Evaluation of frost tolerance of L. centaurea balsamita invasive plant with autumn condition.
In order to evaluate the tolerance of the invasive plant of flower meal to freezing stress, a completely randomized design with five replications was carried out in the Fertility Research Station of Mashhad University of Agricultural Sciences in 2014. Flower-invasive plant was exposed to 7 freezing temperatures (0, 3-, 6-, 9-, 12-, 15- and 18-°C). The plants were kept in a natural environment and after the cultivation of Khosarmaye period from November 1, 2013 to December 30, 1393, under freezing Thermoagradian, they were treated with ice-freezing. The stability of the floral cytoplasmic membrane was evaluated by electrolyte leak test, then the lethal temperature of 50% of the samples was determined based on the percentage of electrolyte leakage (LT50el). The survival rate was also evaluated by counting the number of live plants per pot. Then, lethal temperature was determined for 50% survival (LT50su) and 50% dry weight reduction (RDMT50) at the end of the recovery period (three weeks after the application of freezing). The results showed that temperature decrease from -12°C to -15°C caused a significant increase (P≤0.05) in electrolyte leakage in flour. Also, the temperature decrease from -9°C to -12°C resulted in a significant decrease (P≤0.05) in survival percent and wheat biomass. In the present experiment, the LT50el, LT50su, and RDMT50 were florid flours grown in autumn in the conditions of 13.2°C, 12.6°C and 11.8°C.