The Chittagong Univ.J. Sci., 25(1): 27 - 33, 2001. EFFECTS OF LEAF RETENTION ON ROOTING OF CUTTINGS AND GROWTH OF CUTTINGS OF CHICKRASSIA VELUTINA WIGHT ET ARN. IN THE NURSERY M. AHMED, M. KAMALUDDIN* AND M. A. RAHMAN Department of Botany, University of Chittagong, Chittagong-4331,
Bangladesh
ABSTRACT The lack of dependable supply of seed can be overcome by the application of clonal propagation. Leafless cuttings of Chickrassia velutina Wight et Am. (chikrasi) failed to form roots on cuttings. Increases in leaf area of cuttings increased rooting abilities of cuttings. Retention of leaf area greater than 10 cm2did not increase rooting abilities in terms of rooting successes or number of roots produced in cuttings. Leaf area of around 10 cm2 was sufficient to have maximum rooting successes and maximum number of roots in successful cuttings. Larger leaf area of cuttings did not have deleterious effects on growth of rooted cuttings, rather shoot diameter significantly increased. Since rooted cuttings were grown in containers for a long time in nursery, expected benefits of larger leaf area of cuttings on growth of rooted cuttings might have disappeared. In practice, retention of 3-4 leaflets (around 10 cm2leaf area) per cutting will be sufficient to produce maximum benefits in terms of rooting successes and number of roots per cutting. Trimming of leaf to remove the excess leaflets and distal part of the petiole helps in reducing the sizes of cuttings and thus adds extra benefit allowing planting of larger number of cuttings per unit bed area within the propagators. ~~ c~ m1 i5~~ 'Iff!@:!~S'fJ ~ ~~9frIfi'! ~ on I~~~~ i5<>rn 9fWR! ~
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INTRODUCTION Chikrasi (Chickrassia velutina Wight et Am.), a commercial tree species of family Meliaceae, naturally occurring scattered in moist tropical forests of Bangladesh, Burma, India, Sri Lanka, China and Borneo [1]. Due to rapid loss of natural forests and their inherent biodiversity, currently largescale plantations programme have been received as a better alternative to enhance indigenous forest tree species for timber production in our country. Propagation by stem cuttings may be the most promising technique of vegetative propagation for establishment of indigenous forest tree species, chikrasi plantations on a large-scale. *Institute of Forestry and Environmental Sciences, University of Chittagong, Chittagong-4331
28
M. AHMED ET AL.
Propagation by cuttings involves retention of some leaves in cuttings and sometimes the retained leaves are trimmed to reduce transpiring area. Leaf area of cuttings is known to influence rooting abilities of cuttings [2,3,4,5,6,7] and growth of rooted cutting [8]. The basis of increased root formation in leafy cuttings has been discussed in many published literatures [9, 10]. It has long been acclaimed that the water status of leafy cuttings influences adventitious root development [11, 10] but the detailed nature of this relationship has perceived relatively little attention [12]. Photosynthesis in leafy cuttings is often linked with rooting abilities of cuttings. When photosynthesis is decreased in leafy cuttings by various treatments, root formation is limited [13]. In some cases, however, photosynthesis appears to be of little importance for root formation in leafy cuttings [14] when carbohydrate reserves are sufficient to satisfy rooting demands [15]. Although there have been several studies on leaf area and rooting ability for tropical forest trees, very few studies have examined the effects of leaf retention in cuttings on subsequent growth of rooted cuttings on transfer from propagator [8]. Therefore, it was the aim of this experiments are to explore the rooting abilities of single-nodal stem cuttings through the manipulation of leaflets on the cuttings of stock-plants and growth of rooted cuttings after transfer from propagators to growth tubes. MATERIALS AND METHODS
Experimental procedure One-year old stock-plants grown in polythene bags (24 cm x 15 cm) filled with soil, coconut husk compost and cow-dung compost (1:1:2 by volume) were decapitated to produce shoots in open sun. Six weeks after decapitation, shoots were harvested for making of cuttings. Single-nodal cuttings were taken from apical 2ndand 3rdof the shoots. The cuttings were then grouped into following cutting-types by removal of leaflets of a single leaf; leaf area of each cutting-type was the mean of 30 cuttings: Cutting types Leaf without leaflets Leafwith 1leaflet Leaf with 2 leaflets Leaf with 3 leaflets Leaf with 4 leaflets Leaf with 5 leaflets Leaf with 6 leaflets
Leaf area (cm2)
0 2 3 9 10 18 39
In a trial for studying rooting produced in cuttings, cuttings were planted in a non-mist propagator [16]. It was simply a polythene enclosure consisting of a wooden frame of 1.8 m long and 1 m wide with a height of 60 cm on the rear side and 45 cm on the front side. The sides of the frame were kept clear above 20 cm. A clear polythene sheet was lined inside the frame spreading up to the top of the frame. The frame is then covered with a closely fitting polythene lid. The propagator was then filled
EFFECTS OF LEAF RETENTION ON ROOTING OF CUTTINGS AND GROWTH OF CUTTINGS
29
with a 10 cm thin layer of moist coarse sand mixed with fine gravels. The sand layer acted as rooting medium. The enclosure so formed held humid air. The propagator was placed in propagation shed. It was a bamboo-made propagation shed, approximately 10 m long,S m width and 2 m height. To avoid excessive heat accumulation, the sides, and the roof of the shed were lined with small diameter (2-3 cm diameter) bamboo sticks; by placing the whole-bamboo slats of 20 cm wide leaving 20 cm space in between the slats. Further shading was achieved by putting jute mat over the roof of the shed. In this way, photosynthetic photon flux inside the propagator was reduced to about 10% of full sun by the overhead shade. It was possible to maintain about 85-90% humidity within the propagator. The basal end of each cutting was cut to 45O-angle base with a sharp blade. The cuttings were immersed in solutions of fungicide, Diathane M-45 (Rohn & Hass Co. Ltd., France; 2 g per liter of water) for 10 min. Then the cuttings were rinsed with water and kept under shade for 10min in open air. No rooting hormone was used as treatment for the cuttings. The cuttings were planted in perforated plastic trays (10 cm depth) containing rooting medium. These trays served as plots that were placed in three completely randomized blocks, in the month of June 1999. The number of replicate cuttings per treatment were 30 (10 cuttings per tray-plot). Every day the propagator was opened briefly in the morning and in late afternoon to facilitate gas diffusion. The cuttings were subjected to a weaning period in the propagator before transferring them from the propagator three weeks after setting. For weaning of cuttings, the propagator was kept open at night for two days and then for day and night for another three days. The cuttings were taken out of the propagator four weeks after planting and data was collected. Data on rooting success and number of roots produced in each cutting were recorded. The possible treatment differences were explored by analysis of variance and Duncan's multiple range test. Growth study The rooted cuttings were planted in polythene bags (15 cm x 24 cm) filled with a mixture of forest soil, coconut husks compost and decompost cow-dung at the proportion of 1:1:2 by volume. The potted cuttings were placed on nursery floor in three completely randomized blocks and kept under overhead shade five days. Then they were exposed to full sun. At the age of six months, the cut-lings were harvested and roots made free of soil by washing carefully in tape water. Data on shoot length, collar diameter and number of roots produced in each cut-ling were recorded. Stem, leaf and root samples were dried in oven at 70°C for 72 h for dry weight assessments. The possible treatment differences were explored by analysis of variance and Duncan's multiple range test. RESULTS Effects of leaf area of cuttings on rooting abilities Leaf area of cuttings significantly affected rooting abilities of cuttings (Table 1and 2). Leafless cuttings failed to survive and form roots; this cutting-type was excluded from the analysis. In
M. AHMED ET AL.
30
leafy cuttings, roots appeared 14 d after setting. Across all the treatments, percentages of cuttings rooted within four weeks ranged between 33 and 100. Cuttings with 2 or 3 cm21eafarea showed poor rooting success. Increase in leaf area of cuttings by about 1 cm2increased rooting success from 33% in 2 cm21eafarea regime to 83% in 3 cm21eafarea regime. Almost all the cuttings survived and rooted when leaf area of cuttings was 9 cm2or above. Leaf area of cuttings also significantly affected number of roots produced per cutting. Increase in leaf area of cuttings increased number of roots produced per cutting. Cuttings with leaf area of 10 cm2or more produced significantly higher number of roots per cuttings than those with less than 10 cm2 leaf area. There was no appreciable change in rooting success or number of roots per cutting with increase in leaf area of cuttings from 10 cm2or above (upto 39 cm2). TABLE
1 : RESULTS OF ANALYSIS OF VARIANCE OF DATA ON ROOTING ABILITIES OF CUTTINGS IN RELATION TO LEAF AREA OF CUTTINGS.
Variables
Source
Df
SS
MS
Rooting percentage
Leaf number
5
6841.8
1368.4
16.69
0.000
Replication Error
2
201.3
100.6
1.23
0.334
10
820.0
82.0
Total
17
7863.0
(Arcsin square root)
F
P
Root number per
Leaf number
5
19.7892
3.9578
6.10
0.008
rooted cutting
Replication Error
2
0.3392
0.1696
0.26
0.775
10
6.4905
0.6490
Total
17
26.6189
TABLE 2 : EFFECTS OF LEAF AREA OF CUTfINGS ON ROOTING ABILITIES OF CUTfINGS. THE SAME SUPERSCRIPT LETTERS INDICATE NO SIGNIFICANT DIFFERENCE AT P<0.05 (ANOVA AND DUNCAN'S MULTIPLE RANGE TEST)
Variables
Leaf area of cuttings (cm2) 2
3
9
10
19
39
Rooting percentage
33b
83b
100"
100"
100"
100"
Root number per cutting
4.0d
5.0cd
5.4bd
7.0"
5.8"bc
6.9"b
Effects of leaf area of cuttings on growth of cuttings Leaf area on top of cuttings did not appreciably affect the growth of rooted cuttings in nursery (Table 3 and 4). Mean shoot length and mean dry weight of leaf, stem or root were not significantly different among the rooted cuttings developed from cuttings with different leaf area. However, mean shoot diameter increased with increase in leaf area on cuttings.
EFFECTS OF LEAF RETENTIONON ROOTING OF CUTTINGS AND GROWTH OF CUTTINGS
31
TABLE 3 : RESULTSOF ANALYSISOF VARIANCEOF DATAON GROWTH VARIABLESOF ROOTED CUTTINGS DEVELOPED FROM CUTTINGS WITH DIFFERENT LEAF AREAS. Variables
Source
df
SS
MS
F
P
Shoot length (cm)
Leaf area
5 2 10 17
56.49 10.37 109.68 176.54
11.30 5.19 10.97
1.03 0.47
0.450 0.636
5 2 10 17
10.6918 1.9465 4.5437
2.1384 0.9732 0.4544
5 2 10 17
1.9075 0.2637
5 2 10 17
2.1264 1.0587 3.1214
5 2
2.6239 2.2557 5.2826 10.1622
Replication Error Total Leaf area
Shoot diameter (mm)
Replication Error Total Leaf area
Stem dry weight (g)
Replication Error Total Leaf area
Root dry weight (g)
Replication Error Total Leaf area
Leaf dry weight (g)
Replication Error Total
4.71
0.018
2.14
0.168
0.3815 0.1318 0.2837
1.34 0.46
0.322 0.641
0.4253 0.5294 0.3121
1.36 1.70
0.316 0.232
0.5248 1.1279
0.99 2.14
0.468 0.169
17.1820
2.8373 5.0085
6.3066
10 17
0.5283
TABLE 4: EFFECTS OF LEAF AREA OF CUTTINGS ON GROWTH OF ROOTED CUTTINGS. THE SAME SUPERSCRIPT LETTERS INDICATE NO SIGNIFICANT DIFFERENCE AT P
Leaf area of cuttings (cm2) 2
3
9
10
19
39
Shoot length (cm) Shoot diameter (mm)
15.6" 6.1 b
1.93" 3.05"
21.6" 8.5" 2.33" 3.61"
16.8" 6.4b
1.28" 2.47"
16.9" 6.8b 1.70" 2.91"
17.6" 7.0b
Stem dry weight (g) Root dry weight (g)
16.4" 6.6b 1.60" 2.8"
Leaf dry weight (g)
2.79"
3.01"
3.17"
3.50"
3.99"
3.26"
1.91" 3.00"
32
M. AHMED ET AL.
DISCUSSION
Rooting responses to leaf area of cuttings Leaf area of cuttings significantly affected rooting abilities of cuttings. Leafless cuttings of the study species, chikrasi, failed to form roots and ultimately died. It may be assumed that the preseverance carbohydrate reserves in the leafless cuttings were rapidly used up following planting into the propagator, which ultimately produce roots. Depletion of carbohydrate reserves and the lack of carbohydrate input from photosynthesis, due to leaflessness of the cuttings, led to a condition of negative carbon balance resulting in death of the cuttings. Photosynthesis in some species can be of little importance to root formation in leafy cuttings [14] when the cuttings contain sufficient carbohydrate reserves to satisfy rooting demand [15]. Rooting ability of leafy cuttings is sometimes related to the production of reflux-soluble carbohydrates derived from photosynthesis while cuttings are in propagation unit [17]. In the present experiment, photosynthesis in leafy cuttings possibly played an important role in increasing rooting abilities of cuttings. A rooting success of 33% in cuttings with a small leaf area 2 cm2pointed to the fact that rooting abilities of cuttings mostly depended on photosynthesis in leafy cuttings. Further increases in rooting success with the increase in leaf area up to around 10 cm2 indicated that there was a need for optimum leaf area of the species for the supply of optimum amounts carbohydrates through photosynthesis for maximum rooting successes and maximum number of roots in cuttings. The findings of this experiment are consistent with several previous reports on other forest trees [4,6,7]. Leaky and Coutts [5] observed a deleterious effect oflarger leaf area on rooting of cuttings resulted from decreased leaf water potential in their experiment under intermittent mist for Triplochiton scleroxylon K. Schum. In the present experiment, such an effect of larger leaf area was not observed since the loss of increased amounts of water through transpiration was possibly minimized in the highly humid condition of the non-mist propagator. Growth responses of rooted cuttings to leaf area of cuttings Growth of rooted cuttings in nursery was not largely influenced by the differences in leaf area of cuttings. However, shoot diameter was significantly affected by leaf area of cuttings. Mean shoot diameter was increased with the increases in leaf area on top of cuttings. Rooted cuttings immediately after transfer from propagator to pots required enough materials and energy to initiate growth. At the initial stage of growth, existing leaf area of the cuttings might have played an important role by supplying assimilates from photosynthesis. In previous study with neem (Azadirechta indica), Kamaluddin and Ali [8] recorded higher shoot dry weight and root dry weight in cut-lings developed from cuttings with larger leaf area. However, such a significant effect of larger leaf area of cuttings on subsequent biomass growth of rooted cuttings was not observed in the present study species, chikrasi. It might be possible that in chikrasi the effects of larger leaf area of cuttings on initial growth of rooted cuttings might have disappeared due to long growth period in nursery. In the present experiment, rooted cuttings were grown in polythene pots for six months. When plants are grown in containers for a long time, their growth rates may have ceased with the depletion of nutrients in potting media and (or) with the limitation of space within the container for root growth. This might be the possible explanation for
EFFECTS OF LEAF RETENTION ON ROOTING OF CUTTINGS AND GROWTH OF CUTTINGS
33
insignificant effects of larger leaf area of cuttings on most of the growth variables of rooted cuttings examined in the present experiment. REFERENCES 1. K. R. KIRTIKAR, B.D. BASU AND 1.C. S. An., Indian medicinal Plants. Bishen Singh Mahendra Pal Singh, 23-A, Connaught Place, Dehra Dun-248001, India. p. 560, 1993. 2. T. F. GEARY AND W.G.HARDING, The effects of leaf quantity and trimming on rooting success with Eucalyptus camaldulensis Dehn. Cuttings. Commonw. For. Rev., 63 : 225-230, 1984. 3. R. R. B. LEAKY, The capacity for vegetative propagation in trees. In: Cannell, M. G. R. And Jackson, J. E. (Eds.). Attributes of Trees in Crop Plants. Inst. Terrestrial Ecology, Abbots Ripton, Huntingdon, UK. Pp. 110-113,1985. 4. G .5. SHAMET AND S. KUMAR, Rooting studies of Punica granatum and Dalbergia sisso cuttings under controlled phytoenvironment conditions. Ind. For., 114 : 331-334, 1988. 5. R. R. B. LEAKY ANDM. P. COUTTS, The dynamic of rooting in Triplochitonscierel!xyloncutting s:their relation to leaf area, node position, dry weight accumulation, leaf water potential and carbohydrate composition. Tree Physiol. 5 : 135-146, 1989. 6. M. KAMALUDDIN, M. ALl AND M. K. BHUIYAN, Effects of leaf retention and auxin applications on rootability of green stem cuttings from mature trees of Dalbergia sissoo Roxb. Ann. For., 2(2) : 142-146, 1994. 7. D.C. MAHTOLlA AND M. PAL. Effect of leaf retention and auxin treatment on rooting response of teak (Tectona grandis L.f.). Ann. For., 3(2) : 188-192. 1995. 8. M. KAMALUDDIN AND M. ALl, Effects of leaf area and auxin on rooting and growth of rooted stem cuttings of neem. New Forests, 12 : 11-18, 1996. 9. H. T.HARTMANN AND D. E. KESTER, Plant Propagation: Principles and Practices. Prentice- Hall, New Jersey, US, 1983. . 10. B. McDONALD, Plant Propagation (VoU). Timber Press, Portland, Oegon, Us. 1990. 11. H. EVANS, Physiological aspects of the propagation of cacao from cuttings. Proc. 13th International Horticultural Congress, 2 : 1179-1190, 1952. 12. A. C. NEWTON AND A.c. JONES, The water status of leafy cuttings of four tropical tree species in mist and non-mist propagation systems. J. Hort. Sci., 68(5) : 653-663, 1993. 13.T.D. DAVIS, Photosynthesis during adventitious rooting In: Adventitious Root Formation in Cuttings, edited by TD Davis, S.E. Haissig & N. Sankla. 61-69. Portland, Oreogon, Dioscorides Press. 1988. 14. J. VAN OVERBEEK, S.A. GORDON AND L.E. GREGORY, An analysis of the function of the leaf in the process of root formation in the cuttings. Amer. J. Bot., 33 : 100-107, 1946. 15. M. KANTERLl, Vegetative propagation ofDipterocarps by cuttings in ASEAN (Association of South-East Asian Nations) region. Review Paper No.1, ASEAN-Canada Forest Tree Seed Centre Project, Saraburi, Thailand, pp. 58, 1993 16. M. KAMALUDDIN, Clonal Propagation of Eucalyptus and Acacia Hybrid by Stem Cuttings. Research Report, Forestry Division, Bangladesh Agricultural Research Council. Dhaka, 31 pp., 1996. 17. R. R. B. LEAKY AND R. STORETON -WEST, The rooting ability of Triplochiton scieroxylon cuttings: the interaction between stock-plant irradiance, light quality and nutrients. For. Ecol. Mange., 49: 133-150, 1992. Manuscript received on 25th July, 2001 and revised manuscript received on 31st December, 2002. The Chittagong University Journal of Science, Vol. 25(1), 27 - 33, 2001.