Research On Vigour Test Of Single Counts Of Radicle Emergence For Wheat And Rape Seed

Seed vigour was a comprehensive index to measure seed sowing quality.High vigour seed was very important for agricultural production.Therefore,seed vigour test was particularly important.There were many seed vigour testing methods,most of themhad shortcomings ofheavy work and long time.It was very important to find a simple,fast and accurate method to predict seed vigour.The present study was carried out to investigate the capability of single counts of radicle emergence to be used for testing seed vigour of wheat(Triticum aestivum L.)and rape(Brassica campestris L.)seed lots.Firstly,according to the standard germination test and field emergence determination,seed vigour of 7 varieties of wheat and rape was tested.Then by making progress curves,determining the suitable temperature and time parameters of method for single counts of radicle emergence.The experiment compared the counts of radicle at 20℃ for 48 hours and at 13℃ for 72 hours with the results from normal vigour testing methods.After the determination of seed water absorption,the activity of α-amylaseand cysteine protease,the content of soluble sugar and soluble protein and gene relative expression changes of the related enzyme,and their relationship with the counts of radicle emergence at 20℃ for 48 hours and at 13℃ for 72 hours was measured.The reliability of single counts of radicle emergence for wheat seed vigour test was explored in the perspective of physiology and biochemistry and gene expression.The main results were as follows:1.The results of standard germination test and field emergence showed that there were significantly different in seed vigour among 7 wheat and rape varieties.Wheat varieties,ZF2,h M18,JM8 and AK58 hadhigher seed vigour,LX988 andh M5 had medium vigour,while NM23 seed vigour was lower.Rape varieties ZS72 and SY1 hadhigher vigour,ZS6、ZS3 and ZY50 had medium vigour,while ZZ1 had lower vigour.Radicle emergence counts of wheat and rape seed after 48 hours at 20℃ and 72 hours(84 hours)at 13℃ was significantly positively correlated with field emergence rate,germination energy,germination percentage,germination index,vigour index,complex stressing vigour test and accelerated aging test,but radicle emergence counts with mean germination time and relative of electrical conductivity showed a significantly nagative correlation.The results indicated that single counts of radicle emergence could be applied to test seed vigour of wheat and rape.2.The water absorption content of different vigour seeds in wheat showed S curve,which was not related to the seed vigour,but was related to the different temperature.The α-amylase activity showed gradually increased and then decreased with seed germination time increasing.The soluble sugar content showed a decline trade and then increasing.The cysteine protease activity firstly increased and then decreased,finally increased.The soluble protein content decreased gradually with germination progress.Thehigh vigour seedhadhigher activity of α-amylase and cysteine protease and the content of soluble sugar and protein.Radicle emergence counts(20℃ 48 h and 13℃ 72 h)was significantly positively related to activity of α-amylase cysteine protease and soluble sugar content.From the physiological and biochemical point of view,it was proved that single counts of radicle emergence was suitable for seed vigour test of wheat seed.3.The relative expression level of α-AMY increased firstly and then decreased,and expression level of cysteine protease gene showed an slow upward trend overall,but the genes expression of different varietyhad their own characteristics with seed germination time increasing.Thehigh vigour seedhadhigher relative expression level of α-AMY gene and cysteine protease gene.Radicle emergence counts(20℃ 48 h)was significantly positively related to the relative expression level of α-AMY gene and cysteine protease gene.The α-AMY gene relative expression(20℃ 48 h)was significantly positively correlated with α-amylase activity.From the gene point of view,it provided a theoretical basis that single counts of radicle emergence(20℃ 48 h)was suitable for seed vigour test of wheat seed.