The effect of drought stress on morphological and biochemical characteristics of some lily species under in-vitro condition

Lilium ledebourii Bioss is a rare species belonging to the Liliaceae family, containing valuable secondary metabolites. This flower is one of the most popular plants in the word which used as a cut flower, pot flower and bedding plants .Micro propagation was done in this flower by used of different hormonal combinations and elicitors. The goal of this study was to evaluate the effects of various nitrogen ratios on in vitro regeneration and secondary metabolite production.

In order to study the effects of different nitrogen ratios on the regeneration and secondary metabolite production of Lilium ledebourii, an experiment was conducted based on the completely randomized design with 10 treatments and 8 replications in tissue culture and biotechnology laboratory of the Horticultural Department of Mohaghegh Ardabili University. The MS medium were used to culture the explants. In this experiment some morphological traits were evaluated such as fresh weight, plant height, leaf number, leaf length, root number, root length, bulblet number, bulblet diameter and scale number. The measured biochemical traits were total Chlorophyll, chlorophyll b, chlorophyll a, carotenoid, Flavonoid in 3 different waves (270, 300 and 330 nm), anthocyanin and phenol.

The results of the experiment showed that various treatments significantly (P≤0.05) affected total phenol content, anthocyanin, chlorophyll a, b, and total chlorophyll, fresh weight, seedling height, regenerated root and bulb number. The highest value of total phenol and anthocyanin contents, fresh weight and seedling height was observed in nitrate to ammonium ratio of 40:40. However, the best treatment for chlorophyll a, b and total chlorophyll, was the ratio of nitrate to ammonium at the rate of 60:25. Also, in the case of root and bulblet number, the best treatments were ratios of nitrate to ammonium at the rates of 40:40, 40:25, 60:25 and 40:0. The comparison of means of dada showed that the highest content of carotenoid (4.838 mg/g Fw) was obtained from 80:25 ratio of nitrate to ammonium which had the significant differences with control and other treatments. However, the lowest content of this index was observed in nitrate to ammonium at the rates of 40:120 and 0:25 which also had the significant differences with control.

In general, the nitrate to ammonium ratio of 40:40 in compared to the other treatments had the better effects of measured indices and accumulation of ammonium in the plants texture was interrupted for the normal growth.