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Objective Sugarcane (Saccharum officinarum L.) is a commercial plant that extracts more than 70% of the sugar produced worldwide. Salinity in many arid and semi-arid regions of the world is considered as a major problem and limiting factor for growth, quality and yield of crops including sugarcane. Chromosome manipulation of the plant species is one of the most powerful methods of plant breeding because of its effect on some morphological, physiological and genetic variation. The aim of this study was to investigate the effect of different levels of colchicine mutagen on changes in DNA content and to investigate the effect of increasing DNA content on the transcription rate of catalase gene. Materials and methods In this experiment, sugarcane seedlings were treated with colchicine (concentrations of 0, 100, 200 and 400 mg / L) in two CP48 and CP69 cultivars for 8, 24 and 48 hours, respectively. The plants were then examined for morphological and physiological characteristics. Plants were then exposed to saline stress (200 mM NaCl) and normal. After applying stress, plants with probable polyploidy were examined for genetic content using flow cytometry. Also, to investigate the expression pattern of Catalase gene (CAT2), leaf sampling was done 24 h after salinity stress from control and stressed plants. Results The results showed that viability, height and density of stomata decreased with increasing colchicine concentration and duration of treatment. However, stomata size increased with increasing colchicine concentration and duration of treatment and chlorophyll and photosynthesis increased with increasing duration of treatment. The results showed that the expression of this gene was significantly increased in both CP48 and CP69 cultivars under salinity stress. The expression of this gene was increased in CP69 cultivar treated with colchicine and this increase was significant at 200 mg / L colchicine. While in CP48 cultivar the effect of colchicine treatment was not significant. Conclusions Based on the above results, it can be concluded that increasing the genetic content of sugarcane can improve salinity resistance.

The purpose of this study was to check the possibility of callus and somatic embryogenesis in date palm cv. Khazravi using different explants including leaves, green fruit, immature seed, endosperm and green fruit pericarp. In the culture of leaves in the medium contains different plant growth regulators including 2,4-D, BAP and TDZ, highest callus induction was achieved in medium supplemented with, 5 mg.L-1 2,4-D, 2 mg.L-1 BAP and 4 mg.L-1 TDZ, and in treatment with 5 mg.L-1 2,4-D, 1 mg.L-1 BAP and 4 mg.L-1 TDZ. By using explant of immature fruit, found that when two growths regulative, TDZ and 2, 4-D in amount of 5 mg.L-1 are in the culture medium callugenesis and embryogenesis was achieved. The endosperm cultivation with pericarp and embryo in the same medium showed that the presence of two growth regulators 2,4-D and TDZ have been useful for callus production. Also in endosperm with zygotic embryo culture, embryo development and the root and shoot were formed after three months. Endosperm culture, in the culture medium containing various auxins and pericarp culture showed no any reactions. In general, these results showed that in date palm cv. Khazravi, treating the explants of leave and immature fruits with appropriate concentrations of plant growth regulators auxin and cytokinin, can induce callus and embryo.

An efficient method for direct somatic embryogenesis and callogenesis from date palm (Phoenix dactylifera L. cv. Estamaran) was established using leaf explants. The effect of pretreating leaf explants with three antioxidant combinations on the browning was studied. The results showed that both the pre-treatments were effective against the browning of explants. Surface sterilization of explants, without pre-treatment, enhanced the browning. After recognizing the importance of antioxidants, we cultured the explants on an MS medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) at 0.1, 0.5, 1, 2, and 5 mg/l, thiadiazuron (TDZ) at 0 and 5 mg/l and 6-benzyladeninepurine (BAP) at 0, 5, and 10 mg/l. Callogenesis and direct embryogenesis on the surface of the leaf explants were observed. Only on the medium containing 5 mg/l 2,4-D, 10 mg/l BAP, and 5 mg/l TDZ globular embryos were formed directly on the leaf explants. The percentage of callus formation increased with an increase in the 2,4-D concentration; however, high concentrations of cytokinin caused a reduction of callogenesis. A medium supplemented with 5 mg/l 2,4-D, 5 mg/l TDZ, and 5 mg/l BAP, and 2 mg/l 2,4-D, and 5 mg/l BAP produced the highest number of calli per replication (2.7) on the leaf surfaces and leaf margins. Along with the advantages of direct somatic embryogenesis, this protocol facilitated the prospect of micropropagation without resorting to the intermediary callus stage, an important aspect to commercial production, and without sacrificing the plant by excising the shoot tips, which are commonly used for date palm tissue cultures.