Research Article | | Peer-Reviewed

Optimizing Growth Regulators for Micropropagation of Industrially Adaptable Eucalyptus Hybrids

Received: 23 May 2024     Accepted: 11 June 2024     Published: 27 June 2024
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Abstract

Eucalyptus is one of the highly economic tree species in the developing countries like India. In the present investigation, experiments on optimizing plant growth regulators in the micropropagation of promising inter specific Eucalyptus hybrid clones namely TNPL 191(E. camaldulensis× E. teriticornis), TNPL 192 (E. camaldulensis × E. pellita) and intra specific hybrid clone TNPL 193 (E. camaldulensis× E. camaldulensis) were conducted, following standard protocols developed for Eucalyptus. The results showed that the BAP concentration of 0.50 mg L-1 for bud induction, IAA concentration of 3.0 mg L-1 for shoot elongation and IBA concentration of 1.0 mg L-1 for rooting of all these clones were found optimal. However, these three hybrid clones responded differently to the concentration of BAP at shoot proliferation stage. While the hybrid TNPL 191 showed maximum shoot proliferation rate at the concentration of 0.2 mg L-1 of BAP, the hybrids TNPL 192 and TNPL 193 showed highest response at 0.15 mg L-1. All the in vitro rooted plantlets were acclimatized successfully to the prevailing natural environment. Thus, the protocols developed with respect to optimizing the plant growth regulators can be adapted in large scale micro propagation of inter and intra specific Eucalyptus hybrid clones.

Published in Journal of Plant Sciences (Volume 12, Issue 3)
DOI 10.11648/j.jps.20241203.13
Page(s) 82-89
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Eucalyptus Hybrid, Micropropagation, BAP, IAA, IBA

1. Introduction
The genus Eucalyptus (Family: Myrtaceae; 2n= 22), reportedly having about 900 different species is native to Australia and commercially cultivated in developing countries like India, owing to its high productivity, augmented demand and multi end uses like fiber and hardwood . As an industrial point of view, the Eucalyptus species is mainly exploited as pulpwood by pulp and paper industries and feedstock for renewable bio-energy . In India, E. camaldulensis and E. teriticornis are the most widely cultivated species due to their adaptability in arid and semi- arid conditions with relatively lower productivity. The lack of genetic variability is one of the main reasons for low productivity of commercial eucalyptus plantations in India as compared to other countries . In recent times, genetic improvement programs on Eucalyptus species were initiated with introduction of germplasms from a wide range of natural provenances from Australia and elsewhere from the world. As the demand for wood stocks growing, inter and intra- hybridization using promising Eucalyptus accessions became priority in genetic improvement research.
Planting stock with better genetic quality is the accepted mean for increasing the productivity of plantations, better farm income and sustainable supply to the wood based industries . The conventional regeneration programs involve large scale seedling production with the challenges of persisting genetic load and relatively long generation time . Poor rooting ability of stem cuttings and graft incompatibility are some of the reported constraints experienced with vegetative propagation of Eucalyptus hybrids. The biotechnological tools such as plant tissue culture along with traditional breeding program can be considered as viable solution for meeting the growing demand of forest products by industrial sectors.
In recent times, considerable attention on micropropagation of Eucalyptus has been given to produce large scale Eucalyptus clonal plants for reforestation and raising industrial plantations owing to the advantages of producing disease free and genetically identical plantlets. Well established in vitro propagation protocols for various Eucalyptus species were reported by some researchers . But the process of somatic embryogenesis/ organogenesis and rooting differs within species and among hybrids and therefore, evolving specific protocols for each species/ hybrids need to be developed further. The cost- effective in vitro propagation protocols play key role in the development of low cost tissue culture technologies in the developing countries like India ).
Growth regulators play crucial role in promoting shoot proliferation and rooting of targeted species, especially Eucalyptus and their hybrids. For example, the type and concentration of cytokinins and auxins in the culture medium can affect the quality of shoot formation. The concentrations of plant growth regulators added to media needs careful consideration as an excess will result in antagonistic effect on the explants. Optimizing the hormones in micropropagation protocols can maximize the efficiency of shoot proliferation and production of healthy, true- to-type plantletes.
Therefore, this study was focused on optimizing growth regulators in micropropagation of three Eucalyptus hybrids developed for industrial plantations namely TNPL 191 (Inter- specific hybrid of E. camaldulensis× E. teriticornis), TNPL 192 (Inter- specific hybrid of E. camaldulensis × E. pellita) and TNPL 193 (Intra- specific hybrid of E. camaldulensis× E. camaldulensis) for improvement in adventitious rooting and productivity under large scale plantlets production.
2. Materials and Methods
2.1. Eucalyptus Ex Situ Conservation and Plant Materials
Nodal buds from active coppice shoots of the Eucalyptus clones, grown in sand beds were used as explants. This method is considered to be effective in ex situ conservation of these clones . Shoot intermediate nodes of about 1- 1.5 cm bearing nodal segments with auxiliary buds were detached and washed with liquid detergent initially, then under running tap water for 60 min to clear the microbial load and dust particles. The cleaned explants were washed with deionized water for 3- 5 times followed with the fungicide carbendazim suspension (1: 100 w/v) for 1 h . Finally, the explants were washed with deionized water for 2- 3 times and stored for further culturing.
2.2. Disinfection and Initial Establishment of in Vitro Plant Material
The explants were sterilized with the previously standardized protocol at this laboratory : initial treatment with 70% ethanol for 1 min, followed by treatment with3% sodium hypochlorite (NaOCl) with immersion duration of 12 minutes and finally with 0.1% mercuric chloride (HgCl2) for 1 min. These explants were finally rinsed 4-5 times with sterilized deionized water and placed individually in borosilicate glass test tubes containing Murashige- Skoog (MS) medium . The cultures in all the following experiments were maintained in a plant growth room having 16h/ 8h light/ dark photoperiod under cool white fluorescent lamps (light intensity of 40 µmol m-2s-1) and with day/ night temperature of25 ± 2°C.
2.3. In Vitro Shoot Initiation
The in vitro shoot initiation experiments were conducted using shoot- tip explants derived from the in vitro cultures as explained above. The explants were transferred into borosilicate glass bottles of 300 mL capacity and containing 100 mL of MS culture media, fortified with 0.00, 0.25, 0.50, 0.75 and 1.00 mg L-1 of 6-Benzylaminopurine (BAP). The percent shoot induction and shoot length were measured at 30 days after culture initiation. Each treatment consist 15 explants distributed in 3 culture bottles (each containing 5 explants) and each culture bottles were considered as one replication.
2.4. In Vitro Shoot Proliferation
The shoot proliferation experiments were conducted using adventitious shoot buds obtained from the shoot initiation experiment. The non- contaminated and well initiated buds were transferred into culture bottles containing MS media supplemented with five levels of BAP (0, 0.10, 0.15, 0.20 and 0.25 mg L-1). The number of shoots formed per explant clump and shoot length was measured at 30 days after culturing.
2.5. In Vitro Shoot Elongation
In vitro shoot elongation experiment was conducted using shoot- tip explants derived from in vitro cultures as stated above. The shoot- tips were transferred to the culture bottle containing MS culture medium enriched with different doses of Indole 3-acetic acid (IAA)viz. 0, 2.0, 2.5, 3.0 and 3.5 mg L-1. At 30 days after explants transfer, the number of new shoots formed per clump and length of the shoots were measured. The non- hyperhydric shoots of at least 0.5 cm length were considered for measurement.
2.6. In Vitro Rooting
The in vitro rooting experiments were conducted using the shoot- tip explants obtained from the shoot proliferation above. The explants were transferred to culture bottles containing half strength MS culture medium supplemented with0, 0.5, 1.0, 1.5 and 2.0 mg L-1of Indole butyric acid (IBA). The rooting percent and number of roots per explant were enumerated at after 30 days of culture inoculation.
2.7. Ex Vitro Acclimatization
Ex vitro acclimatization experiment was carried out using rooted explants from the in vitro rooting experiments above. After washing with tap water to remove the adhering medium, the rooted explants were planted in root trainers filled with composted coir pith as rooting medium. The root trainers were initially placed in the mist chambers (80-90% RH, 35-40°C/ 20-25°C day/ night air temperature). After 15 days, the plants were shifted to 50%shade house (50-55% RH and 30-35°C/ 20-25°C day/ night air temperature) for 15 days and then to open nursery having environment of 30-35°C and 45-50% RH. The percent acclimatization in each of the Eucalyptus hybrids was assessed at 30 days after planting of the rooted explants.
2.8. Statistical Analysis
The data for each Eucalyptus hybrid consisting three replicates were processed with descriptive statistics and analyzed for one way analysis of varience (ANOVA). Least Significant Difference (LSD) and the post hoc test of Duncan’s multiple range tests (P ˂ 0.05) were performed to compare the means between various doses of PGRs at each experiments when ANOVA results indicated significant differences at P= ≤ 0.05. Data analyses were performed using SPSS statistics for Windows (IBM SPSS statistics version 29.0).
3. Results and Discussion
3.1. Shoot Initiation
The shoot initiation rate and corresponding shoot length of three Eucalyptus hybrid cultures are shown in Table 1. The different concentrations of BAP were found significantly influencing the shoot induction and shoot length (P< 0.05). The concentration of 0.75 mg L-1 recorded highest shoot initiation in all the clones (Figure 1). However, the BAP concentration of 50 mg L-1 was found statistically on par with the best treatment in the hybrids TNPL 192 and TNPL 193. The influence of BAP was extended to increasing shoot length of eucalyptus clones as the dose of 0.5 mg L-1 was found best for all these hybrids. This was because of the explants apparently derives nutrients and hormones from the medium that favors the development of organogenesis . Further, BAP is most efficient synthetic cytokinin which promotes induction of adventitious buds at the base of explants by stimulating cell division . The effective response of BAP on induction of adventitious bud in Eucalyptus sp. has been reported previously by Baccrinet al. . Therefore, considering the above biometrics, the BAP dose of 0.50 mg L-1 was found optimum for the conversion of excised buds in to shoots, besides increasing the shoot length in all the three hybrid clones.
Table 1. Effect of BAP on shoot initiation on eucalyptus hybrids.

Shoot initiation

BAP(mg L-1)

Shoot initiation rate (%)

Shoot length (cm)

TNPL 191

TNPL 192

TNPL193

TNPL 191

TNPL 192

TNPL 193

0.25

47.07 ± 0.64c

58.78 ± 2.89c

44.40 ± 2.34c

2.30 ±0.40b

2.03 ± 0.25c

1.53 ± 0.35b

0.50

58.79 ± 2.48ab

76.78 ± 2.70ab

55.36 ± 2.70a

3.53 ± 0.45a

3.70 ± 0.20a

2.73 ± 0.25a

0.75

59.67 ± 1.81a

70.43 ± 2.40a

52.27 ± 1.53ab

2.70 ± 0.60ab

3.03 ± 0.45b

2.03 ± 0.25b

1.00

54.57 ± 2.45b

58.37 ± 2.63b

50.41 ± 4.84ab

2.53 ± 0.55b

2.13 ± 0.15c

1.73 ± 0.35b

Control

12.37 ± 1.64d

19.30 ± 1.09d

9.71 ± 0.79d

0.73 ± 0.25c

0.57 ± 0.31d

0.57 ± 0.31c

LSD (P< 0.05)

4.245

8.809

23.96

0.218

0.085

0.093

Note: BAP= 6- Benzylamino purine, LSD= Least Significant Difference, The mean values ± standard deviation (SD) represented in the corresponding column followed by different superscript alphabet are significantly different at P ˂ 0.05 as analyzed by one way ANOVA and by DMRT.
Figure 1. Effect of various concentrations of BAP on the shoot initiation of Eucalyptus hybrid clones.
3.2. Shoot Multiplication
The different doses of BAP significantly persuade the shoot multiplication processes in all the Eucalyptus hybrid clones (P< 0.05; Table 2). MS medium solidified with 0.2 mg L-1 of BAP recorded the highest number of shoots per clump and highest shoot length for the culture TNPL 191. But at 0.15 mg L-1 BAP, the shoots of TNPL 192 and TNPL 193 responded well by registering significantly highest number of shoots and shoot length. The exogenous application of cytokinins needs to be optimized as excess quantity may lead to lesser response in the proliferation of shoots as observed with clones TNPL 192 and TNPL 193in our present study. Thus it was noted that the culture medium containing 0.2 mg L-1 of BAP was optimal for the culture TNPL 191 (E. camaldulensis× E. teriticornis) and 0.15 mg L-1 BAP for the cultures TNPL 192 (E. camaldulensis × E. pellita) and TNPL 193 (E. camaldulensis× E. camaldulensis) respectively for shoot proliferation.
Table 2. Effect of BAP on shoot multiplication of eucalyptus hybrids.

Shoot multiplication

BAP(mg L-1)

Number of shoots per clump

Shoot length (cm)

TNPL 191

TNPL 192

TNPL193

TNPL 191

TNPL 192

TNPL 193

0.10

10.00 ± 4.58c

25.00 ± 5.00b

20.33 ± 2.08c

0.30 ± 0.05cd

0.70 ± 0.07c

0.50 ± 0.04c

0.15

16.67 ± 3.51b

36.33 ± 4.51a

32.33 ± 3.51a

0.50 ± 0.03c

1.30 ± 0.05a

1.00 ± 0.09a

0.20

24.33 ± 5.51a

28.67 ± 4.04b

26.33 ± 5.51b

1.01 ± 0.04a

0.90 ± 0.04a

0.70 ± 0.05b

0.25

21.00 ± 4.00a

23.00 ± 2.00bc

25.33 ± 3.51bc

0.80 ± 0.04b

0.75 ± 0.05c

0.50 ± 0.04c

Control

4.33 ± 0.58d

7.67 ± 2.52c

7.00 ± 2.65d

0.49 ± 0.06d

0.49 ± 0.04d

0.50 ± 0.03c

LSD (P< 0.05)

4.25

8.81

4.77

0.218

0.085

0.093

Note: BAP= 6- Benzylamino purine, LSD= Least Significant Difference, The mean values ± standard deviation (SD) represented in the corresponding column followed by different superscript alphabet are significantly different at P ˂ 0.05 as analyzed by one way ANOVA and by DMRT.
3.3. Shoot Elongation
In this experiment, the transplanted shoots showed difference in the shoot induction and shoot length with various doses of IAA (Table 3). The MS medium with 3.0 mg L-1of IAA was found superior in shoot induction and shoot length in all the three hybrid clones. The concentration of 3.5 mg L-1was found statistically equal in inducing shoots (TNPL 191 and TNPL 192) and increasing shoot length (TNPL 191 and TNPL 193). The analyzed data implies that concentration of 3.0 mg L-1 IAA was optimal for better shoot induction and increasing the shoot length in all the three clones. Shoot growth was stimulated by the effect of optimal IAA dose, as it stimulates shoot elongation under in situ conditions . It appears that the applied IAA was quickly conjugated and metabolized within Eucalyptus tissues which resulted more number of shoots and better shoots length of the inoculated explants. A similar result of increased shoot elongation response in Eucalyptus sp. with IAA was reported by some researchers .
Table 3. Effect of IAA on shoot elongation of eucalyptus hybrids.

IAA(mg L-1)

Shoot elongation

Number of shoots per clump

Shoot length (cm)

TNPL 191

TNPL 192

TNPL193

TNPL 191

TNPL 192

TNPL 193

2.0

3.00 ± 1.00bc

4.33 ± 0.58c

3.33 ± 1.15bc

2.33 ± 0.58b

2.52 ± 0.38c

2.00 ± 0.75b

2.5

4.67 ± 2.08abc

6.67 ±1.53ab

5.33 ± 0.58ab

4.33 ± 1.53a

5.25 ± 1.15b

4.42 ± 1.13a

3.0

7.33 ± 2.52a

9.33 ± 2.52a

7.33 ± 0.58a

6.33 ± 1.36a

7.42 ± 1.91a

5.92 ± 1.38a

3.5

5.33 ± 1.53ab

9.33 ± 4.51a

5.00 ± 2.00b

4.67 ± 0.58a

6.58 ± 0.63ab

5.08 ± 0.63a

Control

1.67 ± 0.58d

3.67 ± 0.58c

2.67 ± 0.58d

1.33 ± 0.45b

1.33 ± 0.29c

0.97 ± 0.10b

LSD (P< 0.05)

2.87

5.93

1.27

1.13

1.12

Note: IAA= Indole 3-acetic acid, LSD= Least Significant Difference, The mean values ± standard deviation (SD) represented in the corresponding column followed by different superscript alphabet are significantly different at P ˂ 0.05 as analyzed by one way ANOVA and by DMRT.
3.4. Rooting
The per cent rooting and number of roots per shoot were significantly influenced by different doses of IBA (0 to 2 mg L-1; Table 4). The control treatment did not root in any of the cultured clones. Among the various doses, ½ strength MS + 1.0 mg L-1 or ½ strength MS + 1.5 mg L-1showed higher rooting percent in all the hybrid clones implying that these two doses were equally efficient in inducing the rooting. However, the number of roots per shoot was found significantly highest with ½ strength MS + 1.0 mg L-1of IBA in all the clones (P< 0.05). Thus, considering the rooting ability and increasing number of roots in these cultured clones, the media½ strength MS + 1.0 mg L-1of IBA was found to be optimal for these three hybrid clones. No callus formation was noticed with any of the cultured clones in the rooting experiment.
Table 4. Effect of IBA on rooting of eucalyptus hybrids.

IBA(mg L-1)

Rooting

Rooting (%)

Number of roots per shoot

TNPL 191

TNPL 192

TNPL193

TNPL 191

TNPL 192

TNPL 193

0.5

18.56 ± 1.22c

25.41 ± 2.17c

23.46 ± 2.35c

2.33 ± 0.64b

3.67 ± 0.68c

4.67 ± 0.58bc

1.0

86.33 ± 2.25a

94.25 ± 2.49a

87.29 ± 2.13a

5.33 ± 1.53a

8.33 ± 0.77a

8.00 ± 1.00a

1.5

87.31 ± 1.94a

94.16 ± 2.65a

85.18 ± 1.69a

5.33 ± 0.58a

6.67 ± 0.58b

5.33 ± 0.86b

2.0

65.24 ± 1.72b

87.12 ±1.91b

73.15 ± 2.66b

3.33 ± 0.64b

4.33 ± 0.56c

3.67 ± 0.58c

Control

0.00 ± 0.00d

0.00 ± 0.00d

0.00 ± 0.00d

0.00 ± 0.00c

0.00 ± 0.00d

0.00 ± 0.00d

LSD (P< 0.05)

5.69

5.38

3.11

0.67

0.27

0.40

Note: IBA= Indole butyric acid, LSD= Least Significant Difference, The mean values ± standard deviation (SD) represented in the corresponding column followed by different superscript alphabet are significantly different at P ˂ 0.05 as analyzed by one way ANOVA and by DMRT.
Figure 2. Effect of different concentrations of IBA on the rooting% of Eucalyptus hybrid clones.
The addition of different doses of plant growth regulators, especially IBA to the media is one of the most important factors that influences on cellular competence, triggering embryogenic re-differentiation, dedifferentiation and organs formation . In addition, the prolonged exposure of the culture to higher dose of IBA could negatively impact the rooting ability of the in vitro cultures . Therefore, significant differences in rooting percent and number of roots were found among different doses of IBA used in the present study. Similar result of enhanced rooting in Eucalyptus camaldulensis by using different concentrations of IBA was reported earlier by Shanthi et al. . The results of the optimization experiment showed that ½ strength MS + 1.0 mg L-1of IBA can be recommended for increasing the rooting percent and number of roots in the Eucalyptus hybrid clones.
Figure 3. In vitro propagation of Eucalyptus hybrid clones; a–d: TNPL 191 (a - initiation; b - multiplication, c - elongation & d – rooting); e-h: TNPL 192 (e - initiation; f - multiplication, g - elongation & h- rooting); i-l: TNPL 193 (i - initiation; j- multiplication, k - elongation & l – rooting).
3.5. Ex Vitro Acclimatization
The rooted shoots were implanted into the root trainers as mentioned in section 2.7. After 30 days from the implantation, the survived plantlets were enumerated under normal prevailed environment. All the in vitro raised plantlets survived in the open nursery and formation of new roots and offsets were observed (Figure 4) indicating 100% successful acclimatization of the in vitro plantlets.
Figure 4. Ex vitro acclimatization of Eucalyptus hybrid clones; A- in the mist chamber; B- in the shade house.
4. Conclusion
The micropropagation of new generation Eucalyptus hybrids were successfully carried out by optimizing the growth regulators at shoot initiation (BAP), shoot proliferation (BAP), shoot elongation (IAA) and rooting (IBA) stages. To sum up, the BAP concentration of 0.50 mg L-1 for bud induction, IAA concentration of 3.0 mg L-1 for shoot elongation and IBA concentration of 1.0 mg L-1 for rooting of Eucalyptus hybrid clones were found optimal. However, for shoot proliferation, the optimum concentration of BAP for these clones differed. The culture medium containing 0.2 mg L-1 of BAP was optimal for the clone TNPL 191 and the BAP strength of 0.15 mg L-1was found best for the clones TNPL 192 and TNPL 193. The results of this study can be applied in large scale micropropagation of inter and intra specific Eucalyptus hybrid clones. Future study is to be focused on successful establishment of these in vitro Eucalyptus hybrid plantlets in the field conditions for developing large scale plantations as a raw material inventory for pulp and paper industries.
Abbreviations

PGR

Plant Growth Regulators

IAA

Indole 3-acetic Acid

IBA

Indole Butyric Acid

BAP

6-Benzylaminopurine

MS

Murashige- Skoog

RH

Relative Humidity

ANOVA

Analysis of Variance

LSD

Least Significant Difference

DMRT

Duncan’s Multiple Range Test

Acknowledgments
The authors are grateful to Tamil Nadu Newsprint and Papers Limited (TNPL), Kagithapuram, Karur District, Tamil Nadu state, India for granting permissions to carry out the research and providing all necessary facilities.
Author Contributions
Malaimuthu Chinnama Naickar: Conceptualization, Methodology, Writing – review & editing
Chezhian Palanisamy: Conceptualization, Writing – review & editing
Prasath Vazram: Methodology, Writing – original draft
Jayakumar Kuppusamy: Project administration, Supervision
Stalin Thangavel: Methodology
Rajesh Ramasamy: Methodology
Conflicts of Interest
The authors declare no conflicts of interest.
References
[1] Sharma, V., Ankita, Karnwal, A., Sharma, S., Kamal, B., Jadon, V. S., Gupta, S. &Sivanasen, I. A. (2023). Comprehensive Review Uncovering the Challenges and Advancements in the In Vitro Propagation of Eucalyptus Plantations. Plants, 12, 3018.
[2] Shanthi, K., Bachpai, V. K. W., Anisha, S., Ganesan, M., Anithaa, R. G., Subhasini, V., Chakravarthi, M., Sivakumar, V. &Yasodha, R. (2014). Micropropagation of Eucalyptus camaldulensis for the production of rejenuvated stock plants for microcuttings propagation and genetic fidelity assessment. New Forests,
[3] Varghese, M., Harwood, C. E., Hegde, R. & Ravi, N. (2008). Evaluation of provenances of Eucalyptus camaldulensisand clones of E. camaldulensisand E. tereticornisat contrasting sites in southern India. SilvaeGenetica, 57, 170–179.
[4] Varghese, M., Harwood, C. E., Bush, D. J., Baltunis, B., Kamalakannan, R., Suraj, P. G., Hegde, D. &Meder, R. (2017). Growth and wood properties of natural provenances, local seed sources and clones of Eucalyptus camadulensis in southern India: Implications for breeding and deployment. New Forests, 48, 67-82.
[5] Kamal, B., Arya, I., Sharma, V. &Jadon, V. S. (2016). In Vitro Enhanced Multiplication and Molecular Validation of Eucalyptus F1 Hybrids. Plant Cell Biotechnology and Molecular Biology, 17, 167–175.
[6] Singh, D., Kaur, S. & Kumar, A. (2020). In Vitro Drought Tolerance in Selected Elite Clones of Eucalyptus tereticornis Sm. ActaPhysiologiaePlantarum, 42, 17.
[7] Shwe, S. S. & Leung, D. W. M. (2020). Plant Regeneration from Eucalyptus bosistoana Callus Culture. In Vitro Cellular & Developmental Biology- Plant, 56, 718–725.
[8] Matheus, D., Souza, S. C., Martins, A. R., Fernandes, S. B., Lopes Martins Avelar, M., Vaz Molinari, L., Santos Gonçalves, D. &Brondani, G. E. (2022). In Vitro Multiplication of Eucalyptus pilularis and Eucalyptus grandis × E. urophylla(Urograndis Eucalypt): Effect of Light Quality in Temporary Immersion Bioreactor. Mindanao Journal of Science and Technology, 20, 72–86.
[9] Rajput, B. S., Jani, M., Ramesh, K., Manokari, M, Jogam, P., Allini, V. R., Kher, M. M. &Shekhawat, M. S. (2020). Large- scale clonal propagation of BambusabalcooaRoxb.: an industrially important bamboo species. Industrial Crops & Products,
[10] Sowmya, K., Seenivasan, R., Subramanian, S., Chinnaraj, S., Brindhadevi, K. &Thamaraiselvi., K. (2019a). Minicutting: a powerful tool for the clonal propagation of selected species of Eucalyptus hybrid clones based on their pulpwood studies. Biocatalysis and Agricultural Biotechnology,
[11] Compton, M. E. & Koch, J. M. (2001). Influence of plant preservative mixture (PPM) TM on adventitious organogenesis in melon, petunia, and tobacco. In Vitro Cellular & Developmental Biology- Plant, 37, 259–261.
[12] Sowmya, K., Seenivasan, R., Subramanian, S., Chinnaraj, S., Rajasree, S., Brindhadevi, K. &Thamaraiselvi., K. (2019b). Optimizing the sterilization methods for initiation of the five different clones of the Eucalyptus hybrid species. Biocatalysis and Agricultural Biotechnology,
[13] Murashige, T. &Skoog, F. (1962). A revised medium for rapid growth and bio assays with tobacco tissue cultures. PhysiologiaPlantarum, 15, 473–497.
[14] Mohamed, S. V., Sung, J. M., Jeng, T. L. & Wang, C. S. (2006). Organogenesis of PhseolusangularisL.: high efficiency of adventitious shoot regeneration from etiolated seedlings in the presence of N6- Benzylaminopurine and thidiazuran. Plant Cell, Tissue and Organ Culture,
[15] Graner, E. M., Calderan-Meneghetti, E., Leone, G. F., Almeida, C. V. & Almeida, M. (2019). Long-term in vitro culture affects phenotypic plasticity of Neoregeliajohannisplants. Plant Cell, Tissue and Organ Culture, 137(3), 511–524.
[16] Agustina, M., Maisura, M. &Handayani, R.S. (2020). The Effect of different seed cutting treatments and concentrations of BAP for the successful in vitromicrografting of mangosteen (GarciniamangostanaL.). Journal of Tropical Horticulture, 3(1), 1–5.
[17] Baccarin, F. J. B., Brondani, G. E., Almeida, L. V., Vieira, I. G., Oliveira, L. S. & Almeida, M. (2015). Vegetative rescue and cloning of Eucalyptus benthamiiselected adult trees. New Forests, 46, 465–483.
[18] Rosa, W. S., Martins, J. P. R., Santos, E. R., Rodrigues, L. C. A., Gontijo, A. B. P. L. I Falqueto, A. R. (2018). Photosynthetic apparatus performance in function of the cytokinins used during the in vitro multiplication of AechmeablanchetianaBromeliaceae). Plant Cell, Tissue and Organ Culture, 133, 339–350.
[19] Surakshitha, N. C., Soorianathasundaram, K., Ganga, M. &Raveendran, M. (2019). Alleviating shoot tip necrosis during in vitro propagation of grape cv. Red Globe. ScientiaHorticulturae, 248, 118–125.
[20] Martins, J. P. R., Wawrzyniak, M. K., Ley-Lopez, J. M., Kalemba, E. M., Mendes, M. M. &Chmielarz, P. (2022). 6-Benzylaminopurine and kinetin modulations during in vitro propagation of Quercusrobur (L.): an assessment of anatomical, biochemical and physiological profiling shoots. Plant Cell, Tissue and Organ Culture,
[21] Abiri, R., Atabaki, N., Abdul- Hamid, H, Sansui, R., Shukor, N. A. A., Shaharuddin, N. A., Ahmad, S. A. & Malik, S. (2020). The prospect of physiological events associated with the microproagation of Eucalyptus Sp. Forests, 11(1211),
[22] Girijashankar, V. (2012). In vitro regeneration of Eucalyptus camaldulensis. Physiology and Molecular Biology ofPlants, 18(1), 79–87.
[23] Ayala, P. G., Brugnoli, E. A., Luna, C. V., Gonzalez, A. M., Pezzutti, R. &Sansberro, P. A. (2019). Eucalyptus nitensplant regeneration from seedling explants through direct adventitious shoot bud formation. Trees, 33, 1667–1678.
[24] Nic-Can, G. I. & Loyola-Vargas, V. M. (2016). The role of the auxins during somatic embryogenesis. In: Somatic Embryogenesis: Fundamental Aspects and Applications; Springer: Berlin/Heidelberg, Germany, pp. 171–182.
[25] Moura, L. C. D., Xavier, A., Cruz, A. C. F. D., Gallo, R., Miranda, N. A. &Otoni, W. C. (2019). Auxin pulse in the induction of somatic embryos of Eucalyptus. RevistaÁrvore, 43, 1–12.
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    Naickar, M. C., Palanisamy, C., Vazram, P., Kuppusamy, J., Thangavel, S., et al. (2024). Optimizing Growth Regulators for Micropropagation of Industrially Adaptable Eucalyptus Hybrids. Journal of Plant Sciences, 12(3), 82-89. https://doi.org/10.11648/j.jps.20241203.13

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    Naickar, M. C.; Palanisamy, C.; Vazram, P.; Kuppusamy, J.; Thangavel, S., et al. Optimizing Growth Regulators for Micropropagation of Industrially Adaptable Eucalyptus Hybrids. J. Plant Sci. 2024, 12(3), 82-89. doi: 10.11648/j.jps.20241203.13

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    AMA Style

    Naickar MC, Palanisamy C, Vazram P, Kuppusamy J, Thangavel S, et al. Optimizing Growth Regulators for Micropropagation of Industrially Adaptable Eucalyptus Hybrids. J Plant Sci. 2024;12(3):82-89. doi: 10.11648/j.jps.20241203.13

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  • @article{10.11648/j.jps.20241203.13,
      author = {Malaimuthu Chinnama Naickar and Chezhian Palanisamy and Prasath Vazram and Jayakumar Kuppusamy and Stalin Thangavel and Rajesh Ramasamy},
      title = {Optimizing Growth Regulators for Micropropagation of Industrially Adaptable Eucalyptus Hybrids
    },
      journal = {Journal of Plant Sciences},
      volume = {12},
      number = {3},
      pages = {82-89},
      doi = {10.11648/j.jps.20241203.13},
      url = {https://doi.org/10.11648/j.jps.20241203.13},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.jps.20241203.13},
      abstract = {Eucalyptus is one of the highly economic tree species in the developing countries like India. In the present investigation, experiments on optimizing plant growth regulators in the micropropagation of promising inter specific Eucalyptus hybrid clones namely TNPL 191(E. camaldulensis× E. teriticornis), TNPL 192 (E. camaldulensis × E. pellita) and intra specific hybrid clone TNPL 193 (E. camaldulensis× E. camaldulensis) were conducted, following standard protocols developed for Eucalyptus. The results showed that the BAP concentration of 0.50 mg L-1 for bud induction, IAA concentration of 3.0 mg L-1 for shoot elongation and IBA concentration of 1.0 mg L-1 for rooting of all these clones were found optimal. However, these three hybrid clones responded differently to the concentration of BAP at shoot proliferation stage. While the hybrid TNPL 191 showed maximum shoot proliferation rate at the concentration of 0.2 mg L-1 of BAP, the hybrids TNPL 192 and TNPL 193 showed highest response at 0.15 mg L-1. All the in vitro rooted plantlets were acclimatized successfully to the prevailing natural environment. Thus, the protocols developed with respect to optimizing the plant growth regulators can be adapted in large scale micro propagation of inter and intra specific Eucalyptus hybrid clones.
    },
     year = {2024}
    }
    

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  • TY  - JOUR
    T1  - Optimizing Growth Regulators for Micropropagation of Industrially Adaptable Eucalyptus Hybrids
    
    AU  - Malaimuthu Chinnama Naickar
    AU  - Chezhian Palanisamy
    AU  - Prasath Vazram
    AU  - Jayakumar Kuppusamy
    AU  - Stalin Thangavel
    AU  - Rajesh Ramasamy
    Y1  - 2024/06/27
    PY  - 2024
    N1  - https://doi.org/10.11648/j.jps.20241203.13
    DO  - 10.11648/j.jps.20241203.13
    T2  - Journal of Plant Sciences
    JF  - Journal of Plant Sciences
    JO  - Journal of Plant Sciences
    SP  - 82
    EP  - 89
    PB  - Science Publishing Group
    SN  - 2331-0731
    UR  - https://doi.org/10.11648/j.jps.20241203.13
    AB  - Eucalyptus is one of the highly economic tree species in the developing countries like India. In the present investigation, experiments on optimizing plant growth regulators in the micropropagation of promising inter specific Eucalyptus hybrid clones namely TNPL 191(E. camaldulensis× E. teriticornis), TNPL 192 (E. camaldulensis × E. pellita) and intra specific hybrid clone TNPL 193 (E. camaldulensis× E. camaldulensis) were conducted, following standard protocols developed for Eucalyptus. The results showed that the BAP concentration of 0.50 mg L-1 for bud induction, IAA concentration of 3.0 mg L-1 for shoot elongation and IBA concentration of 1.0 mg L-1 for rooting of all these clones were found optimal. However, these three hybrid clones responded differently to the concentration of BAP at shoot proliferation stage. While the hybrid TNPL 191 showed maximum shoot proliferation rate at the concentration of 0.2 mg L-1 of BAP, the hybrids TNPL 192 and TNPL 193 showed highest response at 0.15 mg L-1. All the in vitro rooted plantlets were acclimatized successfully to the prevailing natural environment. Thus, the protocols developed with respect to optimizing the plant growth regulators can be adapted in large scale micro propagation of inter and intra specific Eucalyptus hybrid clones.
    
    VL  - 12
    IS  - 3
    ER  - 

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  • Abstract
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    1. 1. Introduction
    2. 2. Materials and Methods
    3. 3. Results and Discussion
    4. 4. Conclusion
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