nouraddin izadi jeloudar

Breeders are always looking for sources of diversity in different plants. Because spontaneous mutations occur rarely in environment, induced mutation is a more appropriate method for plant diversity. Therefore, the ploidy level instruction through mutagens, especially chemical mutagens in somatic cells, has the potential to improve the ability to produce new varieties with superior and desirable traits in many plant species. Plant species with more than two chromosome (polyploid) sequences are of particular importance due to increased genetic variation in their better adaptation to new environments, natural evolution and plant breeding. Accordingly, an investigation was conducted to induce in vitro polyploidy through colchicine in a new species of asiatic hybrid Lilium dandie, which has high potential for ornamental and medicinal.

In this experiment, in vitro bulb scales were treated in a completely randomized design with factorial arrangement in different concentrations of filter sterilized colchicine solution (0.01, 0.05 and 0.1%) for 6, 12 and 24 hours. Then samples were taken to regenerate and grow normally in a culture medium without growth regulators. After assessing the survival rate, ploidy levels of regenerated plantlets by direct counting of the number of root meristem chromosomes were determined. Length, width and density of leaf apertures using bachelor varnish technique and direct counting of chloroplast number of stomatal guard cells in adult and developed leaves as cytological factors between the control (diploid) and polypoid (triploid) plantlets was compared. plantlet fresh weight was also measured using scales and morphological indices of leaf length and width and root length were measured by precise ruler.

The results of this study showed that with increasing concentration and duration of treatment of colchicine, the survival rate of explants decreased. colchicine was completely effective in inducing polyploidy (triploid) L. dandie and the highest amount of polyploidy (14) occurred during 12 hours. The highest efficiency of productivity was obtained during treatment with 0.01% colchicine. In the polyploid plantlets, the stomatal density decreased significantly compared to the control, while the stomatal length and the number of chloroplasts in the stomatal guard cells showed a positive correlation with the increase in ploidy levels. Fresh weight and morphological characteristics of leaf length and width as well as root length in polyploidy plantlets were significantly increased compared to control.

The use of colchicine in polyploidy induction in L. dandie was completely successful and the highest polyploidy productivity (42.85%) was optimized for 12 hours treatment. Low density and longer stomatal length, as well as high chloroplast count in the chloroplast guard cells in polyploid plantlets, are a good indicator of polyploid plantlets screening than diploid plantlets. Fresh weight indices and morphological characteristics of leaf length and root width and plantlets length increased with increasing ploidy level.

Environmental stresses such as high and low light intensity are important limiting factors in the growth and development of plants. . In the natural environment, all plants are shaded to some degree by surrounding plants or themselves during their lifecycle. Salicylic acid, as one growth regulator, can increases plants resistance to high light intensity and shading. Tomato is one of the most important consumable vegetables in the world. Also, it is one of the most valuable sources of supply of minerals and vitamins in the human diet and plays an important role in human health. The objective of this experiment, was to evaluate the application of salicylic acid on some morphological and yield and its effect on reducing tomato damage in low and high light intensity conditions, which the plant growth is possible under shading conditions and excess light.

In order to evaluate the effect of different shading levels (0, 25 and 50% shading) and salicylic acid (0 and 2 mM) on growth, yield and quality of tomato (Solanum lycopersicum L.), an experiment was carried out as split plot based on randomized complete block design with three replications in two cultivars Super beta and Super 6108 at research field of Moghan Pars Abad located to Ardabil province, in 2015. In this experiment stem length, internode length, leaf number, leaf area, stem and leaf dry and fresh weight, chlorophyll content, stomatal conductance and yield were measured.

The results showed that the total length of the plant, leaf number, leaf area and fresh and dry weight of leaf and stem decreased significantly with increasing shading intensity, especially in Salicylic acid control treatment. While the internode length and stomatal conductance increased with increasing shading intensity. The leaf chlorophyll content in cv. Super Beta in full sun light conditions and treated with salicylic acid was 20% higher than tomatoes with shading 50% ant treated with salicylic. The highest yield (3383 g plant) was obtained in plants exposed to full light and treated with salicylic acid, but the lowest yield (1563 g plant) was achieved in plants grown at 50% shading and without salicylic acid treatment.

In general, it is concluded that tomatoes grown in no shading treatment had better growth and yield. Salicylic acid application could improve the morphological properties and yield of tomato in shading conditions.