Evaluation of the effect of in vitro stress and competition on tissue culture response of flax

Abstract

This study was carried out to investigate the in vitro competition in tissue culture of three flax (Linum usitatissimum L.) cultivars using different distances among hypocotyl explants cultured. Hypocotyl fresh and dry masses, shoot regeneration percentage, shoot number per hypocotyl, regenerated shoot length and total chlorophyll content were examined during shoot regeneration, while plantlet height, number of roots and length of roots were recorded during rooting. With decreasing distance among explants we observed increased shoot regeneration and rooting till a certain point from where stress initiated and significant decreases in all parameters observed. Explants cultured at distance 1.0 cm were found to be at their optimum.Additional key words: competition, Linum usitatissimum, plantlet establishment. ⎯⎯⎯⎯Flax (Linum usitatissimum L.) is a dicotyledonous plant of Linaceae family and it is an important source of natural fiber, high quality nutritious food and medicinal plant. Moreover, it has been used as a model crop in biotechnological studies due to its small nuclear genome (Basiran et al. 1987, Dong and McHughen 1991, Millam et al. 1992. It was reported that the most suitable explant for in vitro culture of flax was hypocotyl (Gamborg and Shyluk 1976, Jordan and Mc Hughen 1988a,b, Mc Hughen et al. 1989, Dong and Mc Hughen 1991, 1993, Millam et al. 1992 similarly as for many other species (Tavano et al. 2009). Shoot regeneration from hypocotyl explants and recovery of whole fertile flax plant were achieved by Murray et al. (1977). Plant growth regulators are more effective on in vitro shoot regeneration when they are used together than using alone (Dang and Wei 2009). For flax, the combination of 1 mg dm -3 6-benzylaminopurine (BAP) and 0.02 mg dm -3 naphthalene acetic acid (NAA) was recommended McHughen 1988b, Dong and McHughen 1993). Callus growth and adventitious shoot formation in flax increases up to 1 mg dm -3 BAP while they were negatively affected at higher doses (Xiang et al. 1989).Since high frequency shoot regeneration is a prerequisite for a successful transformation (Tavano et al. 2009), in vitro studies have been carried on perpetually. This study was aimed to obtain higher shoot regeneration frequency from hypocotyls of flax by utilizing the competition among explants in vitro. Flax (Linum usitatissimum L. cvs. Madaras, 1886 Sel and Clarck) seeds, obtained from Northern Crop Science Laboratories, in North Dakota, USA, were surface sterilized with 40 % commercial bleach containing 5 % sodium hypochlorite at 10 ºC for 20 min with continuous stirring and then were washed three times with sterile distilled water at the same temperature according to the protocol described by Yildiz and Er (2002). Sterilized seeds were germinated on a basal Murashige and Skoog (1962; MS) medium containing the mineral salts and vitamins, 3 % (m/v) sucrose and 0.7 % (m/v) agar. All cultures were incubated at 25 ± 1 ºC under cool white fluorescent tubes (27 μmol m -2 s -1 ) with a 16-h photoperiod. The pH of the m...

The Effect of Inter-Plantal Competition on in Vitro Seed Germination and Seedling Growth in Flax (Linum Usitatissimum L.)

“…In general, the results of this study showed that spacing competition causes increases in shoot and root lengths in tree cultivars up to a certain threshold (1.5 cm distance), except for one distance ('2.0x2.0' cm). Similar results were founded by Yildiz et al [19] in Linum usitatissimum L. and Yildiz [21] in three flax (Linum usitatissimum L.) cultivars.…”

“…regenerated shoots. Yildiz [21] stated that, with decreasing distance among explants, chlorophyll contents increase up to a certain point ('1.5x1.5' cm distance) in comparison to the controls in all cultivars.…”

Morphological and Physiological Responses of Hybrid Aspen (Populus tremuloides Michx. × Populus tremula L.) Clones to Light In Vitro

“…Hence the photomixotrophical propagation might have interfered with the effects of illumination, restricting the generalization of the responses to subsequent stages of propagation [ 73 , 74 , 75 ]. Furthermore, jar, which represents the experimental setup, had a notable effect on CHL A+B and CHL A/B (random variances, Table 2 ), which might be explained by intraspecific competition stratifying “canopies”, to which both variables are indicative [ 76 ]. Such effects were negligible ( Table 2 ) for the plantlets grown in solitary test tubes, supporting the influence of competition [ 76 ] and suggesting application of single type of glassware.…”

Effect of magnetic field on in vitro seedling growth and shoot regeneration from cotyledon node explants of Lathyrus chrysanthus boiss

“…These methods are very effective in vigor improvement, but they are not eco friendly and have some handling problems. Manipulation of the physical micro-environment by changing distances among cultured explants has resulted in increased shoot regeneration capacity, root formation, and plantlet establishment by causing positive spacing competition [Yildiz, 2011]. Moreover, physical methods provide significant yield improvement without the toxic hazards of chemical fertilizers and management costs for enhancing seed The values represent mean AE standard error of the mean (experiments were 4 replicates each with 25 seeds).…”