芹菜和结球莴苣春夏季设施幼苗主要生长指标与有效积温研究

以芹菜品种文图拉(西芹)和结球莴苣品种铁人为试材,测定不同苗龄芹菜、结球莴苣幼苗的生长指标及生理指标,研究芹菜和结球莴苣幼苗的生长规律及与有效积温之间的关系。结果表明:芹菜幼苗前期生长缓慢,四叶期后生长速度加快;结球莴苣幼苗子叶期至四叶期快速生长,之后趋缓。芹菜幼苗的叶绿素SPAD值、POD活性呈持续增长的态势,根系活力、CAT活性生长后期趋于平稳;结球莴苣幼苗的叶绿素SPAD值、根系活力、POD活性均呈先增加后降低的趋势,CAT活性先小幅下降、后持续增长,SOD活性出现两次高峰。芹菜育苗阶段的有效积温为949.0℃·d,子叶期和五叶期增幅较大;结球莴苣育苗阶段的有效积温为502.9℃·d,各时期增长平稳。综上,芹菜幼苗适宜的定植时期为四叶期,结球莴苣幼苗适宜的定植时期为五叶期。

Studies on Main Growing Indices and Effective Accumulation Temperature of Celery and Lettuce in Spring and Summer

Taking celery‘wentula’（western celery）and lettuce‘tieren’（head lettuce）as experimental materials，the growth indexs and physiology indexs of celery and lettuce seedlings at different stage were measured．Meanwhile，the rule of seedling growth at different stage and correlation with effective ccumulation temperature were studied．The results showed that celery seedling grew slowly at early stage but grew quickly later．Lettuce seedling grew quickly from the cotyledon stage to the fourth-leaf stage but grew slowly later．The chlorophyll SPAD and POD activity of celery seedlings had sustainably increased， root activity and CAT activity firstly increased and subsequently became stable．However，in lettuce seedlings，the chlorophyll SPAD，root activity and POD activity showed the tendency of firstly increasing and subsequently decreasing，CAT activity showed a little drop and a sustainable grow，SOD activity had two peak times．Effective accumulation temperature of celery seedlings was 949.0 ℃·d with a large increase at the cotyledon stage and fifth-leaf stage．Effective accumulation temperature of lettuce seedlings was 502.9 ℃·d with a stable increase at each stage．Above all，the most appropriate planting stage for celery seedling is the fourth-leaf stage and for lettuce it is the fifth-leaf stage．