壳聚糖复合硅酸钠对冬枣采后苯丙烷代谢及病程相关蛋白的影响

研究了壳聚糖复合硅酸钠浸泡处理对A. alternata挑战接种果实的苯丙烷代谢与防御相关酶的影响。以冬枣为材料,分别用1%的壳聚糖(chitosan,CTS)复合不同浓度(10、40、160 mmol/L)的Na₂SiO₃水溶液浸泡冬枣5 min,以蒸馏水作为对照。室温下贮藏并定期测定其病斑直径、类黄酮、多酚、木质素及相关酶的活性。实验结果显示:在贮藏20 d后,1% CTS+40 mmol/L Na₂SiO₃处理病斑直径为1% CTS处理组病斑直径的57.33%。1% CTS+40 mmol/L Na₂SiO₃处理激活了苯丙氨酸解氨酶(Phenylalane Ammonlalyase,PAL)、肉桂酸4-羧化酶(Cinnamate 4 Hydroxylase,C4H)、4-香豆酰-辅酶A连接酶(4coumarate Coenzyme A Ligase,4CL)、过氧化物酶(Peroxidase,POD)的活性,使得总酚、类黄酮、木质素含量增加。同时,病程相关蛋白几丁质酶(Chitinase,CHT)、β-1,3葡聚糖酶(β-1,3-giucanase,GLU)活性增强。实验结果表明,CTS+Na₂SiO₃处理可以通过诱导果实苯丙烷代谢和病程相关蛋白活性增强采后枣果实抗病性。

Effect of Chitosan Combined with Sodium Silicate on Phenylpropanoid Metabolism and Pathogenesis-Related Proteins of Postharvest Winter Jujube

The effects of chitosan combined with sodium silicate treatment on phenylpropanoid metabolism and defense-related enzymes of postharvest winter jujube inoculated with A. alternata. Winter jujube was treated 1% CTS combined with different concentrations (10, 40, 160 mmol/L) of Na₂SiO₃ for 5 min and stored at room temperature, distilled water treatment was used as control. All physiological indexes such as the lesion diameter, flavonoids, polyphenols, lignin and related enzymes were measured. After 20 d of incubation, the lesion diameters on jujube treated with 1% CTS+40 mmol/L Na₂SiO₃ was 57.33% of the lesion diameters of 1% CTS treatment. Moreover, 1% CTS+40 mmol/L Na₂SiO₃ treatment promoted the accumulation of total phenolics, flavonoids and lignin in fruit which due to stimulate the activities of phenylalanine ammonialyase (PAL), cinnamate-4-hydroxylase (C4H), and 4-coumarate CoA ligase (4CL) and peroxidase (POD). 1% CTS+40 mmol/L Na₂SiO₃ treatment also increased the activities of chitinase (CHT) and β-1, 3-glucanase (GLU) which play a significant role in the pathogenesis-related proteins. These results suggested that CTS+Na₂SiO₃ treatment could decrease A. alternata rot and induce disease resistance of winter jujube through enhancing phenylpropanoid metabolism and pathogenesis-related proteins production.