Study On The Effects Of NaClO On Seed Germination And Seedling Growth Of Celery

Celery(Apium graveolens L.)belonging to Apiaceae,is one of the most important leafy vegetable crops in the world and cultivated extensively.Celery has important economic and edible values and is popular for its abundant nutrition and unique smell.Celery seed is small,having qualitative outer leather and poor water permeability.Many inhibitory substances in the seeds,especially flavonoids,slowdown the germination of celery seed and result in inconsistent germination.The seed germination caused a great impact of cultivation and production of celery.NaClO is a low-toxic disinfectant.Appropriate concentration of NaClO solution can improve the germination rate of some seeds,but high concentration of NaClO solution would burn the seeds.Therefore,the soaking time and concentration of NaClO are the key factors to break the seed coat barrier and improve the germination rate of seeds.However,the mechanism that NaClO can promote the exudation of intraspecular inhibitory substances is still unclear.Therefore,the relationship among sodium hypochlorite concentration,soaking time,seed variety and seed germination rate and the related molecular mechanism need to be further studied to improve the germination rate of celery seeds for the high quality,high efficiency and simplified cultivation of celery.In this study,celery seeds were treated with different concentrations(0,5%,10%,20%,40%)of NaClO and were cultivated in petri dishes and acupoint plates,respectively.Germination index,growth index and physiological index of seedlings were measured.The main research results are as follows:1.Celery seeds were treated with different concentrations of NaClO(0,5%,10%,20%,40%).More intraspecific inhibitor exudated when seeds were treated with higher concentration of sodium hypochlorite.Petri dish cultured celery seeds began to germinate at the 6th day,and unfold cotyledons at the 10th day.Acupoint plate cultured celery seeds began to germinate at the 8th day,and unfold cotyledons at 12th day.5%NaClO promoted the germination of seeds,while 40%inhibited the germination of seeds.2.’Liuhehuangxinqin’ and ’Jingpinsaixue’ celery seeds were treated with different concentrations of NaClO(0,5%,10%,20%,40%).After germination,the growth indexes of seedlings cultured in petri dishes and acupoint plates for 20 days were determined.It was found that root length,hypocotae length,dry and fresh weight of the whole plant showed a trend of first rising and then falling with the increase of NaClO concentration.The plant height,stem diameter,dry and fresh weight of the aboveground and underground parts of the seedlings cultured in acupoint dishes for 40 and 60 days were measured.The seedling strength index was also calculated.Results showed that the highest indexes of healthy seedlings and seedling strength index appeared at 5%sodium hypochlorite level.3.Seeds of ’Liuhehuangxinqin’ and ’Jingpinsaixue’ were treated with different concentrations of NaClO(0,5%,10%,20%,40%).The root vigor of celery seedlings cultured in petri dishes for 20 days and celery seedlings cultured in acupoint plates for 20,40 and 60 days were measured.The contents of soluble sugar and chlorophyll in seedling leaves cultured in acupoint plates for 20 days,40 days and 60 days were measured.The expression levels of the genes related to soluble sugar synthesis and chlorophyll metabolism in celery leaves were detected and analyzed by quantitative real-time PCR.The results showed that celery seeds treated with 5%sodium hypochlorite had stronger root vigor,higher soluble sugar content and chlorophyll content.The expression levels of key genes related to soluble sugar synthesis and chlorophyll metabolism also higher than control.In conclusion,5%sodium hypochlorite is the suitable concentration for treating celery seeds.