عنوان مقاله [English]
Background and Objectives
Citrus is one of the most important and useful fruits in the world. They are usually propagated by grafting on suitable rootstocks such as Troyer citrange. In plants especially fruit trees, synthetic induction of polyploidy makes fruit rootstocks more robust, dwarf, with thicker leaves, stems and higher scion yield. The aim of this study was to investigate the best polyploidy induction treatment by colchicine on dwarfing Troyer citrange rootstock and to evaluate its morphological effects.
Materials and Methods
The experiment was conducted in a greenhouse in Kerman. Four concentrations of colchicines (0.5, 1 and 1.5%) and control (0%) were used in two phases. In the first phase, 96 seeds were soaked in different concentrations of cholchcines for 30 h and planted in pots. In the second phase, when seeds reached the four leaves stage, meristems were treated by cholchicines. The experiment was arranged in completely randomized design (CRD) with four replications.
The results showed that guard cells size, length, width of stomata and secretary vesicles size of colchicine-treated seedlings significantly increased compared to the control. However, lower density of leaves stomata and secretary vesicles in treated plants were observed. Some morphological changes such as leaves thickness, color increase and seedlings dwarfism were detected in treated plants. Moreover, some minor abnormalities on leaves such as asymmetry, lack of lateral leaflets, serrated leaflets existence were evident. The most effective treatment for polyploidy induction was 1% colchicine.
Synthetic induction of polyploidy by cholchicine is commonly practiced by fruit breeders because it is inexpensive and effective. High concentrations of colchicine are toxici for seeds may be due to prevention of mitosis in the cells. Moreover, larger stomata size can improve efficiency of photosynthesis. Although the treated seeds or seedlings with 1 and 1.5% colchicines had lower height and stomata density, they are more robust and stronger than control which can be very valuable in rootstock breeding.
Abdoli, M., Moieni, A., and Naghdi Badi, H. (2013). Morphological, physiological, cytological and phytochemical studies in diploid and colchicine-induced tetraploid plants of Echinacea purpurea (L.). Acta Physiology Plantarum, 35: 2075-2083.
Afshar Mohammadian, M., Pour Akbari, R., Omidi, Z., Ghanati, F., and Torang, A. (2012). The effect of induced polyploidy on morphological and physiological traits of lemon (Citrus aurantifolia L.). Plant Biology Journal, 12: 13-24. [In Farsi]
Allario, T., Brumos, J., Colmenero-Flores, J., Iglesias, D.J., Pina, J.A., Navarro, L., Talon, M., Ollitrault, P., and Morillon, R. (2013). Tetraploid Rangpur lime rootstock increases drought tolerance via enhanced constitutive root abscisic acid production. Plant, Cell & Environment, 36: 856-868.
Anon. (2014). Citrus production. Retrived from. http://fao.org/faostat/en/#data/QC.
Beck, S.L., Dunlop, R.W., and Fossey, A. (2003). Stomatal length and frequency as a measure of ploidy level in black wattle, Acacia mearnsii (de Wild). Botanical Journal of the Linnean Society, 141:177-181.
Chao, D.Y., Dilkes, B., Luo, H., Douglas, A., Yakubova, E., Lahner, B., and Salt, D.E. (2013). Polyploids exhibit higher potassium uptake and salinity tolerance in Arabidopsis.
Science, 341: 658-659.
Chen, C., Hou, X., Zhang, H., Wang, G., and Tian, L. (2011). Induction of Anthurium andraeanum “Arizona’’ tetraploid by colchicine in vitro. Euphytica, 181:137-145.
Ewad, D., Ulrich, K., Naujoks, G., and Schroder, M.B. (2009). Induction of tetraploid poplar and black locust plants using colchicine: chloroplast number as an early marker for selecting polyploids in vitro. Plant Cell Tissue, Organ and Culture, 99: 353-357.
Fawcett, J.A., Maere, S., and Van de Peer, Y. (2009). Plants with double genomes might have had a better chance to survive the cretaceous-tertiary extinction event. Proceedings of the National Academy of Sciences, 106: 5737-5742.
Gu, X.F., Yang, A.F., Meng, H., and Zhang, J.R. (2005). In vitro induction of tetraploid plants from diploid Zizyphus jujube Mill. Cv. Zhanhua. Plant Cell Reporter, 24: 671-676.
Guerra, D., Wittmann, M.T.S., Schwarz, S.F., de Souza, P.V.D., and Gonzatto, M.P. (2014). Comparison between diploid and tetraploid citrus rootstock: morphological characterization and growth evaluation. Bragantia, 73(1): 1-7.
Hamill, S.D., Smith, M.K., and Dodd, W.A. (1992). In vitro induction of banana autotetraploids by colchicine treatment of micropropagated diploids. Australian Journal of Botany, 40(6): 887-896.
Hollister, J.D. (2014). Polyploidy: Adaptation to the genomic environment. New Phytologist, 1-6.
Kadota, M. and Niimi, Y. (2002). In vitro induction of tetraploid plants from a diploid Japanese pear cultivar (Pyrus pyrifolia N. cv. Hosui). Plant Cell Reporter, 21: 282-286.
Levin, D.A. (2002). The role of chromosomal change in plant evolution. New York, NY: Oxford University Press.
Masterson, J. (1994). Stomatal size in fossil plants: Evidence for polyploidy in majority of angiosperms. Science, 264: 421-423
Pierce, B.A. (2012). Genetics: A conceptual approach (4th ed.), Freeman and Company.
Sahar Khiz, M.J. (2010). The effect of polyploidy levels and ecological factors on morphological and physiological traits of feverfew (Tanacethum parthenium L.). M.Sc. thesis, Tarbiat Modaress University. Tehran, Iran. [In Farsi]
Thao, N.T.P., Ureshino, K., Miyajima, I., Ozaki, Y., and Okubo, H. (2003). Induction of tetraploid in ornamental alocasia through colchicines and oryzalin treatments. Plant Cell, Tissue, Organ Culture, 72: 19-25.
Yang, X.M., Cao, Z.Y., An, L.Z., Wang, Y.M., and Fang, X.W. (2006). In vitro tetraploid induction via colchicines treatment from diploid somatic embryos in grapevine (Vitis vinifera L.). Euphytica, 152: 217-224.
Zhang, X.Y., Hu, C.G., and Yao, J.L. (2010). Tetraploidization of diploid dioscorea results in activation of the antioxidant defense system and increased heat tolerance. Journal of Plant Physiology, 167: 88-94.