Treatment with0.4% IBA showed a slight decrease during the first4 weeks, but increased at Week 6 to values similar tothose for the other treatments. The estimated drymass gain over the 6 weeks following insertion wasin the range 0.04-0.06g per cutting.3.2. Experiment 2

A maximum irradiance of 335 pmol m-* s- wasrecorded inside the propagator, with a mean of22 pm01 m- s- . Relative humidity varied between78 and lOO%, with a mean of 97%, and air tempera-ture varied between 20.7 and 37.7C, with a mean of24.2C. Slight differences were found between sub-strate temperatures; gravel showed the lowest meantemperature (22.9(J), followed by sawdust (23.2C)and sand (24.3C). Leaf temperatures also differedbetween treatments, ranging from 24.3C (sawdust)to 25.6C (sand) and 25.8C (gravel). The largest

differences between treatments were found in leaf-to-air vapour pressure deficits (VPD), with maxi-mum values of 0.61 kPa, 2.21 kPa and 6.58 kPa forsawdust, sand and gravel, respectively. When valuesof photosynthetically active radiation (PAR) werecorrelated with VPD, strong positive correlationswere recorded (r* = 0.75, 0.82 and 0.63 in sand,gravel and sawdust, respectively).

The three rooting media showed clear differencesin their relative proportions of solids, water and air.The water component was higher in sawdust (53.8%)than in sand (17.6%) and gravel (4.5%). The aircontent was similar in sawdust (30.3%) and gravel(30.5%), and relatively low (5.5%) in sand.

Rooting percentages were relatively high, withvalues over 75% in al l media. However, high lysignificant differences (P < 0.01) were found be-tween treatments after 6 weeks. Rooting percentagesin both gravel and sand were significantly higherthan in sawdust (Fig. 3(a)). A similar pattern was

Sawdust Sand GravelRooting substrate


Fig. 3. The effects of rooting substrate on (a) the rooting percent-age and (b) the number of roots per rooted cutting of single-node,leafy stem cuttings of Cordia alliodora, 6 weeks after insertion innon-mist propagators at Turrialba, Costa Rica. Values are means(n = 120) of three clones; values grouped by the same letter arenot significan tly different at P < 0.05.


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50 F. Mesh et al. /Forest Ecology and Management 92 (199714.5-54

Sawdust Sand GWJ4Rooting substrate

140 , I


Fig. 4. The effect of rooting substrate on (a) the mean netphotosynthetic rate (P,) and (b) the mean btomatal conductanc e(g,) of single-node. leafy stem cuttings of Cordiu ulliodomduring propagation in non-mist propagators at Turrialba. CostaRica. Values presented are means (II = 18): means grouped by thesame letter are not significantly different at P < 0.05.

found for number of roots per rooted cutting (Fig.3(b)).Clones also showed significant differences inrooting percentage, with Clone 35 displaying a sig-nificantly (P < 0.05, ANOVA) lower value thanClones 19 and 22 (64.2% vs. 97.5% and 90.8% inClones 19 and 22, respectively). A similar rankingwas found for number of roots per rooted cutting,with means of 5.8, 7.3 and 4.6 recorded for Clones19, 22 and 35, respectively. The effect of bothrooting medium and clone was confirmed by analy-sis of deviance; the effect of cutting diameter wasnot signif icant (P > 0.05).

Photosynthetic rates of between 1.67 and3.41 PmolCO, m- s- were recorded in the cut-tings during the first 3 weeks after insertion. Onaverage, values were higher in sand than in the othermedia (Fig. 4(a)). Stomata1 conductances measuredin cuttings in sand and gravel were signif icantlyhigher than those in sawdust (Fig. 4(b)). When val-

ues of PAR were correlated with P,. positive corre-lations were found in al l rooting media (r = 0.54,0.53 and 0.58 for sawdust, sand and gravel, respec-tively).3.3. Experiment 3

A maximum irradiance of 556 p,mol rn- s wasrecorded inside the propagator during the course ofthe experiment. Relative humidity varied between73.7 and lOO%, with a mean of 94.8%. Mean air.substrate and leaf temperatures of 23.9, 21.9 and25.1C were recorded, with a maximum leaf temper-ature of 37.OC. VPD varied between 0.31 and2.41 kPa, with a mean of 0.65 kPa. There was astrong positive correlation between PAR and VPD(2 = 0.71).Nine weeks after insertion, highly significant dif-ferences (P < 0.01) in rooting percentage wererecorded between node positions. However, rootingpercentagedid not show a consistent rend with nodeposition, values varying between 21.3% for Node 2to 46.3% for Node 5 (Fig. 5). No significant differ-ences were obtained for number of roots per rootedcutting, mean values ranging between 2.0 and 3.2.Stepwise regression eveaied that rooting percentagewas significantly influenced by clone, node position,cutting length and cutting diameter. Mean cuttingdiameter increased rom 3.8 to 5.0 mm from Node 1to Node 6, but mean cutting length did not show anysystematic relation to node position, varying from35.4 mm for Node 3 to 39.8mm for Node 6. This

1

12345fiNode position

Fig. 5. The effec ts of node position (1, apical: 6. basal) on therooting percentage of single-node, leafy stem cuttings of Cur&alliodora, 9 weeks after insertion in non-mist propagators at Turri-alba, Costa Rica. R = 80; values grouped by the same letter arenot significantly different at P < 0.05.


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T 805 700 60,g 50g 40p 30g 20= 10

16 19 22 23 25 29 33 35 37 36Clone number

Fig. 6. Clonal variation in rooting of leafy stem cuttings of Cordiaalliodora during propagation in non-mist propagators at Turrialba,Costa Rica. n = 48; values grouped by the same letter are notsignificantly different at P < 0.05.

may account for the lack of a systematic relationshipbetween rooting percentage and node position. Largevariat ion in rooting was also observed betweenclones, values ranging between 6.3% (Clone 23) to70.8% (Clone 22) (Fig. 6). A significant interaction(P < 0.05, ANOVA) between clone and node posi-tion was also recorded.

Photosynthetic rates of between 0.68 and6.70 pmol CO, m- s- were recorded in cuttingsduring propagation. Stepwise regression showed thatPAR and g, accounted for the largest proportion ofthe total variation (58.7% and 14.0%, respectively),whereas clone (2.6%) and node position (1.5%) hada smaller effect. On average, apical (Nodes 1 and 2)and basal (Node 6) nodes displayed higher P,, val-

3.2 ,-

ab

I6

Node positionFig. 7. The effect of node position (1, apical; 6, basal) on themean net photosynthetic rate (I,) of single-node, leafy stemcuttings of Cordia alliodora during propagation in non-mist prop-agators at Turrialba, Costa Rica. Value s presented are means(n = 40); means grouped by the same letter are not significantlydifferent at P < 0.05.

ues, whereas Nodes 3-5 showed the lowest values(Fig. 7). Stomata1 conductances varied between 18.0and 680.0 mmol H 2O mm2 SK during propagation;no signif icant effect of node position was recorded.When values of PAR were correlated with P,, astrong positive correlation was recorded (r* = 0.80).

4. DiscussionThe abili ty of auxins to promote adventitious root

development in stem cuttings is well known, and hasbeen attributed to enhanced transport of carbohydrateto the base of the cutting (Hartmann et al., 1990).However, contrasting effects of IBA addition havebeen recorded with different tree species. For exam-ple, the optimum IBA concentration for rooting ofTriplochiton scleroxylon was found to be 0.4%(Leakey et al. , 19821, substantially lower than thatrecorded here for C. alliodora. A particularly strik-ing feature of the present results was the very lowrooting in the control treatment, supplied with zeroIBA. Successful rooting without applied auxin hasbeen reported in a number of tropical tree species,such as Shorea macrophyllu (Lo, 1985), Mil iciuexcelsa (Ofori et al., 1996) and Nauclea diderrichii(Leakey, 1990). Such contrasting results may reflectvariation in endogenous auxin contents at time ofseverance (Hartmann et al. , 1990).

The negative relationship found between rootingpercentage and shoot development may reflect com-petition for assimilates between the developing rootand shoot during propagation (Davis, 1988), asrecorded in Populus tremulu (Eliasson, 1971). Theinh ibi tion of bud growth at increasing IBA concen-trations supports results with Mili tia excelsa (Oforiet al., 1996), and may be attributed to IBA-inducedbasipetal transport of assimilates. An alternative hy-pothesis is that applied auxins may inhibit budgrowth, as injection of Nauclea diderrichii withauxin delayed sprouting of cuttings taken from them(Leakey, 1990).The importance of propagation medium for therooting of leafy cuttings is also widely recognized(Hartmann et al., 1990). In general, an appropriaterooting medium is described as one with an opt imalvolume of gas-filled porespace and an oxygen diffu-


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sion rate adequate for the needs of respiration(Andersen, 1986). It is also clear that the provisionof sufficient water to prevent wilting is a primerequirement (Loach, 1986). Tree species differ intheir response to different media (Leakey et al. .1990). For example, in Zruingia gabonensis (Shiemboet al., 1996a). Ricinodendron heudelotii (Shiembo etal.. 1996b) and Militia excelsa (Ofori et al., 1996).higher rooting percentageswere recorded in sawdustthan in the other media tested, contrasting with theresults obtained here with C. ulliodom.In general, media with relatively high water con-tents, such as sawdust, are associated with higherrates of water uptake in the cutting (Loach, 1986)and consequently higher rooting percentages.How-ever, water can present a major diffusion barrier tooxygen, and excess water may thereby result inanoxia within the cutting base (Loach, 1986). Rot-ting of the cutting base in sawdust was frequentlyobserved in the present nvestigation, indicating thatC. alliodora requires a relatively well-aeratedmedium for cutting survival. Reduced water absorp-tion through the cutting base resulting from tissuedeath may also explain the reduced stomata1 onduc-tance of cuttings in sawdust observed here (seeGrange and Loach (1983)). The fewer roots perrooted cutting recorded in sawdust may also reflectanoxia, as recorded previously with Chrysanthemumcuttings (Hartmann et al., 1990) and Cupressocy-park leylandii (Loach, 1986).Photosynthesis during propagation is generallythought to positively influence root formation inleafy cuttings (Davis, 19881, but few studies haveactually measuredphotosynthesis during the rootingperiod. The photosynthetic rates recorded in Experi-ments 2 and 3, ranging between 0.68 and6.70 pmol CO, m- s- , are similar to those re-ported for Terminalia spinosa cuttings (O-6 pmol m- s- > under the samepropagation system(Newton et al., 1992). In somecases, ncreasesn thedry mass of the cuttings have been correlated withthe rooting ability of cuttings (Leakey and Coutts,19891, and rooting may also be related to photo-synthesis of cuttings on shoots before severance(Leakey and Storeton-West, 1992). The results of theexperiments describedhere, with measurements othof dry mass ncrement and photosynthetic rate, indi-cate that cuttings of C. alliodora actively photosyn-

thesize during propagation. However. no clear rela-tionship between photosynthetic activity and rootingability was apparent. It has been suggested hat evenlow photosynthetic rates can contribute significantlyto the carbon budget of a cutting (Okoro and Grace,1976). but further research s required to fully evalu-ate the importance of photosynthesisduring propaga-tion for root development in C. alliodoru.Cutting origin has been found to be closely re-lated to rooting ability in a number of other treespecies. For example, in Triplochiton scleroxylon,rooting percentage of cuttings taken from differentnode positions was found to decline basipetally(Leakey and Mohammed, 1985). These and otherresults have led to the suggestion hat cutting stemvolume. as influenced by basipetal gradients n stemlength and diameter, may have a pronounced influ-ence on rooting by determining the storage capacityof carbohydrates produced pre- and post-severance(Leakey et al.. 1994). The results ecorded here withC. alliodoru contrast with those obtained with otherspecies: although higher cutting diameters wererecorded at lower node positions, no consistent rendin rooting percentage was recorded. This suggeststhat other factors than stem volume. such as thecontent of plant growth regulators, may have beeninfluential (Leakey et al.. 1994).One striking feature of these esults was the clonalvariation in rooting ability. Although no attempt wasmade to investigate this in any detail. such variationmay clearly have profound implications for large-scale multiplication programmes.Genetic effects areamong the least studied factors that control or mod-ify rooting by cuttings (Haissig and Riemenschnei-der, 1988). The clonal variation in rooting abilityrecorded here was not easily explicable in terms ofvariation in the morphological or gas exchange char-.acteristics observed.These results indicate that, contrary to previousreports (Dyson, 1981). C. alliodom can be easilyrooted. using the techniques described here. IBAshould be applied to the cutting base o increase herooting percentageand the number of roots producedby the cuttings. The highest concentration tested(1.6%) produced the highest rooting percentage andnumber of roots per rooted cutting, but the nature ofthe responsesuggests hat the optimal IRA concen-tration for the rooting of C. nlliodorrr may be even


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F. Mesh et al. / Forest Ecology and Management 92 (1997) 45-54 53higher than those tested here. Both the rooting per-centage and the number of roots per cutting werereduced when sawdust was used, in comparison withsand and gravel, indicating that rooting substrateswith relatively low water-holding capacities may beappropriate for propagation of this species.Previous measurements have indicated that signif-icant water deficits may occur in cuttings of C.alliodora during propagation, associated with peaksin VPD and PAR (Newton and Jones, 1993b). Theclose relationships recorded here between post-sever-ance photosynthetic rate and PAR, and between PARand VPD, suggest that careful management of thepropagator microclimate may be required for opti-mum rooting of C. alliodora to be achieved (Newtonand Jones, 1993a). For example, the use of shadingmay allow relatively low VPDs to be maintainedaround the cuttings, while providing sufficient irradi-ante for the cuttings to maintain a positive carbonbalance. Further research is required to define moreprecisely the appropriate microclimate for propaga-tion of this species.

AcknowledgementsThe authors thank the UK Overseas DevelopmentAdministration and British Council for financial sup-port, the Tropical Agricultural Research and HigherEducation Centre (CATIE) for logistic support andthe staff of the CATIE Tree Improvement Project fortheir help during the field work.

ReferencesAndersen, AS., 1986. Stockplant conditions . In: M.B. Jackson

(Editor), New Root Formation in Plants and Cuttings. Marti-nus Nijhoff, Dordrecht, pp. 223-255.

Beadle, C.L., Ludlow, M.M. and Honeysett, J.L., 1985. Waterrelations. In: J. Coombs, D.O. Hall, S.P. Long and M.O.Scurlock (Editors), Techn iques in Bioproductivity and Photo-synthesis, 2nd edn. Pergamon, Oxford, pp. 50-61.

Boshier, D.H. and Me&n, J.F., 1987. Proyecto Mejoramiento deArboles de1 CATIE : estado de avance y principales resultados.CATIE , Turrialba, 16 pp.

Boshier, D.H. and Me&, J.F., 1988. Availability of seed ofCordia a lliodora for progeny test ing. FAO For. Gene tic Re-source Inf. No. 15. FAO, Rome, pp. 30-35.

Davis, T., 1988. Photosynthe sis during adventitious rooting. In:T.D. Davis, B .E. Haiss ig and N. Sankhla (Editors), Adventi-tious Root Formation in Cuttings. Dioscorides Press, Portland,OR, pp. 79-87.

Dyson, W.G., 1981. Report to ODA of the UK Government,London. CATIE , Turrialba, 16 pp.Eliass on, L., 1971. Adverse effect of shoot growth in rooted

cuttings of aspen. Physiol. Plant., 25: 268-272.Grange, R.I. and Loach, K., 1983. The water economy of un-

rooted cuttings. J. Hort. S ci., 58(l): 9-17.Greaves, A. and McCarter, P.S ., 1990. Cordia alliodo ra-a

prom ising tree for tropic al agroforestry. Tro pica l ForestryPapers No. 22. Oxford Forestry Instit ute, Department of Plan tScien ces, University of Oxford, 37 pp.

Haissig , B.E. and Riemenschneider, D.E., 1988. Genetic effectson adventitious rooting. In: T.D. Davis, B.E. Haissig and N.Sankhla (Editors), Adventitious Root Formation in Cuttings.Dioscorides Press, Portland, OR, pp. 47-60.

Hartmann, H.T., K ester, D.E. and Davies, F.T., 1990. PlantPropagation-Principles and Practices , 5th edn. Prentice-Hall,Englewood Cliffs, NJ, 647 pp.

Hudson, J.M., 1984. A note on Cordia alliodora in Vanuatu.Comm onw. For. Rev., 63(3): 181-183.

Leakey, R.R.B., 1990. Nauclea diderrichii: rooting of stem cut-tings, clonal variation in shoot dominance, and branch pla-giotropism. Trees, 4: 164-169.

Leakey, R.R.B. and Coutts, M.P., 1989. The dynamics of rootingin Triplochifon scleroxylon K. Schum . cuttings: their relationto leaf areas, node position, dry weight accum ulation, leafwater potential and carbohydrate comp osition. Tree Physiol.,5: 135-146.

Leakey, R.R.B. and Mohammed, H.R.S., 1985. The effects ofstem length on root initiation in sequential single-node cut-tings of Triplochiton scleroxylon K. Schum . J. Hort. Sci.,60(3): 431-437.

Leakey, R.R.B. and Storeton-West, R., 1992. The rooting abilityof Triplochiron scleroxylon cuttings: the interactions betweenstockplant irradiance, light quality and nutrients. For. Ecol.Manage., 49: 133-150.

Leakey, R.R.B., Chapman, V.R. and Longman, K.A., 1982. Phys-iologic al studies for tropical tree improvement and conserva-tion-some factors affecting root initiation in cuttings ofTriplochiron scleroxylon K. Schum. For. Ecol. Manage., 4:53-66.

Leakey, R.R.B., Me&, J.F., Tchound jeu, Z., Longman, K.A.,Dick, J.McP ., Newton, A., Matin, A., Grace, J., Munro, R.C.and Muthoka, P.N., 1990. Low-technology techniques for thevegetative propagation of tropical trees. Commonw. For. Rev.,69(3): 247-257.

Leakey, R.R.B., Newton, A.C. and Dick, J.McP., 1994. Captureof genetic variation by vegetative propagation: processe s de-termining succ ess. In: R.R.B. Leakey and A.C. Newton (Edi-tors), Tropica l Trees: the Potential for Domes tication and theRebuilding of Forest Resources. HMSO, London, pp. 72-83.

Lo, Y.N., 1985. Root initiation of Shorea macrophylla cuttings:effects of node position, growth regulators and misting regime.For. Ec ol. Manage., 12: 43-52.


10/10

54 F. Mesh et ul. /Forest Ecology und Management 92 C1997145-54

Loach, K., 1986. Rooting of cuttings in relation to the propagationmedium. Proc. Int. Plant Propagators Sot., 35: 472-485.

Me&, J.F., Boshier, D.H. and Cornelius, J.P.. 1994. Geneticimprovement of trees in Central America with particular refer-ence to Costa Rica. In: R.R.B. Leakey and AC. Newton(Editors), Tropica l Tree s: the Potential for Domes tication andthe Rebuilding of Forest Resources. HMSO, London, pp.249-255.

Neil. P.E . and Jacov elli, P.A., 1985. Agroforestry as an aid torational rural development in Vanuatu. Commonw. For. Rev.,64(3): 259-266.

Newton, A.C. and Jones, A.C., 1993a. Characterization of micro-climate in mist and non-mist propagation systems . J. Hort.Sci.. 68(3): 42 l-430.

Newton, A.C. and Jones, AC. 1993b. The water status of leafycuttings of four tropical tree spec ies in mist and non-mistpropagation systems. J. Hort. S ci., 68(5): 653-663.

Newton, A.C., Muthoka. P. and Dick, J.McP ., 1992. The influ-ence of leaf area on the rooting physiology of leafy stemcuttings of Termina lia spinos a Engl. Trees, 6: 210-215.

Ofori, D., Newton, A.C., Leakey, R.R.B. and Grace, J., 1996.Vegetative propagation of Militia excelsa Welw. by leafy

stem cuttings: effects of auxin concentration, leaf area androoting medium. For. Eco l. Manage., 84: 39-48.

Okoro, 0.0. and Grace, J., 1976. The physiology of rootingPopulus cuttings I. Carbohydrates and photosynthesis. Physiol.Plant., 36: 133- 138.Payne, R.W.. Lane, P.W., Ainsley, A.E.. Bricknell, K.E.. Digby,P.G.N.. Harding, S.A.. Leech, P.K., Sampson , H.R., Todd,A.D.. Verrier, P.J. and White, R.B., 1987. GENS TAT 5:Reference Manual Clarendon Press, Oxford.

SAS Institute, Inc., 1980. SAS Users Guide: S tatistic s, Version 5edn. Statis tical Analys is Systems In stitute, Inc.. Cary, NC. pp.113-137.

Shiembo, P.N., Newton, AC. and Leakey. R.R.B.. 19%a. Vegeta-tive propagation of Irringiu gabonens is, a West African fruittree. For. Ecol . Manage., 87: 185-192.

Shiembo, P.N., Newton, A.C. and Leakey, R.R.B.. 1996b. Vegeta-tive propagation of Ricinodendron heudelotii. a West Africanfruit tree. J. Trop. For. Sc i., in press.

Snedecor, G.W. and Cochran, W.G., 1980. Statis tical Methods.7th edn. Iowa State University Press, Ames .

Zobel, B. and Talbert. J.A.. 1984. Applied Forest Tree Improve-ment. Wiley. New York.

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Vegetative Propagation of Cordia Alliodora (Ruiz & Pavon) Oken the Effects of IBA