Optimising the preparation method of seeds of Agriophyllum squarrosum prior to staining in tetrazolium solution

Seven samples of Agriophyllum squarrosum seeds were obtained from Minqin County Gansu province, China. These seeds were prepared for tetrazolium testing through three approaches, namely, keeping the seed intact, piercing the centre of the seed and cutting through the basal half of the seed longitudinally. Viability was also assessed through a germination test. Prior to piercing or cutting, the seed should be pre-moistened in 20 degrees C water for at least 24 hours. Intact seeds were unsuitable for tetrazolium testing because most of them remained unstained after 30 hours in the tetrazolium solution. Piercing or cutting the seeds to expose the embryo required a similar optimum staining time (10 hours) and resulted in a similar staining effect and viability percentage. Nonetheless, piercing was recommended as the optimum tissue exposure method over cutting because the latter is time-consuming and may cause damage to the embryo. All seven seed samples exhibited high viability (97.8-99.8%). Four samples displayed similarly high germination (93.3-98.8%), whereas the germination of the other three seed samples was significantly different (89.8-50.0%) to the viabilities recorded (P < 0.05, N = 4). An optimum tetrazolium testing procedure for A. squarrosum seeds is proposed.