Abstract:

In order to explore the effects of exogenous CaCl₂ on physiological characteristics and secondary metabolites of Cannabis sativa L. under salt stress， seedlings of C. sativa were taken as test materials， and 4 treatments were set up through pot-soil culture method， including 300 mmol·L^-1 NaCl （C0） stress treatment and 300 mmol·L^-1 NaCl stress+5 （C1）， 10 （C2） and 20 mmol·L^-1 CaCl₂ （C3）， and no stress was used as control （CK）. The photosynthetic and fluorescence parameters， physiological indexes and the contents of secondary metabolites （total flavonoids and cannabidiol） were determined under different treatments. The results showed that， with the salt stress time prolonged， the photosynthetic parameters such as net photosynthetic rate （P_n）， stomatal conductance （G_s）， transpiration rate （T_r）， photosynthetic pigments， maximum photochemical efficiency （F_v/F_m） decreased significantly， soluble protein content， antioxidant enzyme activity， total flavonoids and cannabidiol content decreased， malondialdehyde， soluble sugar， proline contents increased， and membrane lipid peroxidation degree intensified. After the application of exogenous CaCl₂， the P_n， G_s， T_r， photosynthetic pigment， F_v/F_m， antioxidant enzyme activities and the contents of soluble sugar， soluble protein， free proline and secondary metabolites all showed a trend of first increasing and then decreasing with the increase of CaCl₂， while the malondialdehyde content showed a trend of first decreasing and then increasing. Compared with treatments of CK and C0， the variation amplitude of all indexes of C. sativa treated with exogenous CaCl₂ decreased， and there was obvious dosage effect. Low dosage of exogenous calcium could alleviate salt stress to a certain extent， but high dosage could produce new damage， and the treatment with 10 mmol·L^-1 CaCl₂ had the best effect on enhancing salt resistance of C. sativa seedlings. Above results provided scientific and technological support for cultivation and application of C. sativa in saline soil area.

Key words: Cannabis sativa L., salt stress, exogenous CaCl₂, physiological characteristics, secondary metabolites

摘要：

为探究外源CaCl₂对盐胁迫下火麻生理特性和次生代谢产物的影响，以火麻幼苗为试验材料，通过盆栽土培法，设置300 mmol·L^-1 NaCl（C0）胁迫处理及300 mmol·L^-1NaCl胁迫+5（C1）、10（C2）和20 mmol·L^-1 CaCl₂ （C3）4个处理，以正常生长火麻为对照（CK），测定不同处理下火麻的光合与荧光参数、各生理指标和次生代谢产物（总黄酮和大麻二酚）含量。结果表明，随着盐胁迫时间延长，火麻净光合速率（net photosynthetic rate，P_n）、气孔导度（stomatal conductance，G_s）、蒸腾速率（transpiration rate，T_r）、光合色素、最大光化学效率（F_v/F_m）显著下降，抗氧化酶活性及可溶性蛋白、总黄酮和大麻二酚含量降低，丙二醛、可溶性糖、脯氨酸含量升高，膜脂过氧化程度加剧。外源施加CaCl₂后，火麻的P_n、G_s、T_r、光合色素、F_v/F_m、抗氧化酶活性及可溶性糖、可溶性蛋白、游离脯氨酸、次生代谢产物含量均随CaCl₂用量的增加呈先升后降趋势，而丙二醛含量呈先降低后升高的趋势。与CK和C0处理相比，外源CaCl₂处理后火麻各指标的变幅均减小，并存在明显剂量效应，即施用低剂量外源钙可在一定程度上缓解盐胁迫对火麻幼苗的损伤程度，但高水平反而会加重损伤，其中10 mmol·L^-1 CaCl₂处理对增强火麻幼苗的抗盐性效果最佳。以上研究结果为火麻在盐渍土地区栽培与应用提供技术支持。

关键词: 火麻, 盐胁迫, 外源CaCl₂, 生理特性, 次生代谢产物