Effect Of Exogenous Ca²⁺ On The Cold Resistance Of Fritillaria Przewalskii

Fritillaria przewalskii Maxim. is a perennial herb of Fritillary and belong to Liliaceae, the dry bulb of it which is used as medicine, traditional Chinese medicine known as the "Min Bei", due to the destruction of the ecological environment and excessive wild resource depletion caused by excavation. The main problem is the presence of artificial domestication and cultivation: low temperature sensitive, difficult to resist the cold, susceptible to cold damage; winter survival rate is low, pour in summer seedlings serious. In this study, Fritillaria przewalskii Maxim. as material by spraying exogenous chemical, physiological and biochemical indices measured in order to reveal the mechanism of its cold, cold resistance and seek to improve key technologies, research results are summarized as follows:1. The whole flowering plants of Fritillaria przewalskii Maxim. are under 20,4,0,-4 ℃ treatment conditions, measured changes in antioxidant enzyme（SOD / POD / CAT）, MDA and conductivity and other physiological indicators. The results showed that as the temperature decreases, the content of MDA and relative conductivity is rise. SOD, POD and CAT activity first increased and then decreased. The content of MDA and relative conductivity is highest on-4 ℃ and spend the content of MDA was up 103.42%, the difference was significant; The SOD, POD and CAT activity is highest at 4 ℃.Due to cell activity increased, the content of MDA and relative conductivity become slowed. Leaves have lower SOD activity and higher POD and CAT activity, whereas flower has a high SOD activity and lower POD activity, flower cell peroxide at low temperature stress accumulation, injured seriously.2. The vegetative growth stage Fritillaria przewalskii Maxim. plants of no spraying exogenous Ca²⁺ in different low temperature treatment, the temperature decreases, the membrane plant severely damaged, a lot of electrolyte leakage, MDA content accumulated faster, SOD, POD, CAT activities of three enzymes was firstly increased and then decreased, but in general, as the temperature decreases, the enzyme activity decreased.when the cell membrane damage at-4 ℃ maximum extent, MDA content accumulation has reached the maximum, reflecting the plants of Fritillaria przewalskii Maxim. have a certain adaptability to low temperature, but more than plants after low temperature stress tolerance limits itself seriously undermine freedom based production and scavenging of dynamic balance of plant damage, and even plant death.3. Treated with different concentration of exogenous Ca²⁺（Ca Cl₂） Fritillaria przewalskii Maxim. processing plants, which can effectively activate plant leaf of antioxidant enzyme system, the activation effect with spraying increases with increasing of the concentration, and concentration once over 15 mmol.L-1, the activation of enzyme and began to decline, with a concentration of 15 mmol.L-1 Ca Cl₂ treatment Fritillaria przewalskii Maxim. processing plants, can significantly enhance the enzyme activity in cells, protect cell membranes from damage, improve the cold resistance of plant.4. Fritillaria przewalskii Maxim. seed grain weight average 1.4093 g, the standard deviation is 0.1239 g, the germination rate is only 57%, while the number was 11.7%, while the index of 7.43/2 d.After treated with different concentration of Ca Cl₂ on Fritillaria przewalskii Maxim. seedlings, with the increase of concentration, sprout number of seedlings gradually reduced. It can significantly reduce the down seedling rate when the concentration is 15 mmol.L-1, above ground growth by the control（0 mmol.L-1 Ca Cl₂） 31 d extended to the 41 d,will pour seedling stage delayed around 10 d, indicated that the concentration of exogenous Ca²⁺ can adjust the physiological and biochemical reaction of Fritillaria przewalskii Maxim. seedlings, effectively delay the seedling stage.